奧氏體不銹鋼采用手工鎢極氬弧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(ju)接(jie)(jie)頭的形式，平焊(han)位(wei)置(zhi)包(bao)括對接(jie)(jie)平焊(han)和(he)平角焊(han)兩種。

①. 對接平焊

 焊件(jian)在(zai)裝配時(shi)，為(wei)了防止焊接過程中(zhong)產生變形，應放在(zai)夾具中(zhong)緊固，并在(zai)焊件(jian)坡口背面安放墊板，墊板上應開設凹槽，內通氬氣，保護背面焊縫，如(ru)圖4-11所示。

  焊(han)(han)(han)接時(shi)，首先(xian)在定(ding)位(wei)焊(han)(han)(han)縫(feng)根(gen)(gen)部(bu)(bu)后(hou)10mm左右(you)處(chu)(chu)開始(shi)引燃電(dian)弧(hu)，運(yun)弧(hu)至定(ding)位(wei)焊(han)(han)(han)點根(gen)(gen)部(bu)(bu)，此時(shi)焊(han)(han)(han)槍畫一個(ge)半圓形(xing)的圈，在坡口根(gen)(gen)部(bu)(bu)形(xing)成一個(ge)熔(rong)孔，熔(rong)孔形(xing)成后(hou)向(xiang)(xiang)右(you)側鈍(dun)邊處(chu)(chu)填加焊(han)(han)(han)絲，然(ran)后(hou)得向(xiang)(xiang)左側運(yun)弧(hu)，向(xiang)(xiang)左側鈍(dun)邊處(chu)(chu)填加焊(han)(han)(han)絲，再向(xiang)(xiang)右(you)運(yun)弧(hu)，如(ru)此往(wang)復循環，逐漸形(xing)成熔(rong)透焊(han)(han)(han)縫(feng)。

  操作過(guo)程(cheng)中要(yao)保(bao)持熔(rong)孔(kong)(kong)始終深入母材0.5~1.0mm,出現熔(rong)孔(kong)(kong)后應(ying)立即(ji)填(tian)充焊(han)(han)(han)絲，這時形成(cheng)(cheng)的(de)(de)焊(han)(han)(han)縫(feng)(feng)才(cai)會(hui)均勻。如果(guo)填(tian)充焊(han)(han)(han)絲過(guo)遲，熔(rong)孔(kong)(kong)過(guo)大，反面(mian)焊(han)(han)(han)縫(feng)(feng)就過(guo)高(gao)，甚至產(chan)生焊(han)(han)(han)瘤；填(tian)充焊(han)(han)(han)絲過(guo)早(zao)，若還(huan)未(wei)形成(cheng)(cheng)熔(rong)孔(kong)(kong)，就會(hui)產(chan)生未(wei)焊(han)(han)(han)透(tou)。焊(han)(han)(han)接過(guo)程(cheng)中在不影響視線(xian)的(de)(de)情況下盡(jin)量采(cai)用短弧，以增(zeng)強(qiang)氬(ya)氣的(de)(de)保(bao)護效(xiao)果(guo)和提高(gao)電弧的(de)(de)穿透(tou)能力。鎢極端部距熔(rong)池表(biao)面(mian)以2~3mm為(wei)宜，要(yao)注意觀(guan)察熔(rong)池的(de)(de)形狀，熔(rong)池應(ying)保(bao)持與焊(han)(han)(han)縫(feng)(feng)軸線(xian)對稱，否則焊(han)(han)(han)縫(feng)(feng)就會(hui)偏斜。

  熔(rong)(rong)(rong)透(tou)(tou)的(de)識別(bie)：焊(han)(han)接過(guo)程(cheng)中應通過(guo)仔細觀察熔(rong)(rong)(rong)池(chi)(chi)的(de)變化來(lai)判斷是(shi)否熔(rong)(rong)(rong)透(tou)(tou)，以達(da)到單面(mian)(mian)焊(han)(han)雙面(mian)(mian)成形的(de)目的(de)。當填充焊(han)(han)絲(si)上一(yi)顆熔(rong)(rong)(rong)滴落入熔(rong)(rong)(rong)池(chi)(chi)時(shi)，熔(rong)(rong)(rong)池(chi)(chi)表面(mian)(mian)位置(zhi)就會升高(gao)，隨著熱量向下(xia)傳輸，基(ji)本(ben)金(jin)屬(shu)熔(rong)(rong)(rong)化形成熔(rong)(rong)(rong)孔。由于重力使(shi)熔(rong)(rong)(rong)池(chi)(chi)下(xia)沉(chen)，于是(shi)熔(rong)(rong)(rong)池(chi)(chi)水(shui)平(ping)下(xia)降，熔(rong)(rong)(rong)池(chi)(chi)表面(mian)(mian)積擴(kuo)張，這(zhe)是(shi)焊(han)(han)透(tou)(tou)的(de)重要標志。如果(guo)沒有焊(han)(han)透(tou)(tou)，熔(rong)(rong)(rong)池(chi)(chi)便不會下(xia)沉(chen)。

  當運(yun)弧(hu)(hu)至終焊端的定位(wei)焊縫根(gen)部3~5mm時，焊槍畫圈(quan)，把(ba)(ba)定位(wei)焊縫根(gen)部熔(rong)化，然后填充2~3滴(di)熔(rong)滴(di)，繼續(xu)向(xiang)前施焊10mm左右，把(ba)(ba)定位(wei)焊縫表面熔(rong)化，最后用電流(liu)衰減法(fa)收(shou)弧(hu)(hu)。收(shou)弧(hu)(hu)焊縫應在定位(wei)焊縫后方10mm左右處，以保證(zheng)接頭部位(wei)能焊透。

②. 平角焊(han)

  操作時，焊槍、焊絲和焊件之間的(de)相對位置如(ru)圖4-12所示。電弧長(chang)度1.5mm左右，焊槍與(yu)焊件的(de)傾(qing)角為(wei)40°~50°,焊絲送入傾(qing)角為(wei)15°~20°。