汽车前轴用42CrMoH钢表面脱碳演变规律及控制  

Evolution and Control of Surface Decarburization in Automobile Front Axle Steel 42CrMoH

作　　者：张成成 马潇磊 张朝磊[1] 李戬 赵海东[3] 刘雅政[1] ZHANG Chengcheng;MA Xiaolei;ZHANG Chaolei;LI Jian;ZHAO Haidong;LIU Yazheng(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Mechanical Engineering,Qinghai University,Xining 810016,China;Xining Special Steel Co.Ltd,Qinghai Special Steel Engineering Technology Research Center,Xining 810005,China)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]青海大学机械工程学院,西宁810016 [3]西宁特殊钢股份有限公司,青海省特殊钢工程技术研究中心,西宁810005

出　　处：《材料导报》2020年第12期12127-12131,共5页Materials Reports

基　　金：青海省科技计划项目(2018-ZJ-747)。

摘　　要：采用42CrMoH钢制造的前轴表面存在0.10~0.15 mm深的完全脱碳层,严重影响了工件表面质量、硬度和疲劳性能。本工作通过等温加热实验,研究了加热温度对热轧态42CrMoH钢表面脱碳层类型和深度的影响,并综合分析了影响表面脱碳的因素。结果表明:保温时间为75 min时,42CrMoH钢在650~750℃和875~1250℃时,无完全脱碳层;完全脱碳层出现温度为750~875℃,完全脱碳层中铁素体为粗大的柱状晶,42CrMoH钢的一个完全脱碳的敏感温度为775~825℃,800℃时其完全脱碳层深度达到最大;42CrMoH钢部分脱碳也存在敏感温度(1150~1250℃),1200℃时,部分脱碳层深度达到最大。因此,为避免前轴表面出现完全脱碳层,42CrMoH钢热处理过程中的正火和淬火温度都应控制在875~885℃,且冷却过程中避免在750~875℃停留。此外,锻造余热淬火因省去正火和淬火加热过程,能有效地避免前轴表面出现完全脱碳层。The front axle made of 42CrMoH steel was found to have a complete decarburization layer of 0.10-0.15 mm deep on the surface of the workpiece,which seriously affects the surface quality,hardness and fatigue performance of the front axle.In this paper,the isothermal heating experiment was carried out to study the effects of heating temperature on the depth and type of decarburization layer of 42CrMoH steel,and the factors affecting surface decarburization were analyzed.The results show that when the heating time is 75 min,42CrMoH steel has only partial decarburization layer at 650-750℃and 875-1250℃;and the formation temperature of complete decarburization layer is 750-875℃,and the ferrite is the coarse columnar crystals in the complete decarburization layer,and there is a complete decarburization sensitive temperature range of 775-825℃,and the complete decarburization layer depth reaches the maximum at 800℃.Partial decarburization also has a sensitive temperature range of 1150-1250℃,and the depth reaches a maximum at 1200℃.Therefore,the normalizing and quenching temperatures of the 42CrMoH heat treatment should be controlled at 875-885℃,and avoid staying at 750-875℃for too long during the cooling process,in order to avoid the complete decarburization layer.In addition,due to normalizing and quenching heating processes are eliminated,residual heat of forging quenching can greatly avoid complete decarburization of the workpiece.

关 键 词：汽车零件 表面脱碳 加热温度 锻造余热淬火 

分 类 号：TG142.41[一般工业技术—材料科学与工程]