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Production Process |
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Cold Rolling |
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Process Flow Diagram of CRM Complax |
| daigram 1 |
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HR Black Cold |
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Continous Pickling & Parting |
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Cold Rolling Process |
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Rewinding |
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Annealing of Cold |
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Skin Pass of Cold |
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Cold Rolling Mill Complex (CRM) |
| The various processing units involved in the CRM complex and their functions are given below : |
| The waste liquor from pickling line, recoiling line are treated in effluent treatment plant ensuring pollution free environment. The acid regeneration plant ensures regeneration of hydrochloric acid from waste pickled liquor for reuse in pickling line. |
| Continuous Pickling Line (Cpl) : |
| The HR Coil, which is the basic raw material, is passed through CPL to remove the oxides or scales from strip surface to enable further reduction of thickness to desired level in Cold Rolling Mills. This processing is required since rust is formed on the surface of the coils at room temperature whereas scales are formed at high temperature during rolling in Hot Strip Mill. |
| Cold Rolling Mill |
| Pickled Hot Rolled Coils of higher guages are reduced to required thinner guages by passing through the Mills. In 6 Hi Mill the reduction achieved is upto 0.13mm ultra thin guage whereas 4 Hi can reduce the thickness upto 0.25mm. The computer controlled rolling process ensure closure thickness tolerances and perfectly flat strips. |
| Electrolytic Cleaning Line |
| Electrolytic Cleaning is required in case material rolled with high percentage of oil while reduction in mills goes for annealing in furnace. Oil free base material is essential for the production of bright and corrosion resistant steel. Sodium Orthosilicate is used as cleaning agent in ECL. Tension is given according to thickness, width based on customer requirement. |
| Bell Annealing Furnace |
| The process of annealing of cold rolled coil is carried out to obtain the desired properties in the finished coils. For this, the material is heated to predetermined temperature in a protective atmosphere and soaked for a specified time before it is put to room temperature. Optimum condition with annealing atmosphere, annealing cycle, sealing and purging have to be maintained to obtain a finished product with bright surface, desired micro structure and uniform properties throughout the coil.HSD (High Speed Diesel) is used for heating the surface. Nitrogen is purged inside the inner cover. |
| Skin Pass Mill |
| In this process the cold rolled annealed strips are given a desired surface finish. It improves the flatness and suppresses the yield point elongation. Anti rust oil is used on strip surface as protection from rust. |
