D0L:10.13374/.issn1001-053x.2013.11.009 第35卷第11期 北京科技大学学报 Vol.35 No.11 2013年11月 Journal of University of Science and Technology Beijing Nov.2013 超细晶中锰钢温轧强化增塑机理 曹佳丽，赵爱民☒，李振，尹鸿祥，黄耀 北京科技大学高效轧制因家工程研究中心，北京100083 ☒通信作者，E-mail:aimin.zhao@ustb.edu.cn 摘要采用Gleeble-3500热模拟试验机测定了不同温度下中锰钢的变形抗力，并通过分阶段拉伸、扫描电镜、电子背 散射衍射、X射线衍射等实验手段，对温轧中锰钢中逆转变奥氏体的相变行为进行观察和分析。研究发现，热轧马氏体 中锰钢经过600℃温轧及退火后，获得较多较稳定的残余奥氏体，从而实现强度859MPa和延伸率36%的优良力学性 能。拉伸变形前期，锯齿状流变应力现象明显，残余奥氏体提供持续的TP效应来提高塑性，此过程中尺寸较大的逆 转变奥氏体稳定性差，变形时先发生转变：拉伸变形后期，锯齿状波动消失，超细晶铁素体和马氏体发生塑性变形，马 氏体强化及铁素体中的位错强化为主要强化方式。 关键词中锰钢：轧制：强化：塑性：奥氏体 分类号TG335.3 Mechanism of strengthening and plasticity improvement in warm rolling medium manganese steel with ultrafine grains CAO Jia-li,ZHAO Ai-min,LI Zhen,YIN Hong-riang,HUANG Yao National Engineering Research Center for Advanced Rolling Technology,University of Science and Technology Beijing,Beijing 100083,China Corresponding author,E-mail:aimin.zhaoQustb.edu.cn ABSTRACT The deformation resistance of medium manganese steel at different temperatures was measured on a Gleeble-3500 thermo-simulator system.Reverted austenite transformation in medium manganese steel during warm rolling was investigated by means of tensile testing by stages,scanning electron microscopy(SEM),electron back scattered diffraction(EBSD),and X-ray diffraction (XRD).It is shown that warm rolling at 600 C and annealing after hot rolling result in more reverted austenite,and excellent mechanical properties are gained with 859 MPa strength and 36% elongation.In the earlier stage of tensile deformation,serrate flow stress behavior is obviously observed because of sustained TRIP effect produced by reverted austenite.During the deformation,reverted austenite with a larger grain size is prior to transform because its stability is poor.In the later stage of tensile deformation,serrate flow stress behavior disappears.Ultrafine grain ferrite and martensite undergo plastic deformation,and martensite strengthening and dislocation strengthening of ferrite become the main strengthening mechanism. KEY WORDS medium manganese steel;rolling;austenite;strengthening;plasticity 近年来，中锰TRP钢被认为是性能优异的第完全的马氏体组织.但随之而来的问题是，具有马 三代汽车钢而吸引了较多的研究-到。在中锰钢 氏体组织的钢是高强度和高硬度的，常温变形时抗 中，由于适量锰元素的添加，其过冷奥氏体连续冷 力相当大，现有的试验设备对其进行较大的冷轧压 却转变(CCT)曲线右移，淬透性提高，热轧后得到 下量是相当困难的.为了解决这个问题，李楠等4 收稿日期：2012-11-13 基金项目：高等学校博士学科点专项科研基金资助项目(20110006110007)第 35 卷 第 11 期 北 京 科 技 大 学 学 报 Vol. 35 No. 11 2013 年 11 月 Journal of University of Science and Technology Beijing Nov. 2013 超细晶中锰钢温轧强化增塑机理 曹佳丽，赵爱民 ，李 振，尹鸿祥，黄 耀 北京科技大学高效轧制国家工程研究中心，北京 100083 通信作者，E-mail: aimin.zhao@ustb.edu.cn 摘 要 采用 Gleeble-3500 热模拟试验机测定了不同温度下中锰钢的变形抗力，并通过分阶段拉伸、扫描电镜、电子背 散射衍射、X 射线衍射等实验手段，对温轧中锰钢中逆转变奥氏体的相变行为进行观察和分析。研究发现，热轧马氏体 中锰钢经过 600 ℃温轧及退火后，获得较多较稳定的残余奥氏体，从而实现强度 859 MPa 和延伸率 36%的优良力学性 能。拉伸变形前期，锯齿状流变应力现象明显，残余奥氏体提供持续的 TRIP 效应来提高塑性，此过程中尺寸较大的逆 转变奥氏体稳定性差，变形时先发生转变；拉伸变形后期，锯齿状波动消失，超细晶铁素体和马氏体发生塑性变形，马 氏体强化及铁素体中的位错强化为主要强化方式。 关键词 中锰钢；轧制；强化；塑性；奥氏体 分类号 TG335.3 Mechanism of strengthening and plasticity improvement in warm rolling medium manganese steel with ultrafine grains CAO Jia-li, ZHAO Ai-min , LI Zhen, YIN Hong-xiang, HUANG Yao National Engineering Research Center for Advanced Rolling Technology, University of Science and Technology Beijing, Beijing 100083, China Corresponding author, E-mail: aimin.zhao@ustb.edu.cn ABSTRACT The deformation resistance of medium manganese steel at different temperatures was measured on a Gleeble-3500 thermo-simulator system. Reverted austenite transformation in medium manganese steel during warm rolling was investigated by means of tensile testing by stages, scanning electron microscopy (SEM), electron back scattered diffraction (EBSD), and X-ray diffraction (XRD). It is shown that warm rolling at 600 ℃ and annealing after hot rolling result in more reverted austenite, and excellent mechanical properties are gained with 859 MPa strength and 36% elongation. In the earlier stage of tensile deformation, serrate flow stress behavior is obviously observed because of sustained TRIP effect produced by reverted austenite. During the deformation, reverted austenite with a larger grain size is prior to transform because its stability is poor. In the later stage of tensile deformation, serrate flow stress behavior disappears. Ultrafine grain ferrite and martensite undergo plastic deformation, and martensite strengthening and dislocation strengthening of ferrite become the main strengthening mechanism. KEY WORDS medium manganese steel; rolling; austenite; strengthening; plasticity 近年来，中锰 TRIP 钢被认为是性能优异的第 三代汽车钢而吸引了较多的研究 [1−3]。在中锰钢 中，由于适量锰元素的添加，其过冷奥氏体连续冷 却转变 (CCT) 曲线右移，淬透性提高，热轧后得到 完全的马氏体组织. 但随之而来的问题是，具有马 氏体组织的钢是高强度和高硬度的，常温变形时抗 力相当大，现有的试验设备对其进行较大的冷轧压 下量是相当困难的. 为了解决这个问题，李楠等 [4] 收稿日期：2012-11-13 基金项目：高等学校博士学科点专项科研基金资助项目 (20110006110007) DOI:10.13374/j.issn1001-053x.2013.11.009