蒸汽发电机叶片激光堆焊层的性能

Performances of laser overlay cladding on blade of steam generator

为了提高蒸汽发电机叶片(SUS403不锈钢)的耐磨性能和耐气蚀性能,采用4 kW光纤耦合传输半导体激光器堆焊系统在SUS403不锈钢叶片上堆焊了钴基合金粉末.确定了最佳激光堆焊参数,并通过光学显微镜、扫描电子显微镜、电子探针分析、x-射线衍射分析、显微硬度计和磨损试验机对堆焊层的显微组织、相组成、微区成分、维氏硬度和耐磨性能进行了研究.结果表明,堆焊层组织中的亚共晶组织的初晶相由富Co的γ奥氏体组成,而共晶组织由富Co的γ奥氏体和复杂的碳化物组成.堆焊后的叶片使用寿命提高了3倍以上.

In order to enhance the wear and cavitation resistances of blade of steam generator,the Co-based alloy powder was deposited on the SUS403 stainless steel blade with the 4 kW fiber coupled transmission diodelaser overlaying system. The optimal laser overlay parameters were determined. In addition,the microstructure,phase constitute,micro area composition,Vickers hardness and wear resistance of laser overlay cladding were investigated with the optical microscope（ OP）, scanning electron microscope（ SEM）,electronic probe analysis,x-ray diffraction（ XRD） analysis,micro-hardness tester and wear testing machine. The results showthat the microstructure of overlay cladding belongs to hypoeutectic structure,where the primary phase is the Co-rich γ austenite and the eutectic structure consists of Co-rich γ austenite and complex carbides. The service life of blade after the laser overlay gets enhanced more than 3 times.