What is the difference between cold rolling and hot rolling?
With the continuous casting slab or as raw material, after reheating furnace heating, descaling into the roughing mill of high pressure water, roughing material by cutting head, tail, and then enter the finishing mill, the implementation of computer controlled rolling, after finishing through the laminar cooling (computer controlled cooling rate) and coiler and become straight hair volume. Hair straightenerrollhead, tail tongue shapeand thefishtail shape, thickness, width of poor accuracy, edgehaswavy, folding, tower and other defects. The coil weight is heavy, and the inner diameter of the steel coil is 760mm. (general management industry likes to use. Thestraightthroughcutting) cutting head, tail cutting, trimming and multipass straightening and leveling finishing line processing, cutting board or heavy volume, which becomes: hot rolled steel plate and flat steel coils, slittingstripand other products. Hot finishing rolling by pickling descaling and oil is made by pickling hot-rolled coils.
Hot rolled steel coil as raw material by pickling descaling after cold rolling, the finished rolling hard volumes, due to continuous deformation caused by cold hardening the hard roll strength and hardness of the rise and decline of toughness index, stamping performance deterioration, only for a simple deformation of parts. Rolled hard rolls can be used as raw material for hot galvanizing plants, because the hot galvanizing units are equipped with annealing lines. The roll weight is usually 6~13.5 tons, and the inside diameter of the steel coil is 610mm. Generally, cold continuous rolling plate and roll should be annealed by continuous annealing (CAPL unit) or bell type furnace to eliminate cold work hardening and rolling stress, and meet the standard mechanical performance indexes. The surface quality, appearance and size accuracy of cold rolled steel plate are superior to those of hot rolled plate.
Hot rolling and cold rolling are forming processes of profiled steel or sheet steel. They have a great influence on the microstructure and properties of steels. Steel is rolled mainly by hot rolling, and cold rolled only for the manufacture of small sections of steel and thin plates. I. advantages of hot rolling: it can destroy the casting structure of steel ingot, refine the grain of steel, and eliminate the defects of microstructure, so that the steel structure is compact and the mechanical properties are improved. This improvement is mainly in the direction of rolling, so that the steel is no longer isotropic to a certain extent;
