后桥主减速器壳体轴承座材料裂解性能数值分析  

Numerical Analysis of Material Fracture Splitting Performance of Rear Axle’s Main Reducer Shell Bearing Seat

作　　者：寇淑清[1] 修亭亭 金文明[1] 赵勇[1] 姚娟 KOU Shuqing;XIU Tingting;JIN Wenming;ZHAO Yong;YAO Juan(Roll Forging Institute,Jilin University,Jilin 130022,Changchun,China;College of Materials Science and Engineering,Jilin University,Jilin 130022,Changchun,China;Geely Automobile Research Institute(Ningbo) Co.,LTD.Ningbo 315336,Zhejiang,China)

机构地区：[1]吉林大学辊锻工艺研究所,吉林长春130022 [2]吉林大学材料科学与工程学院,吉林长春130022 [3]吉利汽车研究院(宁波)有限公司,浙江宁波315336

出　　处：《华南理工大学学报（自然科学版）》2019年第7期121-127,135,共8页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家科技重大专项(2013ZX04002021)~~

摘　　要：对基体组织为25%P+75%F和50%P+50%F的后桥主减速器壳体轴承座材料QT450的显微组织进行比较,以研究组织与裂解性的内在联系.首先,对不同金相组织的QT450试件进行拉伸试验,获取数值模拟所需的材料参数,并与模拟相结合,分别确定两种基体组织的临界断裂韧度JIC,利用ABAQUS模拟获得不同显微组织的QT450的裂解载荷及应力集中程度;然后建立回弹模型,分析两种组织的塑性变形及失圆;最后进行裂解试验对数值分析的有效性进行验证.结果表明:基体为50%珠光体+50%铁素体的QT450相比基体为25%珠光体+75%铁素体的QT450更适于裂解;QT450材料的强度和刚度取决于珠光体的含量,随珠光体含量的上升,材料的脆硬性好,缺口敏感性好,其裂解性能更佳;采用基体组织为25%珠光体+75%铁素体的QT450生产的轴承座的失圆度大于0.2mm,无法完成后续精加工及装配,而采用基体组织为50%珠光体+50%铁素体的QT450材料生产的轴承座的失圆度小于0.2mm,裂解产生的塑性变形小,更符合实际生产的工艺要求.The microstructure of rear axle main reducer shell bearing seat material QT450 with 25% P+75%F and 50%P+50%F was compared to study the internal relation between structure and fracture splitting performance .Firstly,tensile tests were performed on the QT450 specimens with different metallographic structure to obtain the material parameters required for numerical simulation.Combined with the simulation,the critical fracture toughness J IC of the two matrix tissues was determined respectively.The fracture-splitting force and the stress concentration of QT450 with different microstructures were obtained by ABAQUS.Then a springback model was established to analyze the plastic deformation and out-of-roundness of the two tissues.Finally,the fracture splitting test was carried out to verify the validity of the numerical analysis.The results show that QT450 with 50% pearlite + 50% ferrite is more suitable for the fracture splitting than QT450 with 25% pearlite + 75% ferrite.The strength and stiffness of QT450 material depend on the content of pearlite.With the increase of pearlite content,the brittleness of the material,the notch sensitivity increase and the fracture splitting performance are all improved.The shell bearing seat produced by QT450 with 25% pearlite + 75% ferrite matrix has an out-of-roundness of more than 0.2 mm,which can not complete the subsequent finishing and assembly.While the shell bearing seat produced by QT450 material with 50% pearlite + 50% ferrite has an out-of-roundness of less than 0.2 mm,and the plastic deformation caused by fracture splitting is small,so it can well meet the requirement of the actual production process.

关 键 词：QT450 后桥主减速器壳体轴承座 裂解性能 金相组织 临界断裂韧度 数值分析 塑性变形 

分 类 号：TK406[动力工程及工程热物理—动力机械及工程]