TIG表面重熔对堆焊层耐空泡腐蚀的影响

用氩弧熔化焊(MIG)在4020碳钢表面堆焊耐空泡腐蚀材料,然后采用TIG（钨极氩弧焊），将堆焊层改性;通过与传统磨削表面加工对比，研究了TIG表面重熔对空泡腐蚀的影响.结果表明 : 在45 h空泡腐蚀试验后，磨削试样的累积失重量是TIG表面重熔试样的157倍；奥氏体到马氏体的相变是Stellite 21材料吸收空泡冲击能的主要途径，而TIG表面重熔加工可以延迟相变，延长吸收空泡冲击的时间，减缓空蚀；TIG重熔表面抑制了片层状马氏体的裂纹发展，避免了大的物质剥落.

EFFECT OF TIG SURFACE REMELTING PROCESS ON CAVITATION EROSION RESISTANCE FOR A PRE-WELD BUILDUP LAYER

A surface layer of cavitation resistant material preprepared by buildup welding on a carbon steel 4020 by MIG process, and which was then remelt by TIG process. Compared with the conventional post grinding process for the weld layer, the effect of TIG surface remelting process on cavitation erosion resistance was investigated. The results show that after 45h of cavitation erosion test, the mass loss of the specimen with ground surface was 1.57 times of that with TIG remehed surface. The fracture of martensite, which was transformed from austenite of the weld steelite 21 layer was the main form of mass loss during cavitation erosion process. TIG surface remelting treatment might delay the transformation process to certain degree and thus decreased mass loss. TIG remelting process might also suppress the extention process of crack so that to eliminate spalling off of fragements.