Cold rolled close annealed steel coils are made from Hot Rolled Coils. Cold Rolling is a process through which the Hot Rolled steel sheet or strip after Pickling process is introduced between rollers by application of high pressure at temperature below the re-crystallization temperature. This method basically imparts smooth surface finish, accurate thickness, high tensile strength, yield strength hardness with corresponding decrease inductility. Hence selection of proper combination of steel composition, degree of cold working and heat treatment play a pivotal role to produce cold rolled sheets / strips having diverse applications and mechanical properties suitable for a wide spectrum of end users.

HINDUSTAN STEEL CORPORATION Processes Cold Rolled sheet in a variety of sizes, grades and surface finishes to meet specific end-use requirements. Cold Rolled Sheet is manufactured from hot rolled coils and Pickling to remove the surface oxide produced during the hot rolling stage, and cold reducing through a Cold Mill to the desired thickness.

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TYPICAL USES FOR COLD ROLLED STEEL

Metal furniture, desks, filing cabinets, shelves, tables, chairs, motorcycle exhaust pipes, computer cabinet and hardware, all home appliances and components, shelving, lighting fixtures, hinges, tubing, steel drums, lawn mowers, electronic cabinetry, lighting fixtures, water heaters, metal containers, and a variety of construction related products.

FORMABILITY

Cold Rolled Steels can be used to produce parts containing simple bends to parts with extreme deep drawing requirements depending on the grade and mechanical properties selected. Cold-rolled sheet metal can be readily welded and is suitable for painting applications when the surface has been well cleaned.

THICKNESS AND WIDTH LIMITS

GALVANIZED STEEL

Hot dip galvanizing of the strip is carried out by immersing it in a zinc bath maintained at 460 degree centigrade. The chemistry of the bath is carefully controlled to ensure proper adhesion and formability of the applied zinc together with bright blemish free uniform spangles.

The galvanized coils are chromated to improve its resistance to white rust. The chromating parameters are continually monitored and sheets are regularly tested through salt-spray tests to ensure the performance of this process.

REGULAR GALVANIZED

Material is produced on continuous hot dip galvanizing lines by passing prepared coils through a bath of molten zinc. There are various styles available Minimized Spangle, Minimized Spangle – Extra Smooth. The zinc coatings on these products help resist corrosion due to the barrier protection and sacrificial characteristics of the coating. The required zinc coating thickness for different coating specifications is achieved as the result of passing the hot dipped strip through a variable low pressure, high volume air stream, called an “air knife.”

MINIMIZED SPANGLE

The coating consists of a layer of zinc on top of a very thin layer of a mixture of intermetallic compounds containing iron, aluminium and zinc. The products produced are almost “spangle” free. The surface has a bright appearance and is normally intended for plain unpainted construction applications or unexposed appliance/ automotive applications.

ZERO SPANGLE SKIN PASSED

This product is skin passed or temper rolled after coating to impart a uniform matte surface appearance. It is developed for use on painted construction applications and semi-exposed automotive applications requiring an improved surface appearance.

TYPICAL USES FOR GALVANIZED STEEL

Air conditioning equipment, HVAC ductwork, wood connectors, slot machine parts, computer cabinets, TV cable boxes, building panels, display cases, electronic equipment, garbage cans, guide rails, heating equipment, highway culverts, garage doors, motor housings, washing machines and dryers, home appliances, lighting fixtures, mailboxes, outdoor signs, refrigerators and freezers, roof flashing, decking, tool boxes, vending machines, framing studs, rain gutters and downspouts.

FORMABILITY

Lends itself to most fabrication processes; it can be roll-formed, brake-formed, lock-seamed, deep drawn, and stretched. It can be joined by various methods including adhesive bonding, riveting, soldering and welding.