123588029 galvannealed ga galvanealed zinc fe zinc ro zinc iron alloy a practical study

7/28/2019 123588029 Galvannealed Ga Galvanealed Zinc Fe Zinc Ro Zinc Iron Alloy a Practical Study

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GALVANNEALED ZINC- IRON ALLOY COATED STEELS

PRODUCT DESCRIPTION

Galvanneal is a carbon steel product coated in a mixture of iron and zinc. This steel product ismost famously used in the manufacture of cars, automobile, appliance and many others like steeldoors, cable trays, material handling equipments and pan, electrical panel and boxes, inverterboxes , press brake and roll forming applications, i.e., including stud, track and metal framing,deck and roof components, and panels etc including in construction of structures and ships.

This product has excellent printability ,good formability, high strength , lower cost compared toElectrogalvanized , completely supplanted Bonderized (phosphatized).

Galvannealed (like hot-dipped Galvanized sheet) is typically produced in accordance with varioussteel standards and tolerances.

The term galvanneal is a portmanteau of galvanized and anneal. Annealing is a process inwhich metal is subjected to a heat treatment to force it to develop specific desired properties.Galvanization is a process in which metal is coated in a material which will help it resist corrosion.Zinc is classically used for galvanization. The blend of these two processes is designed to givegalvannealed steel some unique and very desirable properties which make it ideally suited to anarray of applications.

In galvanneal, the steel is first dipped in a hot bath of zinc, as is done when materials aregalvanized. Then, it is subjected to a secondary process in which iron is annealed with the zinccoating to create an iron-zinc blend on the surface of the metal. The galvanneal coating is a dull

gray in color, unlike the distinctive spangled coating seen on metals galvanized with just zinc.The coating should also stay firmly adhered to the metal for its lifetime, thanks to the heattreatment process. Galvanneal comes in a variety of thicknesses. The dull gray surface ofgalvanneal is very easy to paint, chrome , powder coat , zinc chrome coat etc. The metal will alsoresist corrosion. Over time, however, corrosion can develop. Damage to the surface of thecoating can expose the underlying steel, allowing rust to set in. Some causes of damage includehighly corrosive chemicals, gouges, and collisions.

A hot-dip galvannealed coating differs from a hot-dip galvanized coating. Both products are, asstated, made by the hot-dip coating process. The main difference in the production process isthat, to make a galvannealed coating, the strip is further heated by passing it through a furnace

directly above the coating bath. By heating to approximately 1000 to 1050 F(538 to 565 C) andholding the strip at this temperature for a specific amount of time, the zinc coating alloys with ironby diffusion between the molten zinc and iron from the steel strip. The result is that the finalproduct has a coating that is an alloy of approximately 90% zinc and 10% iron. The final ironconcentration depends on the heating cycle since the total amount of diffusion is a function of thetime/temperature cycle.


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Base Steels Used in Galvanneald Sheet Products

IntroductionZinc and zinc alloy-coated sheet is produced using many different types and grades of steel. This Is brief descriptionof these steels and the basic metallurgy involved in their production and application.

Steel Substrates for Galvanizing

Steels for continuous galvanizing can be categorized into the following major groups (most of the terminology is asdefined in the ASTM product specifications described :-

Commercial Steel (CS) carbon levels range between 0.04% and 0.10%, and manganese from 0.2% to 0.6%,depending on the product being made. The substrate is cold rolled anywhere from 50 to 80%reduction prior to it being processing through a galvanize line.

Forming Steel (FS) carbon levels between 0.04-0.08%, and manganese at about 0.25%. This steel is coldreduced between 60 to 80% and is used to produce a slightly softer product than CS in order to give improvedformability.

Structural Steel (SS) carbon levels range between 0.04% and 0.20%, and manganese from 0.4% to 1.6%,depending on the product being made. The sheet is cold rolled anywhere from 50 to 70%

reduction. SS grades must meet minimum mechanical property requirements and have yield strengths between 33and 80 ksi [230 and 550 MPa].

Deep Drawing Steel (DDS) & Extra Deep Drawing Steel (EDDS) generally made from ultra-low carbon (10-15ppm) stabilized steels, although some DDS is made using extra low carbon (0.015-0.020%) steel. EDDS, and some DDS, is designed to be fully stabilized (non-ageing) after in-line annealing andcoating. To maximize annealing response, cold reduction is generally 75% minimum.

Solution Hardened Steel (SHS) & Bake Hardenable Steel (BHS) ultra-low to low carbon (0.12% max) steel thathas yield strengths from 26 to 44 ksi [180 to 300 MPa]. SHS is strengthened usingsubstitutional elements such as M, P, or Si, while BHS relies on strain ageing after forming for strengthening.


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High Strength-Low Alloy Steel (HSLAS) typically made from micro-alloyed low carbon steel. The primary micro-alloying element is niobium (Nb). Cold reduction rarely exceeds 60% due to the high cold rolling loads necessary toreduce the thickness of these steels. They have a yield strengths of 40 to 80 ksi [275 to 550 MPa].

Advanced High Strength-Low Alloy Steel (AHSS) Produced using higher levels of alloying elements andcarefully controlled annealing and cooling cycles. Cold reduction rarely exceeds 60% due to high cold rolling loads.The yield strength of these steels is typically between 50 and 80 ksi [340 and 545 MPa].

COATING CHARACTERISTICS

The hot dip coating process assures a tightly adherent, uniform coating of zinc on both sides of the product. The strippasses through an induction furnace after the coating pot to allow the iron from the base metal to further diffuse intothe zinc creating a zinc-iron alloy layer. The coating is nominally 8 13% iron. Precise temperature control providessufficient ductility in the coating to permit normal fabrication practices without incurring significant coating damage orpowdering.

GA Steel has a dull gray surface with no spangle which provides a good base for painting , chroming , powdercoated , zinc chrome coating. For best results, the surface should be carefully cleaned with an alkaline cleaner,however in some cases, cleaning by a solvent may be acceptable. Cleaning should be followed by a pre-treatmentprior to painting.

Corrosion Resistance

The zinc coating protects the base metal by providing a barrier to corrosive elements and also by the sacrificialnature of the coating. Ultimate service life depends on coating thickness and the severity of the environment.

Galvannealed coatings provide excellent corrosion protection, even in the event of damage (impact, scratches,gravel impingement), due to the electrochemical behavior of the Fe- Zn galvanic couple (sacrificial anode effect). Inthe event of damage, the presence of iron in the coating gives the Galvannealed corrosion products a reddish tinge,which should not be interpreted as a sign of substrate corrosion.


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Galvannealed has a uniform and pure zinc coating,which is why it prevents corrosion better and increase longevity.

Formability

GA Steel can be used to produce parts containing simple bends to parts with deep drawing requirements.


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Galvannealed`s superior mechanical properties and controlled compositional strength allows for optimumformability.With Galvannealed`s even thickness,wastage during fabrication is minimal,so that your gains can bemaximised.

Paintability

GA Steel is readily paintable ,chromed , powder coated , zinc chrome coated provided proper pre-treatment is

performed.

Galvannealed`s perfectly smooth surface,paint holds better and you save more.

Weldability

GA Steel can be joined using a variety of accepted welding practices. Its spot weldability is improved over free zinccoatings.The hardness and melting point of this coating leads to weldability close to that of uncoated sheet, with excellentelectrode life values.Example based on ISO standard 18278-2: ArcelorMittal 04 steel Galvannealed 45/45 with 0.7 mm thickness:weldability range from 8.6 to 9.6 kA with electrode life of 1200 spots without adjustments.

Adhesive bonding Galvannealed layers have good bonding behavior, adhesion to the coating, adhesion of thecoating to the metal and cohesion of the coating.The most important parameters determining bond quality are the type of adhesive, the joining conditions, the natureof the protective oil, and any chemical treatments that may have been performed.Surface treatment Galvannealed products can be phosphated and painted at the user's premises using currentprocesses. The cataphoresis process may have to be adapted to avoid cratering problems caused by the particularmicro- texture of this coating.


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With Galvannealed`s superior manufacturing processes and standards ensure effortless welding.

Surface QualitySurface quality complies with standards EN 10327 and EN 10326.The products can be delivered with surface quality A, B or C.

Surface quality A: standard surface

Imperfections such as small pits, differences in spangle size, dark spots, stripes and light passivation from thechemical treatment are permissible.

Surface quality B: improved surface

The B quality surface is obtained by skin passing.To a small extent imperfections are permissible, such as stretch levelling breaks, skin pass marks, scratches,indentations, spangle structure, zinc run-off marks and light passivation from chemical treatment. The surface has no

pits.

Surface quality C: best quality surface

The C quality surface is obtained by skin passing. The better side is suitable for the uniform appearance of a high

quality paint finish.The other side must at least conform to the characteristics for surface quality B.

Roughness

As a standard, Surface Types B and C are delivered with a medium roughness value ranging between 1.0 and 1.9

m. Determinationof the median roughness value Ra is subject to a wavelength limit of 2.5 mm in accordance with EN 10049 (standardmeasuringlength of 12.5 mm). Metallic coated steel - with the exception of galvanised steel with standard surface (MA) - can beobtained in differ grades of roughness. If no roughness is specified, normal is delivered.

Description Roughness Ra

(m) Roughness Ra

(m)cut off 2.5 mm cut off 0.8 mmnormal 0.9 - 1.5 0.75 - 1.25rough 1.2 - 1.8 1.00 - 1.55

Surface Protection

Hot-dip galvanized steel strip with a zinc/iron coating is normally delivered with an oiled (O) zinc/iron coating ,chromium-free passivated (CE) or phosphated (P) form. It can also be chromium-free passivated and oiled (CO) orphosphated and oiled (PO). Depending on the defined micro-topography, difficult forming stresses may make itnecessary to increase the oil coating.

The products is delivered with surface protection O, C and CO.

Oils (O)

The material surface can be oiled with preservative oil. Normally steel mills supplies from 0.25 g/m up to 1.6 g/mper side.Chromium-free passivation (C)


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This surface treatment temporarily protects the zinc-coated material against white rust during transportation andstorage.

Chromium-free passivation and oiled (CO)

Request this combination of surface treatments if you require extra protection against white rust formation.

Untreated (U)Steel Companies does not offer untreated galvanised steel because of the risk of rust formation on unprotectedmaterial during storage or shipment.

Surface Appearance

Zinc and zinc alloy coatings can differ in appearance depending on process. Galvanized coating finishes can varyfrom extra smooth and featureless to a flowery "spangle" pattern. Galvanneal (Zn-Fe) coatings have a matt andsmooth grey appearance. Electrogalvanized coatings have the smoothest finish among zinc coatings and provide thebest substrate for a high quality paint finish. There are standards covering all aspects of surface appearance coatingfinishes, surface qualities (from regular to best quality) and surface treatments (chemical passivation, oiling) - all

targeted to enhance further processing.


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Health Safety

With Galvannealed`s unique lead free composition , safety for both your health and the environment is ensured.


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Mechanical Properties of Different Types of Galvannealed zinc- iron alloy

coated steel available


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Use of Different Types of Galvannealed zinc- iron alloy coated steels

The formability of all steel products is a result of the interaction of many variables. These variables include: themechanical properties of the steel, the forming system (tooling) used to manufacture parts, and the lubrication usedduring forming..

Commercial Steel Type B (CS Type B) and Forming Steel Type B (FS Type B) should be used for moderate forming bending applications. These products are produced from aluminum-killed continuously cast slabs and unless otherwispecified, have a carbon content of 0.02 to 0.15% C and 0.02 to 0.10% C respectively. To prevent the occurrence offluting or stretcher strains during forming or processing. These products are subject to aging and the temper rolling efis temporary.

For more stringent forming applications, Deep Drawing Steel (DDS), should be ordered. DDS has a controlled carboncontent (< 0.06% C) and is produced in such a manner that parts formed from DDS steel should not exhibit stretcherstrain.

Extra Deep Drawing Steel (EDDS) or Extra Deep Drawing Steel Plus (EDDS+) should be ordered for the mostdemanding forming applications. These steels, also known as Interstitial Free (I-F) steel, are produced from vacuumdegassed (< 0.010% C), stabilized grades. EDDS+ has the lowest carbon content available and has been speciallyformulated to be most ductile .

For high strength applications, GA Steel is available as Structural Steel (SS) or High Strength Low Alloy Steel (HSLA


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Bake Hardenable (BH), Dent Resistant (DR) and Dual Phase (DP) Steels are also available.

With zero-spangled Galvannealed the surface remains even and lustrous.So any product made with Galvannealed losuperior. Above are some application with numerous to name them.


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Who we are

We Ashish Steel Traders (P) Ltd. a registered private limited company was started in the year 1992 in Naraina ,LohaMandi ,New Delhi area for the purpose of trading of Iron & Steel as a proprietor concern by Shri Aashish Gupta as itsproprietor and Late.Shri Ashok Kumar Gupta who is into the steel business from 1965 as its mentor. In 1995 it wasconverted into a private limited company and joined by Shri Raju Gupta an ACMA (Cost & Management Accountant)and other family members. In previous years we had also operated as consignment agents of M/s Essar SteelLimited for Delhi region.

How can we create value for you

Currently we are procuring materials which are prime , seconds and surplus of prime from various companies andmarket place . We then conduct physical and chemical inspection of the material and identify the use of variousquality of materials for the various manufacturing applications . These materials are either then sold in market placeto the retailers or offered to various manufacturers as per their requirements .

We provide exact chemical and physical details of the materials to our customers so that least rejections are thereand we also conduct third party processing such as cutting , bending, cut to length , etc on behalf and as perrequirements of the customers . We use high end CAD software to suggest the minimum wastage for size of thesheets and also provides drawings to cut sheets to maximize productivity. Our targeted customers are small tradersand manufacturers who do not possess or have sufficient resources for the technical know how about the steel andthe new type of advanced steel and advance manufacturing processes .

Although we are general order suppliers but to add value to our customers we are currently laying emphasis onproducts Galvannealed , Skin pass galvanized sheets cromated and non cromated and Cut to length CRCA andHRPO.

Contact Information

Ashish Steel Traders (P) Ltd.

X-36/37, Loha Mandi, Naraina, New Delhi-110028 (India)

Landline :- +91 11 25897008 , Fax :- +91 11 47322983 , E.Mail :- [email protected]

Aashish Gupta :- +91 9811038245 Raju Gupta :- +91 8010678645

E.Mail :- [email protected] E.Mail :- [email protected]

123588029 galvannealed ga galvanealed zinc fe zinc ro zinc iron alloy a practical study

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