摘要
Three kinds of welds were made using low frequency pulse current variable polarity tungsten inter gas （LPVPTIG） with argon shielding, direct current TIG （DCTIG） with helium shielding and high frequency pulse current variable polarity TIG （HPVPTIG） with argon shielding, respectively. It was found that macrosegregation bands with large amount of thick continuous eutectics and microporosities formed in the LPVPTIG weld due to the fluctuation of the pulse varied heat input. Only microsegregation existed in the DCTIG weld and HPVPTIG weld. However,the HPVPTIG weld had lower extent of Cu microsegregation since its welding speed was slower. The tensile results indicated that the mechanical properties of the weld decreased with the increase of the segregation extent of Cu and porosities, and LPVPTIG weld had lower tensile properties in the longitudinal direction than those in the transverse direction due to the macrosegregation bands.
采用氩气保护的低频脉冲变极性氩弧焊(LPVPTIG)、氦气保护的直流氩弧焊(DCTIG)和氩气保护的高频脉冲变极性氩弧焊(HPVPTIG)等焊接方法获得了3种不同的焊缝。结果表明:由于热输入的波动,LPVPTIG焊缝存在宏观偏析带,带内聚集了粗大的共晶和显微气孔;DCTIG和HPVPTIG焊缝仅存在微观偏析,但由于焊接速度较慢,HPVPTIG焊缝Cu元素微观偏析程度低于DCTIG焊缝。力学性能测试结果表明:焊缝的力学性能随着Cu元素和气孔偏析程度的增加而降低,LPVPTIG焊缝由于存在宏观偏析带,其纵向拉伸力学性能低于横向拉伸力学性能。
