摘要
设计了一种热轧型TRIP800汽车用钢,研究了其高温热塑性和热加工后的连续冷却相变行为,并对热轧后的TRIP800钢进行了力学性能测试和微观组织标定。试验结果表明:750~1050℃为试验钢的低塑性区,1100~1350℃为高塑性区。在高塑性区间,ψ值先增加后降低,在1150~1250℃温度区间具有ψ的最大值,均大于90%;热变形后,以5℃/s为临界冷速,低于此冷速时,只发生铁素体相变,高于此临界冷速后开始发生贝氏体相变,冷速增大至30℃/s后,开始发生马氏体相变;热轧后,随卷取温度的升高,屈服强度和抗拉强度均降低,伸长率提高,在600℃的卷取温度下具有最优的综合力学性能。热轧卷取后的组织由铁素体、贝氏体和残留奥氏体组成,其中残留奥氏体存在两种形态,一是呈膜状分布在铁素体晶界或贝氏体板条间,二是呈块状分布于铁素体晶界。
A hot rolling TRIP800 steel was designed,the high temperature thermoplasticity and the continuous cooling phase transformation behavior after hot processing were studied,the mechanical property test and microstructure calibration of the steel were carried out after hot rolling.The results indicate that the low thermoplasticity zone is ranging from 750℃to 1050℃,while the high zone is ranging from 1100℃to1350℃.In the high plasticity zone,ψvalue increases first and then decreases and has its peak value of 90%in the range of 1150-1250℃.After hot working,only ferrite transformation occurs when the cooling rate is lower than 5℃/s,and bainite transformation occurs after the cooling rate is higher.Martensite transformation occurs when the cooling rate is higher than 30℃/s.For hot rolled TRIP800 steel,the yield strength and tensile strength increase with the decreasing of coiling temperature,while the elongation decreases.The best comprehensive mechanical properties are obtained at 600℃.The microstructure after hot rolling is composed of ferrite,bainite and retained austenite(RA),where the RA has two morphologies,the film RA between ferrite or bainite plates,and the blocky ones between ferrite grains.
作者
王军庆
张倩
刘晓滕
李辉
Wang Junqing;Zhang Qian;Liu Xiaoteng;Li Hui(Yantai Nanshan University,Yantai Shandong265713,China;National Engineering Research Center for Plastic Working of Aluminum Alloys,Shandong Nanshan AluminumCo.,Ltd.,Yantai Shandong265700,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2019年第9期64-68,共5页
Heat Treatment of Metals
基金
山东省自然科学基金(ZR2018MEM007)
