同轴双层喷嘴辅助气体对激光深熔焊接光致等离子体的控制

采用同轴双层侧吹喷嘴，研究了在不同的辅助气体种类及配比、喷嘴高度和焊接速度的条件下对光致等离子体控制的影响。结果表明，利用外层喷嘴压缩等离子体，随着外层喷嘴环形气体压力的增大可以很好地控制光致等离子体，有利于激光深熔焊接的进行；用He 15％Ar混合气体代替纯He作保护气体能显著改善熔深；随着喷嘴高度的增加，焊缝熔深会逐渐减小；随着焊接速度的提高，控制金属蒸汽等离子体所需的辅助气体临界气流量将降低。

Control of Laser-induced Plasma by Assistant Gas through Co-axial Double Nozzle

In this paper using co-axial inclined double-nozzle the effects of controlling plasma by blowing different kinds of assistant gases with variable percentage are investigated, and the influences of various nozzle height and welding speed are studied. It is found that laser-induced plasma can be controlled well along with the augment of outside-nozzle gas pressure, and that is propitious to penetration fusion welding. Using He 15%Ar instead of pure He as the assistant gas the welding penetration-depth can be efficiently improved. But with increasing the nozzle height the penetration-depth will be decreased. In addition, the low critical flux of outside-nozzle gas controlling the metallic vapor plasma will reduce with the increase of welding speed.