奧氏體不銹鋼采用手工鎢極氬弧(hu)焊(han)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(jie)頭的形式，平(ping)焊(han)(han)位置包(bao)括對(dui)接(jie)平(ping)焊(han)(han)和平(ping)角焊(han)(han)兩(liang)種。

①. 對接(jie)平焊(han)

 焊(han)(han)件在裝配(pei)時，為了防止焊(han)(han)接過程(cheng)中產生變形，應(ying)放在夾(jia)具中緊固，并在焊(han)(han)件坡口背(bei)面(mian)安放墊(dian)(dian)板，墊(dian)(dian)板上應(ying)開設凹槽，內通氬氣，保(bao)護背(bei)面(mian)焊(han)(han)縫，如圖4-11所示。

  焊(han)(han)接時，首先在(zai)(zai)定(ding)位(wei)(wei)焊(han)(han)縫根(gen)(gen)部(bu)后10mm左(zuo)右處(chu)(chu)開始引燃電弧(hu)(hu)，運弧(hu)(hu)至定(ding)位(wei)(wei)焊(han)(han)點(dian)根(gen)(gen)部(bu)，此時焊(han)(han)槍畫(hua)一個半圓形(xing)的圈，在(zai)(zai)坡口(kou)根(gen)(gen)部(bu)形(xing)成一個熔(rong)孔，熔(rong)孔形(xing)成后向(xiang)(xiang)右側鈍邊(bian)處(chu)(chu)填(tian)加焊(han)(han)絲(si)(si)，然后得向(xiang)(xiang)左(zuo)側運弧(hu)(hu)，向(xiang)(xiang)左(zuo)側鈍邊(bian)處(chu)(chu)填(tian)加焊(han)(han)絲(si)(si)，再向(xiang)(xiang)右運弧(hu)(hu)，如此往復(fu)循環，逐漸形(xing)成熔(rong)透焊(han)(han)縫。

  操作過(guo)程中(zhong)要(yao)保持熔(rong)(rong)(rong)孔(kong)始(shi)終深(shen)入(ru)母材0.5~1.0mm,出現熔(rong)(rong)(rong)孔(kong)后應(ying)立即填充(chong)焊(han)絲(si)，這時(shi)形(xing)成(cheng)的(de)焊(han)縫才會均勻。如果填充(chong)焊(han)絲(si)過(guo)遲，熔(rong)(rong)(rong)孔(kong)過(guo)大，反面(mian)焊(han)縫就(jiu)過(guo)高(gao)，甚至產(chan)生(sheng)焊(han)瘤；填充(chong)焊(han)絲(si)過(guo)早(zao)，若還未形(xing)成(cheng)熔(rong)(rong)(rong)孔(kong)，就(jiu)會產(chan)生(sheng)未焊(han)透(tou)。焊(han)接過(guo)程中(zhong)在不影響視(shi)線的(de)情況(kuang)下(xia)盡量采(cai)用短弧(hu)，以(yi)增(zeng)強氬氣的(de)保護效(xiao)果和提高(gao)電弧(hu)的(de)穿透(tou)能力。鎢極端部(bu)距熔(rong)(rong)(rong)池(chi)表面(mian)以(yi)2~3mm為宜，要(yao)注(zhu)意觀察熔(rong)(rong)(rong)池(chi)的(de)形(xing)狀(zhuang)，熔(rong)(rong)(rong)池(chi)應(ying)保持與焊(han)縫軸線對(dui)稱，否則焊(han)縫就(jiu)會偏斜。

  熔(rong)(rong)(rong)(rong)透(tou)(tou)(tou)的(de)(de)識別：焊接過程中應通過仔細(xi)觀察熔(rong)(rong)(rong)(rong)池(chi)的(de)(de)變化來判斷是(shi)否熔(rong)(rong)(rong)(rong)透(tou)(tou)(tou)，以達到單面焊雙(shuang)面成形的(de)(de)目的(de)(de)。當(dang)填充焊絲(si)上一顆(ke)熔(rong)(rong)(rong)(rong)滴(di)落入熔(rong)(rong)(rong)(rong)池(chi)時，熔(rong)(rong)(rong)(rong)池(chi)表面位置就會升高，隨著熱量向(xiang)下(xia)傳輸，基(ji)本金屬熔(rong)(rong)(rong)(rong)化形成熔(rong)(rong)(rong)(rong)孔。由(you)于重(zhong)力使熔(rong)(rong)(rong)(rong)池(chi)下(xia)沉，于是(shi)熔(rong)(rong)(rong)(rong)池(chi)水平(ping)下(xia)降，熔(rong)(rong)(rong)(rong)池(chi)表面積擴(kuo)張，這是(shi)焊透(tou)(tou)(tou)的(de)(de)重(zhong)要標志。如果沒有焊透(tou)(tou)(tou)，熔(rong)(rong)(rong)(rong)池(chi)便不會下(xia)沉。

  當運弧至(zhi)終焊(han)(han)(han)(han)(han)端的定位(wei)(wei)焊(han)(han)(han)(han)(han)縫根部(bu)3~5mm時，焊(han)(han)(han)(han)(han)槍畫圈，把(ba)定位(wei)(wei)焊(han)(han)(han)(han)(han)縫根部(bu)熔化，然后填充2~3滴熔滴，繼續向前施焊(han)(han)(han)(han)(han)10mm左右(you)，把(ba)定位(wei)(wei)焊(han)(han)(han)(han)(han)縫表(biao)面熔化，最后用電流衰減法(fa)收弧。收弧焊(han)(han)(han)(han)(han)縫應在定位(wei)(wei)焊(han)(han)(han)(han)(han)縫后方10mm左右(you)處，以保證(zheng)接頭部(bu)位(wei)(wei)能焊(han)(han)(han)(han)(han)透。

②. 平角焊

  操作時，焊槍、焊絲和焊件之間的相對位置如圖4-12所示(shi)。電弧(hu)長度1.5mm左右，焊槍與焊件的傾(qing)角(jiao)為40°~50°,焊絲送(song)入傾(qing)角(jiao)為15°~20°。