Use of Cold-Rolled Plates and Hot-Rolled Plates

Hot rolled plate —— with continuous cast slab or primary rolled slab as raw material, heated by step by step heating furnace, high pressure water scaling into the coarse rolling machine, through the head, tail, then into the fine rolling machine, computer controlled rolling, after rolling is through laminar flow cooling (computer controlled cooling rate) and rolling machine roll, become direct hair roll. The head and tail of straight hair roll are often tongue shape and fish tail shape, the thickness and width accuracy is poor, and there are often defects such as wave shape, folding edge, tower shape and so on.The volume weight is heavier and the steel volume inner diameter is 760mm.(The general management industry likes to use it.) After the straight coil is cut into head, cut tail, cut edge and multiple times, then cut plate or rerolled, that is, become: hot rolled steel plate, flat hot rolled steel roll, longitudinal cutting belt and other products.If the hot rolled plate is removed byoxidation skin and coated, the hot rolled acid washing plate.

Cold-rolled plate —— is made of hot-rolled steel coil as raw material, and after the oxidation skin is removed by pickling, cold-continuous rolling. The finished product is rolled hard coil. Due to the cold hardening caused by continuous cold deformation, the strength, hardness and toughness index decrease, and stamping performance deteriorate, and can only be used for simple deformed parts.Rolling hard roll can be used as raw material for hot galvanizing plant, because hot galvanized units are equipped with backfire wire.Rolling hard roll weight is generally 6~13.5 tons, steel roll inner diameter is 610mm.Generally, cold-rolled plate and rolling shall be continuously annealed (CAPL unit) or deannealed furnace to eliminate cold hardening and rolling stress and meet the mechanical performance indexes specified in the standard.The surface quality, appearance and size precision of cold rolled steel plate are better than that of hot rolled plate.