奧氏體不銹鋼采用手工鎢極氬弧(hu)焊可以進行各種位置的操作，其中包括水平固定管（全位置）的對接焊，但主適用于薄壁件和打底層的焊接。

  根據接頭的形式，平焊位置包括對接平焊和(he)平角焊兩種。

①. 對接平焊

 焊件在裝配時，為了防止焊接過程中產生變形，應(ying)放在夾具中緊固，并在焊件坡口背面安(an)放墊板，墊板上應(ying)開設凹槽，內通(tong)氬氣，保護背面焊縫(feng)，如圖(tu)4-11所示。

  焊(han)(han)(han)接(jie)時，首(shou)先在定(ding)位(wei)焊(han)(han)(han)縫根(gen)部(bu)后10mm左右(you)處(chu)開始引燃電弧(hu)(hu)，運弧(hu)(hu)至定(ding)位(wei)焊(han)(han)(han)點根(gen)部(bu)，此時焊(han)(han)(han)槍畫一個(ge)半圓形(xing)的圈，在坡口根(gen)部(bu)形(xing)成一個(ge)熔(rong)孔，熔(rong)孔形(xing)成后向(xiang)右(you)側(ce)(ce)鈍(dun)邊處(chu)填加焊(han)(han)(han)絲，然后得向(xiang)左側(ce)(ce)運弧(hu)(hu)，向(xiang)左側(ce)(ce)鈍(dun)邊處(chu)填加焊(han)(han)(han)絲，再向(xiang)右(you)運弧(hu)(hu)，如此往復循環，逐漸形(xing)成熔(rong)透焊(han)(han)(han)縫。

  操作過(guo)程(cheng)中(zhong)(zhong)要(yao)保持熔(rong)(rong)孔(kong)始終深(shen)入母材0.5~1.0mm,出(chu)現熔(rong)(rong)孔(kong)后應立即填(tian)充焊(han)絲(si)(si)，這時(shi)形成(cheng)的(de)(de)焊(han)縫(feng)(feng)才會均勻。如果(guo)填(tian)充焊(han)絲(si)(si)過(guo)遲，熔(rong)(rong)孔(kong)過(guo)大，反面焊(han)縫(feng)(feng)就(jiu)過(guo)高，甚至產(chan)生焊(han)瘤；填(tian)充焊(han)絲(si)(si)過(guo)早，若還未形成(cheng)熔(rong)(rong)孔(kong)，就(jiu)會產(chan)生未焊(han)透。焊(han)接過(guo)程(cheng)中(zhong)(zhong)在(zai)不影響(xiang)視線的(de)(de)情況下(xia)盡量采用(yong)短(duan)弧，以(yi)增強氬氣的(de)(de)保護效果(guo)和提高電弧的(de)(de)穿透能(neng)力。鎢極(ji)端(duan)部(bu)距熔(rong)(rong)池表面以(yi)2~3mm為宜，要(yao)注意觀(guan)察(cha)熔(rong)(rong)池的(de)(de)形狀(zhuang)，熔(rong)(rong)池應保持與焊(han)縫(feng)(feng)軸線對稱，否則焊(han)縫(feng)(feng)就(jiu)會偏斜。

  熔(rong)(rong)(rong)(rong)透的識別：焊(han)接過(guo)程中應通過(guo)仔細觀(guan)察熔(rong)(rong)(rong)(rong)池(chi)的變化來判(pan)斷是(shi)否熔(rong)(rong)(rong)(rong)透，以達到單面(mian)焊(han)雙(shuang)面(mian)成形(xing)的目的。當(dang)填充焊(han)絲(si)上一顆熔(rong)(rong)(rong)(rong)滴落(luo)入熔(rong)(rong)(rong)(rong)池(chi)時，熔(rong)(rong)(rong)(rong)池(chi)表面(mian)位置就會升高(gao)，隨著熱量向下(xia)傳(chuan)輸，基本金(jin)屬熔(rong)(rong)(rong)(rong)化形(xing)成熔(rong)(rong)(rong)(rong)孔。由(you)于重(zhong)力(li)使熔(rong)(rong)(rong)(rong)池(chi)下(xia)沉(chen)，于是(shi)熔(rong)(rong)(rong)(rong)池(chi)水平(ping)下(xia)降(jiang)，熔(rong)(rong)(rong)(rong)池(chi)表面(mian)積擴張，這是(shi)焊(han)透的重(zhong)要標志(zhi)。如(ru)果沒有焊(han)透，熔(rong)(rong)(rong)(rong)池(chi)便(bian)不會下(xia)沉(chen)。

  當(dang)運弧至終(zhong)焊(han)(han)端的(de)定(ding)位(wei)焊(han)(han)縫(feng)(feng)根(gen)部3~5mm時(shi)，焊(han)(han)槍(qiang)畫圈，把定(ding)位(wei)焊(han)(han)縫(feng)(feng)根(gen)部熔化，然后(hou)(hou)填充2~3滴熔滴，繼續向前施焊(han)(han)10mm左(zuo)右(you)，把定(ding)位(wei)焊(han)(han)縫(feng)(feng)表面熔化，最后(hou)(hou)用(yong)電流衰減法收(shou)弧。收(shou)弧焊(han)(han)縫(feng)(feng)應在定(ding)位(wei)焊(han)(han)縫(feng)(feng)后(hou)(hou)方(fang)10mm左(zuo)右(you)處(chu)，以保證接頭部位(wei)能焊(han)(han)透。

②. 平角焊(han)

  操作時，焊槍、焊絲和焊件之(zhi)間的相對位置如圖(tu)4-12所(suo)示。電(dian)弧長度1.5mm左右(you)，焊槍與焊件的傾角(jiao)為40°~50°,焊絲送入傾角(jiao)為15°~20°。