对X5CrNiCuNb16-4不锈钢汽轮机末级叶片的叶根进行了喷丸强化, 对喷丸前后的表面粗糙度、残余应力分布以及叶根的表面形貌进行了研究。结果表明: 喷丸后叶根的表面粗糙度从喷丸前的5.2 μm增大到约10 μm; 喷丸后叶根表层的残余压应力沿深度方向先增大后减小, 并在50 μm层深处达到最大值635 MPa; 喷丸后叶根上形成了深约100 μm的组织细化层, 点状凹坑均匀地分布在叶根表面, 未发现折皱、裂纹和鳞刺等缺陷, 各项指标均达到了客户的要求。

Shot peening was performed on last stage blade root of turbine of stainless steel X5CrNiCuNb16-4, and the surface roughness, residual stress distribution and surface morphology of blade root were studied. The results show that the surface roughness of blade root after shot peening was increased from 5.2 μm, before shot peening, to 10 μm. After shot peening, the residual compressive stress of surface layer increased firstly and then decreased, and the maximum value reached to 635 MPa at the depth of 50 μm. Microstructure refined layer with the depth of 100 μm was formed after shot peening, the point-like pit distributed on the blade root surface evenly, and some defects, such as fold, crack and burr were not found on blade surface. All indexes met the requirement of the customer.