Processes – Cold Rolled

COLD REVERSING MILL (CRM)

The CRM is a single-stand 4 high mill for cold rolling hotrolled and pickled material from the pickling line. The overhead crane deposits a coil on to one of the coil storage stations of the entry coil car. After coil diameter and width measurement, the coils are transferred by the coil car centrally on the pay off-reel mandrel. The strip head is fed through the pinch roll and leveller unit and reaches the mill stand via strip guide tables and the strip press. The strip head is then fed to the exit-side tension reel at threading speed. The strip head is coiled on to the exit side tension reel by means of the belt wrapper. When 2 to 3 windings have been coiled the wrapper is retracted and the cold mill is then accelerated to rolling speed for the first pass. For the 2nd pass in reversing operation, the strip tail is now fed onto the mandrel of the entry side tension reel with the aid of a threading table and belt wrapper. With the correct strip tension now obtained, the mill accelerates to rolling speed. For further reversing passes the strip remains wound on the two tension reel mandrels. The strip tension is measured at the reels and the thickness is measured by the two x-ray thickness gauges, one entry side and one exit side of the mill stand. Strip shape is measured by two shape meters positioned both at the exit as well as the entry sides of the mill and controlled by the multi-zone spray headers on entry and exit sides of the work rolls. This ensures that shape can be closely monitored through the entire pass schedule in both directions and results in excellent shape control.

COLD REVERSING TEMPER MILL (CRTM)

The CRTM is identical to the CRM in every respect except that it can temper roll as well as cold roll. The mill will temper roll the cold finished product downstream of the batch anneal. Its extra rolling capacity will be utilized to roll product for the Galvanising Line as well as Cold Rolled Product.

BATCH ANNEALING

The Batch Anneal Facility comprises of 12 bases, each capable of annealing a batch of 4 to 5 coils at a time. The Batch Anneal System anneals coils from the CRM for the Cold Finished Product.

Annealing is by Ebner Hicon 100% H2 ensuring very consistent mechanical properties and a uniform grain size throughout the coils. Once the coils have undergone the annealing cycle they are cooled to a core temperature of 160˚C using a combined air and water cooling system and unloaded from the bases for further cooling prior to the temper rolling and oiling process.