SA508-3钢铸态粗晶组织热压缩变形行为与晶粒演化规律  

Hot deformation behavior and grain evolution of as-cast SA508-3 steel with coarse grain

作　　者：高亮[1] 陈飞[1] 隋大山[1] 冯国卫[1] 

机构地区：[1]上海交通大学模具CAD国家工程研究中心,上海200030

出　　处：《塑性工程学报》2015年第6期130-135,共6页Journal of Plasticity Engineering

基　　金：国家973资助项目(2011CB012903)

摘　　要：为获得SA508-3钢铸态粗晶组织热变形过程中的晶粒细化和均匀化规律,通过Gleeble单道次高温热压缩实验（950℃~1250℃,0.001s-1~1s-1,真应变ε=0.8）,发现铸态粗晶在低温硬化-回复阶段时的应力水平较锻态细晶的略高,通过金相分析发现,该现象是由铸态粗晶组织含有大量形变孪晶及其较差的变形协调性所致。同时分析了不同变形条件（温度和应变速率）对再结晶晶粒尺寸和混晶程度的影响规律,得到了动态再结晶完成后,变形温度为1 050℃~1 200℃、应变速率为0.01s-1~1s-1的变形参数对SA508-3钢铸态粗晶组织具有较好的细化晶粒作用,最高晶粒度可达6级~7级;1050℃~1200℃、0.001s-1~0.1s-1的变形参数可有效地降低SA508-3钢铸态粗晶组织的混晶程度,动态再结晶完成后组织比较均匀。In order to obtain the evolution of coarse-grain refinement and homogenization for as-cast SA508-3steel,the isothermal compression tests were conducted at different temperatures（950℃~1 250℃）and strain rates（0.001s-1~1s-1）on Gleeble-3500thermo-mechanical simulator.It is found that,in low temperatures,the as-cast coarse structure has higher flow stress compared to the forged fine structure in strain hardening stage,because the former one has poor deformation compatibility and numerous deformation twining.The grain size evolution with temperatures and strain rates was analyzed.It is shown that the optimal hot working conditions through dynamic recrystallization（DRX）for grain refinement of in-cast SA508-3steel were at the temperatures of 1 050℃~1200℃and strain rates of 0.01s-1~1s-1,and the optimal hot working conditions for structure homogenization were at the temperatures of 1 050℃~1 200℃ and strain rates of 0.001s-1~0.1s-1.

关 键 词：SA508-3钢 高温流动应力 粗晶细化 混晶 微观组织 

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