冷轧DC01钢板屈服强度偏高的原因

Cause for Cold Rolled DC01 Steel Sheet Exhibiting Unacceplably High Yield Strength

冷轧DC01钢板屈服强度高于要求的≤240 MPa。为此对屈服强度偏高的冷轧DC01钢板进行了化学成分分析、金相检验以及冷轧压下率、退火工艺和平整延伸率的复查。结果表明:钢板的含氮量偏高,退火过程中析出的AlN量过多,阻碍晶粒的回复和再结晶,导致其屈服强度偏高。通过控制DC01钢的含氮量≤60×10^(-6)和调整退火工艺,冷轧DC01钢板的屈服强度达到了要求。

Cold-rolled DC01steel sheets exhibited yield strength higher than required 240 MPa or less.For this reason,chemical composition analysis,metallographic examination were performed on the DC01 steel sheet exhibiting unacceptably high yield strength,and its cold-rolling reduction,annealing process and leveling elongation were reviewed.The results showed that nitrogen content in the sheet was on the high side,and,as a result,too more amount of AlN precipitated during annealing,the recovery and recrystallization of grains were hindered and leaded to unacceptably high yield strength.By controlling nitrogen content of DC01 steel within≤60×10^(-6) and adjusting annealing practice the yield strength of the cold rolled DC01 steel sheet fulfilled desirable level.