中锰TRIP钢两相区温轧退火碳化物演变行为

Carbide evolution behavior of medium manganese TRIP steel during intercritical warm-rolled annealing

采用CR+WR+IA(冷轧+温轧+退火)热处理工艺,研究了两相区退火过程中碳化物演变行为及其对0.1C-5Mn钢组织、性能、残留奥氏体体积分数与稳定性的影响。结果表明:冷轧试验钢经温轧退火处理后,获得了超细晶铁素体与残留奥氏体复相组织,其中退火10 min与30 min试样基体上弥散少量碳化物。伴随碳化物的析出与溶解行为,残留奥氏体体积分数出现先降低后升高的趋势;在退火10 min与60 min组织中,受碳化物与新生奥氏体钉扎作用,使得铁素体以小角度取向差为主,而残留奥氏体以大角度取向差为主;高密度位错、TRIP效应、细晶强化以及析出强化为试验钢提供良好的强塑性。

The carbides evolution behavior in two-phase region annealing process and its effect on microstructure,mechanical properties,and volume fraction and stabilization of retained austenite in 0.1 C-5 Mn steel were studied by means of a new treatment process of cold-rolled+warm-rolled+intercritical annealing(CR+WR+IA).The results show that the ultra-refined multiphase microstructure comprised of ferrite and retained austenite is obtained after intercritical warm-rolled annealing,in which a small amount of carbides are dispersed on the substrate under intercritical annealing for 10 min and 30 min.With precipitation and dissolution of carbides,volume fraction of retained austenite first decreases and then rises in the fluctuation trend.In the microstructures annealed for 10 min and 60 min,due to pinning of carbides and newformed austenite,the misorientation of ferrite is mainly at low angle grain boundaries,but the retained austenite is dominated by high angle boundaries.The excellent properties can be attributed to high dislocation density,transformation induced plasticity,grain refinement strengthening and precipitation strengthening effects.