耐汽蚀喷熔涂层质量控制研究

Investigation into Quality Control of Spray-welded Cavitation Resisting Coating

本文深入研究了涂层材料、喷熔工艺对喷熔涂层质量控制的影响。氧-乙炔火焰喷熔法对水轮机过流部件进行修复或预保护的关键之一是采用耐汽蚀抗泥砂磨损自熔合金粉末,以保证喷熔涂层具有良好的强韧性配合,满足工况要求;此外使过流部件实现最小的变形,则关系到整个喷熔工艺的成败。针对不同过流部件的结构特点,采用了对称喷熔法、预热缓冷法、控制不同部位冷却速度和分段喷熔法等工艺措施,成功地控制了涂层质量,保证了过流部件的尺寸与型线要求。经真机考核表明,喷熔后可使机组寿命提高3～5倍以上。

The effects of coating materials and spray welding processes on quality control of spray welded coating are thoroughly investigated in this paper. One of the cruces for repairing or pre-protect-ing the flow passage components of a hydraulic turbine with oxy-acetylene spray welding technology is using a self-fusible alloy powder, which resists cavitaition and abrasion in silt-laden water flow, so as to ensure a good combination of strength and toughness of the coating and meet the requirements of practical application. Futhennore,whether the minimum deformation could be obtained for flow passage components is related to the success or failure of the entire spray welding process. Considering the different structure features of different components, some processings such as symm-etrical spray welding, preheating and slow cooling, controlling the cooling rate at different positions, spray welding with separating process,etc are employed to successfully control the quality of the coating and ensure the dimensions and configurations of flow passage components. The results obtained from the operation in power plant show that the service life of the turbine set is increased by more than two to four times.