摘要
初始组织为片层珠光体的Fe-0.39C-3.69Mn(wt.%)钢板被快速加热到730℃保温90 s后淬火至室温,获得包含13.2%残余奥氏体的板条马氏体组织。借助SEM、TEM、XRD和单向拉伸力学测试等试验手段,研究了在200℃回火时不同保温时间对微观组织和力学性能的影响,特别是对残余奥氏体体积分数和稳定性的影响。结果表明,随回火时间的增加,过渡碳化物逐渐增多并粗化,残余奥氏体含量先减少后不变;硬度、强度和均匀伸长率均逐渐降低,但断后伸长率由于马氏体回复而有所增加。片状残余奥氏体由于富Mn而具有较高稳定性,在200℃长时间回火后基本不发生分解。回火15 min后获得最佳的综合力学性能,其屈服强度为1544 MPa,抗拉强度为2031 MPa,断后伸长率为10.1%。
The Fe-0.39 C-3.69 Mn(wt.%)steel with the initial microstructure of lamellar pearlite was fast heated to 730℃and held at this temperature for 90 s followed by water quenching to room temperature,resulting in the formation of lath martensite structure containing 13.2%retained austenite.The effect of tempering time at 200℃on microstructures and mechanical properties was systematically studied,especially on the volume fraction and stability of retained austenite.The results show that with increasing tempering time,the amount of transition carbides is increased and their size is coarsened;the volume fraction of retained austenite decreases firstly and then remains unchanged;the hardness,strength and uniform elongation gradually decreases,but the total elongation increases due to recovery in lath martensite.It is worth noting that the film retained austenite is hardly decomposed after a long time tempering at 200℃,indicating a high thermal stability due to the Mn enrichment.After 15 min tempering,a good combination of high yield strength(1544 MPa),high ultimate tensile strength(2031 MPa)and decent total elongation(10.1%)is achieved.
作者
杨德振
熊志平
张超
程兴旺
YANG Dezhen;XIONG Zhiping;ZHANG Chao;CHENG Xingwang(National Key Laboratory of Science and Technology on Materials under Shock and Impact,School of Materials Science and Engineering,Beijing Institute of Technology,Beijing 100081,China)
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2021年第11期1161-1170,共10页
Journal of Iron and Steel Research
基金
国家自然科学基金资助项目(51901021)
北京理工大学青年教师学术启动计划资助项目(XSQD-201808006)。
关键词
快速奥氏体化
回火时间
残余奥氏体
力学性能
fast austenitization
tempering time
retained austenite
mechanical property
