冷轧汽车中锰钢的逆相变退火与组织性能研究  

Microstructure&Properties of Cold Rolled Medium Manganese Steel Used in Automobile After Austenitic Reverse Transformation by Annealing

作　　者：张丽凤 王社则 田博彤 ZHANG Lifeng;WANG Sheze;TIAN Botong(Shanxi Vocational University of Engineering Science and Technology,Taiyuan 030031,Shanxi,China;Taiyuan University of Technology,Taiyuan 030024,Shanxi,China)

机构地区：[1]山西工程科技职业大学,山西太原030031 [2]太原理工大学,山西太原030024

出　　处：《矿冶工程》2024年第5期159-162,167,共5页Mining and Metallurgical Engineering

基　　金：国家重点研发计划(2020YFB0301012-4);山西省重点研发计划项目(2017KKJH)。

摘　　要：为提高汽车中锰钢的强塑积,对冷轧态中锰钢进行了不同温度(650~680℃)和不同时间(10~50 min)的逆相变退火处理,研究了退火温度和退火时间对中锰钢显微组织和力学性能的影响。结果表明,原始冷轧态中锰钢板的组织由铁素体(F)+马氏体(M)组成,微观结构中可见弥散分布的尺寸20~45 nm的碳化物。退火温度从650℃升至680℃,中锰钢屈服强度、断后伸长率、强塑积和残余奥氏体体积分数均先增大后减小,而抗拉强度一直增大。退火时间从10 min增至50 min,中锰钢屈服强度、抗拉强度、断后伸长率、强塑积和残余奥氏体体积分数均先增大后减小。冷轧中锰钢适宜的退火制度为:退火温度660℃、退火时间30 min,此时中锰钢组织为F+M+奥氏体(γ),奥氏体体积分数24.12%,超细晶铁素体平均晶粒尺寸0.29μm,板条马氏体平均宽度0.27μm,强塑积23.33 GPa·%。In order to improve the strength-ductility balance of medium manganese steel for automobiles,cold-rolled medium manganese steel was treated by annealing at different temperatures(650-680℃)and for different time(10-50 min)for austenitic reverse transformation.Then,effects of annealing temperature and holding time on the microstructure and mechanical properties of medium manganese steel were explored.It is found that the microstructure of the original cold-rolled medium manganese steel plate is composed of ferrite(F)and martensite(M),and the dispersed carbides with sizes ranging from 20 nm to 45 nm can be observed in the microstructure.As the annealing temperature rises from 650℃to 680℃,the yield strength,elongation,strength-ductility balance,and residual austenite volume fraction of medium manganese steel increase followed by a decrease,but tensile strength increases all the time.As the annealing time is prolonged from 10 min to 50 min,the yield strength,tensile strength,elongation,strength-ductility balance and residual austenite volume fraction of medium manganese steel decrease after an initial increase.It is found that after annealing treatment at 660℃for 30 min,the cold-rolled medium manganese steel has a structure composed of F+M+austenite(γ),with austenite at a volume fraction of 24.12%,ultrafine grained ferrite with an average grain size of 0.29μm,lath martensite with an average wideness of 0.27μm,and strength-ductility balance of 23.33 GPa·%.

关 键 词：中锰钢 逆相变退火 退火温度 退火时间 显微组织 力学性能 汽车用钢 

分 类 号：TG142[一般工业技术—材料科学与工程] U465[金属学及工艺—金属材料]