加热温度对TRIP钢连续冷却转变曲线及室温组织的影响.PDFVIP

第33卷 第4期 北 京 科 技 大 学 学 报 Vol.33 No.4 2011年 4 月 Journal of University of Science and Technology Beijing Apr. 2011 加热温度对 TRIP钢连续冷却转变曲线及室温组织的 影响 苣 范东亮摇 米振莉 摇 李志超摇 刘摇 强 北京科技大学高效轧制国家工程研究中心,北京 100083 苣 通信作者,E鄄mail:mizl@nercar.ustb.edu.cn 摘摇 要摇 采用膨胀法在DIL805热膨胀仪上测定了不同加热温度下实验钢的连续冷却转变(CCT)曲线,通过光学显微镜和扫 描电镜分析不同加热温度对CCT 曲线和冷却试样显微组织的影响. 结果表明:当加热温度由完全奥氏体化温度降低到两相 区内较高温度时,CCT 曲线中铁素体转变区左移;当加热温度处在两相区范围内时,随着加热温度的降低,铁素体转变被推 迟,使得CCT 曲线右移;新生铁素体外延生长方式和奥氏体中碳富集程度的差异是导致上述变迁的主要因素. 关键词摇 TRIP钢;连续冷却转变;微观组织;外延生长 分类号摇 TG151郾2 Effect of heating temperature on the continuous cooling transformation and mi鄄 crostructure of TRIP steel 苣 FAN Dong鄄liang,MI Zhen鄄li ,LI Zhi鄄chao,LIUQiang National Engineering Research Center for Advanced Rolling Technology,University of Science and Technology Beijing,Beijing 100083,China 苣 Corresponding author,E鄄mail:mizl@nercar.ustb.edu.cn ABSTRACT摇 The continuous cooling transformation (CCT) curves of experimental steel were determined by thermal dilation method with a DIL805 thermal dilatometer. Optical microscopy andscanelectronmicroscopy (SEM)wereusedtoanalyzetheeffect of heating temperature on the CCT curves and the microstructure of cooled samples. Experimental results show thatwhentheheatingtemperature decreasesfrom the complete austenitizing temperature to a higher temperature of the two鄄phase region,theferrite transformation of the CCT curve shifts totheleft. Andwhentheheatingtemperaturechangesinthetwo鄄phaseregion,theferritetransformationispostponed with the heating temperature decreasing,leading tothatthe CCT curve shiftstotheright. Theepitaxial growthmodeof newferriteand the carbon enrichment difference of austenite are principal factors that cause the shifts mentioned above. KEY WORDS摇 TRIP steel;continuous cooling transformation;microstructure;epitaxial growth 摇 摇 TRIP (transfo