42CrMo4钢高温拉伸断裂准则与机理的研究  

Study on Tensile Fracture Criterion and Mechanism of 42CrMo4 Steel at High Temperature

作　　者：单陇红 王凌浩 刘顺彭 李家学 SHAN Longhong;WANG Linghao;LIU Shunpeng;LI Jiaxue(Department of Industrial Automation,Guang Dong Polytechnic College,Zhaoqing 526100,China)

机构地区：[1]广东理工学院工业自动化系,广东肇庆526100

出　　处：《热加工工艺》2021年第4期59-62,67,共5页Hot Working Technology

基　　金：广东省普通高校青年创新人才类项目(自然科学类)(2018-KQNCX311);广东理工学院创新强校工程项目(GKJ2018003)。

摘　　要：由于变形温度和应变速率是影响42CrMo4钢高温变形损伤断裂行为的重要因素,因此综合考虑了变形温度和应变速率对材料断裂的影响。基于Cockroft-Latham断裂准则,引入温度补偿应变速率因子Zener-Hollomon参数作为修正系数对Cockroft-Latham断裂准则进行改进。通过Gleeble-3800D热模拟试验机对42CrMo4钢进行了温度为950~1100℃、应变速率为0.01~10 s-1条件下的高温拉伸试验。利用试验结果采用线性拟合确定修正系数,得到改进后的断裂准则,将准则预测结果与试验结构对比验证,二则能很好吻合。利用扫描电镜观察试样拉伸断裂断口的组织形貌。结果表明:42CrMo4钢高温拉伸断裂是典型韧窝型韧性断裂,随着温度的提升,材料塑韧性明显提高;随应变速率的提高,材料塑韧性随之不显著降低。Because the deformation temperature and strain rate are important factors affecting the deformation damage and fracture behavior of 42CrMo4 steel at high temperature, the influence of deformation temperature and strain rate on the material fracture was considered comprehensively. Based on the Cockroft-Latham fault criterion, the temperature compensation strain rate factor Zener-Hollomon parameter was introduced as a correction coefficient to improve the Cockroft-Latham fault criteria. Through the Gleeble-3500 D thermal simulation test machine, 42CrMo4 steel was tested with the temperature from 950 ℃ to 1 100 ℃ and the strain rate from 0.01 s-1 to 10 s-1. Using the results of the experiment, the correction coefficient was determined by using linear fitting results, and the improved fracture criteria are obtained. The comparison between the predicted results and the experimental results show that they are in good agreement. The microstructure of tensile fracture was observed by SEM. The results show that the high temperature tensile fracture of 42CrMo4 steel is a typical ductile fracture. With the increase of temperature, the material plastic toughness obviously improves, and with the increase of strain rate, the plastic toughness the material does not significantly reduce.

关 键 词：42CrMo4钢 Cockroft-Latham断裂准则 ZENER-HOLLOMON参数 韧性断裂 

分 类 号：TG146.2[一般工业技术—材料科学与工程]