逆相变退火温度对低密度中锰钢组织和力学性能的影响  

Effect of reverse transformation annealing temperature on microstructure and mechanical properties of a low-density medium manganese steel

作　　者：余灿生 蒋家乐 李云杰[1] 常智渊 康健[1] 袁国[1] Yu Cansheng;Jiang Jiale;Li Yunjie;Chang Zhiyuan;Kang Jian;Yuan Guo(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang Liaoning 110819,China;State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization,Pangang Group Research Institute Co.,Ltd.,Panzhihua Sichuan 617000,China)

机构地区：[1]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819 [2]攀钢集团研究院有限公司、钒钛资源综合利用国家重点实验室,四川攀枝花617000

出　　处：《金属热处理》2024年第11期118-122,共5页Heat Treatment of Metals

基　　金：辽宁省科学技术计划(2022-MS-109);钒钛资源综合利用国家重点实验室开放基金(2021P4FZG07A)。

摘　　要：针对实现汽车轻量化成本过高且高强度和高塑性无法兼具的问题,设计了一种成分为0.36C-4.5Al-7.6Mn-0.31V-0.31Si-0.07Ti的低密度中锰钢,利用OM、SEM、EBSD、XRD和拉伸试验机,探究了不同逆相变退火温度对低密度中锰钢微观组织构成、残留奥氏体(含量、稳定性及奥氏体内位错密度)和力学性能的影响。结果表明,试验钢逆相变退火态为沿轧制方向长条状的δ铁素体、板条状马氏体和块状残留奥氏体的混合组织。逆相变退火温度由650℃升高至780℃时,马氏体含量减少,残留奥氏体含量由50.14%升高至58.97%,奥氏体平均晶粒尺寸先增大后减小,奥氏体KAM值(与位错密度成正比)呈相反趋势。当采用780℃逆相变退火1 h时,试验钢可获得最佳的力学性能,屈服强度为739.1 MPa,抗拉强度为884.2 MPa,伸长率为37.80%,强塑积为33.42 GPa·%。To address the high costs of achieving lightweight automobiles while simultaneously obtaining high strength and high plasticity,a low-density medium manganese steel with the composition 0.36C-4.5Al-7.6Mn-0.31V-0.31Si-0.07Ti was developed.The effect of various reverse transformation annealing temperature on the microstructure,retained austenite(content,stability and dislocation density)and mechanical properties of the low-density medium manganese steel was explored by means of OM,SEM,EBSD,XRD and tensile testing machine.The results indicate that the reverse transformation annealed experimental steel comprises a mixed structure of elongatedδferrite,lath martensite and blocky retained austenite along the rolling direction.As the reverse transformation annealing temperature increases from 650℃to 780℃,the martensite content decreases,the retained austenite content rises from 50.14%to 58.97%,the average austenite grain size increases first and then decreases,while the austenite KAM value(proportional to dislocation density)shows the opposite trend.Optimal mechanical properties of the tested steel are achieved when reverse transformation annealed at 780℃for 1 h,with yield strength of 739.1 MPa,tensile strength of 884.2 MPa,elongation of 37.80%and the product of strength and elongation of 33.42 GPa·%.

关 键 词：低密度中锰钢 TRIP效应 逆相变退火 残留奥氏体 

分 类 号：TG156.21[金属学及工艺—热处理]