paresh jadav 23

8/7/2019 PARESH JADAV 23

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EXPERIMENT NO: 1 Dt: ____________

LEHIGH RESTRAINT TEST

Aim:

To study about Lehigh restraint welding test.

Apparatus/Equipment/ Required:

- Welding machine (SMAW)

- Electrode E-7018

- Work piece (300 X 200 mm)

- Safety equipment

Consumables:

- Electrode E-7018

Material Required With Size:

- M. S. Plate (300 X 200 mm)

Defination of Restraint:

- A measure of condition that keeps something under control of within limits.

The action of keeping someone or something under control.



Theory:

y The le high restraint test has been found to be particularly useful for quantitatively

rating. The crack susceptibility of weld metal as affected by the electrode.

y Slots are cut in the sides and ends of the specimen as shown. By changing thelength of the slots the degree of plate resistant is varied from one specimen to

another.

y The groove is filled with and electrode using knows current and welding speed for

the root bead or for each pass.

y In this manner a controllable severity of restraint can be imposed on the root bead

for root cracking test.

y The weld cross-section is subjected to macro examination to observe weld metal

crack formed if any.

Figure:



Reading Table:

SR.

NO.SLOT NO.

DIMENSION

BEFORE

WELDI NG

DIMENSION

AFTER

WELDI NG

REMARKS

Result Analysis:

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Conclusion:

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Signature



EXPERIMENT NO:2 Dt: ____________

JOMINY TEST

Aim:

-To determine the harden ability of test piece by Jominy test.

-The jominy test is covered by BS 4437: 1987.

Apparatus:

- MS round bar 2inch dia. x 4 inch long.

Equipment:

1. Furnace

2. water jet

3. Rockwell hardness testing machine

4. Fixture

5. Thermo stick

Hardness Testing Theory:-y

Hardness tests measure the resistance to penetration of the surface of a material bya hard object. The

y Depth of penetration is measured by the testing machine and converted to a

hardness number. C-Scale

y Rockwell Hardness (HRC) numbers can be converted to Brinell Hardness (HB)

numbers and then used to

y Approximate the tensile strength in steels.

Procedure:

y Preheat the oven to 1500°F (816°C).

y Check that the Jominy Test Set-Up tank is full of room-temperature water.

y Adjust the water spout height on the Jominy Test Set-Up to 2 and 1/2 inches above

the final resting

Position of the Test-Bar bottom when placed in the specimen fixture.



y Properly place the specimen fixture directly over the water spout of the Jominy

Test Set-Up with the

y Fixture center placed directly above the water spout center. Practice rapidly

placing a cool sample into

y The fixture before proceeding.

y Remove the Jominy Sample from the oven with the oven tongs and place it in the

Jominy Fixture as

y Quickly as possible.

y Let the Test Bar cool to room temperature (approximately 20 to 30 minutes) then

turn off the water.

y Each group of 2-3 students must check out the lab session¶s Jominy Test Bar from

the lab instructor

y And grind a flat onto the curved surface of the lab session¶s Jominy Test Bar. All

Scale (oxide) on the

y Flat should be removed such that a shinny, smooth flat results. Try to remove the

minimal amount of

y Material to obtain a shinny flat!

y Using a pencil, clearly mark the positions along the bar on the ground flat at the

distances from the

y Test Bar End as indicated on the blank Jominy End-Quench Data Sheet.

y Take a single set of Rockwell C hardness measurements along the bar on the

ground flat at the

y Distances marked in Step 8; record the values on the data sheet.

y Return the Jominy Test Bar to the lab instructor

Harden ability: Jominy End-Quench Testy Harden ability refers to the relative ability of a steel to be hardened by the

formation of martensite. The

y curves shown in Figure 3 are Harden ability Curves produced from Jominy End

Quench Tests where water is

y Sprayed on the end of a heated steel bar. Note the following:

y the 5140 steel is only hard near the quenched end (low harden ability)y the 4340 steel is relatively hard all along the bar (high harden ability



Figure:

Continuous Cooling Transformation (CCT) Diagrams



Hardenability Curves For Some Common Alloy Steels.

Ultimate Tensile Test For Steel Parts.



Result Analysis:

Conclusion:

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Signature



EXPERIMENT NO.3 Dt: ____________

T-TEST JOINT CRACK TEST

Aim: To perform the T-joint crack test

Equipment required:

1. SMAW machine

2. Hand glows

3. Screen guard

4. Wire brush

5. Cleaner

6. Penetrant

7. Developer

Consumable:1. Welding electrode- E7018

Material size:250 mm X 40 mm x 10 mm

Qty: 2 pieces

Concept:

(i) Testing the weld ability of a material with a certain electrode type mainly with

regard to the risk of hot cracks,

(ii) Testing the suitability of an electrode for welding fillets in a given material.

The T crack test is often used to compare the crack resistance of different types

of electrodes.

(iii) The stresses generated by the contraction of the first bead are imposed on the

second bead during deposition. Cracks formed, if any, in the second bead give

an idea of the tendency towards hot cracking.



Definition of Hot Crack

³Hot cracks are intercrytsalline micro-cracks formed at high temperature in the

immediate vicinity of the fusion line as the molten weld metal is solidifying´

How the Hot Crack produce?

y Hot cracks occur when the weld metal contains low-melting non-metallic

inclusion.

y The welding heat produces thin films of liquid on the austenitic grain boundaries

in the heat affect zone, derived from the low melting portion of the non metallic

inclusion.

y As the weld cools, the austenite grains undergo plastic deformation as a result of

growing tensile stress.

y The film low-melting non metallic inclusion is unable to absorb the deformation,

resulting in what is known as Hot Cracking

Remedies of Hot Crack

Hot cracking can be minimized by

y Using standard weld able steels

y Ensuring that the weld metal gives Mn/s ratio of over 14

y Reduce the temparture

Figure:

Procedure:

1) The material to be tested is cut into pieces

2) The pieces are tack welded to each other

3) The test piece is placed so that welding will be carried out in the flat position.



4) The first side is welded and after that the test piece is turned.

5) The fillet weld on the other side is immediately deposited without waiting to deslag

the first bead.

6) The fillet weld on the other side is immediately deposited without waiting to deslag

the first bead

7) After fillet weld on the other side wait for weld metal is solidify.

8) Done the liquid penetrant test on the weld metal.

9) Check that any hot crack is formed or not.

10) If any crack found take the photograph of it and measure the size.

Reading Table:

Sr no. Electrode Test perform Crack size Remark

12

3

4

5

Result analysis:

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Conclusion:

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Signature



Transverse Contraction Can Be Prevented By:

1. Proper tack welding

2. Placing a wedge between the plates.

3. Separating the plates (before welding) to provide allowance about 1 mm/100 mmof weld) for contraction.

4. Increasing the arc travel speed.

Figure:

Fig. Transverse Distortion



Transverse Shrinkage Calculation:-

1= -0.35 x q x x 150

VA Cp

= -0.35 x 4 x 0.8 x 3.1X150X0.56

6 X 10

= 0.05 MM

Where, q= Heat input rate (w or j/s)

P = Welding Speed (M/S)

T = Thickness (m)

Cp=Volumetric thermal capacity (j/m )

= Co-Efficient of expansion



Procedure:

1. Collect the work piece as req. dimension

2. Prepare 10 m.s work piece WEP

3. Weld those piece differently4. Measure the distance with the standard formula

5. Also measure the hardness at three diff. place

- At base metal

- At HAZ

- At Weld metal

Calculation:

Figure:



Before W.E.P calculation:-

Area= l x b

= 125 x 25

= 3125 mm²

Volume = l x b x h

= 3125 x 6

= 18750 mm

= 18.75 cm

Weight = volume x density

= 18.750 x 7.86

= 147.37 gm

Total 2 piece weight = 147.37 + 147.37

= 294.75 gm



After W.E.P weight calculation:

120° angle

Tan 60 = x

a.s

x = tan 60 x 5

x = 8.5 mm

Area of triangle = ½ x b x h

= ½ x 8.5 x 5

= 21.25 mm²

Volume = area x h

= 2125 x 125

= 2656.25 mm


Weight = 2.56 x 7.86

Weight = 20.87 gm

2 piece weight after W.E.P = 20.87 + 20.87

= 41.75 gm



Electrode weight Calculation:-

120° angle = 400 - 60 (un-used size)

= 340 mm

90° angle = 400 - 90

= 310 mm

60° angle = 400 ± 100

= 300 mm

45° angle = 400-105

= 295 mm

30° angle = 400-120= 280 mm.

Weight calculation:

120° angle = /4 x d² x l

= 0.785 x 3.15² x 340

= 2623 mm

= 2.62 cm


= 2.62 x 7.86

= 20.61 gm



Heat input Calculation:

Heat input = v x amp

100 x travel speed

= 22 x 900.62

= 31.93 j/sec

Weld Metal Calculation:

Tan 60 = x

a.s

x = tan 60 x 5

x = 8.5 mm

Area of triangle = ½ x b x h

= ½ x 8.5 x 5

= 21.25 mm²

Volume = area x h= 21.25 x 125

= 2656.25 mm

= 2.65 cm ««««««.. (1) & (2)

Volume rectangle = l x b x h

= 125 x 1 x 6

= 750 mm²= 0.75 cm ««««««« (2)

Total Area = 2.56+2.56+0.75

= 5.87 cm




= 5.87 x 7.86

= 46.13 gm «««««««««««. Ans

Reading Table:

Table no:1

Sr

NoAngle Weight Of Test Piece Diff

Electrode

(3.15x400 Mm)

Weld

Metal

Cal.

Diff.

After

W.E.P

Weight

+ Elec.

Weight

(gm)

Act.

Weig

ht

After

Weld.

(gm)

Diff.

BEFOREW.E.P

(Gm)

AFTER W.E.P

(Gm)

USE

(MM)WEIGHT

1 120° 294.75 253 41.75 340 20.61 46.13 -25.52 273.61 274 0.39

2 90° 294.75 270.19 24.56 310 18.98 30.41 -11.43 289.17 314 -24.8

3 60° 294.75 282.47 12.28 300 18.37 18.75 0.38 300.84 280 20.84

4 45° 294.75 284.93 9.82 295 18.00 15.64 2.36 302.93 292 10.93

5 30° 294.75 289.85 4.90 280 17.14 10.77 6.37 306.99 298 8.99

Table no: 2

Sr.no Angle Hardness Heat input

B.M W.M HAZ

1 120° 31.93

2 90° 39.02

3 60° 39.53



4 45° 48.29

5 30° 40.68

Result analysis:

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Conclusion:

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Signature



EXPERIMENT NO. 5 Dt: ____________

TENSILE TESTING

Aim:

- To determine tensile properties such as tensile strength yield point or yield strength

and modulus of elasticity.

Equipment:

y Standard test piece

y Venire caliper

y Universal testing m/c

y Centre punch

y Hammer

y Marker pen

Figure:



Sr no. Specification Standard

specification

Remarks

1 G- Gauge length 200 (0.25)

2 w- width 40(+3,-6)

3 T- thickness

4 R- radius of fillet 13

5 L- overall length 450

6 B- length of grip section 75

7 C- width of grip section 50

8 A-length of reduction section

Test Procedure:

y Tensile test is carried out by gripping the end of the specimen in a tensile testing

machine and applying and increasing poll on to the specimen till it fracture.

y During the test, the tensile load as well as the elongation of a previously marked

gauge length in the specimen is measured with the help of load dial of the machine

and extensometer respectively these readings help plotting stress- strain curve as

shown fig.

y After fracture the two pieces of the broken specimen are placed as if fixed together

(fig.) and distance if between two gauge marks and the area of at the place of

fracture are noted.



Sr.

no.

Tensile Properties Equation value

1 Yield strength Load at yield point

AO

2 UTS UTS Load P max.AO

3 % Reduction in area Ao ± Af x100

AO

4 % Elongation Lf ± Lo x 100

AO

Where, P = load at any point up to the elastic limit

Lo = gauge length

Ao = original area

Lf = final length

Af = final length (After the specimen break)

Result Analysis:

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IMPACT TEST

Aim:

y To determine the behavior of welds, when subjected to high rates of loading,usually in bending.

y The purpose of impact testing is to determine the amount of impact a specimen

will absorb before fracturing.

Figure:

Test Procedure:

y The swinging pendulum weight is raised to standard height depending upon the

type of specimen to be tested.

y With reference to the vise holding the specimen, the higher the pendulum, the more

potential energy it has got.

y As the pendulum is released its potential energy is converted into kinetic energy

until it strikes the specimen.

y The charpy specimen is hit behind the v notch while the izod specimen, placed

with the v notch facing the pendulum, will be hit above the v notch.

y A portion of the energy possessed by the pendulum is used to rupture the specimen

and the pendulum rises on the other side of the impact testing machine.

y He energy consumed in breaking the specimen is the weight of the pendulum times

the difference in two heights of pendulum on either side of the machine.

y This energy is foot-pounds or meter-kg is the notched impact strength and can be

read from the dial of the impact testing machine.



Reading Table:

SR.NO. REPORT VALUE

1 nature of specimen

2 Testing temperature

3 Energy absorbed

BASIC TERMINOLOGY

Toughness:

y Toughness is the ability of the material to absorb energy during plastic

deformation up to fracture.

Plasticity:

y Plasticity is that property of material by virtue of which it may be

permanently deformed when it exceed the elastic limit. has been

subjected to an externally applied force great enough to exceed the

elastic limit.

Tensile Strength:

y In a tensile test the ratio of the maximum load to original cross section

area is called tensile strength.

Yield Strength:

y When metals are subjected to a tensile force they stretch or elongate asthe stress increases. The point where the stretch suddenly increases is

known as the yield strength of material.



Elasticity:

y All solid materials can be deformed when subjected to external load. It is

further found that up to certain limiting loads a solid will recover it is

original dimension when the load is removed the recovery of the

original dimensions of deformed body when the load is removed is

known as elasticity.

Ductility:

y It is measure of the deformability of the material, determined by the

percentage of elongation or reduction of area.

Resilience:

y The ability of material to absorb energy when deformed elastically and

to return it when unloaded is called resilience.

The Difference Between Ductile And Brittle Material

y The material which elongates more than 5% before fracture is called

ductile material otherwise brittle material. Gold, silver, copper aretypical example ductile materials, and cast iron, concrete are brittle

material. In failure theory yield strength is used for ductile material,

where as ultimate strength used for brittle material.

Conclusion:

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Signature




VARESTRAINT TEST

Aim:

- To determine the susceptibility of hot cracking occurrence in heat affected zone

(HAZ).

Equipments:

- GTAW machine, Welding torch, Tungston electrode

- Press machine

Material Required:

- Stainless steel (SS 304)

152mm x 25mm x 3mm (2 NOS.)

- Bolts & Nuts (M.S)

- Angle bar (C-Mn steel)

Theory:

- The varestraint test is general applied to understand micro crack after GTA

welding.

- It is developed especially to estimate hot cracking susceptibilities and micro

fissures occurrence in HAZ.

- The term micro fissures applied to small-scale micro cracks that cannot be

detect even using NDT method.- Therefore, the HAZ cracking susceptibility of super alloy and titanium alloy

are evaluated using the varestraint (weld ability) test.

- The VWT allows material developers and end users to evaluate a given

alloys weld ability with a simple and well accepted procedure.



Procedure:

- First of all prepare the specimen having the size of 152mm x 25mm x 3mm

as shown in figure.

-

After the preparation of sample clean it in order to free from burr, oil dustand dirt.

- After the cleaning is over place the sample in fixture.

- Now apply the load in just middle of the block (HAZ) with a press ram.

- End curvature radius (), deformation is selected between 0.07-0.25 and

radius (r) calculated from the equation no 1.

= t/2r

Where,

= Deformation

t = Sample thickness

r = Press ram radius

Reading Table:

SR NO. DEFORMATION () APPLIED LOAD (P)

1

2

3

4

152 mm

25 mm

3 mmweld



Result analysis;-

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Conclusion

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Signature



EXPERIMENT NO. 7 Dt.____________

LONGITUDINAL DISTORTION

Aim: To calculate longitudinal distortion.

Equipment Requirement:

1. Welding machine 5. Chipping hammer

2. Right angle 6. Wire brush

3. Steel scale 7. Safety equipment

4. Measuring tap

Consumable Requirement: E-7018

Material Requirement: carbon steel (6mm x 40mm x 250mm)

Theory/Concept:

Definition: Undesirable change in original shape is called as distortion.

Concept:

As a metal are heated they expand and when cooled they contract.

During welding heating and cooling of metals occurs universally resulting in

high stresses and the metal distorts (deform).

If the high stresses pass the elastic limit and go over the yield point, some

permanent distortion of the metals will occur.

A metal yield stress is reduced at high temperature.

Distortion is the result of uneven expansion and concentration of heated metals.

Metallurgical Aspect:

During most of the welding, filler metal is added from the electrode.

The molten filler metal and melted base metal combine to form the weld metal.



Just as the weld metal solidifies, it is in its maximum expanded state actually

occupying the greatest volume it can occupy as a solid.

Upon cooling, it attempts to contract to the volume it would normally occupy at

the lower temperature, but is restrained from doing so by the adjacent base

metal. At the time the weld reaches room temperature assuring completed restraint of

the base metal so that it cannot move the weld tends to have locked in tensile

stresses approximately equal to the yield strength.

If one or more of the restraint are removed such as clamps holding the work

piece the locked in stresses find partial relief by causing he base metal to move

thus deforming of distorting the weldment.

y There are three type of distortion:

Transverse

Angular

Longitudinal

Longitudinal Distortion:

When a weld is deposited lengthwise on al light, narrow and perfectly flat strip

of metal that is neither clamped nor held in any way, the strip will tend to bow

upward in the direction of bead.

This is due to the longitudinal contraction of the weld metal as it cools.

Longitudinal contraction is maximum along the weld centre line and decrease

towards the edges.

High current-large size electrode maximum distortion

An in-between situation maximum distortion

Low current-small size electrode minimum distortion

Longitudinal distortion depends upon:

1. Contraction forces.

2. Stiffness of the section being welded.

3. Distance between the centroids of weld and section.



Causes of distortion

- Distortion is caused by the unequal heat and cooling at a metallic body

during welding.

- Distortion is also caused by construction of the weldmetal during

solidification and cooling to room temperature.

- The construction of the surrounding parent metal as it cools from high

welding temperature, when these portion contract, they try to pull the parts

together and the result is distortion.

Remedies of distortion

- Use minimum weld metal avoid overwelding.

- Use correct fit-up. Avoid wide bevels and wide root gaps.

- Use correct sequence.

- Control the shape and size of component being welded.

- Try to present the parts correctly before welding whenever this is possible.

- Distortion is minimized by depositing minimum number of runs using the

heaviest electrode possible.



Procedure:

First of all take two work piece of carbon steel plate (6mm thickness).

Arranged parallel plane with 2mm root gap.

Set current & voltage in welding machine. Feed the earthling clamp on the plane on which our work piece are lying.

Increase the current from its required Range.

Now start the welding and complete a one whole pass.

After that observe the longitudinal Contraction on the welded joint with the

scale and compared calculation contraction.

Result Analysis:

Calculate distortion

= q vA cp

Where, q = heat input rate (V*A/100*S)v = welding speed ( 3.40mm/sec)

A = total cross sectional area (480mm²)

cp = volumetric thermal capacity (mm /J)

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Reading Table:

Before welding length After welding length Contraction

Conclusion:

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Signature



EXPERIMENT NO: 8 Dt ____________

CIRCULAR PATCH TEST

Aim:y A Circular patch test was selected to evaluate sensitivity to hot crack formation of

the weld.

Apparatus/Equipments required:y Scale

y Marking tools y Drilling machine with tools

y Welding machine with power source

Consumable required:y E 7018 (2.5mm Ø)

Figure:



Material with size:

y MS Plate with size having 50 x 50 x 6mm ( Ø20 mm)

y MS round bar patch with 6mm thk ( Ø18 mm)

Theory/Concept:

y A circular patch test (CPT), was selected to evaluate sensitivity to hot crack

formation of the welds.

y The materials samples for evaluation were; 6 mm thick mild steel plate, and a 2.5

mm diameter AWS classified electrode

y Welding parameters used during welding of the CPT samples covered the range of

parameters recommended in the welding procedure specifications (WPS).

y A sample foe CPT consists of a plate 50 x 50 x 6 mm with a central hole of 20 mmdiameter.

y A disc of 18 mm diameter with a center hole of 6 mm diameter fits into the plate

hole.

y Both the plate and disc were made with of the same plate supplied for the testing.

y The edge of the hole in the sample plate and outer edge of the disc were prepared

in such a way that square butt or single Vee welds could be completed.

y The amount of restraint in the CPT welds decreases with increases radius of a

circular weld, root gap of the weld and decreased heat input.

y Both square butt and single Vee weld configuration welds were used in weldingtests.

y In addition to these, a single Vee weld in the upside down position was used to

simulate a penetration weld made from the other side of the plate.

y This was thought to simulate the bottom part of the single Vee welds made during

simultaneous welding from both sides.

HOT CRACK:

y The weld metal solidification starts from the fusion line towards the centre line of

the weld and in this process, concentrations of alloying elements and impurities are

pushed ahead of the inward growing crystals or dendrites.

y Solidification cracking is caused in the weld metal itself by tearing of the grain

boundaries before complete solidification has taken place and while the metal is

still in the plastic state.



CAUSES OF HOT CRACK:

y High current density

y Weld metal composition having wide freezing range.

y The distribution of heat and hence stresses in the weld metal itself.

y Impurities such as S and C or Ni content and those which form low freezing point

liquid films.

y Joint restraint and high thermal severity.

y Crack sensitivity of the electrode.

y Dilution of weld metal

REMEDIES:

y Proper current setting

y Dilution control

y Control of impurities

y Proper Heat input

Procedure:

y A circular hole is cut into the plate.

y A patch is fitted to create a circular weld groove.

y A weld bead is deposited along the circular configuration.y Welding stresses developed in the weld metal may give rise to cracking.

y Restraint can be varied in a given plate thickness by adjusting the

(i) plate size

(ii) patch diameter



Reading table:

Test No. Current (A) Voltage (V)

Edge

Preparation

Crack

(Y/N)

Crack

Length

Result analysis: ________________________________________________________________________

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Conclusion:

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Signature




CONTROLLED THERMAL SEVERITY TEST

Aim:

y To check weld ability of steel by controlled thermal severity test (CTS TEST)

Apparatus:

(1) Drilling machine

(2) Welding machine(3) Chipping hammer, wire brush

(4) Microscopic telescope

Consumable required:

(1) Electrode

(2) Penetrant, Developer & C leaner

Material required:

(1) Bottom plate 175 X 100 X 8

(2) Top plate 75 X 75 X 8

(3) Nut & Bolt M12 X 40L (All dimension are in mm)

Theory:

y The CTS test is based on principle of the fillet weld joint. Particularly for accessingweldability in relation to steel welded by arc welding process for establishing safe

welding process for low alloy steel.

y Armour steels are generally low alloy steel which are hardenable. Steel develop

high hardness with adequate fracture toughness. Hence a fine balance should be

maintained in the chemistry of the steel and its heat treatment, as told earlier the



steel had passed all the ballistic tests and what was required to be proved was that

the steel can be welded

y High hardness steels are susceptible for what is called underbead cracking. These

cracks are buried cracks which develop under the weld bead and extremely

dangerous since they are not detected after welding and generally take some timeto develop. Three conditions are essential for this type of cracks to develop.

y There must be hydrogen in the weld. This hydrogen comes from the coating on the

electrode or from some external agent such as grease or oil used for preserving the

steel

y Tensile stress must be present in the welded structure

y There should be susceptible microstructure, that is microstructure such as marten

site

Figure:



Procedure:

y First take the bottom plate whose dimension are 175 X 100 X 8 thickness whose

cutting is require to give accurate dimension

y Then cut another rectangular plate of dimension are 75 X 75 X 8 thickness

y Drill both the plate which will come pass through similar to both of plate. Drill size

is dia 12mm.

y Then put both the plate on each other and weld in opposite site which is known as

the anchor welds.

y After the anchor weld we weld the second joint which is known as bi-thermal

weld joint.

y Finally join the plate with tri-thermal welded joint and complete the all assembly

y Then perform the D.P test. Then clean the weld and slightly grind it and with a

sequence of D.P. procedure take the D.P. test.

y Finally with the help of microscopic telescope see the crack which will occur in

welding or HAZ

Table no. 1

Sr.

No.

Seam

no.

No. of

layer

Welder

name

Welder

qualification

position current

1 A1 2

2 A2 2

3 T1 1

4 T2 1



Table no. 2

Voltage Electrode

Material

Electrode

Size

Travel speed

(mm/min)

Crack size

(mm)

Remark

Result Discussion:

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Conclusion:

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Signature



EXPERIMENT NO. 10 Dt: __________

IMPLANT TEST

Aim:

y It is aimed at providing a quantitative evaluation of the influence of restraint

on cold cracking sensitivity of weldments.

Figure:

Apparatus / Equipment Requirement:

- Cylindrical notched specimen.

- Welding machine.

Consumable Required:

- Electrode

- Power



Material Required With Size:

- C.S round bar (8mm dia. 150mm length)

- C.S backing plate (120mm X 120mm)

Theory / Concept:

y The implant cracking test applies a known stress to a real heat affected zone

(HAZ) and can thus asses the susceptibility to HAZ hydrogen cracking by

means of a mechanical test parameter.

y An attractive feature of the implant test is that it needs only a small quantity

of the steel to be tested; just enough to machine out a specimen of 8mm dia

and with a maximum length of 150mm.

The Implant Test Procedure:

1. The implant cracking test uses a cylindrical sample called implant made of steel

under investigation which is notched at some distance from one of its ends.2. This notched steel sample is inserted in to a hole drilled in a backing plate of the

same or a comparable grade of steel, so that the notched end is flush with the plate

surface.

3. In order to execute the test a weld bead is deposited on the plate in one pass under

carefully controlled condition using the welding process and the consumable to be

tested.

4. The penetration must be such that the notch is located in the heat affected zone.

5. After welding and before complete cooling the specimen is put under a tensile

static load and the stress thus applied is determined in relation to the cross ±

section at the notch.6. After a specified load holding time (max 16 hours) in the event of no structure

having occurred the assembly backing plate / implant is released and any crack

which may be present at the level of the notch in the HAZ are then located.



Reading Table:

SR NO LOAD /STRESS

MINUTE DEFECT

BEHAVIOR

OF

MATERIAL

1

2

3

4

5

Result Discussion:

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_______________________________________________________________ Conclusion:

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paresh jadav 23

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