42CrMo钢圆坯芯部热裂形成条件热模拟  

Thermal simulation of hot tearing formation conditions in center of 42CrMo steel round bloom

作　　者：陈美成 赵宇[1] 郭庆涛 林增煌 仲红刚[1] 翟启杰[1] CHEN Meicheng;ZHAO Yu;GUO Qingtao;LIN Zenghuang;ZHONG Honggang;ZHAI Qijie(Center for Advanced Solidification Technology,Shanghai University,Shanghai 200444,China;Ansteel Beijing Research Institute Co.,Ltd.,Beijing 102209,China)

机构地区：[1]上海大学先进凝固技术中心,上海200444 [2]鞍钢集团北京研究院有限公司,北京102209

出　　处：《中国冶金》2023年第6期65-72,132,共9页China Metallurgy

基　　金：国家自然科学基金资助项目(52171039);河北省重点研发计划资助项目(20311006D)。

摘　　要：芯部裂纹是大断面连铸圆坯的主要缺陷,严重影响铸坯及轧材质量。由于缺乏定量判据,铸坯芯部裂纹的准确预测成为业界难题。结合数值模拟和凝固过程热模拟方法,研究了42CrMo钢连铸圆坯芯部热裂纹形成条件,并对铸坯芯部热裂风险进行了评估。首先,通过有限元模型计算了42CrMo钢圆坯芯部冷却速率和凝固末期的应变速率,为热模拟试验提供控制参数;然后,利用凝固裂纹热模拟装置再现了铸坯芯部凝固过程并在凝固末期主动加载,获得42CrMo钢圆坯芯部热裂纹形成的临界应变速率为2.12×10^(-4)~2.82×10^(-4)/s,热裂温度为1452℃,断裂应力为0.67 MPa。比较数值模拟与热模拟结果表明,当前连铸条件下铸坯中心热裂风险高,极易形成热裂纹。本研究也为连铸坯热裂风险评估提供了新的途径。The central crack is the main defect of large section continuous casting round blooms,which seriously affects the quality of blooms and rolled products.Due to the lack of quantitative criteria,the accurate prediction for central crack of bloom has become a difficult problem in metallurgy industry.Combined with numerical simulation and thermal simulation method of solidification process,the critical conditions of hot tearing formation in the center of 42CrMo steel continuous casting round bloom were studied,and its risk in the center of bloom was evaluated.Firstly,through finite element simulation,the cooling rate at the center of 42CrMo steel round bloom and the strain rate at the end of solidification were calculated under continuous casting conditions to provide control parameters for thermal simulation test.Furthermore,taking the center of bloom as the characteristic unit,using the hot tearing thermal simulator to reoccure its cooling rate and actively loading at the end of solidification,the critical conditions for hot tearing of 42CrMo steel under continuous casting conditions were obtained.The critical strain rate for hot tearing is 2.12×10^(-4)~2.82×10^(-4)/s,the fracture temperature is around 1452℃,and the fracture stress is O.67 MPa.The comparison of numerical simulation and thermal simulation result shows that under the current continuous casting conditions,the risk of hot tearing in the center of bloom is high,and hot tearing is easily formed and propagated.This study also provides a new way of the assessment for hot tearing risk of continuous castings.

关 键 词：连铸 热裂 热模拟 数值模拟 应变速率 

分 类 号：TF777[冶金工程—钢铁冶金]