The difference between automobile steel plate and ordinary steel plate

Different properties: Automobile plate is divided into hot rolled steel plate, cold rolled steel plate and coated steel plate according to the production process characteristics. Steel plate is a plate of steel poured with molten steel and pressed after cooling.

The characteristics are different: the steel plate is flat, rectangular and can be rolled directly or sheared from a wide strip of steel. The parts that constitute the body of the automobile plate are roughly divided into panel parts, structural parts, walking parts and reinforcing parts.

Different uses: car plate used in luggage, motorcycle shell, car, bus roof, dashboard, seat panel, car door panel, window frame and so on. Steel plate is mainly used in the manufacture of Bridges, ships, vehicles, boilers, high pressure vessels, oil and gas pipelines, large steel structures, etc.

Cold rolling and hot rolling concepts

1. Hot rolled

The continuous casting slab or the first rolled slab is used as raw material, which is heated by a stepping furnace and dephosphorized by high pressure water, and then enters the roughing mill. The roughing material enters the finishing mill after cutting head, tail and then enters the finishing mill to implement computer-controlled rolling. After the final rolling, it passes through laminar cooling (computer-controlled cooling rate) and coiling machine to become a straight roll. The head and tail of straight hair roll are often tongue and fish tail, the thickness and width accuracy is poor, and the edge often has wave shape, hem, tower shape and other defects. The coil weight is heavier and the inner diameter of the steel coil is 760mm. (The general pipe industry likes to use.) After finishing the straight hair coil by cutting the head, cutting the tail, cutting the edge, straightening and leveling several times, then cutting the plate or rewinding, it becomes: hot rolled steel plate, flat hot rolled steel coil, slitting strip and other products. The hot rolled pickling plate roll is formed after removing the oxide skin by pickling and applying oil.

2. The cold rolling

The HOT rolled steel coil is used as raw material, the oxide skin is removed by pickling, and the finished product is rolled hard coil. The cold work hardening caused by continuous cold deformation increases the strength and hardness of rolled hard coil, decreases the toughness and plastic index, and deteriorates the stamping performance, so it can only be used for simple deformed parts. Hard rolling coil can be used as raw material for hot dip galvanizing plant because hot dip galvanizing units are equipped with annealing line. The rolling coil weight is generally 6~13.5 tons, and the inner diameter of the steel coil is 610mm. In order to eliminate cold working hardening and rolling STRESS and reach THE mechanical properties SPECIFIED in the STANDARD, the plate and reel should be annealed by continuous annealing (CAPL unit) or hood furnace. The surface quality, appearance and dimensional accuracy of cold rolled steel plate are better than those of hot rolled steel plate.