NM400钢终轧温度对其相变行为及残余应力的影响  

Effect of final rolling temperature on phase transformation behavior and residual stress of NM400 steel

作　　者：陈浩[1] 丁文红 方玉 鲁小轩 周莹涛 陈灏 Chen Hao;Ding Wenhong;Fang Yu;Lu Xiaoxuan;Zhou Yingtao;Chen Hao(School of Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan Hubei 430081,China;State Key Laboratory of Refractory Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan Hubei 430081,China)

机构地区：[1]武汉科技大学材料与冶金学院,湖北武汉430081 [2]武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北武汉430081

出　　处：《金属热处理》2023年第9期14-22,共9页Heat Treatment of Metals

基　　金：湖北省技术创新专项重大项目(2018AAA005)。

摘　　要：为研究某钢厂NM400钢不同终轧温度下的板形缺陷差异,借助Gleeble-3500热模拟试验机进行了压应力载荷作用下的膨胀试验,研究了终轧温度对NM400钢相变动力学及相变塑性的影响,并利用修正后的相变动力学以及相变塑性参数建立了ABAQUS有限元模型。使用裂纹柔度法对NM400钢进行残余应力测试,并将实测与模拟结果进行对比,验证了有限元模型的准确性。同时,采用EBSD对不同终轧温度试样的微观组织进行表征分析。结果表明,连续冷却过程中残余应力的形成分为3个阶段,包括温度应力主导阶段、表面相变主导阶段和心部相变主导阶段;终轧温度为860℃时,相变速率最大,导致表面先相变体积比820℃时大了17%,使心部开始相变时所受到的拉应力水平变大,轧后残余应力亦最大,生产加工过程中产生板形问题;终轧温度对轧后微观组织和相变塑性参数Κ的影响较小,不是造成轧后残余应力差异的决定性因素。In order to study the difference of shape defects of NM400 steel at different finishing rolling temperatures,the expansion test under compressive stress load was carried out by means of Gleeble-3500 thermal simulation testing machine.The effect of finishing rolling temperature on the phase transformation kinetics and phase transformation plasticity of the NM400 steel was studied,and the ABAQUS finite element model was established by using the modified phase transformation kinetics and phase transformation plasticity parameters.The residual stress of the NM400 steel was tested by crack flexibility method,and the accuracy of the finite element model was verified by comparing the measured and simulated results.At the same time,EBSD was used to characterize and analyze the microstructure of specimens with different finishing rolling temperatures.The results show that the formation of residual stress in the continuous cooling process is divided into three stages,including the dominant stage of temperature stress,the dominant stage of surface phase transformation and the dominant stage of core phase transformation.When the final rolling temperature is 860 ℃,the phase transformation rate is the largest,resulting in the surface phase transformation volume is 17 % larger than that at 820 ℃,so that the tensile stress level at the beginning of phase transformation becomes larger,and the residual stress after rolling is also the largest,resulting in plate shape problems during production and processing.The finishing rolling temperature has little effect on the microstructure and transformation plasticity parameter K after rolling,which is not the decisive factor causing the difference of residual stress after rolling.

关 键 词：马氏体 相变动力学 相变塑性 相变速率 残余应力仿真 

分 类 号：TG156.6[金属学及工艺—热处理]