光纤激光淬火对凸轮用45钢表面磨损性能的影响

为了提升凸轮表面耐磨性,采用YLS-4000型光纤激光器通过不同的激光功率对基体材料45钢表面进行激光淬火。通过SEM观察激光淬火前后材料表面和界面形貌,金相显微镜观察组织形貌,通过HVS-1000A型显微硬度仪测试了试样表面硬度,并测试了试样的摩擦因数和磨损形貌。结果表明:淬火层界面显微组织为淬火马氏体及少量残余奥氏体,在激光功率1 000~1 800 W时分别获得淬硬层深度为0.3~0.8mm的单道热影响区;淬硬层硬度分布基本均匀,平均硬度约为547~765HV,比基体硬度提高了2~3倍,激光淬火后组织细化和形成大量马氏体是硬度提高的主要原因;在一定激光功率范围内(1 200~1 800 W),激光淬硬层的抗磨损性能比基体有较大的提升,且当激光功率为1 600 W时能获得最佳的磨损性能。

Effects of Fiber Laser Quenching on Wear Performance of 45 Steel Used for Cam

To enhance the wear resistance of the cam surface, YLS4000 fiberoptic laser material was used to 45 steel surface for laser quenching in this research. The surface and crosssection morphology before and after laser hardening were observed by SEM. Additionally, crosssection metallographic structure, surface hardness, friction coefficients and attrition rates were analyzed by metallographic microscope, HVS1000A microhardness tester and friction wear tester, respectively. The results show that microstructure of the quenched layer is composed of quenched martensite and a small amount of austenite. The single channel heat affected zone of the hardened layer with a depth of 0.30.8 mm is obtained with a laser power of 1 0001 800 W. The hardness of hardened layer is uniform and the average hardness is about 547765 HV, which are almost 23 times of the matrix hardness. The micro structure refinement and large amount of high carbon martensite caused by laser quenching are the mainly cause for the increase in hardness. Wear resistance of the laser hardened layer is obviously improved within the laser power range of 1 2001 800 W. The best wear performance is obtained when the laser power is 1 600 W.