液压缸活塞杆表面高速激光熔覆涂层高效后处理技术研究

Study on High Efficiency Post-treatment Technology of High Speed Laser Cladding Coating on Piston Rod Surface of Hydraulic Cylinder

为了提高高速激光熔覆涂层后处理加工效率,研究了车削-超声光整复合高效后处理技术,以促进该技术在工程机械液压件活塞杆上的推广应用。利用高速激光熔覆技术制备了马氏体不锈钢涂层,分析了涂层显微组织和硬度,利用硬车削和超声光整加工工艺对涂层进行了后处理加工,研究了不同工艺参数对涂层粗糙度和表面形貌的影响规律。试验结果表明,高速激光熔覆涂层组织细小、致密,平均显微硬度不低于700 HV。车削加工后涂层表面形貌呈较强的各向异性,均匀分布着残留沟槽和波峰。与切削线速度相比,进给量对车削后涂层粗糙度的影响较为显著。超声光整加工过程中涂层波峰处单位面积受到的压应力最大,塑性变形和材料蠕动使波峰高度变小、波谷宽度变小,最终改善了涂层表面粗糙度。田口分析结果显示超声光整工艺参数影响程度依次为:输出功率>进给量>工件转速,最优工艺参数为输出功率500 W、进给量0.15 mm/r、工件转速50 r/min。

In order to improve the processing efficiency of high speed laser cladding coating post-treatment,the turning and ultrasonic finishing composite high-efficiency post-treatment technology was studied,so as to promote the popularization and application of this technology in the piston rod of hydraulic parts of construction machinery.Martensitic stainless steel coating was prepared by high-speed laser cladding technology.The microstructure and hardness of the coating were analyzed,and the coating was post-processed by hard turning and ultrasonic finishing.The influence of different process parameters on the roughness and surface morphology of the coating was studied.The experimental results show that the microstructure of high-speed laser cladding coating is fine and dense,and the average microhardness is not less than 700 HV.The surface morphology of the coating after turning is anisotropic with residual grooves and wave peaks uniformly distributed.Compared with the cutting line velocity,the feed rate has a significant effect on the roughness of the coating after turning.In the process of ultrasonic finishing,the compressive stress per unit area of the coating crest is the largest.The plastic deformation and material peristalsis reduce the height of the crest and the width of the trough,and finally improve the surface roughness of the coating.Taguchi analysis results show that the influence degree of ultrasonic finishing process parameters is:output power>feed>workpiece speed,the optimal process parameters are output power 500 W,feed rate 0.15 mm/r,workpiece speed 50 r/min.