残留奥氏体含量对20SiMn2MoV钢强韧性的影响  

Effect of Residual Austenite Content on Strength and Toughness of 20Si Mn2MoV Steel

作　　者：武保增[1] 高万夫[1] 雷晓维[1] 张东东[1] 

机构地区：[1]中国石油大学(北京)材料科学与工程系,北京102249

出　　处：《热加工工艺》2014年第20期51-55,共5页Hot Working Technology

摘　　要：采用新型Q-P-T（淬火-碳分配-回火）工艺对20SiMn2MoV钢进行热处理，通过改变淬火介质温度（QT）和碳分配＋回火时间（PT＋TT），改变其组织，旨在提高钢的强韧性。利用扫描电镜（SEM）、X射线衍射仪（XRD）和力学性能测试等手段，研究了新型Q-P-T工艺对20SiMn2MoV钢、微观组织及其对力学性能的影响。结果表明，20SiMn2MoV钢经Q-P-T工艺处理获得了板条马氏体＋含量较多的残留奥氏体，残留奥氏体含量为8％～11％；试样拉断后，测量试样中残留奥氏体的体积分数变化，显示了残留奥氏体量明显减少。通过对比应力-应变曲线发现，在缩颈前试样曲线斜率发生了明显变化．因此，20SiMn2MoV钢在拉伸过程中表现出明显的相变诱发塑性（TRIP）效应；淬火介质温度为110℃，碳分配90s时。钢的抗拉强度为1331MPa，伸长率达23．0％，强塑积为30613MPa％，具有优良的强韧性匹配．强韧性得到提高。Adopting a new Q-P-T（Quenching-＇Partitioning-Tempering） technique to heat 20SiMn2MoV steel, by changing the quenching temperature （QT） and carbon partitioning＋tempering time （PT＋TT）, aiming at altering the texture of the steel, the strength and toughness of the alloy improve. In order to study the influence of the new Q-P-T technique on the microstructure and mechanical property of the steel. The scanning electron microscopy （SEM）, X-ray Diffraction （XRD） and mechanics performance testing were employed. The results show that the process of the new Q-P-T technique to the steel have obtained the lath martensite and lots of the retained austenite, the percentage composition is between 8% and 11%. After the samples are pulled, the variation of the volume percentage of the retained austenite indicates that the percentage composition of it reduces significantly. In addition, it finds that obvious changes have taken place in the sample curve slope anterior portion by comparing the stress-train curves before the shrinkage. So the steel shows obvious TRIP effect during the stretching process. When the steel is quenched at the medium temperature of 110℃, as well as the carbon allocation being 90s, the tensile strength is 1331MPa, the elongation is 23.0% and the product of strength and elongation reaches 30613MPa .%. The performance parameter manifests that the strength and toughness of the steel obviously increase.

关 键 词：20SiMn2MoV钢 淬火-碳分配-回火工艺 强韧性 相变诱发塑性(TRIP)效应 显微组织 

分 类 号：TG156.3[金属学及工艺—热处理] TG156.5[金属学及工艺—金属学]