镍基合金火焰喷焊层气孔成因分析及预防

泥浆泵中的闸板起着调节流量的作用，由于其工况的要求，闸板必须具有耐磨损、耐腐蚀的性能，一般采用火焰喷焊的方法在闸板表面熔敷一层镍基合金，生产过程中发现，喷焊层常含有大量的气孔，致使该零件的合格率很低，且影响其使用寿命。本文对其喷焊工艺、喷焊材料、喷焊层的组织进行了研究，指出了气孔形成的原因，并提出采用二步法喷焊工艺、改手工喷焊为自动喷焊的改进措施，并进行了火焰自动喷焊机构的设计。

ANALYSIS AND PREVENTION OF POROSITIES IN FLAME SPRAY WELDING OF NICKEL- BASED ALLOYS COATING

The gate of mud pump plays a very important role in the pump, which can adjust the flow of the pump. In order to meet the requirements of working condition, the gate plate must has very high wearing resistance and very high corrosion resistance. Generally it is deposited with nickel-based alloys through flame spray welding. It is found that there are always a lot of porosities in the deposited metal during this procedure, which make many parts are below to the standard and even affects the service life of the gate. In this paper the flame spray welding process, the spray welding consumables and the microstructure of the coating are all studied. The reason of forming porosities and the improving measure of using two step automatic flame spray welding process are presented, the automatic welding equipment is also designed.