Cold Rolling Mill Complex (CRM)

The various processing units involved in the CRM complex and their functions are given below :-  
  • 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.   
The installed production capacity of CPL is 3,55,806 MT per annum.
  • COLD ROLLING MILL

There are two types of Cold Rolling Mills operates, which are 6 Hi Cold Rolling Mill and 4 Hi 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.   

The installed production capacity of 6 Hi Mill is 2,30,856 MT/annum and 4 Hi Mill is 43,502 MT per annum.  

  • 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. 

   The installed production capacity of the line is 86102 MT/Annum.  

  • BATCH 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 is used for heating the surface.  Nitrogen is purged inside the inner cover.  Nitrogen is obtained from PSA Unit. 

          The installed production capacity of the line is 75881 MT/annum.

  • 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. 

The installed production capacity of Skin Pass Mill is 82,319 MT/annum.

  • CR SLITTER
In slitter CR coils are slitted length-wise and also to remove side trims to obtain uniform width throughout the coil as customer requirement.  

The installed production capacity of the CR Slitting Line is 96,006 MT/annum.
  • CUT TO LENGTH LINE
In CTL slitted coils are sheared to the desired length as per customer requirement.  There are a total of 4 Cut-to-length Lines in operation.  The installed production capacity of total CTLs is 83289 MT/annum.

Back