1. 焊接設備、材料及(ji)焊接規范
①. 焊接設(she)備：A120-400熔化極氣體保護焊機。
②. 母材：06Cr18Ni11Ti,厚度10mm, 600mm×300mm.裝配簡圖見圖4-20.
③. 實心焊絲：0Cr18Ni12V,?1.2mm.
④. 保護氣體：98%Ar+2%O2.
⑤. 焊(han)接規范(fan)：直流(liu)反接，焊(han)接規范(fan)見表4-7。
2. 操作要點
①. 焊槍的(de)擺動
底(di)層焊(han)接(jie)采用左(zuo)向(xiang)焊(han)法(fa)月牙(ya)形擺(bai)(bai)動(dong)，擺(bai)(bai)動(dong)幅度要(yao)(yao)均勻，在(zai)焊(han)縫兩側要(yao)(yao)作短時(shi)(shi)(shi)停留(liu)，停留(liu)時(shi)(shi)(shi)電弧不得(de)拉長。蓋面(mian)焊(han)同樣采用左(zuo)向(xiang)焊(han)法(fa)，月牙(ya)擺(bai)(bai)動(dong)，與(yu)底(di)層焊(han)接(jie)不同的(de)是，在(zai)焊(han)縫兩側停留(liu)的(de)時(shi)(shi)(shi)間要(yao)(yao)比底(di)層焊(han)接(jie)時(shi)(shi)(shi)更長一些(xie)。
在(zai)(zai)底層焊(han)接(jie)(jie)時(shi)，當(dang)第一個(ge)熔(rong)池(chi)形成后，焊(han)絲(si)必須壓(ya)在(zai)(zai)熔(rong)池(chi)的(de)沿(yan)焊(han)縫縱向的(de)1/2處(chu)橫向擺(bai)動運行（圖4-21).在(zai)(zai)焊(han)接(jie)(jie)過(guo)程中，焊(han)絲(si)始終在(zai)(zai)熔(rong)池(chi)內(nei)(nei)擺(bai)動，如果一旦焊(han)絲(si)超過(guo)熔(rong)池(chi)往(wang)坡口外擺(bai)動時(shi)，會出現(xian)竄絲(si)和(he)頂絲(si)現(xian)象，造(zao)成飛濺和(he)根部(bu)燒穿、保(bao)護(hu)不好等(deng)缺陷。當(dang)焊(han)接(jie)(jie)中斷(duan)需要(yao)再次(ci)接(jie)(jie)頭(tou)時(shi)，起弧(hu)點必須在(zai)(zai)熔(rong)池(chi)的(de)前端5~8mm處(chu)，此時(shi)在(zai)(zai)坡口一側引弧(hu)，當(dang)電弧(hu)穩定燃燒時(shi)快速將焊(han)絲(si)拉到熔(rong)池(chi)內(nei)(nei)開始正常焊(han)接(jie)(jie)。
②. 熔池的控(kong)制
在正(zheng)常焊(han)(han)接(jie)過程中，必須保證要有一定(ding)的(de)(de)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)深。當(dang)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)深達到(dao)一定(ding)程度(du)(du)時，能夠保證背(bei)面(mian)焊(han)(han)縫焊(han)(han)透(tou)(tou)。操(cao)作時要及(ji)時觀察(cha)焊(han)(han)接(jie)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)池(chi)(chi)前端的(de)(de)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)，熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)尺(chi)寸始終保持在大(da)于間隙0.5~1mm.當(dang)發現熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)尺(chi)寸逐(zhu)漸增(zeng)大(da)時，說(shuo)(shuo)明背(bei)面(mian)焊(han)(han)縫在逐(zhu)步(bu)增(zeng)高，再(zai)繼續(xu)下去(qu)將會導致焊(han)(han)瘤(liu)或(huo)(huo)燒穿現象(xiang)，此(ci)(ci)時應(ying)放慢速(su)度(du)(du)，將焊(han)(han)絲往坡口(kou)兩邊運送或(huo)(huo)壓在熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)池(chi)(chi)后面(mian)運行，直到(dao)熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)尺(chi)寸恢(hui)復原狀，再(zai)繼續(xu)進行正(zheng)常送絲焊(han)(han)接(jie)。如(ru)果發現熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)尺(chi)寸逐(zhu)漸減小(xiao)直至(zhi)沒(mei)有熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)，說(shuo)(shuo)明背(bei)面(mian)焊(han)(han)縫過低(di)甚(shen)至(zhi)出現未焊(han)(han)透(tou)(tou)，此(ci)(ci)時應(ying)加快前進速(su)度(du)(du)，焊(han)(han)絲壓在熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)池(chi)(chi)的(de)(de)前半部或(huo)(huo)直線運絲，直到(dao)打開熔(rong)(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)為正(zheng)常尺(chi)寸，再(zai)進行正(zheng)常的(de)(de)焊(han)(han)接(jie)。
在蓋(gai)面(mian)焊(han)過程中，由(you)于在大電流下(xia)熔(rong)滴(di)過渡屬(shu)于射流過渡，此時把握不(bu)當會出現熔(rong)寬增加、熔(rong)深減小、咬邊、焊(han)縫(feng)表面(mian)不(bu)規則等缺陷(xian)。
③. 導電嘴距離的控制(zhi)
操(cao)作時應注意導(dao)電(dian)(dian)(dian)嘴與焊(han)縫表(biao)面(mian)的距(ju)離。導(dao)電(dian)(dian)(dian)嘴距(ju)離過(guo)(guo)低：第一，會影焊(han)工視線；第二，使過(guo)(guo)渡金屬受保(bao)(bao)護氣體(ti)(ti)的壓縮(suo)后沖(chong)擊熔池，使熔池產生(sheng)(sheng)較大的波動而造成焊(han)縫表(biao)面(mian)的不平(ping)；第三，氣體(ti)(ti)保(bao)(bao)護過(guo)(guo)近易(yi)造成紊(wen)流產生(sheng)(sheng)氣孔(kong)。導(dao)電(dian)(dian)(dian)嘴距(ju)離過(guo)(guo)高會使氣體(ti)(ti)保(bao)(bao)護效果變差，也容(rong)易(yi)產生(sheng)(sheng)氣孔(kong)、飛(fei)濺、咬(yao)邊等缺陷。
合(he)理的(de)方法是，導(dao)(dao)電嘴距離焊縫表(biao)面(mian)8~10mm,焊接時中間快，兩邊停(ting)留，尤其在兩邊停(ting)留時，應控(kong)制導(dao)(dao)電嘴的(de)高度，否則易出現咬邊缺陷。
④. 焊(han)槍角度的(de)控(kong)制
焊(han)縫(feng)表(biao)面(mian)的(de)余高(gao)、熔寬與(yu)焊(han)槍角度有著很(hen)大的(de)關系，焊(han)槍前(qian)傾(qing)角越小或垂直于工(gong)件（圖4-22(a)),得(de)到的(de)是窄而(er)高(gao)的(de)焊(han)縫(feng)，前(qian)傾(qing)角大得(de)到的(de)是平(ping)而(er)寬的(de)焊(han)縫(feng)（圖4-22(b))。
