汽车用驻车棘轮制造过程中裂纹形成原因分析  

Analysis on cause of crack formation in manufacturing process of automotive parking ratchet

作　　者：谢小春 胡静[1,2] Xie Xiaochun;Hu Jing(Jiangsu Key Laboratory of Materials Surface Science and Technology,Changzhou University,Changzhou Jiangsu 213164,China;National Experimental Demonstration Center for Materials Science and Engineering,Changzhou University,Changzhou Jiangsu 213164,China)

机构地区：[1]常州大学江苏省材料表面科学与技术重点实验室,江苏常州213164 [2]常州大学材料科学与工程国家级实验教学示范中心,江苏常州213164

出　　处：《金属热处理》2025年第3期297-302,共6页Heat Treatment of Metals

基　　金：江苏省第三期优势学科建设项目(PAPD-3);江苏高校品牌专业建设工程项目(TAPP);常州市科技项目(CJ20245044)。

摘　　要：在实际生产过程中,驻车棘轮经渗碳淬火后,在磨削平面时发现磨面存在裂纹,致使其报废。为寻找驻车棘轮热处理+磨削后表面开裂原因和提出后续管控措施,利用显微硬度计、扫描电镜及能谱仪、X射线应力分析仪等表征手段对裂纹件进行测试和分析,并对正常件进行再现性测试和对比分析。结果表明,驻车棘轮裂纹件渗碳淬火后组织正常,表面残余应力状态正常,裂纹处没有氧化脱碳和增碳,磨削无烧伤,零件表面有氧化物夹杂。因此,判断本批次驻车棘轮产生表面裂纹的根本原因为原料自身存在氧化物夹杂含量过高的缺陷。本研究为生产过程中汽车驻车棘轮裂纹的失效分析提供一个可行的方法,并提出监测原材料来料表面夹杂、缩短热处理淬火和回火的间隔时间、控制热处理表面金相组织和优化磨削参数等防止裂纹产生的管控措施。In the actual production process,cracks are found in the grinding surface of the parking ratchet after carburizing and quenching,and it would lead to the scrap of the parts.In order to find out the cause of surface cracking after heat treatment and grinding of the parking ratchet and subsequent control measures,the crack parts were tested and analyzed by using microhardness tester,scanning electron microscope,energy spectrometer,X-ray stress analyzer and other characterization means,and the reproducibility test was conducted with normal parts and relevant indicators were compared.The results show that the carburizing and quenching microstructure of the cracked parts of the parking ratchet is normal,the surface residual stress is normal,there is no oxidation decarburization and carburization at the crack,there is no burn in grinding,and there are metal oxide inclusions on the surface of the parts.The root cause of surface cracks is the defects of oxide inclusions in the raw materials.This study provides a feasible direction for failure analysis.Some control measures to prevent cracks are put forward,such as monitoring the inclusions on the surface of raw materials,shortening the interval time of quenching and tempering,controlling the microstructure of the surface of heat treatment and optimizing the grinding parameters.

关 键 词：20MnCrS5 HL钢 驻车棘轮 渗碳淬火 裂纹 磨削 压应力 拉应力 金属氧化物 

分 类 号：TG156.8[金属学及工艺—热处理]