20CrMnTi钢齿轮残余奥氏体异常分析及解决方案  

Analysis and Solution for Abnormal Retained Austenite of 20CrMnTi Steel Gear

作　　者：刘洪波 高力 芈志杰 李红印 邹鹏 陈炳欣 LIU Hong-bo;GAO Li;MI Zhi-jie;LI Hong-yin;ZOU Peng;CHEN Bing-xin(Fin Dreams Powertrain Co.,Ltd.,Grear Factory,Anyang Henan 455000,China)

机构地区：[1]弗迪动力有限公司齿轮工厂,河南安阳455000

出　　处：《热处理技术与装备》2024年第1期33-36,共4页Heat Treatment Technology and Equipment

摘　　要：采用金相显微镜和维氏硬度计对20CrMnTi钢齿轮发白部位进行金相组织观察和硬度测试,分析齿轮经真空低压渗碳热处理后产生表面局部发白现象的原因,并提出解决方案。结果表明发白部位存在大量残余奥氏体,齿面残余奥氏体深度范围为45~170μm,且齿面存在大尺寸碳化物。距表面0.05 mm处硬度只有505 HV_(1),远低于技术要求的660~750 HV_(1)。通过对设备及工艺过程检查,发现齿轮表面残余奥氏体超标是由乙炔泄漏进入转移通道内造成工件在淬火转移过程中表面二次渗碳导致的。The microstructure and hardness of the white area on 20CrMnTi steel gear were observed and teseted by metallographic microscope and hardness tester.The main reason for the white area after vacuum low-pressure carburizing heat treatment was analyzed,and the solution was put forward.The results showed that large amount of residual austenite in the white area with depth of 45 to 170μm on the tooth surface,and there were large-sized carbides on the tooth surface.The hardness at a distance of 0.05 mm from the surface was only 505 HV_(1),which was far below the technical requirements characteristics of 660 to 750 HV_(1).It was found that the main reason for excessive retained austenite on the surface of gears was that the leakage of acetylene into transfer channel,which caused secondary carburization on the surface of the surface of workpiece during transfer process.

关 键 词：真空低压渗碳 20CRMNTI钢 残余奥氏体 

分 类 号：TG156.81[金属学及工艺—热处理]