多级降压调节阀阀芯表面堆焊Stellite12合金的组织和性能

Microstructure and properties of Stellitel2 alloy surfacing welded on multi-stage step-down control valve spool

为了提高多级降压调节阀阀芯的耐磨和耐蚀性能,并缩短该类零件的生产制造周期,采用激光熔覆和钨极气体保护电弧焊两种表面堆焊技术,在阀芯表面上制备Stellite12合金。对比研究了堆焊合金层的微观组织、显微硬度、摩擦磨损性能和均匀腐蚀性能。结果表明,两种工艺制备Stellite12合金层均与基体形成良好的冶金结合,微观组织主要由平面晶、粗大的柱状枝晶和细小致密的等轴枝晶组成。相比于钨极气体保护电弧焊,激光熔覆合金层具有更加致密、细小的枝晶组织,枝晶成分分布也更加均匀。同时,激光熔覆合金层的显微硬度更高、耐磨性能更优。另外,激光熔覆合金层相比钨极气体保护电弧焊的具有更低的均匀腐蚀速率,表现出较为均匀的腐蚀行为。

In order to improve the abrasion resistance and corrosion resistance of multi-stage step-down control valve spool,and shorten the manufacturing cycle of such parts,Stellitel2 alloy was prepared on the surface of valve spool by laser cladding and gas tungsten arc welding(GTAW).The microstructure,microhardness,friction and wear properties,uniform corrosion properties of the surfacing welded Stellitel2 alloy layer were compared and studied.The results show that the surfacing welded alloy layer prepared by both methods forms a good metallurgical bond with the substrate,and the microstructure is mainly composed of dendrite structures of plane crystal,coarse columnar dendrites,fine and dense equiaxed dendrites.Compared with that of GTAW,the laser clad alloy layer has more dense and fine dendrite structure,and more uniform distribution of dendrite composition.At the same time,the laser clad alloy layer has higher microhardness and better abrasion resistance.In addition,the laser clad alloy layer has lower uniform corrosion rate and more uniform corrosion behavior than the GTAW alloy layer.