熔化極惰性氣體保護焊的惰性氣體，通常采用氬氣。該焊接工藝已開始在許多領域中得到使用，其中以機械操作的縱縫焊應用最多。焊接時選擇直流反極性電源，以短路過渡和噴射過渡的熔滴形式進行操作，用熔化極氬弧焊短路過渡焊接奧(ao)氏體不(bu)銹鋼的焊接參數見表4-44，用熔化極氬弧焊噴射過渡焊接奧氏體型不銹鋼的焊接參數見表4-45。

  在(zai)熔(rong)(rong)化(hua)(hua)極氬(ya)(ya)(ya)氣保(bao)護焊(han)(han)(han)(han)的基(ji)礎(chu)上(shang)加入脈(mo)(mo)沖(chong)電流即成(cheng)脈(mo)(mo)沖(chong)熔(rong)(rong)化(hua)(hua)極氬(ya)(ya)(ya)弧焊(han)(han)(han)(han)，它不僅(jin)具有(you)熔(rong)(rong)化(hua)(hua)極氬(ya)(ya)(ya)氣保(bao)護焊(han)(han)(han)(han)的所有(you)特點，同(tong)時(shi)(shi)能控制焊(han)(han)(han)(han)接熱輸(shu)入，控制金屬(shu)熔(rong)(rong)池，使焊(han)(han)(han)(han)縫(feng)正反(fan)面(mian)成(cheng)形(xing)良好，實現單面(mian)焊(han)(han)(han)(han)背面(mian)成(cheng)形(xing)。表4-46為脈(mo)(mo)沖(chong)熔(rong)(rong)化(hua)(hua)極氬(ya)(ya)(ya)弧焊(han)(han)(han)(han)的單面(mian)焊(han)(han)(han)(han)背面(mian)成(cheng)形(xing)對接焊(han)(han)(han)(han)縫(feng)的焊(han)(han)(han)(han)接參(can)數(shu)。表4-47為脈(mo)(mo)沖(chong)熔(rong)(rong)化(hua)(hua)極氬(ya)(ya)(ya)弧焊(han)(han)(han)(han)焊(han)(han)(han)(han)接角焊(han)(han)(han)(han)縫(feng)的焊(han)(han)(han)(han)接參(can)數(shu)。在(zai)焊(han)(han)(han)(han)接同(tong)樣厚度的材料時(shi)(shi)，焊(han)(han)(han)(han)接熱輸(shu)入比非脈(mo)(mo)沖(chong)熔(rong)(rong)化(hua)(hua)極焊(han)(han)(han)(han)小，相應地(di)減(jian)少(shao)了熱影(ying)響區(qu)，有(you)利于提(ti)高耐(nai)腐蝕性(xing)能；同(tong)時(shi)(shi)減(jian)少(shao)了焊(han)(han)(han)(han)接應力與變形(xing)。脈(mo)(mo)沖(chong)電流的熱循環對金屬(shu)熔(rong)(rong)池能起到攪拌(ban)作用，有(you)利于細化(hua)(hua)焊(han)(han)(han)(han)縫(feng)結(jie)晶，降低產(chan)(chan)生(sheng)裂(lie)紋(wen)的傾向。此(ci)外，這種焊(han)(han)(han)(han)接方(fang)法可以減(jian)輕(qing)勞動強度，提(ti)高生(sheng)產(chan)(chan)效率。