42CrMo汽车转向节热处理裂纹形成机理  

Formation mechanism of heat treatment crack in 42CrMo automobile steering knuckle

作　　者：秦怡 汪西 周杰[1] 李生仕 朱荣宇 王国文 彭海军 QIN Yi;WANG Xi;ZHOU Jie;LI Sheng-shi;ZHU Rong-yu;WANG Guo-wen;PENG Hai-jun(College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China;Hubei Tri-Ring Forging Co.,Ltd.,Xiangyang 441700,China;Chongqing Jiepin Technology Co.,Ltd.,Chongqing 401329,China)

机构地区：[1]重庆大学材料科学与工程学院,重庆400044 [2]湖北三环锻造有限公司,湖北襄阳441700 [3]重庆杰品科技股份有限公司,重庆401329

出　　处：《塑性工程学报》2024年第8期216-224,共9页Journal of Plasticity Engineering

基　　金：型腔表层梯度强化与网构化制备长寿命大型锻模新方法基础研究(52075058);重庆市技术创新与应用发展专项项目(cstc2022ycjh-bgzxm0224)。

摘　　要：针对锻件热处理后出现的单枝上表面裂纹问题,基于宏微观热处理有限元数值仿真模拟对裂纹进行了分析,并探究了裂纹的形成机理。通过光学显微镜和能谱仪分析可知该裂纹与典型淬火裂纹形貌相似,且裂纹附近没有脱碳现象,但是存在明显氧化现象,确定该裂纹在淬火阶段产生,在回火阶段发生氧化。结合应力模拟结果可以判定前期单枝表面急速冷却收缩,主要是由于产生了表面x方向拉应力而导致的裂纹。由此分析了单枝表面在该时期的最大x方向拉应力的分布情况,发现其与实际裂纹出现区域基本重合,进一步证明了该裂纹产生机理的正确性。Aiming at the problem of crack on the upper surface of a single branch of forging after heat treatment,the crack was analyzed based on the finite element numerical simulation of macro and micro heat treatment,and the forming mechanism of the crack was explored.Optical microscope(OM)and energy dispersive spectrometer(EDS)analysis show that the crack is similar to the typical quenching crack,and there is no decarburization phenomenon near the crack but obvious oxidation phenomenon.It is determined that the crack is generated in quenching stage and oxidized in tempering stage.Combined with the stress simulation results,it can be concluded that the rapid cooling shrinkage of the single branch surface in the early stage is mainly due to the crack caused by the surface tensile stress in x direction.The distribution of the maximum tensile stress in x direction on the single branch surface during this period was analyzed,and it is found that it basically coincides with the actual crack occurrence area,which further proves the correctness of the crack generation mechanism.

关 键 词：转向节 淬火裂纹 数值模拟 

分 类 号：TG162.7[金属学及工艺—热处理]