PRODUCT & PRODUCT MIX

Cold Rolled Full Hard (CRFH) Coil

Based on the degree of drawing required for the steel to undergo for different applications, Cold Rolled products are categorized as Ordinary (O), Drawn (D), Deep Drawn (DD) or Extra Deep Drawn (EDD) variety with EDD variety being the premium category. CR products are further classified in terms of width as ‘wide width’ and ‘narrow width’ products and thickness as thin gauge or thick gauge. CRFH coils find applications in furniture and, automobile sectors etc. Further CRFH coils are used as input material in processing industry as a raw material for Galvanizing and further Color coating.

Cold Rolled Closed Annealed (CRCA) Coil

Cold Rolled sheet is subjected to heat treatment for recrystallization annealing in order to remove the internal hardness and stress induced during the cold rolling process. Annealing re‐crystallizes the structure making the surface smooth and provides consistency in thickness and flatness. The process provides superior mechanical and workable properties to these cold rolled sheets and coils making them suitable for drawing and forming and metallic coating, painting or for other such treatments. A variety of mechanical and metallurgical properties are imparted to cold rolled products by having proper combination of steel composition, degree of cold rolling and heat treatment. CR coils/sheets have high strength to weight ratio which enables them to be suitable for use in automobile industry. In addition, cold rolled sheets and coils are used in electrical appliance and other fabrication processes requiring large tonnages of highly workable steel of uniform quality. Due to reduced thickness and improved surface conditions, they are essential base metal for tin plates, galvanized steels and other coated steel products.

The following process steps are being followed for the production of CRFH and CRCA product from hot rolled pickled and oiled (HRPO) coils and are outlined below:

• Cold rolling of the pickled coils to the required thickness in a reversing cold rolling mill (CRM)
• A part of the cold rolled produced in CRM coil can be sold as CRFH and balance to be further processed for production of CRCA coil.
• Cleaning of the strip from oil, dirt, etc. in the electrolytic cleaning line (ECL) prior to annealing.
• Recrystallisation annealing in hydrogen atmosphere to relieve the internal stress developed during cold rolling and to re-crystallize the deformed grain in bell/batch type furnaces.
• Temper rolling (skin passing) of annealed coils to suppress yield point elongation phenomenon and to improve flatness in tension leveler cum skin pass mill.
• A part of the above coils will be further processed in a Shearing Line (SHL) and slitting to produce CRCA product in sheet form and for production of slit coils respectively as per market demand.