welding slides.ppt

INTRODUCTION TO INTRODUCTION TO FABRICATION FABRICATION TECHNOLOGYTECHNOLOGY

MAILAM INDIA LIMITED,MAILAM INDIA LIMITED,

PONDICHERRYPONDICHERRY

EVOLUTION OF WELDINGEVOLUTION OF WELDING

HOW ?HOW ?

WHEN ?WHEN ?

WHERE ?WHERE ?

TUBAL CAINFORGE WELD

KJELLBERGMETAL ARC

1910

BERNADO CARBON ARC

1885

BC

DEVELOPMENT OF WELDINGDEVELOPMENT OF WELDING

11 Forge WeldingForge Welding BC Tubal Cain -Middle East BC Tubal Cain -Middle East 22 Electric ArcElectric Arc 1801 1801 Sir Humphrey Davy,UKSir Humphrey Davy,UK 33 CorbonArc WeldingCorbonArc Welding 18811881 De Meritens -FrenchDe Meritens -French 44 CorbonArc WeldingCorbonArc Welding 18851885 N.V.Bernardo -RussianN.V.Bernardo -Russian 55 Electric ResistanceElectric Resistance 18861886 Elihu Thompson -USAElihu Thompson -USA 66 Metal Arc WeldingMetal Arc Welding 18881888 Slavianoff -RussianSlavianoff -Russian 77 Thermit WeldingThermit Welding 18971897 H. Goldschmidt -GermanyH. Goldschmidt -Germany 88 Oxyacetylene WeldingOxyacetylene Welding 19061906 Eugene Davis -USAEugene Davis -USA A.Bournonvile -FrenchA.Bournonvile -French 99 Metal Arc Welding Metal Arc Welding 19101910 Oscar Kjellberg -SwedeOscar Kjellberg -Swede

WELDINGWELDING

A METAL JOINING A METAL JOINING METHODMETHOD

IN WHICH THE JOINING IN WHICH THE JOINING

EDGES ARE HEATED EDGES ARE HEATED AND AND

FUSED TOGETHER TO FUSED TOGETHER TO FORM A FORM A

PERMANENT BOND PERMANENT BOND

( HOMOGENEOUS)( HOMOGENEOUS)

IS KNOWN AS WELDINGIS KNOWN AS WELDING

ADVANTAGESADVANTAGES

HIGH STRENGTH

FREEDOM IN DESIGN

WITHSTANDS HIGH PRESSURE

MORE ECONOMY OF MATERIAL

LESS WEIGHT

DISADVANTAGESDISADVANTAGES

WELDING RESULTS IN DISTORTION.

EDGE PREPARATION IS REQUIRED.

SKILLED WORKMAN IS REQUIRED.

CHANGES IN METALURGICAL PART.

HEAT TREATMENT IS REQUIRED IN SOME CASES

APPLICATIONS OF WELDINGAPPLICATIONS OF WELDING

FABRICATION OF PRESSURE VESSELSFABRICATION OF PRESSURE VESSELS CONSTRUCTION OF PROJECTSCONSTRUCTION OF PROJECTS MAINTENANCE OF PROCESS PLANTS MAINTENANCE OF PROCESS PLANTS FABRICATION OF INDUSTRIAL BOILERSFABRICATION OF INDUSTRIAL BOILERS CONSTRUCTION OF PIPE LINESCONSTRUCTION OF PIPE LINES ERECTION OF POWER PROJECTSERECTION OF POWER PROJECTS NUCLEAR AND DEFENCE PROJECTSNUCLEAR AND DEFENCE PROJECTS

APPLICATIONS

AUTOMOBILE INDUSTRY

BRIDGES & TANKS

BUILDINGS

PIPE LINE WORKS

SHIPS & AIRCRAFT

PRESSURE VESSELS

A method of welding in which similar and dissimilar metals are joined together by melting and fusing their joining edges with or without the addition of filler metal but without the application of any kind of pressure is known as fusion welding.The joint made is permanent. The common heating sources are:- arc welding.- gas welding.

Fusion welding without pressure (Fig 1)

Non-fusion welding(Fig 3)

This is a method of welding in which similar or dissimilar metals are joined together without melting the edges by using a low melting point filler rod but without the application of pressure.

The joint made is temporary.

Heat source may be arc or gas in fusion welding.

Examples are silver soldering, brazing etc.

WELDING METHODS

Pressure welding

Forge Resistance Thermit(Pressure welding)

Projection Spot SeamButt

Plain Flash

Fusion welding

Arc Gas Thermit(Fusion welding)

Metal Carbon Inert gas Atomichydrogen

Oxy-acetylene Oxygen-other fuel gases

ELECTRON IN MOTION IS ELECTRON IN MOTION IS CALLED CURRENTCALLED CURRENT

CURRENT

PRINCIPLE OF ARC WELDINGPRINCIPLE OF ARC WELDING

WHEN HIGH CURRENT PASSES WHEN HIGH CURRENT PASSES THROUGH AN AIR GAP FROM ONE THROUGH AN AIR GAP FROM ONE CONDUCTOR TO ANOTHER, IT CONDUCTOR TO ANOTHER, IT PRODUCES VERY INTENSE AND PRODUCES VERY INTENSE AND CONCENTRATED HEAT IN THE FORM CONCENTRATED HEAT IN THE FORM OF A SPARK. OF A SPARK.

SPARK TEMP APPROX. 3600 DEG SPARK TEMP APPROX. 3600 DEG WHICH CAN MELT AND FUSE THE WHICH CAN MELT AND FUSE THE METAL VERY QUICKLY TO PRODUCE METAL VERY QUICKLY TO PRODUCE A WELDA WELD

Today, welding is the most commonly used method of fabrication of structural works, pressure vessels etc. Welded joint is the best solution for leak proof joints.

Welded joints can be classified as follows based on position.

Butt

Tee

Lap

Corner

Edge

For thin metal, say 2 mm, edge preparation not required. For thick sections, weld edge preparation is required to achieve full penetration welds.

For C.S / LAS materials, edge preparation is done by gas cutting / machining

For S.S materials, edge preparation is done by plasma cutting / machining

GROOVE WELDS

FILLET WELDS

PLUG WELDS

Groove weld

Fillet weld

Provides better joint and takes more loads

Needs edge preparation, which facilitates weld penetration.

Used in butt, tee or corner weld joints.

Careful fit-up is required for butt joints but slight mismatch is permitted

Preferred for cyclic loads.

Strength of weld is almost same as base materials.

No significant stress concentration due to weld shape.

Joint efficiency depends on the type of weld examination, welding procedure and type of load.

Weld reinforcement is a source of stress concentration and potential failure under repetitive load.

Removal of weld reinforcement increases fatigue strength of the weld.

Weld with an approximately triangular cross section joining two surfaces at right angles.

Size is specified by leg size of its largest inscribed right

triangle. No weld edge preparation required. Cheaper in cost. Stress concentration at root or toe causes failure

under variable loads.

One sided fillet weld in tee or lap joining is generally avoided because of very low static and fatigue strength of this weld.

Face of fillet weld may vary from convex to concave to

reduce stress concentration. Stress induced in fillet weld is complex because of

eccentricity of applied load, weld shape and notch effects. They consist of shear, tension and compressive stresses.

Excessive welding may be a major factor contributing to an increase in welding cost, residual stresses and distortion.

Circular weld made either by arc or gas welding through one member of lap or tee joint.

Plug weld holes are completely filled in case of thin

plates and are partially filled in case of heavier plates.(i. e. above 10mm)

Used to fix corrosion resistant lining to base metal Used as strength weld in single lap joints or non-

pressure structural attachments.

ASME SEC.VIII DIV.1

Table-UW12 specifies joint efficiency for welded joints of pressure vessel. Joint efficiency depends on type of weld and degree of radiographic examination.

For butt weld joints, Joint Efficiency

Spot radiography 0.85

Full radiography 1.0

No radiography 0.7

Allowable load on fillet weld = Weld area based on min. leg size x 0.55 (Joint Efficiency) x Sa ( Allow. stress of material)

ASME SEC.VIII DIV.2

Full radiography for all pressure shell welds. Strength of weld is same as strength of base material Welds subject to fluctuating stresses must be designed

and evaluated according to design values based on fatigue analysis. Allowable stresses for welds under fluctuating loads will be substantially lower than the allowable stresses for welds subject to static load

only. They will be based on endurance strength of material and member of cycles.

Due to geometry of welded joints, defects and imperfections in welds, different metallurgical structures of weld metals.

Effect of stress concentration in ductile materials can be ignored. Stress concentration becomes significant if weld is hard

and brittle or under shock or fluctuating loads. Stress concentration factors are used in design to ensure safer welded construction.

Weld joint design primarily depends on load requirements. Generally the following guidelines are to be followed for better design.

Select the joint design that requires the least amount of weld metal.

Use square-groove and partial joint penetration weld, wherever possible.

Use lap and fillet welds instead of groove welds if fatigue is not a design consideration.

Use double-V or U-groove instead of single-V or U-groove welds as thick plates to reduce the amount of weld metal and to control distortion.

For corner joints in thick plates where fillet welds are not adequate, beveling both members should be considered to reduce the tendency for lamellar tearing.

Design the assembly and the joints for good accessibility for welding.

The above types mean the shape of the joint, that is, how the joining edges of the parts are placed together. (Joint design is very important in fabrication work, especially where cost is important).

Flat or down hand position

Basic welding positions

WELDING POSITION

Horizontal position

Vertical position

Overhead position

All welding action takes place in the molten pool, formed in the welding joint/welding line. The position of the welding joint line in respect of ground axis indicates the welding position. All joints may be welded in all positions.

BASIC WELDING JOINTS AND POSITION (PIPES)

Pipes of all types and sizes are used a great deal today in transporting oil, gas and water. They are also used extensively for piping systems in buildings, refineries and industrial plants. Advantages of welded pipe Pipes are mostly made of ferrous and non-ferrous metals and their alloys. They possess the following advantages.

Improved overall strength. Ultimate saving in cost including maintenance. Improved flow characteristics. Reduction in weight due to its compactness. Good appearance.

Methods of pipe welding The following are the methods of pipe welding. Metallic arc welding. Gas metal arc welding Tungsten inert gas welding Submerged arc welding Carbon arc welding

All these methods, except carbon arc welding are commonly used and the choice of welding depends upon the size of the pipe and its application.

Types of pipe joints Butt joint`T’ jointLap jointAngle jointComposite jointY joint (Fig 2)Elbow joint (Fig 3)

(Fig 1)

(Fig 2)

(Fig 3)

Welding of pipe butt joints Normally joints in pipes and tubes cannot be welded from the inside of the bore. Hence before starting to learn pipe welding, a person should be proficient in welding in all positions, i.e. flat, horizontal, vertical and overhead. All these positions are used to weld pipes.

Pipe welding positions (Figs 4 and 5)

(Figs 4 and 5)

1 G – Pipe weld in flat (roll)2 G – Pipe weld in horizontal5 G – Pipe weld in flat (fixed)6 G – Pipe weld in inclind (fixed) During the welding of butt joints the pipe may be

Rolled or rotated (1 G position) Fixed (5G position)

Rolled position (1 G)In the rolled position welding is done the same way as is done in flat position. Fixed position (5 G) (Fig 6)

Weld symbol convey design requirements to the shop in a concise manner. Welding symbol include the following.

Reference line

Arrow

Basic weld symbol

Dimensions and other data

Supplementary symbols

Finish symbols

Specification, process or other reference

REPRESENTATION OF WELDS

TYPES OF ARC WELDINGTYPES OF ARC WELDING

Shielded Metal

Arc WeldingSMAW

Tungsten Inert

Gas Welding TIG

Metal Inert/Active Gas

Welding MIG / MAG/FCAW

SubmergedArc

WeldingSAW

ElectroSlag

WeldingESW

PlasmaArc

WeldingPAW

•Home

SMAWSMAW

SHIELDED METAL ARC SHIELDED METAL ARC WELDINGWELDING

SMAW IS A PROCESS IN SMAW IS A PROCESS IN WHICH HEAT WHICH HEAT GENERATED BY THE GENERATED BY THE ELECTRIC ARC IS ELECTRIC ARC IS UTILISED FOR FUSING UTILISED FOR FUSING THE METALS TO BE THE METALS TO BE WELDEDWELDED

When an arc is struck between the When an arc is struck between the metal rod (electrode) and the metal rod (electrode) and the workpiece, both the rod and workpiece workpiece, both the rod and workpiece surface melt to form a weld pool. surface melt to form a weld pool.

Simultaneous melting of the flux coating Simultaneous melting of the flux coating on the rod will form gas and slag on the rod will form gas and slag which protects the weld pool from the which protects the weld pool from the surrounding atmosphere. surrounding atmosphere.

The slag will solidify and cool and The slag will solidify and cool and must be chipped off . must be chipped off .

SHIELDED METAL ARC SHIELDED METAL ARC WELDINGWELDING

FUNCTION OF FLUX MATERIALSFUNCTION OF FLUX MATERIALS

Deoxidation of Scavengers- Helps to Deoxidation of Scavengers- Helps to Purify The Weld MetalPurify The Weld Metal

Slag Formers -Slag Protects Weld Slag Formers -Slag Protects Weld Puddle From Atmosphere During Puddle From Atmosphere During SolidificationSolidification

Arc Stabilisers - Produce a Smooth Arc & Arc Stabilisers - Produce a Smooth Arc & Help Reduce Spatter & Smoke Help Reduce Spatter & Smoke

Alloying Elements - Provide the Alloying Elements - Provide the Necessary mechanical PropertiesNecessary mechanical Properties

Gasifier - Provide a Shielding GasGasifier - Provide a Shielding Gas

SMAWSMAW AdvantagesAdvantages Variety of electrodes with different Variety of electrodes with different

featuresfeatures Most versatile in use –all position joints Most versatile in use –all position joints

/joints with limited access/joints with limited access Suitable for most alloysSuitable for most alloys Equipment simple,inexpensive & portable.Equipment simple,inexpensive & portable. DisadvantagesDisadvantages Finite lengthFinite length High dependence on welder skillHigh dependence on welder skill Not amenable for automationNot amenable for automation

Arc stability, depth of penetration, Arc stability, depth of penetration, metal deposition rate and positional metal deposition rate and positional capability are greatly influenced by capability are greatly influenced by the chemical composition of the the chemical composition of the flux coating on the electrode. Electrodes flux coating on the electrode. Electrodes can be divided into three main groups: can be divided into three main groups:

Cellulosic Cellulosic Rutile Rutile Basic Basic

Types of flux/electrodesTypes of flux/electrodes

Rutile electrodes Rutile electrodes

Rutile electrodesRutile electrodes contain a high contain a high proportion of titanium oxide (rutile) in the proportion of titanium oxide (rutile) in the coating. Titanium oxide promotes easy arc coating. Titanium oxide promotes easy arc ignition, smooth arc operation and low ignition, smooth arc operation and low spatter.spatter.

These electrodes are general purpose These electrodes are general purpose electrodes with good welding properties. electrodes with good welding properties.

They can be used with AC and DC power They can be used with AC and DC power sources and in all positionssources and in all positions

Rutile electrodes Rutile electrodes

Features:Features: Moderate weld metal mechanical Moderate weld metal mechanical

properties properties Good bead profile produced through the Good bead profile produced through the

viscous slag viscous slag Positional welding possible with a fluid Positional welding possible with a fluid

slag (containing fluoride) slag (containing fluoride) Easily removable slag Easily removable slag

Basic electrodes Basic electrodes Basic electrodesBasic electrodes contain a high proportion of contain a high proportion of

calcium carbonate (limestone) and calcium calcium carbonate (limestone) and calcium fluoride (fluorspar) in the coating. fluoride (fluorspar) in the coating.

This makes their slag coating more fluid than This makes their slag coating more fluid than rutile coatings - this is also fast-freezing which rutile coatings - this is also fast-freezing which assists welding in the vertical and overhead assists welding in the vertical and overhead position.position.

These electrodes are used for welding medium These electrodes are used for welding medium and heavy section fabrications where higher and heavy section fabrications where higher weld quality, good mechanical properties and weld quality, good mechanical properties and resistance to cracking (due to high restraint) are resistance to cracking (due to high restraint) are requiredrequired

Features:Features: Low hydrogen in weld metal Low hydrogen in weld metal Requires high welding Requires high welding

currents/speeds currents/speeds Convex and coarse bead profileConvex and coarse bead profile Slag removal difficult Slag removal difficult

Basic electrodes Basic electrodes

Power sourcePower source

Electrodes can be operated with Electrodes can be operated with AC and DC power supplies. Not AC and DC power supplies. Not all DC electrodes can be all DC electrodes can be operated on AC power sources, operated on AC power sources, however AC electrodes are however AC electrodes are normally used on DCnormally used on DC

Welding currentWelding current Welding current level is determined by the Welding current level is determined by the

size of electrode - the normal operating range size of electrode - the normal operating range and current are recommended by and current are recommended by manufacturers. manufacturers.

Typical operating ranges for a selection of Typical operating ranges for a selection of electrode sizes are illustrated in the table. electrode sizes are illustrated in the table.

As a rule of thumb , an electrode will require As a rule of thumb , an electrode will require about 40A per millimeter (diameter). about 40A per millimeter (diameter). Therefore, the preferred current level for a Therefore, the preferred current level for a 4mm diameter electrode would be 160A, but 4mm diameter electrode would be 160A, but the acceptable operating range is 140 to the acceptable operating range is 140 to 180A180A

Tungsten inert gas (TIG) welding became an Tungsten inert gas (TIG) welding became an overnight success in the 1940s for joining overnight success in the 1940s for joining magnesium and aluminium. magnesium and aluminium.

Using an inert gas shield instead of a slag to Using an inert gas shield instead of a slag to protect the weld pool, the process was a protect the weld pool, the process was a highly attractive replacement for gas and highly attractive replacement for gas and manual metal are welding. manual metal are welding.

TIG has played a major role in the TIG has played a major role in the acceptance of aluminium for high quality acceptance of aluminium for high quality welding and structural applicationswelding and structural applications using AC using AC power source.power source.

TIG WELDINGTIG WELDING

TIG WELDINGTIG WELDING

Process characteristicsProcess characteristics

Arc is formed between a pointed tungsten Arc is formed between a pointed tungsten electrode and the workpiece in an inert electrode and the workpiece in an inert atmosphere of argon or heliumatmosphere of argon or helium

The small intense arc provided by the The small intense arc provided by the pointed electrode is ideal for high quality pointed electrode is ideal for high quality and precision weldingand precision welding

Process characteristicsProcess characteristics

Because the electrode is not consumed Because the electrode is not consumed during welding, the welder does not have during welding, the welder does not have to balance the heat input from the arc as to balance the heat input from the arc as no metal is deposited from the melting no metal is deposited from the melting electrodeelectrode

When filler metal is required, it must be When filler metal is required, it must be added separately to the weldpooladded separately to the weldpool. .

Power source Power source

TIG must be operated with a drooping / TIG must be operated with a drooping / constant current power source - either DC or constant current power source - either DC or ACAC

A constant current power source is essential A constant current power source is essential to avoid excessively high currents being to avoid excessively high currents being drawn when the electrode is short-circuited drawn when the electrode is short-circuited on to the work-piece surface. This could on to the work-piece surface. This could happen either deliberately during arc happen either deliberately during arc starting or inadvertently during welding starting or inadvertently during welding

Electrodes – DC Welding Electrodes – DC Welding

It is important to select the It is important to select the correct electrode diameter and correct electrode diameter and tip angle for the level of tip angle for the level of welding current. As a rule, the welding current. As a rule, the lower the current the smaller lower the current the smaller the electrode diameter and tip the electrode diameter and tip angleangle

Metal inert gas (MIG) welding was first Metal inert gas (MIG) welding was first patented in the USA in 1949 for welding patented in the USA in 1949 for welding aluminium.aluminium.

The arc and weld pool formed using a The arc and weld pool formed using a bare wire electrode was protected by bare wire electrode was protected by helium gas, readily available at that time helium gas, readily available at that time

MIG WELDINGMIG WELDING

From about 1952 the process became From about 1952 the process became popular in the UK for welding aluminium popular in the UK for welding aluminium using argon as the shielding gas, and using argon as the shielding gas, and for carbon steels using COfor carbon steels using CO22. .

COCO22 and argon-CO and argon-CO22 mixtures are known mixtures are known as metal active gas (MAG) processes. as metal active gas (MAG) processes.

MIG is an attractive alternative to MMA, MIG is an attractive alternative to MMA, offering high deposition rates and high offering high deposition rates and high productivity. productivity.

MIG WELDINGMIG WELDING

Heat for welding is produced by forming an Heat for welding is produced by forming an arc between a metal electrode and the arc between a metal electrode and the workpiece, the electrode melts to form the workpiece, the electrode melts to form the weld bead.weld bead.

The main difference is that the metal The main difference is that the metal electrode is a small diameter wire fed from a electrode is a small diameter wire fed from a spool. As the wire is continuously fed, the spool. As the wire is continuously fed, the process is often referred to as semi-process is often referred to as semi-automatic welding. automatic welding.

Process characteristics Process characteristics

Synergic pulsed MIG refers to a Synergic pulsed MIG refers to a special type of controller which special type of controller which enables the power source to be enables the power source to be tuned (pulse parameters) for the tuned (pulse parameters) for the wire composition and diameter, wire composition and diameter, and the pulse frequency to be set and the pulse frequency to be set according to the wire feed speed.according to the wire feed speed.

Pulsed Pulsed

In addition to general shielding of In addition to general shielding of the arc and the weld pool, the the arc and the weld pool, the shielding gas performs a number shielding gas performs a number of important functionsof important functions Forms the arc plasma Forms the arc plasma Stabilises the arc on the material Stabilises the arc on the material

surface surface Ensures smooth transfer of molten Ensures smooth transfer of molten

droplets from the wire to the weld pool droplets from the wire to the weld pool

Shielding gasShielding gas

General purpose shielding gases General purpose shielding gases for MIG welding are mixtures of argon, for MIG welding are mixtures of argon, oxygen and C02, and special gas oxygen and C02, and special gas mixtures may contain helium. mixtures may contain helium.

The gases which are normally used for The gases which are normally used for the various materials are: the various materials are: steels steels

COCO22 argon +2 to 5% oxygen argon +2 to 5% oxygen argon +5 to 25% COargon +5 to 25% CO22

non-ferrousnon-ferrousargon argon

argon / helium argon / helium

Shielding gasShielding gas

MIG is widely used in most industry MIG is widely used in most industry sectors and accounts for almost 50% of sectors and accounts for almost 50% of all weld metal deposited. all weld metal deposited.

Compared to MMA, MIG has the Compared to MMA, MIG has the advantage in terms of flexibility, advantage in terms of flexibility, deposition rates and suitability for deposition rates and suitability for mechanizationmechanization

However, it should be noted that while However, it should be noted that while MIG is ideal for high deposition rates, a MIG is ideal for high deposition rates, a high degree of manipulative skill is high degree of manipulative skill is demanded of the welder. demanded of the welder.

ApplicationsApplications

GAS METAL ARC WELDINGGAS METAL ARC WELDINGGMAW/MIG-MAG/CO2/SOLID WIREGMAW/MIG-MAG/CO2/SOLID WIRE

AdvantagesAdvantages Continuous electrodeContinuous electrode Higher currents possibleHigher currents possible Minimal post weld cleaning requiredMinimal post weld cleaning required Highly amenable to automationHighly amenable to automation DisadvantagesDisadvantages Equipment more complex & Costlier than SMAWEquipment more complex & Costlier than SMAW Welder skill dependence still high,especially for Welder skill dependence still high,especially for

out-of position weldingout-of position welding Not amenable for customisationNot amenable for customisation

FLUX CORED ARC FLUX CORED ARC WELDINGWELDING

FLUX CORED WIRE- FCAWFLUX CORED WIRE- FCAW

FCAW Consumable is Often known as “Inside FCAW Consumable is Often known as “Inside Out “ as flux is inside & metal is outside .Out “ as flux is inside & metal is outside .

Modern Technology of Manufacture of FCAW Modern Technology of Manufacture of FCAW wire involves Strip & Dry Premixed Flux as Basic wire involves Strip & Dry Premixed Flux as Basic Raw Materials Raw Materials

The Quantum of Flux Addition & Flux Fill Ratio The Quantum of Flux Addition & Flux Fill Ratio are Continuously Monitored to deliver Consistent are Continuously Monitored to deliver Consistent Quality Products.Quality Products.

FUNCTION OF FLUX MATERIALSFUNCTION OF FLUX MATERIALS

Deoxidation of Scavengers- Helps to Purify Deoxidation of Scavengers- Helps to Purify The Weld MetalThe Weld Metal

Slag Formers -Slag Protects Weld Puddle Slag Formers -Slag Protects Weld Puddle From Atmosphere During SolidificationFrom Atmosphere During Solidification

Arc Stabilisers - Produce a Smooth Arc & Arc Stabilisers - Produce a Smooth Arc & Help Reduce Spatter & SmokeHelp Reduce Spatter & Smoke

Alloying Elements - Provide the Necessary Alloying Elements - Provide the Necessary mechanical Propertiesmechanical Properties

Gasifier - Provide a Shielding GasGasifier - Provide a Shielding Gas

`̀TYPES OF CORED WIRESTYPES OF CORED WIRES

CS/LAS SSCS/LAS SS Gasless (Self Shielded) A 5. 20 5.22 Gasless (Self Shielded) A 5. 20 5.22

Gas Shielded Flux Cored A 5.20 5.22Gas Shielded Flux Cored A 5.20 5.22

Composite Submerged ArcComposite Submerged Arc

Gas Shielded Metal Cored A5.18 Gas Shielded Metal Cored A5.18

GASLESS (SELF SHIELDED)GASLESS (SELF SHIELDED)

Generates its Own Protective Shielding Gas. Generates its Own Protective Shielding Gas. Normally used in Flat & Horizontal Positions only Normally used in Flat & Horizontal Positions only ..

For CS most commonly used for Out Door For CS most commonly used for Out Door Fabrication & also extensively used for Repair & Fabrication & also extensively used for Repair & Maintenance application Maintenance application

For SS Mainly used for Joining & Overlay For SS Mainly used for Joining & Overlay Welding ApplicationWelding Application

GAS SHIELDED FLUX CORED WIRESGAS SHIELDED FLUX CORED WIRES

For CS/LAS Currently Available in Two TypesFor CS/LAS Currently Available in Two Types

Positional Welding type - Rutile SlagPositional Welding type - Rutile Slag

Flat/ Horizontal type - Basic SlagFlat/ Horizontal type - Basic Slag Both Types Typically Run with Ar-25%Co2 or Both Types Typically Run with Ar-25%Co2 or

100% CO2100% CO2 Diameter Down to 0.9 mm AvailableDiameter Down to 0.9 mm Available For SS Positional Welding Type available in For SS Positional Welding Type available in

all grades suitable for CO2 Shielding all grades suitable for CO2 Shielding

COMPOSIT SUBMERGED ARCCOMPOSIT SUBMERGED ARC

FCAW Consumables used mainly with Neutral Flux to FCAW Consumables used mainly with Neutral Flux to give desired Weld metal Chemistrygive desired Weld metal Chemistry

Typical Application include High Alloy Steel Typical Application include High Alloy Steel Compositions with special TDC Required in Small Compositions with special TDC Required in Small Quantity.(Tailor Made Product)Quantity.(Tailor Made Product)

GAS SHIELDED METAL COREDGAS SHIELDED METAL CORED Composit or Metal Cored FCAW consumables most Composit or Metal Cored FCAW consumables most

commonly used for robotic application in view of commonly used for robotic application in view of Higher Deposition Efficiency Higher Deposition Efficiency Bead on Bead Welding (NO Slag )Bead on Bead Welding (NO Slag ) Better Wire Feeding.Better Wire Feeding.

CLASSIFICATION OF FCAW CLASSIFICATION OF FCAW CONSUMABLESCONSUMABLES

For Metal Cored Wires as per AWS A 5.18For Metal Cored Wires as per AWS A 5.18

E 70 C –X Y N HZE 70 C –X Y N HZ For FCAW Wires as per AWS A 5.20For FCAW Wires as per AWS A 5.20

E XXT –XMJ HZE XXT –XMJ HZ For SS FCAW Wires as per A 5.22For SS FCAW Wires as per A 5.22

E XXX T X-X E XXX T X-X

`̀ FCAW -CORED WIREFCAW -CORED WIREADVANTAGESADVANTAGES High productivity of Continuous Wire WeldingHigh productivity of Continuous Wire Welding Metallurgical Benefit of FluxMetallurgical Benefit of Flux Higher Current than Solid WireHigher Current than Solid Wire Versatile Use-All Positional ,Wide Thickness RangeVersatile Use-All Positional ,Wide Thickness Range Visible Arc -Easy to UseVisible Arc -Easy to UseDISADVANTAGESDISADVANTAGES Equipment more complex & Costlier than SMAWEquipment more complex & Costlier than SMAW FCAW Wires more Expensive on Weight Basis but FCAW Wires more Expensive on Weight Basis but

compensated by higher Productivitycompensated by higher Productivity

SHIELDING GASES

Arc Characteristics Penetration Profile Mode Of Transfer Spatter Level Alloy Recovery Material Types

SHIELDING GAS COMPARISONSHIELDING GAS COMPARISONE 81T-1-Ni1 VERTICAL UP @21 KJ/CME 81T-1-Ni1 VERTICAL UP @21 KJ/CM

95Ar/5CO2 75Ar/25CO2 50Ar/50CO2 100CO2

TYPICALCHEMICALANALYSIS

CMnSi

.0591.29..44

.0551.29.44

.0421.24.39

.0411.16.31

TYPICALMECH.PROP(Mpa)

YS

UTS

540

603

531

586

502

568

457

565TYPICALIMPACTPROP(J)

0 Deg C

-40Deg C

123

91

125

84

109

48

104

40

BEADSHAPE

FLAT FLAT CONVEX CONVEX

IMPORTANTIMPORTANT

Making a Gas DecisionMaking a Gas Decision

Deciding on a particular shielding gas should be Deciding on a particular shielding gas should be based on the specific manufacturer’s based on the specific manufacturer’s recommendation. Failure to do so may result in recommendation. Failure to do so may result in weld metal defects or in an deterioration in weld metal defects or in an deterioration in Mechanical properties.The manufacture’s Mechanical properties.The manufacture’s guaranteed values are obtainable only when guaranteed values are obtainable only when specified technical parameters are followed in specified technical parameters are followed in full .full .

The first patent on the submerged-The first patent on the submerged-arc welding (SAW) process was taken arc welding (SAW) process was taken out in 1935 and covered an electric out in 1935 and covered an electric arc beneath a bed of granulated fluxarc beneath a bed of granulated flux

Developed by the E O Paton Electric Developed by the E O Paton Electric Welding Institute, Russia, during the Welding Institute, Russia, during the Second World War, SAW's most Second World War, SAW's most famous application was on the T34 famous application was on the T34 tank.tank.

SAW WELDINGSAW WELDING

Similar to MIG welding, SAW Similar to MIG welding, SAW involves formation of an arc involves formation of an arc between a continuously-fed bare between a continuously-fed bare wire electrode and the workpiecewire electrode and the workpiece

The process uses a flux to generate The process uses a flux to generate protective gases and slag, and to protective gases and slag, and to add alloying elements to the weld add alloying elements to the weld poolpool

Process features Process features

A shielding gas is not required. A shielding gas is not required. Prior to welding, a thin layer of flux Prior to welding, a thin layer of flux powder is placed on the workpiece powder is placed on the workpiece surfacesurface

The arc moves along the joint line The arc moves along the joint line and as it does so, excess flux is and as it does so, excess flux is recycled via a hopper.recycled via a hopper.

Remaining fused slag layers can be Remaining fused slag layers can be easily removed after welding easily removed after welding


As the arc is completely covered by As the arc is completely covered by the flux layer, heat loss is the flux layer, heat loss is extremely low.extremely low.

This produces a thermal efficiency This produces a thermal efficiency as high as 60% (compared with 25% as high as 60% (compared with 25% for manual metal arc) for manual metal arc)

There is no visible arc light, There is no visible arc light, welding is spatter-free and there is welding is spatter-free and there is no need for fume extraction no need for fume extraction


According to material thickness, According to material thickness, joint type and size of component, joint type and size of component, varying the following can increase varying the following can increase deposition rate and improve bead deposition rate and improve bead shapeshape

Process variants Process variants

SAW is normally operated with a SAW is normally operated with a single wire on either AC or DC single wire on either AC or DC current. Common variants arecurrent. Common variants are Twin wire Twin wire Triple wire Triple wire Single wire with hot wire addition Single wire with hot wire addition

Metal powdered flux additionMetal powdered flux addition

Process variants Process variants

Fluxes used in SAW are granular Fluxes used in SAW are granular fusible minerals containing oxides fusible minerals containing oxides of manganese, silicon, titanium, of manganese, silicon, titanium, aluminium, calcium, zirconium, aluminium, calcium, zirconium, magnesium and other compounds magnesium and other compounds such as calcium fluoridesuch as calcium fluoride

The flux is specially formulated to The flux is specially formulated to be compatible with a given be compatible with a given electrode wire type so that the electrode wire type so that the combination of flux and wire yields combination of flux and wire yields desired mechanical propertiesdesired mechanical properties

FluxFlux

All fluxes react with the weld pool to All fluxes react with the weld pool to produce the weld metal chemical produce the weld metal chemical composition and mechanical propertiescomposition and mechanical properties

It is common practice to refer to fluxes It is common practice to refer to fluxes as 'active' if they add as 'active' if they add manganese,silicon and any other manganese,silicon and any other alloying elementsalloying elements

The amount of manganese and silicon The amount of manganese and silicon added is influenced by the arc voltage added is influenced by the arc voltage and the welding current level and the welding current level

FluxFlux

SAW is ideally suited for SAW is ideally suited for longitudinal and circumferential longitudinal and circumferential butt and fillet welds butt and fillet welds

However, because of high fluidity However, because of high fluidity of the weld pool, molten slag and of the weld pool, molten slag and loose flux layer, welding is loose flux layer, welding is generally carried out on butt joints generally carried out on butt joints in the flat position and fillet joints in the flat position and fillet joints in both the flat and horizontal-in both the flat and horizontal-vertical positions vertical positions

Applications Applications

SUBMERGED ARC SUBMERGED ARC WELDINGWELDING

SAWSAW AdvantagesAdvantages Highest deposition rateHighest deposition rate Most suited for automationMost suited for automation Consumables can be customisedConsumables can be customised Lower operator fatigueLower operator fatigue DisadvantagesDisadvantages Not versatile-no positional capabilityNot versatile-no positional capability Generally not used for thin sectionGenerally not used for thin section Joint fit-up very criticalJoint fit-up very critical Arc not visibleArc not visible

Electro slag welding is a very Electro slag welding is a very efficient, single pass process carried efficient, single pass process carried out in the vertical or near vertical out in the vertical or near vertical position and used for joining steel position and used for joining steel plates/sections in thicknesses of plates/sections in thicknesses of 25mm and above.25mm and above.

It was developed by the Paton It was developed by the Paton Institute in the Ukraine in the early Institute in the Ukraine in the early 1950s and superseded the very high 1950s and superseded the very high current submerged arc process for current submerged arc process for making longitudinal welds in thick-making longitudinal welds in thick-walled pressure vessels. walled pressure vessels.

ELECTRO SLAG WELDINGELECTRO SLAG WELDING

Unlike other high current fusion Unlike other high current fusion processes, electro slag welding is not processes, electro slag welding is not an arc processan arc process

Heat required for melting both the Heat required for melting both the welding wire and the plate edges is welding wire and the plate edges is generated through a molten slag's generated through a molten slag's resistance to the passage of an resistance to the passage of an electric current.electric current.


In its original form, plates are held vertically In its original form, plates are held vertically approximately 30mm apart with the edges of the approximately 30mm apart with the edges of the plate cut normal to the surface. A bridging run-on plate cut normal to the surface. A bridging run-on piece of the same thickness is attached to the piece of the same thickness is attached to the bottom of the plates. Water cooled copper shoes bottom of the plates. Water cooled copper shoes are then placed each side of the joint, forming a are then placed each side of the joint, forming a rectangular cavity open at the top. Filler wire, rectangular cavity open at the top. Filler wire, which is also the current carrier, is then fed into which is also the current carrier, is then fed into this cavity, initially striking an arc through a small this cavity, initially striking an arc through a small amount of flux. amount of flux.

Speed of joint completion; typically 1 hour Speed of joint completion; typically 1 hour per metre of seam, irrespective of thickness per metre of seam, irrespective of thickness

Lack of angular distortion Lack of angular distortion Lateral angular distortion limited to 3mm Lateral angular distortion limited to 3mm

per meter of weld per meter of weld High quality welds produced High quality welds produced Simple joint preparation, i.e. flame-cut Simple joint preparation, i.e. flame-cut

square edge square edge Major repairs can be made simply by cutting Major repairs can be made simply by cutting

out total weld and re-welding out total weld and re-welding

BenefitsBenefits

Plasma welding is very similar to TIG Plasma welding is very similar to TIG as the arc is formed between a pointed as the arc is formed between a pointed tungsten electrode and the workpiece.tungsten electrode and the workpiece.

However, by positioning the electrode However, by positioning the electrode within the body of the torch, the within the body of the torch, the plasma arc can be separated from the plasma arc can be separated from the shielding gas envelope. Plasma is then shielding gas envelope. Plasma is then forced through a fine-bore copper forced through a fine-bore copper nozzle which constricts the arc nozzle which constricts the arc

PLASMA WELDINGPLASMA WELDING

Three operating modes can be Three operating modes can be produced by varying bore produced by varying bore diameter and plasma gas flow diameter and plasma gas flow rate:rate:

Microplasma: 0.1 to 15A Microplasma: 0.1 to 15A Medium current: 15 to 200A Medium current: 15 to 200A Keyhole plasma: over 100AKeyhole plasma: over 100A

PLASMA WELDINGPLASMA WELDING

The microplasma arc can be The microplasma arc can be operated at very low welding operated at very low welding currents. The columnar arc is currents. The columnar arc is stable even when arc length is stable even when arc length is varied up to 20mm varied up to 20mm

Microplasma: 0.1 to Microplasma: 0.1 to 15A15A

The plasma arc is normally operated The plasma arc is normally operated with a DC, drooping characteristic with a DC, drooping characteristic power source. Because its unique power source. Because its unique operating features are derived from operating features are derived from the special torch arrangement and the special torch arrangement and separate plasma and shielding gas separate plasma and shielding gas flows, a plasma control console can flows, a plasma control console can be added on to a conventional TIG be added on to a conventional TIG power source. Purpose-built plasma power source. Purpose-built plasma systems are also available. systems are also available.

Power source Power source

At higher currents, from 15 to 200A, At higher currents, from 15 to 200A, the process characteristics of the the process characteristics of the plasma arc are similar to the TIG arc, plasma arc are similar to the TIG arc, but because the plasma is constricted, but because the plasma is constricted, the arc is stiffer.the arc is stiffer.

Although the plasma gas flow rate Although the plasma gas flow rate can be increased to improve weld pool can be increased to improve weld pool penetration, there is a risk of air and penetration, there is a risk of air and shielding gas entrapment through shielding gas entrapment through excessive turbulence in the gas shield. excessive turbulence in the gas shield.

Medium current: 15 to Medium current: 15 to 200A 200A

By increasing welding current and plasma By increasing welding current and plasma gas flow, a very powerful plasma beam is gas flow, a very powerful plasma beam is created which can achieve full created which can achieve full penetration in a material, as in laser or penetration in a material, as in laser or electron beam welding. electron beam welding.

During welding, the hole progressively During welding, the hole progressively cuts through the metal with the molten cuts through the metal with the molten weld pool flowing behind to form the weld pool flowing behind to form the weld bead under surface tension forces.weld bead under surface tension forces.

This process can be used to weld thicker This process can be used to weld thicker material (up to 10mm of stainless steel) material (up to 10mm of stainless steel) in a single pass in a single pass

Keyhole plasma: over Keyhole plasma: over 100A 100A

Microplasma weldingMicroplasma weldingMicroplasma was traditionally used for Microplasma was traditionally used for

welding thin sheets (down to 0.1 mm welding thin sheets (down to 0.1 mm thickness), and wire and mesh sectionsthickness), and wire and mesh sections

The needle-like stiff arc minimises arc The needle-like stiff arc minimises arc wander and distortion. Although the wander and distortion. Although the equivalent TIG arc is more diffuse, the equivalent TIG arc is more diffuse, the newer transistorised (TIG) power newer transistorised (TIG) power sources can produce a very stable arc sources can produce a very stable arc at low current levels at low current levels


Medium current weldingMedium current weldingWhen used in the melt mode this is an When used in the melt mode this is an

alternative to conventional TIG. The alternative to conventional TIG. The advantages are deeper penetration (from advantages are deeper penetration (from higher plasma gas flow), and greater higher plasma gas flow), and greater tolerance to surface contamination tolerance to surface contamination including coatings (the electrode is including coatings (the electrode is within the body of the torch). within the body of the torch).

The major disadvantage lies in the The major disadvantage lies in the bulkiness of the torch, making manual bulkiness of the torch, making manual welding more difficult. In mechanised welding more difficult. In mechanised welding, greater attention must be paid welding, greater attention must be paid to maintenance of the torch to ensure to maintenance of the torch to ensure consistent performance.consistent performance.


Keyhole weldingKeyhole weldingDeep penetration and high welding Deep penetration and high welding speeds. speeds.

It can penetrate plate thicknesses It can penetrate plate thicknesses up to l0mm, but when welding up to l0mm, but when welding using a single pass technique, it is using a single pass technique, it is more usual to limit the thickness to more usual to limit the thickness to 6mm.6mm.


WELDINGWELDING CONSUMABLESCONSUMABLES

SELECTION CRITERIA OF WELDING SELECTION CRITERIA OF WELDING CONSUMABLESCONSUMABLES

MATERIALS OF CONSTRUCTIONMATERIALS OF CONSTRUCTION METALLURGICAL PROPERTIESMETALLURGICAL PROPERTIES MECHANICAL PROPERTIESMECHANICAL PROPERTIES CORROSION PROPERTIESCORROSION PROPERTIES WELDING FACILITIESWELDING FACILITIES DEPOSITION RATEDEPOSITION RATE POSITION OF WELDINGPOSITION OF WELDING WELDING PROCESSWELDING PROCESS AVAILABILITY IN MARKETAVAILABILITY IN MARKET

TYPE OF WELDING CONSUMABLESTYPE OF WELDING CONSUMABLES

**FLUX COVERED STICK ELECTRODESFLUX COVERED STICK ELECTRODES LIGHT COATEDLIGHT COATED MEDIUM COATEDMEDIUM COATED HEAVY COATEDHEAVY COATED *BARE SOLID ROD (FILLER ROD)*BARE SOLID ROD (FILLER ROD) *BARE SOLID WIRE (ELECTRODE / FILLER ROD)*BARE SOLID WIRE (ELECTRODE / FILLER ROD) *FLUX CORED WIRE (ELECTRODE)*FLUX CORED WIRE (ELECTRODE) *BARE SOLID STRIP (ELECTRODE)*BARE SOLID STRIP (ELECTRODE) *SHILEDING GAS (IN CYLINDERS)*SHILEDING GAS (IN CYLINDERS) *SHIELDING FLUX (GRANULAR POWDER)*SHIELDING FLUX (GRANULAR POWDER)

IS (Indian)IS (Indian) AWS/ASME (American)AWS/ASME (American) DIN (German)DIN (German) EN (British)EN (British) National/International National/International

Inspection/licenser Inspection/licenser SpecificationSpecification

Welding consumable standards

ADVANTAGES OF FLUX COATINGADVANTAGES OF FLUX COATING

TO STRIKE AND MAINTAIN ARCTO STRIKE AND MAINTAIN ARC TO PROVIDE A GAS SHEILD OVER TO PROVIDE A GAS SHEILD OVER

MOLTEN WELDPOOLMOLTEN WELDPOOL TO DEOXIDISE AND REFINE WELDMETALTO DEOXIDISE AND REFINE WELDMETAL TO ADD ALLOYING ELEMENTS IN TO ADD ALLOYING ELEMENTS IN

WELDMETAL WELDMETAL TO PROVIDE A SLAG BLANKET ON TO PROVIDE A SLAG BLANKET ON

MOLTEN WELDPOOLMOLTEN WELDPOOL TO INCREASE DEPOSITION EFFICIENCY TO INCREASE DEPOSITION EFFICIENCY

FLUXING AGENTSFLUXING AGENTS SLAG FORMERSSLAG FORMERS ARC STABILISERSARC STABILISERS GAS FORMERSGAS FORMERS SLIPPING AGENTSSLIPPING AGENTS BINDING AGENTS BINDING AGENTS DEOXIDISERS AND ALLOYING ELEMNTSDEOXIDISERS AND ALLOYING ELEMNTS

Ingredients of Flux coating

Mandatory parametersMandatory parameters

CHEMICAL COMPOSITIONCHEMICAL COMPOSITION MECHANICAL PROPERTIESMECHANICAL PROPERTIES NOTCH TOUGHNESSNOTCH TOUGHNESS ELCTRICAL CHARECTERISTICSELCTRICAL CHARECTERISTICS TYPE OF COVERINGTYPE OF COVERING

OPTIONAL PARAMETERSOPTIONAL PARAMETERS

NOTCH TOUGHNESS REQUIREMENTSNOTCH TOUGHNESS REQUIREMENTS MOISTURE CONTENT MOISTURE CONTENT DIFFUSIBLE HYDROGENDIFFUSIBLE HYDROGEN

SUPPLEMENTARY SUPPLEMENTARY PARAMETERSPARAMETERS

HARDNESSHARDNESS CORROSION RESISTANCECORROSION RESISTANCE FERRITE CONTENTFERRITE CONTENT HOT TENSILE TESTHOT TENSILE TEST WEAR RESISTANCE WEAR RESISTANCE HOT CRACKING TEST HOT CRACKING TEST COLD CRACKING TESTCOLD CRACKING TEST TEMPER EMBRITTLEMENT TESTTEMPER EMBRITTLEMENT TEST

TYPES OF COVERINGTYPES OF COVERING

0-HIGH CELLULOSE SODIUM0-HIGH CELLULOSE SODIUM 1-HIGH CELLULOSE POTASSIUM 1-HIGH CELLULOSE POTASSIUM 2-HIGH TITANIA SODIUM2-HIGH TITANIA SODIUM 3-HIGH TITANIA POTASSIUM3-HIGH TITANIA POTASSIUM 4-IRON POWDER,TITANIA4-IRON POWDER,TITANIA 5-LOW HYDROGEN SODIUM5-LOW HYDROGEN SODIUM 6-LOW HYDROGEN POTASSIUM6-LOW HYDROGEN POTASSIUM 7-HIGH IRON OXIDE,IRON POWDER7-HIGH IRON OXIDE,IRON POWDER 8-LOW HYDROGEN POTASSIUM,8-LOW HYDROGEN POTASSIUM, IRON POWDERIRON POWDER 9-IRON OXIDE TITANIA POTASSIUM9-IRON OXIDE TITANIA POTASSIUM

E.G. E 70 1 8

AWS CLASSIFICATION FOR AWS CLASSIFICATION FOR

CARBON STEEL ELECTRODECARBON STEEL ELECTRODE

E-Manual Metal Arc Welding Electrode

70- Minimum UTS of 70 Ksi(70000psi)

1- Usability of electrode in all positions

8- Basic type of covering with Iron powder

AWS CLASSIFICATION OF LOW ALLOY AWS CLASSIFICATION OF LOW ALLOY STEEL ELECTRODESTEEL ELECTRODE

E-MANUAL METAL ARC WELDING ELECTRODEE-MANUAL METAL ARC WELDING ELECTRODE 80-MINIMUM UTS OF 80KSI(80000 psi)80-MINIMUM UTS OF 80KSI(80000 psi) 1-USABILITY OF ELECTRODE IN ALL POSITIONS1-USABILITY OF ELECTRODE IN ALL POSITIONS 8-BASIC TYPE OF COVERING WITH IRON POWDER8-BASIC TYPE OF COVERING WITH IRON POWDER B2-CHEMICAL COMPOSITION OF B2-CHEMICAL COMPOSITION OF

1CHROME - 1/2 MOLY STEEL1CHROME - 1/2 MOLY STEEL

E.G. E 80 1 8 B2

AWS CLASSIFICATION OF STAINLESS STEEL AWS CLASSIFICATION OF STAINLESS STEEL ELECTRODEELECTRODE

E-Manual metal arc welding electrodeE-Manual metal arc welding electrode 316-Chemical composition of 17 to 20 316-Chemical composition of 17 to 20

Chrome,11 to14 Nickel,2 to 3 MolyChrome,11 to14 Nickel,2 to 3 Moly L-low carbon varietyL-low carbon variety

E.G. E 316 L

AWS CLASSIFICATION OF NON AWS CLASSIFICATION OF NON FERROUS ELECTRODEFERROUS ELECTRODE

E-MANUAL METAL ARC WELDING E-MANUAL METAL ARC WELDING ELECTRODEELECTRODE

NICU7-CHEMICAL COMPOSITION OF NICU7-CHEMICAL COMPOSITION OF MONEL(70%NICKEL&BALANCE MONEL(70%NICKEL&BALANCE COPPER)COPPER)

E.G. E Ni Cu 7

AWS SPECIFICATION FORAWS SPECIFICATION FOR

BARE RODS BARE RODS A5.7-COPPER AND ALLOYS A5.7-COPPER AND ALLOYS A5.9-CHROMIUM AND CHROMIUM NICKEL STEELSA5.9-CHROMIUM AND CHROMIUM NICKEL STEELS A5.10-ALUMINIUM AND ALLOYSA5.10-ALUMINIUM AND ALLOYS A5.13-SURFACINGA5.13-SURFACING A5.14-NICKEL AND ALLOYSA5.14-NICKEL AND ALLOYS A5.15-CAST IRONSA5.15-CAST IRONS A5.16-TITANIUM AND ALLOYSA5.16-TITANIUM AND ALLOYS A5.17-CARBON STEEL(SAW)A5.17-CARBON STEEL(SAW) A5.18-CARBON STEEL(GTAW)A5.18-CARBON STEEL(GTAW) A5.23-LOW ALLOY STEEL(SAW)A5.23-LOW ALLOY STEEL(SAW) A5.28-LOW ALLOY STEEL(GTAW)A5.28-LOW ALLOY STEEL(GTAW)

SAWSAW

F-SAW FLUX F-SAW FLUX 7-MINIMUM UTS OF 70 KSI(70000psi)7-MINIMUM UTS OF 70 KSI(70000psi) P-POST WELD HEAT TREATED CONDITIONP-POST WELD HEAT TREATED CONDITION 4-MINIMUM CVN IMPACT ENERGY OF 20 Ft Lb 4-MINIMUM CVN IMPACT ENERGY OF 20 Ft Lb

AT MINUS 40°FAT MINUS 40°F EXXX-ELECTRODE WIREEXXX-ELECTRODE WIRE HX- HYDROGEN DESIGNATORHX- HYDROGEN DESIGNATOR

E.g. F 7 P 4 EXXX HX

AWS CLASSIFICATION OF AWS CLASSIFICATION OF CARBON STEEL FILLER RODCARBON STEEL FILLER ROD

ER-Electrode RodER-Electrode Rod 70-minimum UTS of 70 Ksi70-minimum UTS of 70 Ksi S-solid RodS-solid Rod 2-minimum CVN Impact Value of 20 2-minimum CVN Impact Value of 20

Ftlb at Minus 20 Deg FahrenheitFtlb at Minus 20 Deg Fahrenheit

E.g. ER 70 S 2

ER-ELECTRODE ROD ER-ELECTRODE ROD 90-MINIMUM UTS OF 90KSI 90-MINIMUM UTS OF 90KSI S-SOLID ROD S-SOLID ROD B3-CHEMICAL COMPOSITION OF B3-CHEMICAL COMPOSITION OF

2.25 CHROME-1 MOLY STEEL2.25 CHROME-1 MOLY STEEL L-LOW CARBON VARIETYL-LOW CARBON VARIETY

AWS Classification of Low Alloy Steel Filler AWS Classification of Low Alloy Steel Filler RodRod

E.g. ER 90 S B3 L

AWS CLASSIFICATION OF AWS CLASSIFICATION OF STAINLESS STEEL FILLER RODSTAINLESS STEEL FILLER ROD

ER-ELECTRODE RODER-ELECTRODE ROD 308-CHEMICAL COMPOSITION OF 308-CHEMICAL COMPOSITION OF

19 TO22 CHROME,9 TO 11 19 TO22 CHROME,9 TO 11 NICKEL,0.75 MOLYNICKEL,0.75 MOLY

L-LOW CARBON VARIETYL-LOW CARBON VARIETY

E.g. ER 308 L

AWS CLASSIFICATION OF NON AWS CLASSIFICATION OF NON FERROUS FILLER RODFERROUS FILLER ROD

ER-Electrode Rod ER-Electrode Rod NICR-3-chemical composition of NICR-3-chemical composition of

70%Nickel and 20%Chromium 70%Nickel and 20%Chromium

E.g. ER NiCr - 3

FCAW CONSUMABLES AVILABILITYWITH AWS SPECIFICATION

E70T-1 FOR E71T-1 BOILER

E70T5 QUALITY E81T1-W WHEATHERING

E80T1-A1 FOR E80T1-B2 LOW ALLOY E8-T1-B3 STEEL E80T5-G FOR E90T5-K2 HSLA E100T5K3 STEELS E110T5-K4

E308TX-X FOR SS E316TX-X POSITIONAL E312TX-X WELDING E309TX-X E308.T0-3 FOR E309T0-3 CLADDING

CLASSIFICATION OF FLUX CORED CLASSIFICATION OF FLUX CORED ELECTRODES AWS 5.20ELECTRODES AWS 5.20

ElectrodesElectrodes

Min. Tensile Strength x 10,000 psiMin. Tensile Strength x 10,000 psi Position : 1 - All PositionPosition : 1 - All Position 0 - Flat & Horizontal0 - Flat & Horizontal

UsabilityUsability E X X T- XMJ HZE X X T- XMJ HZDesignates Spl. Impact Prop. At -40Deg C -27 JDesignates Spl. Impact Prop. At -40Deg C -27 J

Meeting Diffusible H2 Content 4/8/16 ml Meeting Diffusible H2 Content 4/8/16 ml per 100 gms as indicated by “Z” per 100 gms as indicated by “Z”

--

CLASSIFICATION OF METAL CORED CLASSIFICATION OF METAL CORED WELDING AWS 5.18WELDING AWS 5.18

ElectrodeElectrode UTS X1000 psiUTS X1000 psi Indicates Composit RodIndicates Composit Rod

E 70 C - X Y N HZE 70 C - X Y N HZ Diffusible HydrogenDiffusible Hydrogen Higher Impact &Lower ImpuritiesHigher Impact &Lower Impurities (N Application)(N Application) Type of Gas C / MType of Gas C / M Impact PropertiesImpact Properties

FLUX CORED ARC WELDINGAWS A FLUX CORED ARC WELDINGAWS A 5.225.22

ElectrodeElectrode

Alloy CompositionAlloy Composition

Alloy additionAlloy addition

L-Low CorbonL-Low Corbon

Tubular or Flux CoredTubular or Flux Cored

External Gas ShieldingExternal Gas Shielding

E XXX XX X T - XE XXX XX X T - X

PERFORMANCE CHARACTERSPERFORMANCE CHARACTERS

UNIFORM COVERINGUNIFORM COVERING CONCENTRICITYCONCENTRICITY GRIP END/ARC END TRIMMING GRIP END/ARC END TRIMMING CUP FORMATION CUP FORMATION ARC INTENSITY/STABILITYARC INTENSITY/STABILITY SMOOTH ARCSMOOTH ARC FLUIDITY/VISCOSITYFLUIDITY/VISCOSITY SLAG/OXIDE INCLUSIONSSLAG/OXIDE INCLUSIONS MOISTURE ABSORPTIONMOISTURE ABSORPTION LOW SPATTERLOW SPATTER COVERING THICKNESSCOVERING THICKNESS CRATER CRACKING CRATER CRACKING IDENTIFICATIONIDENTIFICATION SLAG DETATCHABILITYSLAG DETATCHABILITY

SPECIFIC TESTS FOR WELDING SPECIFIC TESTS FOR WELDING

CONSUMABLES (CS&LASCONSUMABLES (CS&LAS))

CARBON STEEL CONSUMABLESCARBON STEEL CONSUMABLES WELDMETAL CHEMISTRYWELDMETAL CHEMISTRY CVN IMPACT VALUE AT -50DEG CCVN IMPACT VALUE AT -50DEG C TENSILE/YIELD AFTER PWHTTENSILE/YIELD AFTER PWHT HARDNESS REQUIREMENTHARDNESS REQUIREMENT LOW ALLOY STEEL CONSUMABLESLOW ALLOY STEEL CONSUMABLES WELDMETAL CHEMISTRYWELDMETAL CHEMISTRY DIFFUSIBLE HYDROGEN CONTENTDIFFUSIBLE HYDROGEN CONTENT

SPECIFIC TESTS FOR WELDING SPECIFIC TESTS FOR WELDING CONSUMABLES(SS&NF)CONSUMABLES(SS&NF)

STAINLESS STEELCONSUMABLESSTAINLESS STEELCONSUMABLES FERRITE CONTENTFERRITE CONTENT WELDMETAL CHEMISTRYWELDMETAL CHEMISTRY CORROSION RESISTANCECORROSION RESISTANCE CVN IMPACT VALUE AT -196 DEG CCVN IMPACT VALUE AT -196 DEG C

NON FERROUS CONSUMABLESNON FERROUS CONSUMABLES WELDMETAL CHEMISTRYWELDMETAL CHEMISTRY CORROSION RESISTANCECORROSION RESISTANCE WELDABILITY WELDABILITY

STORAGE AND DRYING OF STORAGE AND DRYING OF CS&LAS CONSUMABLESCS&LAS CONSUMABLES

CELLULOSIC TYPE-REDRYING CELLULOSIC TYPE-REDRYING TEMP-70 TO 80 DEG C/HRTEMP-70 TO 80 DEG C/HR

BASIC TYPE-REDRYING TEMP- 260 BASIC TYPE-REDRYING TEMP- 260 TO 420 DEG C /2HR ,HOLDING TO 420 DEG C /2HR ,HOLDING TEMP-30 TO 140 DEG CTEMP-30 TO 140 DEG C

STORAGE&DRYING OF STORAGE&DRYING OF SS&NF CONSUMABLESSS&NF CONSUMABLES

RUTILE TYPE- REDRYING TEMP-RUTILE TYPE- REDRYING TEMP-120TO150 DEG C /2HR120TO150 DEG C /2HR

SEMI BASIC TYPE-REDRYING SEMI BASIC TYPE-REDRYING TEMP-180 TO 200 DEG C/2HRTEMP-180 TO 200 DEG C/2HR

BASIC TYPE-REDRYING TEMP-200 BASIC TYPE-REDRYING TEMP-200 TO 250 DEG C/2HRTO 250 DEG C/2HR

WELDING WELDING DEFECTS DEFECTS

AND AND DESTRUCTIVE DESTRUCTIVE

TESTINGTESTING

PROPERTIE OF METALSPROPERTIE OF METALS

Physical PropertiesPhysical Properties density, thermal & electrical conductivity, density, thermal & electrical conductivity,

melting point, boiling point, magnetic melting point, boiling point, magnetic permeability etc.permeability etc.

Mechanical PropertiesMechanical Properties strength, ductility, hardness, toughness, fatigue strength, ductility, hardness, toughness, fatigue

strengthstrength Chemical PropertiesChemical Properties

for chemical composition of alloysfor chemical composition of alloys

ANDAND

Metallographic StructureMetallographic Structure

TEST TYPE VS TEST TYPE VS PROPERTIESPROPERTIES

Tensile TestTensile Test Ultimate tensile strengthUltimate tensile strength Yield strengthYield strength Ductility ( % elongation, % reduction in area)Ductility ( % elongation, % reduction in area) Modulus of elasticityModulus of elasticity Proportional limitProportional limit

Hardness Test (Brinel, Vickers, Rockwell, Knoop)Hardness Test (Brinel, Vickers, Rockwell, Knoop) Hardness of weld, HAZ & base materialHardness of weld, HAZ & base material UTS for some materialUTS for some material

Toughness TestToughness Test ToughnessToughness Ductile - Brittle transition temperatureDuctile - Brittle transition temperature

Bend TestBend Test DuctilityDuctility FormabilityFormability Soundness of weldSoundness of weld

DEFECTS USUALLY DEFECTS USUALLY APPEARS IN THE WELDINGAPPEARS IN THE WELDING

DESIGN RELATEDDESIGN RELATED

WELDING PROCESS RELATEDWELDING PROCESS RELATED

METALLOGRAPHIC STRECTURE METALLOGRAPHIC STRECTURE RELATEDRELATED

WELDING PROCESS RELATED WELDING PROCESS RELATED DEFECTSDEFECTS

SHIELDED METAL ARC WELDINGSHIELDED METAL ARC WELDING Slag inclusionsSlag inclusions PorosityPorosity LOF / LOPLOF / LOP UndercutUndercut

SUBMARGED ARC WELDINGSUBMARGED ARC WELDING LOP / LOPLOP / LOP Slag inclusionsSlag inclusions PorosityPorosity

GAS TUNGSTEN ARC WELDING (TIG WELDING)GAS TUNGSTEN ARC WELDING (TIG WELDING) PorosityPorosity Tungsten inclusionsTungsten inclusions

SOUNDNESS TESTIONSOUNDNESS TESTION

Bend TestBend TestNick-break TestNick-break TestFillet Break TestFillet Break TestMicro ExaminationMicro Examination

METALLOGRAPHIC TESTMETALLOGRAPHIC TESTMacro Examination Macro Examination

(Magnification below 10X)(Magnification below 10X)

MICRO ExaminationMICRO Examination

(Magnification above 10X)(Magnification above 10X)

WELDING WELDING DEFECTS DEFECTS

ARC BLOW IN DC ARC WELDING

Cause and effects of arc blow

When the arc deviates from its regular patch due to the magnetic disturbances it is called ‘Arc blow’

Whenever a current flows in the electrode a magnetic field is formed around the electrode. Likewise a similar magnetic field is also formed around the base metal.

Due to the interaction of these two magnetic fields, the arc is blown to one side forward or backward of the joint.

Due to this the following effects occur.

More spatters with less deposition of weld metal.

Poor fusion/penetration.

Weak welds.

Difficulty in deposition welds metal at the required place in the joint.

Methods used to control the arc blow

The arc blow can be controlled by:- welding away from the earth connection (Fig4 )- changing the position of the earth connection on the work- changing the position of the work on the welding table.- wrapping the welding cable fewer times around the work (Fig5)- welding towards a heavy welding tack or a weld already made- Keeping a magnetic bridge on the top of the groove joint- Holding the correct electrode angle with a short arc.

Use ‘run on’ and ‘run off’ plates If all the above methods fail to control the ‘arc blow’, change to AC supply.

(Fig4 )

(Fig5)

WELDING FAULTS

The appearance of a sound weld is characterized by a uniformly rippled surface, even contour, bead width, good penetration and absence of external defects. Fault A fault is one which does not allow the finished joint to withstand the required strength (load).

Defects in welding may be considered under two heads. External defects Internal defects

External defects Undercut A groove or channel formed in the parent metal at the toe of the weld. (Fig 1, 2 & 3) CAUSES Current too high.Welding speed too fast.Overheating of job due to continuous welding.Faulty electrode manipulation.Wrong electrode angle.

REMEDIES

Ensure

proper current correct welding speed correct arc length correct manipulation of electrode

Fig 1

Fig 2

Overlap

An overlap occurs when the molten metal from the electrode flows over the parent metal surface without fusing into it.

Fig 3

CAUSESPresence of contaminants on the job or electrode surface, presence of high sulphur in the job or electrode materials. Trapped moisture between joining surfaces. Fast freezing o weld metal. Improper cleaning of the edges. REMEDIESRemove oil grease, rust paint, moisture, etc. from the surface. Use fresh and dried electrodes. Use good fluxcoated electrodes. Avoid long arcs.

CAUSESLow current.Slow are travel speed.Long arc.Tool large a diameter electrode. REMEDIESCorrect current setting.Correct arc travel speed.Correct arc length.Correct diameter electrode as per metal thickness.Proper manipulation of electrode.

Porosity Blow hole or gas pocketOrGroup of pine holes on the surface of the weld caused by gas entrapment.

PorosityPorosity

Porosity is the presence of cavities in the weld metal caused by the freezing in of gas released from the weld pool as it solidifies

PorosityPorosity

SpatterSmall metal particles which are thrown out of the arc during welding along the weld.

CAUSES Welding current too high. Wrong polarity (in DC). Use of long arc. Arc blow. Uneven flux coated electrode. REMEDIESUse correct currentUse correct polarity (DC)Use correct arc length.Use good flux-coated electrode.

Edge of plate melted offEdge of plate melted off in lap and corner joints only.(Fig)

CAUSESUse of oversize electrode.Use of excessive current.Wrong manipulation of the electrode. REMEDIESSelect correct size electrode.Set correct current.Ensure correct manipulation of electrode.Deposit additional weld metal to increase throat thickness.

CrackA hairline separation exhibits in the root or middle or surface of the weld metal or parent metal.

CrackCrack

Hydrogen CrackHydrogen Crack

Crack: It is a discontinuity produced either by tearing of the weld metal when it is in plastic stage and is solidifying from the molten state and is still above 550 degree C which is called hot crack, or by fracture when cold when it is termed as cold crack.

Crack which is visible on the surface is called a surface crack and a crack which can only be detected by radiography or fracturing, say by nick break test, is called Internal crack.

Cracks in fusion welded joints may occur either in weld metal or in parent metal, e.g. in HAZ. Weld metal crack can generally be classified as longitudinal, transverse, crater and "hairline" which are usually associated with slag inclusions. Sometimes longitudinal crack in a weld seam may emanate from crater cracks.Parent metal crack usually means crack within the blackish HAZ, which may be longitudinal, or transverse to seam or sometimes just under the run. Transverse crack in Parent metal may also originate from crack in the weld metal.

CAUSESPresence of localized stress.Fast cooling.Improper welding techniques.Poor ductility,Absence of preheating and post-heating on high carbon steels. REMEDIESPreheat and post-heating to be done on high carbon steels.Cool slowly.Use fewer passes.Use proper welding technique.

Internal defects Incomplete penetrationFailure of weld metal to reach the root of the joint .

CAUSESEdge preparation too narrow-lesser bevel angle.Welding speed too much.Less current.Use of larger dia. electrode.Inadequate cleaning or gouging before depositing sealing run.Wrong angle of electrode.Insufficient root gap. REMEDIES Correct edge preparation is required. Ensure correct angle of bevel and required root gap.Use correct size of electrode.Correct welding speed required.Correct current setting required.

Incomplete root fusionIncomplete root fusion

A - Excessively thick root face

B - Too small a root gap

C - Misplaced welds

D - Power input too low

E - Arc (heat) input too low

A

B

C

D

E

Incomplete root fusionIncomplete root fusion

A – LARGER DIAMETER ELECTRODE

B – SMALLER DIAMETER ELECTRODE

B

C

Slag inclusion Slag or other non-metallic foreign materials entrapped in a weld. (Fig)

CAUSES Incorrect edge preparation.Wrong size and type of electrode.Excessive current.Long are length.Improper welding technique.Inadequate cleaning of each run in multi-run welding. REMEDIES Use correct joint preparation.Use correct type of electrode.Use correct arc length.Use correct welding technique.Ensure thorough cleaning of each run in multi-run welding.

Slag InclusionsSlag Inclusions

Effects of faults Thickness of base metal reduced. Weakens the strength of weld. Reduces the throat thickness. Consumes more electrode. Change in base metal properties. Poor weld appearance. Waste of labour and materials. Failure of joints will lead to accidents.

•WELDING

INSPECTION

AND TESTING

INSPECTION OF WELD

Necessity of inspection The purpose of inspection is to locate and determine the type of fault, Quality of joint and quality of workmanship. Types of tests Non-destructive test (NDT)Destructive test Determining the quality of the weld without destroying the weld is called a non-destructive test (NDT). The job can be used after the test. The test to be carried out on welded specimens by destruction is called destructive test. The job cannot be used after the test.

Visual inspection (non-destructive test) This is one of the important inspection methods without much expense. This method of inspection needs a magnifying glass, a steel footrule, try square and welding gauges. Visual inspection is made in three stages namely: - before weldingduring weldingafter welding

Visual inspection before welding (The operator must be familiar with the type of work, electrode and welding machine). The following factors are to be ensured. The material to be welded is of weldable quality.

The edges have been properly prepared for welding as per thickness of the plate.

Setting of root gap.

Proper procedure to be followed to control distortion.

Polarity of the electrodes in the case of DC welding current.

Current setting according to the size of the electrode and position of welding.

Whether any jigs and fixtures are necessary to ensure proper alignment.

Whether any jigs and fixtures are necessary to ensure proper alignment.

Proper facilities should exist for storing and drying of the electrodes.

Visual inspection during welding The following points are to be checked. Studying the sequence of weld deposit.

Examining whether each weld is cleaned adequately before making the next run in multi-run welding.

The following factors are to be ensured.

Shape of the bead, angle of electrode during welding, amperage, speed of travel, arc length, correct manipulation of the electrode and control of spatters.

Inspection after welding Surface defects in and around the welds, such as cracks, (longitudinal and transverse), undercut, overlap, excessive convexity of contour, the weld surface smoothness of the run and penetration and control of distortion are to be inspected.

Check points for inspection Shape of profile shall be checked by measuring the dimensions of the weld. In butt welds the surface should be slightly convex.In fillet welds the contour may be convex or concave. Uniformity of (surface) height and spacing of the ripples are an indication of the quality of workmanship.

Degree of undercut. Smoothness of joint where welding is recommended.

Freedom from surface cavities and trapped slag. Deposition of runs, single or multiple.

Penetration bead in butt weld.

Quality of the weld metal.

TESTING OF WELDS

Necessity of testing of welds To obtain a dependable joint, it is necessary to inspect and exercise adequate control before, during and after welding. The various tests to be conducted on welded joints are determined mainly by the service conditions to which the welded components will be subjected to. It is also necessary to draw samples on a scientific basis and test them not only to control the quality of the weld, but also to assess the skill and ability of the welder.

TYPES OF TESTING All forms of testing can be grouped into two categories. Non-destructive testingDestructive testing

Non-destructive testing (NDT)

In this method the test to be carried out is done on the job itself without destroying it and after the test, the job can still be used.

Destructive testing

In this method the tests are carried out on welded specimens by destruction.

The specimen will be spoiled during the test and cannot be reused. In general the above mechanical tests are the least expensive and most reliable for assessing the weld quality.

Therefore, these tests are most widely carried out.

Non-destructive testing methods are classified as common testing and special testing methods. Common non-destructive testing

Visual inspection Leak or pressure test Stethoscopic test (Sound) Special non-destructive tests

Magnetic particle test Liquid penetrant test Radiography (X-ray) test Gamma ray test Ultrasonic test

METHODS OF NON-DESTRUCTIVE TESTS

Visual inspection Visual inspection is the simplest, fastest, economical and most commonly used test for detecting defects on the surface of the welded job. The weld surface and joint are examined visually with naked yes preferably with the help of a magnifying with naked eyes preferably with the help of a magnifying lens. Visual examination can help in detecting the following defects on the surface of the weld. Porosity Surface defects Undercut Improper profile and dimensional accuracy Poor weld appearance Incomplete penetration.

Leak or pressure test This test is used to test welded pressure vessels, tanks and pipelines to determine if leaks are present.

The welded vessel, after closing all its outlets, is subjected to internal pressure using water, air or kerosene.

The internal pressure depends upon the working pressure in the welded joint.

The internal pressure may be raised to two times the working pressure of the vessel.

The weld may be tested as follows. 1. The pressure on the gauge may be noted immediately after applying the internal pressure and again after, say, 12 to 24 hours. Any drop in pressure reading indicates a leak.

2. After generating air pressure in the vessel, soap solution may be applied on the weld seam and carefully inspected for bubbles which would indicate leak.

Stethoscopic (sound) test The principle of this test is that defect-free weld metal gives a good ringing sound when struck with a hammer whereas a weld metal containing defects give a flat sound. An ordinary physician’s stethoscope and a hammer may be used to magnify and identify the sound. Structural welds and welds in pressure vessels have been successfully tested using this method.

Dye is applied on cleaned test surface

After hold time, surface is cleaned using cleaner.

A liquid developer (white in colour) is then sprayed on the weld.

The coloured dye comes out in the shape of surface defects into the white developer coating.

The defect can be seen in normal light with naked eyes.

Stages of LPI

Following steps are involved in penetrant inspection :

Surface preparation

Application of the penetrant

Controlling time for penetration.

Removal of excess penetrant.

Application of developer.

Inspection

Interpretation and Evaluation

Post cleaning

Magnetic Particle InspectionLiquid Penetrant Inspection is sufficient for locating only surface flaws while for locating slightly subsurface and surface flaws, magnetic particle inspection can be used.

Magnetic Particle Inspection (MPI) is a technique used for testing ferromagnetic materials. The technique is basically simple and easy to operate.

Austenitic stainless steels cannot be tested with this technique. This can be used for detecting discontinuities on surface or subsurface defects at a depth of a maximum of 6 mm under favourable conditions.

PrincipleThe job is suitable magnetised and magnetic lines of force or magnetic flux of enough density is made available.

Discontinuities in the path of the magnetic flux create a disturbance in the uniform magnetic field causing flux leakage.

The flux leakage set up of magnetic poles attracts iron powder when dusted over the testing zone and forms a pattern of the discontinuity.

The flaw is indicated as a pattern on the surface giving the location and to some extent the nature of discontinuity.

Magnetic particle test This test is used to detect surface defects as well as sub-surface (up to 6 mm depth) defects in ferrous materials.

While the test piece is magnetized, the iron particles will gather at the edges of the defect (crack or flaw) and can be seen as dark hair line marks with naked eyes.

Ultrasonic test

Sound waves of high frequency are used in this test. This test is used to find out the discontinuities in the weldment. The sound waves can penetrate even up to 6 to 10 metres of steel.

A sound wave producing transmitter is placed on the job. The echo of the sound waves is directly shown on the calibrated screen attached with the ultrasonic testing unit. If there is any obstruction due to the welding defect, it will be easily found out on the screen.

This test also can be used to find the thickness of metals.

Radiographic Testing

Radiography employs the penetrating capacity of ionising radidation like X or Gamms rays to produce a shadow of the internal condition of a job on a recording medium. The record in a film is known as Radiograph.

Radiographic test This is also called X-ray or gamma ray test. In this test internal photographs of the welds are taken. The test specimen is placed in between the X-ray unit and film. (Fig) Then the X-ray is passed. If there is any hidden defect, that will be seen in the film after developing it. Defects appear in the same manner as bone fractures of human beings appear in X-ray films.

Tensile Test

The tensile test gives the values of the tensile strength of the weld and the percentage of elongation of the weld.

This reveals the suitability of a joint welded with certain electrodes and base metals for a particular service condition.

DT

They are :transverse tensile test specimen .(Fig).all-weld metal tensile specimen. (Figures).

DT

DT

Guided bend test

A guided bend test is one in which the specimen as in Fig 1 is bent to 180 through a bend testing jig as in Fig 2.

There are two types of specimens prepared for this – one for face bend and the other for root bend. (Fig.) This test measures the ductility of the weld metal in a butt joint in a plate. This test shows most weld faults quite accurately and it is very fast. A sample specimen can be tested on destruction to determine (a) the physical condition of the weld and thus check on the weld procedure and (b) the welder’s capability.

DT

Impact test

Impact means application of a sudden force on an object. In an impact test of a weld, a test specimen with (Fig) is prepared from a test plate.

This is further machined to have a V notch as in Fig. The test specimen with 10 mm square cross-section is used for charpy V impact test and one with 11 mm diameter circular cross-section is used for the izod impact test.

DT

Fig shows an impact testing machine. The impact test is used to determine the impact value of welds and base metals in welded products to be used at room temprature /low temperatures which are subjected to severe dynamic loading.

DT

Welding codesA code of Construction is a set of Rules, Regulations and Ethical practices, required to be observed by Manufacturers either as a statutory requirement; or as a Contractual obligation to Statutory Authorities.

Public Sector Organizations and Engineering Societies such as:

Indian Boiler Regulations (IBR)

Indian Railway Services (IRS)

Bureau of Indian Standards (BIS)

American Welding Society (AWS)

American Society of Mechanical Engineers (ASME)

American Petroleum Institute (API)

have established Committees for the purpose of formulating Standard Rules for the Construction of Welded Vessels & Structures.

Primary aim of these Societies is to establish Rules of Safety governing Design, Fabrication and Inspection during Construction and Interpretation of the Rules and their Intent.

ASME CODE SECTION VIII DIV 1 & ASME SEC IX

The American Society of Mechanical Engineers set up a committee in 1911 to formulate standard rules for construction of steam boilers and other pressure vessels. The committee is calle the BPV Committee.

The ASME Boiler and Pressure vessle Code establishes rules of safety governing the design, fabrication and inspection during construction of boilers and pressure vessels. The ASME Code is a statutory code of construction for Boilers and pressure vessels in USA and Canada.

The BPV Committee interprets the rules when questions arise regarding their content. Code Cases are used to amplify the rules.

Each manufacturer or contractor is responsible for welding work done by his organization, and must conduct the training and tests required to qualify in advance the welding procedure he will be using in construction and the performance of his welding personnel.

Welding parameters (also called welding variables) which affect the quality of weldment are listed in great detail in the Section IX of the Code.

•WELDING PROCEDURE AND

PERFORMANCE QUALIFICATIONS

WELDING DOCUMENTSWELDING DOCUMENTS

Welding Procedure Specification (WPS)Welding Procedure Specification (WPS) Procedure Qualification Record (PQR)Procedure Qualification Record (PQR) Welders Performance Qualification (WPQ)Welders Performance Qualification (WPQ)

APPROACHES TO PROCEDURE APPROACHES TO PROCEDURE QUALIFICATIONQUALIFICATION

Actual Procedure Qualification TestingActual Procedure Qualification Testing Pre-qualified ProcedurePre-qualified Procedure Mock-up testsMock-up tests

PROCEDURE QUALIFICATION PROCEDURE QUALIFICATION TESTINGTESTING

• Welding VariablesWelding Variables

Essential VariablesEssential VariablesSupplementary Supplementary

essential variablesessential variables Non essential Non essential variablesvariables

ESSENTIAL VARIABLES ESSENTIAL VARIABLES

Base Metal P No.Base Metal P No. Process (es)Process (es) Filler Metal A No.Filler Metal A No. PWHTPWHT GasGas Base Metal ThicknessBase Metal Thickness Weld Metal ThicknessWeld Metal Thickness

SUPPLEMENTARY ESSENTIAL SUPPLEMENTARY ESSENTIAL VARIABLESVARIABLES

Base Metal Group No.Base Metal Group No. AWS ClassificationAWS Classification Welding PositionWelding Position Heat InputHeat Input

NON ESSENTIAL VARIABLESNON ESSENTIAL VARIABLES

Electrode LengthElectrode Length Joint DesignJoint Design BG & Method of BGBG & Method of BG Product formProduct form

TESTS REQUIRED FOR PQRTESTS REQUIRED FOR PQRASMEASME

Transverse Tensile Test (2 Nos.)Transverse Tensile Test (2 Nos.) Bend Tests (4 Nos.)Bend Tests (4 Nos.) Impacts ( if required) ( 2 - 3 sets)Impacts ( if required) ( 2 - 3 sets)

TYPES OF TENSILE TESTSTYPES OF TENSILE TESTS

Transverse Tensile TestTransverse Tensile Test Longitudinal Tensile Test Longitudinal Tensile Test

TYPE OF BEND TESTSTYPE OF BEND TESTSASMEASME

Transverse BendsTransverse Bends1. Root1. Root2. Face2. Face3. Side3. Side

Longitudinal BendsLongitudinal Bends1. Root1. Root2. Face2. Face

OVERLAYSOVERLAYS

Corrosion Resistant OverlaysCorrosion Resistant Overlays Hard Facing OverlaysHard Facing Overlays

TESTS FOR OVERLAYS (PQR)TESTS FOR OVERLAYS (PQR)

Corrosion Resistant OverlaysCorrosion Resistant OverlaysDP (Barrier / Final layer)DP (Barrier / Final layer)Chemistry (at qualifying height)Chemistry (at qualifying height)

Side BendsSide Bends Hard Facing OverlaysHard Facing Overlays

DP (Barrier / Final layer)DP (Barrier / Final layer)Chemistry (at qualifying height)Chemistry (at qualifying height)

HardnessHardness

WELDERS QUALIFICATIONWELDERS QUALIFICATION

Essential variablesEssential variables Process Process (es)(es) Base Metal Base Metal

ThicknessThicknessProduct Product

formform Pipe Pipe DiameterDiameter Welding Welding PositionPosition BackingBacking

F NumberF Number

SUMMARY

Welding is a special process, and as such welding procedures and welders' performances (skill) must be pre-qualified and the parameters established during procedure qualification tests must be maintained during actual production.

Infrastructure industries must follow this philosophy in all those areas, where welding fabrication is undertaken and be guided by the stipulation of Welding Codes.

Weld Quality ManagementWeld Quality Management

Quality ManagementQuality Management

Objectives and Responsibility for QualityObjectives and Responsibility for Quality Concept of CustomerConcept of Customer Generic Product CategoriesGeneric Product Categories Facets of QualityFacets of Quality Concept of ProcessesConcept of Processes Quality System EvaluationQuality System Evaluation

Quality Management PracticesQuality Management Practices

Quality System design and DevelopmentQuality System design and Development Coordination of all Quality ActivitiesCoordination of all Quality Activities Monitor Quality SystemMonitor Quality System Creating Quality AwarenessCreating Quality Awareness Training & Motivation of EmployeesTraining & Motivation of Employees Quality Improvement PlanQuality Improvement Plan

Yields of Quality ManagementYields of Quality Management

Lower Rework and Scrap LevelLower Rework and Scrap Level Lower Defect RateLower Defect Rate Higher Productivity and PerformanceHigher Productivity and Performance Higher Quality LevelHigher Quality Level On time deliveryOn time delivery Higher Profits and Market ShareHigher Profits and Market Share Customer SatisfactionCustomer Satisfaction

Facets of QualityFacets of Quality

Need for the ProductNeed for the Product Product DesignProduct Design Conformance to Product DesignConformance to Product Design Product SupportProduct Support

Design ConsiderationsDesign Considerations

Product reliability Product reliability Fitness for the purposeFitness for the purpose Adequacy of designAdequacy of design Conformance to specifications and CodeConformance to specifications and Code Operation and MaintenanceOperation and Maintenance

Weld QualityWeld Quality

Higher quality than is needed is not only Higher quality than is needed is not only costly but also unnecessarycostly but also unnecessary

Levels of quality may vary depending on Levels of quality may vary depending on service requirementsservice requirements

Low quality welds leads to higher Low quality welds leads to higher operational costsoperational costs

Use of fabrication codes and standardsUse of fabrication codes and standards Fitness for the purposeFitness for the purpose

Inspection MethodsInspection Methods

Visual InspectionVisual Inspection Non-Destructive EvaluationNon-Destructive Evaluation

Liquid PenetrantLiquid Penetrant Magnetic ParticleMagnetic Particle RadiographyRadiography UltrasonicUltrasonic Eddy CurrentEddy Current

Inspection Methods (Contd..)Inspection Methods (Contd..)

Destructive ExaminationDestructive Examination Tensile TestTensile Test Hardness TestHardness Test Impact TestImpact Test Bend TestBend Test Corrosion TestCorrosion Test MetallographyMetallography

Role of Welding InspectorRole of Welding Inspector

Familiarity withFamiliarity with Products and Engineering DrawingsProducts and Engineering Drawings National and International Codes and Specs.National and International Codes and Specs. PQRs, WPSs and Welder QualificationPQRs, WPSs and Welder Qualification Testing Methods and EvaluationTesting Methods and Evaluation

Inspection of WeldsInspection of Welds

Prior to WeldingPrior to Welding PQRs, WPSs and Welder QualificationPQRs, WPSs and Welder Qualification Fabrication and testing PlansFabrication and testing Plans Materials Specification and QualityMaterials Specification and Quality Welding ConsumablesWelding Consumables Welding EquipmentWelding Equipment Joint design and preparationJoint design and preparation

Inspection of Welds (Contd..)Inspection of Welds (Contd..)

During WeldingDuring Welding Joint Fit-up, distortion control and Tack WeldsJoint Fit-up, distortion control and Tack Welds Conformance to WPS and Qualified WeldersConformance to WPS and Qualified Welders Pre-Heat and Inter pass TemperaturesPre-Heat and Inter pass Temperatures Control and Handling of Welding ConsumableControl and Handling of Welding Consumable Visual and Non Destructive EvaluationVisual and Non Destructive Evaluation

Inspection of Welds (Contd..)Inspection of Welds (Contd..)

After WeldingAfter Welding Conformity to drawings and SpecificationsConformity to drawings and Specifications Cleaning and Visual InspectionCleaning and Visual Inspection Non Destructive EvaluationNon Destructive Evaluation RepairRepair Post Weld Heat Treatment and TestingPost Weld Heat Treatment and Testing DocumentationDocumentation

HEAT TREAMENTHEAT TREAMENT

ANNEALINGANNEALING NORMALISING NORMALISING HARDENING & TEMPERINGHARDENING & TEMPERING POST HEAT POST HEAT THERMAL STRESS RELIEFTHERMAL STRESS RELIEF

•

WELDING MANAGEMENT

Base metalBase metal

Weld

Heat effected Zone (HAZ

WELD JOINT DETAIL

MANAGEMENTMANAGEMENT

Management in an Organization Management in an Organization meansmeans

ManagingManaging MenMen

MachineMachine

MaterialMaterial

MANAGEMENT IN WELDINGMANAGEMENT IN WELDING

MenMen Welding EngineerWelding Engineer Welding supervisorsWelding supervisors WeldersWelders Welding InspectorsWelding Inspectors NDT and DT TechniciansNDT and DT Technicians

Welding power sourcesWelding power sources Welding GeneratorsWelding Generators RectifiersRectifiers HF unitsHF units Welding headsWelding heads Cooling systemsCooling systems Safety equipmentSafety equipment

MACHINESMACHINES

ACCESSORIESACCESSORIES

Welding HoldersWelding Holders Welding CablesWelding Cables Cable lugsCable lugs TIG welding Torches, Cups ColletsTIG welding Torches, Cups Collets Welding Helmet, Goggles, Gloves Welding Helmet, Goggles, Gloves

Etc.Etc.

MATERIALSMATERIALS

Welding consumablesWelding consumables ElectrodesElectrodes Wire and FluxWire and Flux Filler rodsFiller rods Shielding GasesShielding Gases Welding Test PlatesWelding Test Plates

CommercialCommercial EngineeringEngineering Material ManagementMaterial Management Quality ControlQuality Control Production EngineeringProduction Engineering Fabrication Shops and Fabrication Shops and

SitesSites

OTHER DEPARTMENTS TO OTHER DEPARTMENTS TO BE COORDINATEDBE COORDINATED

COMMERCIALCOMMERCIAL

Comments on Customer EnquiriesComments on Customer Enquiries Previous Experience and Development Previous Experience and Development

neededneeded Available FelicitiesAvailable Felicities Consumables and Equipment Cost and Consumables and Equipment Cost and

Time requirementTime requirement Indigenous or Import requirementsIndigenous or Import requirements

Technical requirements and Technical requirements and AcceptabilityAcceptability

Deviation or Clarifications neededDeviation or Clarifications needed Review and Approval of welding Review and Approval of welding

DocumentsDocuments Progress coordinationProgress coordination

ENGINEERING DEPARTMENTENGINEERING DEPARTMENT

Comment on Preliminary drawingsComment on Preliminary drawings Welding approach,Weld joint bevel Welding approach,Weld joint bevel

design and Location of jointdesign and Location of joint Material and Consumables requirementsMaterial and Consumables requirements Test plates for Procedures and Welders Test plates for Procedures and Welders

QualificationQualification PWHT requirementsPWHT requirements

MATERIALS MANAGEMENTMATERIALS MANAGEMENT

Welding ConsumablesWelding Consumables Vendor DevelopmentVendor Development Technical capabilitiesTechnical capabilities Previous historyPrevious history MI and TDC RequirementsMI and TDC Requirements Cost, Time, AccessibilityCost, Time, Accessibility Reliability on Quality and Schedule Reliability on Quality and Schedule

deliverydelivery

QUALITY CONTROLQUALITY CONTROL

Quality Assurance Plan Preparation Quality Assurance Plan Preparation Third Party Inspection Co-ordinationThird Party Inspection Co-ordination

Materials Test certificates & Heat treatmentMaterials Test certificates & Heat treatment RequirementsRequirements

Production Test Coupon Requirements Production Test Coupon Requirements

Welding Procedures & Welders QualificationWelding Procedures & Welders Qualification TestingTesting Welders Qualification Continuity RecordsWelders Qualification Continuity Records NDT Requirements NDT Requirements Documents Submission Documents Submission

PRODUCTION ENGINEERINGPRODUCTION ENGINEERING

Materials arrival MonitoringMaterials arrival Monitoring Work distribution to Fabrication ShopsWork distribution to Fabrication Shops Arrangement of WPS and Welding Arrangement of WPS and Welding

ConsumablesConsumables Welding progress and Schedule Welding progress and Schedule

MonitoringMonitoring

MANAGEMENT IN WELDINGMANAGEMENT IN WELDING

MenMen Welding EngineerWelding Engineer Welding supervisorsWelding supervisors WeldersWelders Welding InspectorsWelding Inspectors NDT and DT TechniciansNDT and DT Technicians

ROLE OF WELDING ROLE OF WELDING TECHNOLOGISTTECHNOLOGIST

Study of Base Metal WeldabilityStudy of Base Metal Weldability Selection of Welding ProcessSelection of Welding Process Selection of Welding ConsumablesSelection of Welding Consumables Selection of Welding Equipment Selection of Welding Equipment

Development of Welding ProcedureDevelopment of Welding Procedure Development of Welding TechniquesDevelopment of Welding Techniques Corrective actions During WeldingCorrective actions During Welding

Knowledge of Welding applicationKnowledge of Welding application Base Materials and Their ApplicationsBase Materials and Their Applications Welding Process Advantages and LimitationsWelding Process Advantages and Limitations Consumables Storage and Handling PracticesConsumables Storage and Handling Practices Welding Parameters and Their Effect on Weld QualityWelding Parameters and Their Effect on Weld Quality Preheat, Interpass, Post Heat and PWHT Preheat, Interpass, Post Heat and PWHT Welding Equipment and Their ApplicationsWelding Equipment and Their Applications Welders Qualification RequirementsWelders Qualification Requirements Welding Accessories Maintenance and Their UsageWelding Accessories Maintenance and Their Usage Ability to Guide the WelderAbility to Guide the Welder Weld Inspection and Testing techniquesWeld Inspection and Testing techniques

WELDING SUPERVISOR

WELDERSWELDERS

Should Perform the Weld As Per the WPSShould Perform the Weld As Per the WPS Should Have Theoretical Understanding and Should Have Theoretical Understanding and

Practical SkillPractical Skill Should Know the Base Metal Characteristics Should Know the Base Metal Characteristics

for Weldingfor Welding Should Operate the Welding EquipmentShould Operate the Welding Equipment Should Understand The Weld Joint CriticalityShould Understand The Weld Joint Criticality Should Have the Required QualificationShould Have the Required Qualification

Should have the knowledge of Welding ProcessesShould have the knowledge of Welding Processes Should Inspect the Welding PerformanceShould Inspect the Welding Performance Should Ensure the parameters implementation as per WPSShould Ensure the parameters implementation as per WPS Should Record and Maintain the Welding HistoryShould Record and Maintain the Welding History Should Inspect and Organise testingShould Inspect and Organise testing Should Identify defect and suggest repair procedureShould Identify defect and suggest repair procedure Should interpret the tested results and judge the quality.Should interpret the tested results and judge the quality.

Welding Inspector

WELDING TECHNOLOGYWELDING TECHNOLOGY GROUP GROUP FUNCTIONSFUNCTIONS

Welding Procedure Specification (WPS)Welding Procedure Specification (WPS) Procedure Qualification Record (PQR)Procedure Qualification Record (PQR) Welder Performance Qualification (WPQ)Welder Performance Qualification (WPQ) Welding Consumables Qualification (WCQ)Welding Consumables Qualification (WCQ) Welding Equipment Welding Equipment Welding Technology Experimental ShopWelding Technology Experimental Shop Welding Trouble ShootingWelding Trouble Shooting

WELDING PROCEDURE WELDING PROCEDURE QUALIFICATIONQUALIFICATION

Study the Requirements of QualificationsStudy the Requirements of Qualifications Arrange Test Plates, Consumables and Arrange Test Plates, Consumables and

EquipmentEquipment Weld the Test PlateWeld the Test Plate Conduct NDE testsConduct NDE tests Physical TestingPhysical Testing Compare the Results With the requirementsCompare the Results With the requirements Approval and RecordingApproval and Recording

WPS GROUP ACTIVITIESWPS GROUP ACTIVITIES

Comment on Enquiries, work order Data Comment on Enquiries, work order Data sheets customer specification etc.sheets customer specification etc.

Comments on Preliminary DrawingsComments on Preliminary Drawings Welding Consumables EstimationWelding Consumables Estimation Welding Procedures and Welders Welding Procedures and Welders

Qualifications RequirementsQualifications Requirements Welding Documents (WPS &WDS) Welding Documents (WPS &WDS)

Preparation and ApprovalPreparation and Approval Welding Progress MonitoringWelding Progress Monitoring

Consolidate the requirements given by the WPS groupConsolidate the requirements given by the WPS group Define Technical Delivery Condition Material Indent and Define Technical Delivery Condition Material Indent and

Float EnquiresFloat Enquires Technical Clarification on OffersTechnical Clarification on Offers Recommendation and Purchase order ReleaseRecommendation and Purchase order Release Material Receipt, Material Receipt, Test certificates Comparison with TDCTest certificates Comparison with TDC Material testing and Acceptance Material testing and Acceptance Storage, Issue and MonitoringStorage, Issue and Monitoring

Welding consumables

WELDERS QUALIFICATION WELDERS QUALIFICATION RECORDSRECORDS

Training and Qualification of New WeldersTraining and Qualification of New Welders Monitoring old QualificationMonitoring old Qualification Maintain Continuity RecordsMaintain Continuity Records Renewal of QualificationRenewal of Qualification

COMMOMLY AVAILABLE FCAW COMMOMLY AVAILABLE FCAW PRODUCTSPRODUCTS

FCAW Product for Positional Welding of FCAW Product for Positional Welding of CS / LAS With Gas Shielding.CS / LAS With Gas Shielding.

Self Shielded FCAW Product for CSSelf Shielded FCAW Product for CS Self Shielded for HF ProductsSelf Shielded for HF Products Gas Shielded SS Small Dia.Cored Wire Gas Shielded SS Small Dia.Cored Wire

Product for FabricationProduct for Fabrication Self shielded SS Cored Wire for SS Self shielded SS Cored Wire for SS

Overlay /Cladding Overlay /Cladding

SELECTION CRITERIASELECTION CRITERIA

Chemical & Mechanical PropertiesChemical & Mechanical Properties Commercial Availability of ProductCommercial Availability of Product Suitability for Restraint Welds -Hydrogen Suitability for Restraint Welds -Hydrogen

Level in Weld MetalLevel in Weld Metal Type of Gas Shielding to be usedType of Gas Shielding to be used Feasibility of ApplicationFeasibility of Application Cost FactorCost Factor

ACID vs BASIC vs METAL CORED vs ACID vs BASIC vs METAL CORED vs RUTILE BASICRUTILE BASIC

E70T-1 vs E70T-5 vs E70C-6M vs E70T-1E70T-1 vs E70T-5 vs E70C-6M vs E70T-1

ACID BASIC METALCORED RUTILE BASIC

UTS,MpaYS Mpa%E

58551823

53545028

57551727

58549727

IMPACT J-18 DeG C-29 Deg C

40-6520-45

110-16080-135

75-10025-55

80-12565-100

HYDROGENMl/100 GMS

5-10 2-5 3-8 2-5

OPE.CHARAC.BEAD SHAPE

FLAT CONVEX FLAT FLAT

WETTINGACTION

VERY GOOD FAIR GOOD VERY GOOD

STORAGE & RECONDITIONING STORAGE & RECONDITIONING FOR SMAW /FCAWFOR SMAW /FCAW

SMAWSMAW Low Hydrogen Store 100-150 Deg CLow Hydrogen Store 100-150 Deg C Recondition at 400 Deg C- 1Hr Recondition at 400 Deg C- 1Hr Stainless Recondition at 200 Deg C- 1Hr Stainless Recondition at 200 Deg C- 1Hr FCAWFCAW Plastic Recondition at 50 Deg C- 48Hr MinPlastic Recondition at 50 Deg C- 48Hr Min Coils Store 100-125 Deg CCoils Store 100-125 Deg C Recondition at 150 Deg C- 6-8HrsRecondition at 150 Deg C- 6-8Hrs Wire Spool Store 150 Deg CWire Spool Store 150 Deg C Basket Recondition at 250 Deg C- 2-3Hrs Basket Recondition at 250 Deg C- 2-3Hrs Higher Rebake Temperature , Faster ReconditioningHigher Rebake Temperature , Faster Reconditioning

FCAW CONSUMABLES AVILABILITYFCAW CONSUMABLES AVILABILITY

E70T-1 FORE70T-1 FOR E71T-1 BOILER E71T-1 BOILER E70T5 QUALITYE70T5 QUALITY E81T1-W E81T1-W WHEATHERING WHEATHERING

E80T1-A1 FORE80T1-A1 FOR E80T1-B2 LOW ALLOYE80T1-B2 LOW ALLOY E8-T1-B3 STEELE8-T1-B3 STEEL E80T5-G FORE80T5-G FOR E90T5-K2 HSLAE90T5-K2 HSLA E100T5K3 STEELS E100T5K3 STEELS E110T5-K4E110T5-K4

E308TX-X FOR SSE308TX-X FOR SS E316TX-X POSITIONAL E316TX-X POSITIONAL E312TX-X WELDINGE312TX-X WELDING E309TX-XE309TX-X E308.T0-3 FOR E308.T0-3 FOR E309T0-3 CLADDINGE309T0-3 CLADDING

CORED STAINLESS STEEL WIRESCORED STAINLESS STEEL WIRES

Metal Cored - Metal Cored - Mostly metallic Powders in the Mostly metallic Powders in the Core.Welding Characteristics similar to solid wireCore.Welding Characteristics similar to solid wire

Self ShieldedSelf Shielded -Generates its Own Protective -Generates its Own Protective Gas .Used in Flat & Horizontal Position onlyGas .Used in Flat & Horizontal Position only

Down Hand Gas ShieldedDown Hand Gas Shielded - For Flat & Horizontal - For Flat & Horizontal PositionsPositions

All -Position Gas ShieldedAll -Position Gas Shielded -Newest Type for Welding -Newest Type for Welding in all-positionin all-position

TYPICAL APPLICATIONSTYPICAL APPLICATIONS

For Joining Similar MaterialFor Joining Similar Material For Cladding & Overlay WeldingFor Cladding & Overlay Welding For Corrosion Resistance ApplicationFor Corrosion Resistance Application For Cryogenic ApplicationFor Cryogenic Application For Dissimilar Metal WeldingFor Dissimilar Metal Welding

METAL COREDMETAL CORED

Deposition Efficiencies : 98%Deposition Efficiencies : 98% Shielding Gases : 98% Ar 2% O2Shielding Gases : 98% Ar 2% O2

95% Ar 5% CO295% Ar 5% CO2 Higher Deposition Rates Than Solid WireHigher Deposition Rates Than Solid Wire

Types Commonly Available: 409 TiTypes Commonly Available: 409 Ti

410410

430430

439439

SELF- SHIELDED CSS AWS 5.22SELF- SHIELDED CSS AWS 5.22

Application :Joining & CladdingApplication :Joining & Cladding Deposition Efficiencies : 75 - 85 %Deposition Efficiencies : 75 - 85 %Increasing the Voltage Increase N2 LevelIncreasing the Voltage Increase N2 Level at a Constant Current Decrease Ferriteat a Constant Current Decrease FerriteIncreasing Electrode Extension Decreases N2 LevelIncreasing Electrode Extension Decreases N2 Level at a Constant Current Increases Ferriteat a Constant Current Increases FerriteTypes Generally availableTypes Generally available E 307T-3 E309T-3E 307T-3 E309T-3 E308MoT-3 E316LT-3E308MoT-3 E316LT-3 E308LT-3 E 347T-3E308LT-3 E 347T-3

DOWNHAND GAS SHIELDED CSS DOWNHAND GAS SHIELDED CSS AWS 5.22AWS 5.22

Deposition Efficiency : 87 - 92%Deposition Efficiency : 87 - 92% Shielding Gases : 100 % CO2Shielding Gases : 100 % CO2 75% Ar & 25% CO275% Ar & 25% CO2 ADVANTAGESADVANTAGES Faster Travel Speeds Than Solid Wire Faster Travel Speeds Than Solid Wire Spray Arc TransferSpray Arc Transfer Low SpatterLow Spatter Fine Rippled BeadFine Rippled Bead Self Releasing SlagSelf Releasing Slag

ALL-POSITION GAS SHIELDED ALL-POSITION GAS SHIELDED CSSCSS

Deposition Efficiencies : 86 -90%Deposition Efficiencies : 86 -90% Shielding Gases : 75% Ar & 25% Co2Shielding Gases : 75% Ar & 25% Co2

100% CO2100% CO2 Fast Freezing Slag SystemFast Freezing Slag System High Current Levels For Welding in the Vertical & High Current Levels For Welding in the Vertical &

Overhead PositionOverhead Position

Types AvailableTypes Available

E 308Lt-1 E317LT-1E 308Lt-1 E317LT-1

E309LT-1 E309MoLT-1E309LT-1 E309MoLT-1

E316LT-1 E347LT-1E316LT-1 E347LT-1

MMAW ELECTRODE -CONSTITUENTS & MMAW ELECTRODE -CONSTITUENTS & THEIR FUNCTIONS```THEIR FUNCTIONS```

CONSTITUENTS

IRON OXIDETITANIUM DIOXIDEMAGNESIUM OXIDECAL. FLOURIDEPOT. SILICATEOTHER SILICATES

CAL. CORBONATEOTHER ORBONATESCELLULOSEFERRO MANGANESEFERRO CHROMEFERRO SILICON

PRIMARY FUNCTION

SLAG FORMERSLAG FORMERFLUXING AGENTSLAG FORMERARC STABILISERSLAG FORMER &BINDERGAS FORMERGAS FORMERGAS FORMERALLOYINGALLOYINGDE-OXIDISING

SECONDARY FUNCTION

ARC STABILISERARC STABILISERNILFLUXING AGENTBINDERFLUXING AGENT

ARC STABILISERNILNILDEOXIDISERNILNIL

SHIELDED METAL ARC WELDING-SMAWSHIELDED METAL ARC WELDING-SMAWSTICK/MANUAL/MMAWSTICK/MANUAL/MMAW

AdvantagesAdvantages Variety of Electrodes with Different featuresVariety of Electrodes with Different features Most versatile -All Positional Joints /Joints with Most versatile -All Positional Joints /Joints with

Limited AccessLimited Access Suitable for most AlloysSuitable for most Alloys Equipment Simple ,Portable & InexpensiveEquipment Simple ,Portable & Inexpensive DisadvantagesDisadvantages Finite LengthFinite Length High dependence on Welders SkillHigh dependence on Welders Skill Not Amenable to AutomationNot Amenable to Automation

TYPES OF SLAG SYSTEMTYPES OF SLAG SYSTEM

AcidAcid

BasicBasic

Metal cored Metal cored

Rutile Basic (Semi- Basic)Rutile Basic (Semi- Basic)

SELECTING A WELDING PROCESSSELECTING A WELDING PROCESS

Available Forms of Filler Metal NeededAvailable Forms of Filler Metal Needed Available Welding EquipmentsAvailable Welding Equipments Dimension of the WeldmentsDimension of the Weldments Number of Pieces to be WeldedNumber of Pieces to be Welded

SOURCE OF HYDROGEN IN WELDSOURCE OF HYDROGEN IN WELDWelding Consumables Welding Consumables Moisure in Flux (SAW)Moisure in Flux (SAW)

Excess Lubricant on Electrodes (FCAW Excess Lubricant on Electrodes (FCAW &GMAW)&GMAW)

Moisure / Hydrogen in Shielding Gas (FCAW Moisure / Hydrogen in Shielding Gas (FCAW &GMAW)&GMAW)

Moister in Coating (SMAW) Moister in Coating (SMAW) Moister in Fluxing Ingredients (FCAW)Moister in Fluxing Ingredients (FCAW)

Work PieceWork PieceMoisture ,Oils .Rust . PaintMoisture ,Oils .Rust . Paint

Ambient ConditionsAmbient Conditions

EFFECTS OFEFFECTS OF

HHYDROGEN ON STEELYDROGEN ON STEEL Porosity /Worm TrackingPorosity /Worm Tracking

Loss of DuctilityLoss of Ductility

Hydrogen CrackingHydrogen Cracking

SELECTION OF PROPER GASSELECTION OF PROPER GAS Material TypesMaterial Types

-Carbon ,Stainless , Aluminium ,Etc-Carbon ,Stainless , Aluminium ,Etc Material ConditionMaterial Condition

- Rusty ,Oily , Primed , Etc- Rusty ,Oily , Primed , Etc Types Of Metal TransferTypes Of Metal Transfer

- Short Circuit ,Spray , Pulse , Etc- Short Circuit ,Spray , Pulse , Etc Weld Metal Mechanical PropertiesWeld Metal Mechanical Properties Job RequirementsJob Requirements

- Fit- Up- Fit- Up

- Penetration- Penetration

- Spatter Levels- Spatter Levels

PROPER SELECTION OF PROPER SELECTION OF CONSUMABLESCONSUMABLES

Base Material StrengthBase Material StrengthBase Material CompositionBase Material Composition

Welding Position Welding Position Joint Design &Fit-UpJoint Design &Fit-Up

Thickness & Shape of MaterialThickness & Shape of MaterialService Condition & /or SpecificationService Condition & /or SpecificationProduction Efficiency & Job ConditionProduction Efficiency & Job Condition

SELECTION CRITERIASELECTION CRITERIA

Chemical & Mechanical PropertiesChemical & Mechanical Properties Commercial Availability of ProductCommercial Availability of Product Suitability for Restraint Welds -Hydrogen Suitability for Restraint Welds -Hydrogen

Level in Weld MetalLevel in Weld Metal Type of Gas Shielding to be usedType of Gas Shielding to be used Feasibility of ApplicationFeasibility of Application Cost FactorCost Factor

COSTINGCOSTING

FIXED COSTFIXED COST

Joint PreparationJoint Preparation

FixturingFixturing

TackingTacking

PreheatingPreheating

CleaningCleaning

InspectionInspectionRs

Costing

COSTINGCOSTING

Power & 2-5% Power & 2-5% EquipmentEquipment

Electrode Electrode

Cost 8-15 %Cost 8-15 %

Labour & 80-85 %Labour & 80-85 %

Overhead CostOverhead CostLABOUR &OVERHEAD

POWER &EQUIP.

ELECTRODECOST

Costing

INCREASED WELDING PRODUCTIVITY

REDUCED WELDING COST

Costing

ELECTRODE EFFICIENCYELECTRODE EFFICIENCY & STUB END LOSS & STUB END LOSS

DATA ON EFFECT OF STUB END LOSSESDATA ON EFFECT OF STUB END LOSSES

TYPE -E7018 ELECTRODESTYPE -E7018 ELECTRODES

EFFICIENATY AT 50 mm STUB LOSS -70 %EFFICIENATY AT 50 mm STUB LOSS -70 %

EFFICIENATY AT 75 mm STUB LOSS -64.5%EFFICIENATY AT 75 mm STUB LOSS -64.5%




450mm

WELD METAL COST FORMULAS

1 Labour & Labour & Overhead Cost/HrOverhead = ---------------------------------------- Deposition Operating Rate (Kg/Hr) X Factor

Electrode Cost / Kg2 Electrode: = ---------------------------------

Deposition Efficiency

Gas Flow Rate Cu.Meters/ Hr. X Gas Cost / litre

3 Gas = ------------------------------------ Deposition Rate (Kg/Hr)

Flux Cost/kg X 1.44 Flux = -------------------------------------

Deposition Efficiency

Cost Rs/KWH x Volts x Amps5 Power Cost = ----------------------------------

1000 X Deposition Rate (kg/Hr)

Total Cost per kg = Sum of 1-5 , Aboveof Deposited Weld Metal

WELD METAL COST WORKSHEET

FCAW AS COMPARED TO SMAW - WELDING POSITION - FLAT

CALCULATING COST CAL. COST CAL FCAWCOST PER KG FCAW SMAW Vs. DEP. WELD E 71T-1 / 1.6 DIA. E 7018 / 5mm SMAW

AT 300 A/28 V AT 250 A/28 V * COST RED.-

Labour & Overhead 150/5X0.45 66.67 150/2.5 X0.30 200 -133.33

Electrode: 150/0.87 172.4 60 /0.65 92.3 80.4

Gas 990 x 0.04 /5 7.92 NA 7.92

Power Cost 4 x 300 x 28 / 4 x 250 x 28 / 1000 x 5 6.72 1000 x 2.5 11.2 -4.48

Sum of Total Variable 253.7 Total Variable 304 -49.29

the Above cost/kgDeposite Cost/kg Deposite :

Rework at 3% at 15%

COST 253.72 /0.97 261.56 303.51 /0.85 357 -95.54

Basic Cost Saving per Kg with FCAW =49.29Actual Cost Saving pr Kg with FCAW =95.54

HOW WELDING SMARTER SAVED 120,000 HOW WELDING SMARTER SAVED 120,000 MAN-HOURSMAN-HOURS

Walking Dragline - 12,000 MT WeightWalking Dragline - 12,000 MT Weight Boom Height : 95 MBoom Height : 95 M Hoist Depth : 55 MHoist Depth : 55 M Bucket Load :325 MTBucket Load :325 MT Cylindrical Steel BaseCylindrical Steel Base 32 M Dia. 2.5 M Wide & 140 MT Weight32 M Dia. 2.5 M Wide & 140 MT Weight Replacement of the BaseReplacement of the Base Estimated 160,000 Man- Hour with SMAW(80 Estimated 160,000 Man- Hour with SMAW(80

Months)Months) Estimated 40,000 Man- Hour with FCAW (20 Estimated 40,000 Man- Hour with FCAW (20

Months)Months)

32M

2.5M

Wedge Shaped Segments Make Up Dragon Base

150 mm

SS FCAW TO RESCUE OF ASPRIN MAKER’S HEAD ACHE

SS Half Coil Reactor Found Leaking.

Leak Spots Identified as likely restart points in OH Position.

Small Dia. SS FCAW made it possible to reduce restart points

Better approach made improved Fusion Possible.

HALF COIL

ONE MINUTE WELD VERTICAL UP POSITION-6MM FILLET

One Minute Welds made using SMAW 3.2mm –70mm, GMAW-0.9mm –105 mm FCAW 1.2mm –300 mm

Cost aspect based on above productivity.

FCAW SMAWGMAW

9001300

2900

DEP. COST PER KG

CO

ST

IN

RS

. LABOUR &OVERHEAD-RS.500

SMAW

FCAW

GMAW

PROCESS SHARE FOR VARIOUS PROCESS SHARE FOR VARIOUS COUNTRIESCOUNTRIES

INDIA USA

SMAW80%

SMAW35%

GMAW55%

SAW8%

GTAW2%

SAW 8%GMAW

10%

GTAW 2%

GTAW

SMAW

SAW

GMAW

GTAW

SMAW

SAW

GMAW

EUROPE JAPAN

GMAW60%

SMAW30%

SAW8%

GTAW 2%

SMAW20%

GTAW 2%

SAW8%GMAW

70%

GLOBAL PROCESS SHARE GLOBAL PROCESS SHARE OF WELD METAL OF WELD METAL

JAPANJAPAN EUROPEEUROPE USAUSA INDIAINDIA

SMAWSMAW 20%20% 30%30% 35%35% 80%80%

SAWSAW 8%8% 8%8% 8%8% 8%8%

GTAWGTAW 2%2% 2%2% 2%2% 2%2%

GMAWGMAW 70%70% 60%60% 55%55% 10%10%

PROCESS SHARE IN GLOBAL PERSPECTIVE

Steady Increase in Solid & Core Wire Consumption

Covered Electrode Consumption will Decline & Stabilise around 30%

In Developed Countries, CO2 Welding Accounts for more than 50%

In Developing Countries like China & Korea CO2 Process Share is already around 15%