激光熔覆技术在汽轮机末级叶片水蚀防护中的应用

Application Status of Laser Cladding Technique inWater Erosion Protection of Last Stage Blades of Steam Turbine

水蚀是汽轮机末级叶片损伤的主要原因之一,为了保证汽轮机安全稳定运行,总结了末级叶片的水蚀影响因素,包括微观的二次水滴参数和宏观的工况容量的改变;对比了水蚀防护方法,指出激光熔覆工艺应用于汽轮机末级叶片防水蚀的优势,从涂层材料制备和工艺参数两方面阐述了激光熔覆技术在水蚀防护领域的应用现状,指出防水蚀涂层的研究与制备具有极大发展潜力,提出涂层与叶片基材的结合强度及后期熔覆工件涂层的维修是当前需要重点关注的问题。

As one of the main causes of the last stage bladedamage of steam turbine,water erosion seriously affects the safety and stability of steam turbine operation.Laser cladding is a more effective and practical surface strengthening technology.In recent years,it has been continuously applied to the strengthening of water erosion resistance of the substrate surface of the last stage blades of steam turbines.In this paper,the influencing factors of water erosion of the last stage blade are summarized,including the change of micro secondary droplet parameters and macro working condition capacity.Then the water-erosion protection methods are introduced and compared,and the advantages of laser cladding technology applied to the last stage blade of steam turbine are pointed out.At the same time,the application status of laser cladding technology in the field of water erosion protection is expounded from the aspects of coating material preparation and process parameters.It is concluded that the research and preparation of coating with high water-erosion resistance has great development potential.It is proposed that the bonding strength between the coating and the blade substrate and the maintenance of the coating of the cladded workpiece should be paid more attention at present.