缸套内壁激光渗硫复合层的组织与抗高温磨损性能

Microstructure and high temperature wear resistance of laser quenching and ion sulphidizing composite layer on cylinder inwall

针对大功率密度柴油机缸套高温磨损失效问题,利用低温离子渗硫技术在42MnCr52钢激光淬火表面制备了渗硫层,采用扫描电子显微镜(SEM)、X射线衍射(XRD)、纳米硬度仪、划痕仪和台架试验装置分析了复合层的形貌组成、组织结构、力学性能与高温磨损性能。结果表明,复合层表面疏松多孔,其相组成主要为FeS,厚度约为5μm,与基底结合紧密。在发动机台架试验条件下,激光渗硫复合处理能降低缸套的磨损量,同时减轻了对磨活塞环的磨损,其主要原因是复合层表面的固体润滑硫化物有效抑制了高温粘着磨损和磨粒磨损,改善了缸套/活塞环摩擦副表面的匹配性能,使缸套的抗高温磨损性能得到提高。

In view of worn failure at high temperature for cylinder of high-power density diesel engine,the sulfurizing layer was prepared on the laser quenched 42MnCr52 steel surface by low temperature ion sulphurizing technology.The surface morphologies,phase structures,mechanical properties and high temperature wear resistance at the composite treated layer were analyzed by scanning electron microscope,X-ray diffraction,nano-hardness tester,scratch instrument and bench test instrument.The experimental results show that the surface of the composite layer is loose and porous,and the phase structure of which is mainly FeS phase with thickness of about 5 μm,tightly combined with substrate.The sulfide layer on laser quenching surface can reduce the wearing capacity of the cylinder and the opposite piston rings under engine bench testing conditions.The main reason for which is that the lubrication sulfide films of the composite treatment layer surface effectively restrain the abrasive wear and adhesive wear at high temperature,and improve the match property between cylinder and the opposite piston rings,and hence increase the wear resistance at high temperature for cylinder.