Hot-rolled steel sheet, the mechanical properties are far inferior to cold working, and inferior to forging, but have better toughness and ductility
Cold-rolled steel sheets have a certain degree of work hardening and low toughness, but they can achieve a good yield-to-strength ratio and are used to cold-form springs and other parts. At the same time, because the yield point is closer to the tensile strength, there is no danger during use. Predictive, prone to accidents when the load exceeds the allowable load
1) The cold plate is cold-rolled and has no oxide skin on the surface, and the quality is good. The hot plate is processed by hot rolling with oxide skin on the surface, and the thickness of the plate is different.
2) Hot-rolled sheet has poor toughness and surface flatness, and the price is lower, while cold-rolled sheet has good stretchability and toughness, but the price is more expensive
3) Rolling is divided into cold rolling and hot rolling, and the recrystallization temperature is the distinguishing point
4) Cold rolling: Cold rolling is generally used to produce strip, and its rolling speed is high,
Hot rolling: The temperature of hot rolling is similar to that of forging
5) The surface of the hot-rolled sheet without electroplating is dark brown, and the surface of the cold-rolled sheet without electroplating is gray. After electroplating, it can be distinguished from the smoothness of the surface, and the smoothness of the cold-rolled sheet is higher than that of the hot-rolled sheet.
6) The strength of the hot-rolled sheet is relatively low, and the surface quality is poor (with oxidation and low finish), but the plasticity is good, generally medium and heavy plate, cold-rolled sheet: high strength, high hardness, high surface finish, generally thin plate, can be as a stamping plate.
7) Hot-rolled steel plates are divided into two types: thick plates (thickness greater than 4mm) and thin plates (thickness of 0.35~4mm); cold-rolled steel plates are only thin plates (thickness of 0.2~4mm).
