淬火-等温-回火(Q-I-T)对60Si2CrVA弹簧钢显微组织的影响

来源期刊：钢铁2010年第11期

论文作者：梁益龙 杨刚 王兴安 杨小弟

文章页码：68 - 71

关键词：弹簧钢； 淬火-等温-回火； 贝氏体； 复相组织； 残余奥氏体

Key words：spring steel； quenching-isothermal-tempering； bainite； duplex microstructure； retained austenite

摘    要：研究了淬火-等温-回火(Q-I-T)新工艺对60Si2CrVA弹簧钢显微组织的影响。通过残余奥氏体的测定、金相观测和TEM分析研究,结果表明:淬火-等温(Q-I)处理后获得50%~60%马氏体M(针束状)+30%~40%贝氏体B+大于10%残余奥氏体Ar组织;据统计贝氏体条宽度在100~500 nm之间,亚单元尺寸在50~250 nm之间,残余奥氏体以薄膜状分布于马氏体、贝氏体束条之间;经400℃回火后残余奥氏体大量分解,并析出部分细小碳化物。与传统淬火回火工艺相比,新工艺组织得到分割细化,并获得复相组织。

Abstract: The effect of quenching-isothermal-tempering(Q-I-T)process on microstructure of 60Si2CrVA spring steel was studied.The volume fraction of retained austenite was measured by XRD and the microstructures of all samples were analyzed by metallurgical microscopy and TEM.The results show that volume fraction of the microstructure is: 50%-60% fine-acicular or lath martensite(M) +30%-40% bainite(B) + more than 10%retained austenite(Ar),respectively.Most of the bainite lath width is 100-500 nm and sub-unit size is 50-250 nm.The retained austenite is film-like distribution between the laths and packets of the martensite and bainite after Q-I heat treatment.The fine carbide is precipitated and the retained austenite is decomposed during tempering at 400 ℃.Compared with conventional heat treatment,the structure of the 60Si2CrVA spring steel is refined and the duplex microstructure is obtained by the new heat treatment.