摘要
为了研究激光淬火对LZ50车轴钢组织形貌及摩擦磨损性能的影响,对LZ50车轴钢进行表面激光淬火处理。采用金相显微镜分析了LZ50车轴钢淬火前后的组织及晶粒度,通过场发射扫描电镜分析了淬火硬化层的界面形貌,利用X射线残余应力衍射仪分析了残余应力及残余奥氏体含量,利用摩擦磨损试验机研究了摩擦系数和磨损形貌,讨论了激光淬火对摩擦系数和磨损机制的影响。结果表明:激光淬火之后,LZ50车轴钢组织由粗大的珠光体+铁素体+奥氏体变为细小的珠光体+残余奥氏体,晶粒度等级由3级变为7级;淬火硬化层厚3μm,残余应力由原来的拉应力(137.1±38.0)MPa降低为压应力(-165.5±15.0)MPa,奥氏体含量由11.2%降低为3.1%;LZ50车轴钢激光淬火后平均摩擦系数较淬火前降低了13.9%,磨损机制由黏着磨损变为磨粒磨损。
Laser surface quenching of LZ50 axle steel was conducted.The microstructure and grain size of the axle steel before and after laser surface quenching were analyzed with a metallographic microscope.The morphology of the hardened layer was observed with a field emission scanning electron microscope.The residual stress and residual austenite content of the laser quenched axle steel were analyzed with an X-ray residual stress diffractometer.Moreover,a friction and wear tester was performed to evaluate the friction and wear behavior of the laser quenched axle steel,and the influence of laser quenching on the friction and wear behavior as well as wear mechanism of the axle steel was discussed.Results showed that,after laser quenching,the thick pearlite + ferrite + austenite of the axle steel were transformed into pearlite + residual austenite,and the grain size rose from level 3 to level 7,in association with the formation of 3 μm thick hardened layer.In the meantime,after laser surface quenching,the residual tensile stress of the axle steel(137.1 ± 38.0)MPa was transformed into compressive stress(- 165.5 ± 15.0)MPa,while the austenite content decreased from 11.2%to 3.1%.Moreover,after laser surface quenching,the average friction coefficient of the axle steel was reduced by 13.9%,and its wear mechanism turned from severe adhesion wear to abrasive wear.
出处
《材料保护》
CAS
CSCD
北大核心
2015年第4期63-65,9,共3页
Materials Protection
基金
江苏省产学研联合创新资金--前瞻性联合研究项目(BY2014037-24)资助
关键词
激光淬火
LZ50车轴钢
残余应力
摩擦系数
磨损形貌
laser quenching
LZ50 axle steel
residual tensile stress
friction and wear behavior
wear mechanism
