连续退火过时效温度对热处理双相钢组织性能的影响

 采用光亮连续退火模拟实验机研究了0.08C 1.7Mn 0.03Si钢在不同连续退火过时效温度下组织和性能的变化规律，并构造了各相在连续退火工艺期间的反应关系式。试验结果表明：过时效温度在450 ℃时，组织中的第二相主要为粒状贝氏体＋马氏体，350 ℃时为板条状贝氏体＋马氏体，250 ℃时为马氏体或M A岛；过时效温度降低，试验钢抗拉强度明显升高，屈服强度明显降低，而n值、值和杯突值变化不大；350 ℃过时效时，试验钢的伸长率有增高的趋势，因此调整第二相组分比例可能是提高试验钢塑性的有效手段。

Effect of Overaging Temperature in Continuous Annealing on Microstructure and Properties of Heat-Treated DP Steel

With bright continuous annealing simulator, the microstructure and properties of 0.08C 1.7Mn 0.03Si steel treated with different overaging temperature and the phase transformation during continuous annealing process were studied. The results show that second phase was mostly of granular bainite and martensite in the specimen overaged at 450 ℃, mostly lath bainite and martensite in the specimen overaged at 350 ℃ and mostly martensite or M A island in the specimen overaged at 250 ℃; Tensile strength was increased and yield strength decreased, obviously, but n, and Erichsen value changed only a little with reduction of overaging temperature, thus, adjusting constituent ratio of second phase perhaps is an effective way for promoting plasticity of the steel due to the fact that elongation of the steel overaged at 350 ℃ was increased.