车身用22MnB5超高强热成形钢的热变形行为及热加工图  

Hot Deformation Behavior and Hot Processing Map of Hot-formed 22MnB5 Ultra-high Strength Steel for Automobile Body

作　　者：汤迁 郭鹏程 罗红[1] 马洪浩 张立强 李落星[2] TANG Qian;GUO Pengcheng;LUO Hong;MA Honghao;ZHANG Liqiang;LI Luoxing(College of Mechanical and Electrical Engineering,Central South University of Forestry and Technology,Changsha 410004,China;State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,Hunan University,Changsha 410082,China)

机构地区：[1]中南林业科技大学机电工程学院,长沙410004 [2]湖南大学汽车车身先进设计制造国家重点实验室,长沙410082

出　　处：《材料导报》2023年第18期206-212,共7页Materials Reports

基　　金：国家自然科学基金(U20A20275);湖南省教育厅科学研究项目(18B193);湖南省研究生科研创新项目(CX20220734)。

摘　　要：为确定22MnB5硼钢的热成形工艺,采用Gleeble-1500D热模拟试验机进行热模拟拉伸实验,变形温度为773~1223 K,应变速率为0.01~10 s^(-1)。结果表明:22MnB5硼钢具有较强的正应变速率敏感性,其峰值应力随变形温度的升高而减小;除773 K/0.01 s^(-1)外,硼钢的流变应力随应变的增大逐渐增大,当达到峰值后趋于稳定;采用Arrhenius双曲正弦函数模型建立了硼钢的力学本构方程,确定了峰值应力下的热变形激活能Q为26.54~53.77 kJ/mol,其值随应变速率的增加先增大后减小,随变形温度的升高先减小后增大;基于动态材料模型构建了峰值应力下的硼钢热加工图,其热成形显微组织与变形温度和应变速率密切相关。基于此,确定了硼钢的热加工工艺:成形温度988~1058 K、应变速率0.01~0.1 s^(-1);成形温度1143~1223 K、应变速率0.01~0.02 s^(-1)。To determine the hot forming processes of 22MnB5 boron steel,hot tensile tests were carried out at temperatures of 773—1223 K and strain rates of 0.01—10 s^(-1)using Gleeble-1500D thermal simulation machine.The results show that the studied steel shows strong positive strain rate sensitivity,and its peak stress decreases with the increase of deformation temperature.Except for that deformed at 0.01 s^(-1)and 773 K,the flow stress increases gradually with the increase of applied strain,and then tends to be stable when it reaches the peak stress.The mechanical constitutive equation of the studied steel is established based on the Arrhenius hyperbolic sine function model,and the activation energy Q of thermal deformation at peak stress is determined(26.54—53.77 kJ/mol).The Q first increases followed by decrease with the increase of applied strain rate,and decreases followed by increase with the increase of deformation temperature.The hot working map of the studied boron steel with peak stress is constructed based on the dynamic material model,and the hot forming microstructure is closely related to deformation temperature and strain rate.Based on the above analysis,the hot working process of the studied boron steel is confirmed:forming temperature 988—1058 K,strain rate 0.01—0.1 s^(-1);forming temperature 1143—1223 K,strain rate 0.01—0.02 s^(-1).

关 键 词：22MnB5硼钢 热变形行为 热加工图 显微组织 

分 类 号：TG306[金属学及工艺—金属压力加工]