Hot-rolled steel sheet, mechanical properties are far inferior to cold processing, also inferior to forging processing, but has better toughness and ductility. Cold-rolled steel sheet has a certain degree of work hardening and low toughness, but can achieve a good yield strength ratio. It is used for cold bending spring pieces and other parts. At the same time, because the yield point is closer to the tensile strength, there is no danger during use. Predictability, accidents easily occur when the load exceeds the allowable load 1) The cold plate is processed by cold rolling without surface oxide scale, and the...