红石电站水轮机转轮叶片裂纹的分析及处理

Crack analysis and treatment of Kaplan runner blade of Hongshi Hydropower Station

红石电站的 5 0MW轴流定桨式水轮机 ,大修时 ,发现 3号机的 5个叶片根部 (正、背面 )和正面出水边处都有不同程度的裂纹。产生裂纹的主要原因是 :叶片所受基本应力较高 ,叶片根部有应力集中和材料疲劳。裂纹的处理是采用堆焊加大叶片根部法兰连接处的过渡圆角 ,在裂纹尾端钻止裂孔 ,并对不同的裂纹采用不同形状的坡口 。

Some cracks at the root and face of the outlet edge of five runner blades of the ZD fixed blade propeller turbine of 50MW in Hongshi Hydropower Station were found. The primary reasons of cracks were that the basic stresses effecting on vanes are in the high side, the stresses centralizes at the blades' roots, and the materials fatigue. The treatment of cracks was enlarging the transition rounded corners of the joint of the face of the outlet edge and flange at the blades' roots by bead welding; another treatment was boring hole at the end of the cracks to stop worse ones and introducing various shape of groove against various cracks and processing preheating, overlaying welding and insulation according prescript working procedure.