退火温度对超细晶中锰TRIP钢组织性能的影响  

Effects of annealing temperature on the microstructure and mechanical properties of ultrafine grained medium-manganese TRIP steel

作　　者：尹鸿祥[1] 赵爱民[1] 赵征志[1] 程俊业[1] 曾尚武[1] 惠亚军[1] 

机构地区：[1]北京科技大学冶金工程研究院,北京100083

出　　处：《北京科技大学学报》2014年第3期308-314,共7页Journal of University of Science and Technology Beijing

基　　金：国家自然科学基金资助项目(50904006);中央高校基本科研业务费专项资金资助项目(FRF--TP--10--001A);教育部博士学科点专项科研基金资助项目(20110006110007)

摘　　要：为研究连续退火工艺生产中锰TRIP钢汽车板的可行性，在钢板连续退火模拟机CCT- AY-域上研究了590~710℃不同退火温度下保温3 min对低碳中锰钢组织性能的影响.利用扫描电镜、透射电镜、电子背散射衍射和X射线能谱分析等微观分析方法对实验钢进行了组织结构和成分表征，利用X射线衍射法测量了残余奥氏体量，通过拉伸试验机测试了钢的单轴拉伸性能.结果表明：保温3 min时，随着保温温度的升高，残奥含量先增加后减少.在650℃退火时断后伸长率（21.3%）和强塑积（28 GPa·%）获得最大值，抗拉强度达到1330 MPa.马氏体基体通过回复，而残余奥氏体通过孪晶，获得超细晶组织.亚稳奥氏体的TRIP效应和超细晶铁素体（马氏体）共同提供了实验钢高的塑性.实验钢真实应力-应变曲线上呈现锯齿状现象，且稳定阶段加工硬化指数远高于传统TRIP钢.To study the feasibility of producing automobile steel from medium-manganese TRIP steel by continuous annealing processes, the effects of annealing temperature on the microstructure and mechanical properties of low-carbon medium-manganese steel were investigated on a heat treatment system CCT-AY-II for thin steel sheet at 590 to 710℃. The microstructure and components of the steel during annealing were characterized by scanning electron microscopy, transmission electron microscopy, electron backscatter diffraction, and energy dispersive X-ray spectroscopy. The amount of retained austenite in the steel was determined by X-ray diffraction analysis. The mechanical properties of the steel were investigated by uniaxial tensile testing. Experimental results show that after hold-ing for 3 min, the amount of retained austenite first increases and then decreases with increasing annealing temperature. The elongation and the product of strength and elongation reach their maximum values of 21.3% and 28 GPa·% for the steel annealed at 650℃, respectively, and the tensile strength is 1330 MPa. Ultra-fine grain structures are obtained by recovering for the martensitic matrix and by twinning for retained austenite. It is believed that the high plasticity is provided by the TRIP effect of metastable austenite and ultra-fine grained ferrite or martensite together. A zig-zag shape appears on the true stress-strain curve. The work hardening exponent of the steel is much larger than that of traditional TRIP steel at the relatively stable stage.

关 键 词：汽车材料 中锰钢 退火 微观结构 力学性能 加工硬化 

分 类 号：TG142.1[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]