叶片材料FV520B再制造熔覆层冲蚀损伤行为及评价

Erosion damage and evaluation of remanufacturing cladding layer for impeller metals FV520B

利用激光熔覆和钨极氩弧(TIG)熔覆技术在FV520B钢表面制备与材料成分相同的熔覆层,并对TIG熔覆层分别进行470°C和615°C回火,分析了熔覆层的微观组织、抗冲蚀能力及冲蚀后的熔覆层表面特性。试验结果表明:激光熔覆层均匀致密,平均显微硬度最高;回火TIG熔覆层性能与母材相似。随着硬度提高,冲蚀率最高点向高角度方向移动。冲蚀角度小于30°时,激光熔覆层抗冲蚀性能及表面粗糙度较好;高角度冲蚀时,激光熔覆层冲蚀率高于回火TIG熔覆层。在冲蚀率最高的角度附近,冲蚀硬化程度最低,正向冲蚀下的硬化程度最高。熔覆层越硬,冲蚀产生的残余拉、压应力越高。

Coating layer with the same composition as the FV520 Bsteel was deposited on the base material by laser cladding and Tungsten Inert Gas（TIG）cladding.Then,TIG cladding was tempered at 470°C and 615°C,respectively.The microstructure,hardness,erosion resistance of the cladding layers were investigated,and the surface quality,micro-hardness and residual stress were also tested after erosion.The results show that laser cladding with compact and symmetrical microstructure has the highest hardness,and TIG cladding with tempering has similar microstructure compared with the base material.With the increase in hardness,the erosion peak will move towards the high angle.When the impacting angle is less than 30°,the anti-erosion performance and surface quality of the laser cladding are better.At higher impacting angle,anti-erosion performance the laser cladding is worse than that of TIG cladding layer.For all the layers,erosion hardness is the lowest at the impacting angle with highest erosion rate,and erosion hardness is highest at the impacting angle of 90°.Both residual extend stress and residual compressive stress,which are caused by erosion,are maximal for laser cladding layer with highest hardness.