1. 焊接設備、材料及焊接規范
①. 焊接設備：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. 焊接規范(fan)：直流反接，焊接規范(fan)見表(biao)4-7。
2. 操作(zuo)要點
①. 焊槍的擺動(dong)
底(di)層焊(han)接采用左向焊(han)法月(yue)牙形擺(bai)動(dong)，擺(bai)動(dong)幅度要均(jun)勻，在焊(han)縫兩(liang)側(ce)要作短(duan)時(shi)停留(liu)，停留(liu)時(shi)電(dian)弧不得拉長。蓋(gai)面焊(han)同樣采用左向焊(han)法，月(yue)牙擺(bai)動(dong)，與底(di)層焊(han)接不同的是，在焊(han)縫兩(liang)側(ce)停留(liu)的時(shi)間要比底(di)層焊(han)接時(shi)更長一些(xie)。
在底層焊(han)接(jie)時(shi)，當第一個熔池(chi)(chi)(chi)形成后，焊(han)絲必(bi)須(xu)壓在熔池(chi)(chi)(chi)的(de)(de)(de)沿焊(han)縫縱向(xiang)的(de)(de)(de)1/2處橫向(xiang)擺動運行（圖4-21).在焊(han)接(jie)過(guo)程中(zhong)，焊(han)絲始終在熔池(chi)(chi)(chi)內擺動，如果一旦焊(han)絲超過(guo)熔池(chi)(chi)(chi)往坡(po)口外擺動時(shi)，會(hui)出現竄絲和頂絲現象，造成飛濺和根部燒穿、保(bao)護不好等缺(que)陷(xian)。當焊(han)接(jie)中(zhong)斷(duan)需(xu)要再次接(jie)頭時(shi)，起(qi)弧(hu)點必(bi)須(xu)在熔池(chi)(chi)(chi)的(de)(de)(de)前端5~8mm處，此時(shi)在坡(po)口一側引弧(hu)，當電弧(hu)穩定(ding)燃燒時(shi)快速將焊(han)絲拉到熔池(chi)(chi)(chi)內開始正常焊(han)接(jie)。
②. 熔池的控制
在正常焊(han)(han)(han)接過程中，必須保(bao)證(zheng)要有一(yi)定的(de)熔(rong)(rong)(rong)(rong)(rong)(rong)深(shen)。當熔(rong)(rong)(rong)(rong)(rong)(rong)深(shen)達到(dao)一(yi)定程度(du)(du)時，能夠保(bao)證(zheng)背面(mian)(mian)焊(han)(han)(han)縫(feng)焊(han)(han)(han)透(tou)。操(cao)作(zuo)時要及時觀察(cha)焊(han)(han)(han)接熔(rong)(rong)(rong)(rong)(rong)(rong)池前(qian)(qian)(qian)端的(de)熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)，熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)尺(chi)寸(cun)始終保(bao)持在大(da)于間(jian)隙0.5~1mm.當發現(xian)熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)尺(chi)寸(cun)逐漸增(zeng)大(da)時，說(shuo)明(ming)背面(mian)(mian)焊(han)(han)(han)縫(feng)在逐步(bu)增(zeng)高，再(zai)繼續下去將會導致焊(han)(han)(han)瘤或燒穿現(xian)象，此(ci)時應放慢速度(du)(du)，將焊(han)(han)(han)絲往坡口兩(liang)邊運(yun)送或壓在熔(rong)(rong)(rong)(rong)(rong)(rong)池后面(mian)(mian)運(yun)行，直到(dao)熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)尺(chi)寸(cun)恢復原狀，再(zai)繼續進行正常送絲焊(han)(han)(han)接。如果發現(xian)熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)尺(chi)寸(cun)逐漸減小直至(zhi)沒(mei)有熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)，說(shuo)明(ming)背面(mian)(mian)焊(han)(han)(han)縫(feng)過低(di)甚至(zhi)出現(xian)未焊(han)(han)(han)透(tou)，此(ci)時應加快前(qian)(qian)(qian)進速度(du)(du)，焊(han)(han)(han)絲壓在熔(rong)(rong)(rong)(rong)(rong)(rong)池的(de)前(qian)(qian)(qian)半(ban)部或直線運(yun)絲，直到(dao)打開熔(rong)(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)為正常尺(chi)寸(cun)，再(zai)進行正常的(de)焊(han)(han)(han)接。
在(zai)蓋面焊(han)過(guo)程中，由于在(zai)大(da)電(dian)流下熔滴過(guo)渡屬于射流過(guo)渡，此(ci)時把握(wo)不當(dang)會出現熔寬增加(jia)、熔深減小、咬(yao)邊、焊(han)縫表面不規則等缺陷。
③. 導電(dian)嘴距離的(de)控(kong)制
操作時應注意導(dao)(dao)電嘴(zui)(zui)與(yu)焊縫表(biao)面的(de)(de)距離(li)。導(dao)(dao)電嘴(zui)(zui)距離(li)過低：第(di)一，會影(ying)焊工視線；第(di)二，使過渡金(jin)屬受(shou)保護氣(qi)體的(de)(de)壓縮(suo)后(hou)沖擊熔(rong)池(chi)，使熔(rong)池(chi)產(chan)生(sheng)較(jiao)大的(de)(de)波動(dong)而造成(cheng)焊縫表(biao)面的(de)(de)不(bu)平(ping)；第(di)三，氣(qi)體保護過近易(yi)造成(cheng)紊流產(chan)生(sheng)氣(qi)孔。導(dao)(dao)電嘴(zui)(zui)距離(li)過高會使氣(qi)體保護效果(guo)變差，也容易(yi)產(chan)生(sheng)氣(qi)孔、飛濺、咬(yao)邊等缺陷。
合理的(de)方(fang)法是(shi)，導電嘴距離焊縫表(biao)面8~10mm,焊接時(shi)中間快，兩邊(bian)停留(liu)，尤其在兩邊(bian)停留(liu)時(shi)，應控制導電嘴的(de)高度，否則易出(chu)現咬邊(bian)缺陷。
④. 焊槍角(jiao)度的控制
焊縫表面的余高(gao)、熔寬與焊槍(qiang)角度有著很大(da)的關系，焊槍(qiang)前傾角越(yue)小或垂直(zhi)于工(gong)件(jian)（圖(tu)4-22(a)),得到(dao)的是窄而高(gao)的焊縫，前傾角大(da)得到(dao)的是平而寬的焊縫（圖(tu)4-22(b))。
