极薄规格IF钢罩式退火工艺的研究

Study on Batch Annealing Process of Thin Specification Cold-rolled IF Steel

采用罩式退火模拟实验分析了薄规格IF钢板的再结晶规律,在确定了再结晶温度后,研究退火温度和保温时间对0.3 mm厚IF钢微观组织和力学性能的影响。同时,通过透射电镜分析了薄规格IF钢在退火后的析出物特征。结果表明:薄规格IF钢的再结晶温度比常规IF钢低50～80℃。IF钢经700℃退火保温13 h后,深冲性能优异,抗拉强度可达297.25 MPa,伸长率为42.8%,塑性应变比为2.58。退火后表现出较强的γ织构和较弱的α织构,γ纤维织构主要为{111}<110>和{111}<112>,γ织构强度可达14.0以上,{001}<110>织构强度小于2.0。在透射电镜下可观察到,在晶界和晶粒内有FeTiP团聚析出。

The recrystallization rule of thin specification cold-rolled IF steel was analyzed by batch annealing process. After confirming the recrystallization temperature of IF steel, the effects of batch annealing temperature and holding time on the microstructure texture and mechanical performance of IF steel （0.3 mm） were studied. At the same time, combined with transmission electron microscope, the precipitation behavior of thin specification IF steel was analyzed. The results show that the recrystallization temperature is lower 50-80℃ than the normal ones. After heating at 700 ℃ for 13 h, the steel has a good deep-drawing performance： tensile strength is 297.25 MPa, the elongation is 42.8%, the plastic strain ratio is 2.58. The annealed texture consists of strong γ fiber and weak α fiber texture, the former is mostly composed of { 111 }〈110〉 texture and {111}〈112〉 texture. The strength value of γ texture can reach more than 14.0 after annealing. And the strength of {001} 〈110〉 is weaker than 2.0. FeTiP precipitations concentrating is observed in the grain and grain boundary by transmission electron microscope.