Galvannealed Steel Sheets Manufacturer, Supplier & Stockist In India - Nirvaan Overseas

Nirvaan Overseas is one of the leading Galvannealed Steel Sheet Manufacturer, Supplier, Dealer, Exporter & Stockist in India. Galvannealed (or galvanneal) Steel is the result of the processes of galvanizing followed by annealing of sheet steel. It is a carbon steel sheet coated with zinc on both sides by the continuous hot-dip process. Immediately as the strip exits the coating bath, the molten zinc coating is subjected to an in-line heat treatment that converts the entire coating to a zinc-iron alloy. Such product is most prevalent in automobile manufacturing, although it has other uses in construction and ship manufacturing. Galvannealed and galvanized steel are zinc coated at the steel mills and are designed for rust and corrosion resistance. Both plates of steel are passed through a hot dip coating process for rust prevention. Typical applications: automotive body panels, electrical enclosures

Production of JSW Galvannealed Sheet steel begins with hot dip galvanization of sheet steel. After passing through the galvanizing zinc bath the sheet steel passes through air knives to remove excess zinc and is then heated in an annealing furnace for several seconds causing iron and zinc layers to diffuse into one another causing the formation of zinc-iron alloy layers at the surface. Hot dip galvannealed sheet steel is produced in a continuous hot dip galvanizing line equipped with a special, additional, in-line process where induction heating is used to alloy the zinc coating with the steel resulting in a coating that contains 9-12% bulk iron. Hot Dip Galvannealed Sheet is available in various coating thicknesses. The main benefits of using Galvanneal over galvanize are improved spot-weldability and ease of painting.

Galvannealed Steel Sheet Manufacturer, Galvannealed Steel Sheet Supplier, Galvannealed Steel Sheet Stockist in India.

The annealing step is performed with the strip still hot after the galvanizing step, with the zinc still liquid. The galvanizing bath contains slightly over 0.1% aluminium, added to form a layer bonding between the iron and coated zinc. Annealing temperatures are around 500 to 565 °C. Pre-1990 annealing lines used gas-fired heating; post-1990s the use of induction furnaces became common. Galvannealed steel is a matte uniform grey colour, which can be easily painted. In comparison to galvanized steel, the coating is harder and more brittle. Three distinct alloys are identified in the galvannealed surface. From the steel boundary these are named the Gamma (Γ), Zeta (ζ), and Delta (δ) layers, of compositions Fe3Zn10, FeZn10, FeZn13 respectively; resulting in an overall bulk iron content of 9-12%.

The layers also contain around 1-4% aluminium. Composition depends primarily on heating time and temperature, limited by the diffusion of the two metals.Galvannealed sheet can also be produced from electroplated zinc steel sheet. The resulting coating has a matte appearance, and is hard and brittle - under further work such as pressing or bending powder is produced from the degradation of the coating, together with cracks on the surface. In comparison to zinc (galvanized) coating JSW hot dip galvannealed has better spot weldability, and is paintable, Due to iron present in the surface alloy phase galvanneal develops a reddish patina in moist environments - it is generally used painted. Zinc phosphate coating is a common pre-painting surface treatment.

Galvannealed steel holds several advantages over uncoated steel and other coated materials. Here, Galvanneal process is designed primarily for painting. Standard galvanized steel has the matte finish due to the presence of the zinc coating. Here, zinc coating is more absorbent than standard galvanized steel. It allows paints to stick to the surface firmly. Galvannealed steel also holds a zinc coating that is stronger compared to many other types of galvanized steel. Here, this ability increases product resistance to scratching. It also causes different kinds of coating damage that may result in the steel’s exposure to the environment. Also, Galvanneal coating shows good formability and weldability compared to other types of galvanized steel. The process of Galvannealed also provides better corrosion resistance compared to uncoated carbon steels. The Galvanneal process’s disadvantage includes that it does not offer corrosion resistance as that of galvanized steel. We are also manufacturer of Chequered Sheet & Plate .