Raw Material Preparation: Steel billets (such as continuous casting billets) are selected as raw material and their quality is inspected (e.g., for cracks and inclusions).
Heating: The billets are heated in a heating furnace to the rolling temperature (hot rolling requires high temperature, while cold rolling does not require heating).
Rolling:
Hot rolling: The hot billet is rolled through a roughing mill into an intermediate billet, which is then rolled through a finishing mill to the target thickness and width. During this process, the rolling speed and temperature must be controlled to ensure uniform properties.
Cold rolling: Using hot-rolled coil as raw material, the product is subjected to multiple rolling passes at room temperature (such as a reversing mill) to reduce the thickness while improving surface finish and strength.
Cooling and Coiling:
Hot-rolled coil: After rolling, the product is cooled at a controlled rate using a laminar cooling system before being coiled by a coiler.
Cold-rolled coil: After rolling, the product is coiled directly, with some parts undergoing annealing (to eliminate internal stress and improve toughness).
Subsequent processing: pickling, galvanizing, color coating, cutting and other processing are carried out according to needs to form the final product.