1. 焊接(jie)設備、材料及(ji)焊接(jie)規范(fan)
①. 焊接設備(bei)：A120-400熔(rong)化極氣體(ti)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(gui)范(fan)：直流反接，焊接規(gui)范(fan)見表4-7。
2. 操(cao)作要點
①. 焊槍的擺(bai)動(dong)
底(di)層焊接(jie)采用左向(xiang)焊法(fa)月(yue)牙(ya)形擺(bai)動(dong)，擺(bai)動(dong)幅度要(yao)均(jun)勻，在焊縫兩側(ce)要(yao)作短時(shi)停留(liu)，停留(liu)時(shi)電(dian)弧不(bu)得拉長(chang)。蓋面焊同樣采用左向(xiang)焊法(fa)，月(yue)牙(ya)擺(bai)動(dong)，與底(di)層焊接(jie)不(bu)同的是，在焊縫兩側(ce)停留(liu)的時(shi)間要(yao)比(bi)底(di)層焊接(jie)時(shi)更長(chang)一些。
在(zai)(zai)底層焊(han)(han)(han)接(jie)時，當第(di)一(yi)個(ge)熔(rong)池(chi)形成后，焊(han)(han)(han)絲必(bi)須(xu)壓在(zai)(zai)熔(rong)池(chi)的(de)沿(yan)焊(han)(han)(han)縫縱向(xiang)的(de)1/2處橫向(xiang)擺(bai)動運行（圖4-21).在(zai)(zai)焊(han)(han)(han)接(jie)過程中，焊(han)(han)(han)絲始終在(zai)(zai)熔(rong)池(chi)內擺(bai)動，如果(guo)一(yi)旦焊(han)(han)(han)絲超(chao)過熔(rong)池(chi)往坡口外擺(bai)動時，會出現竄(cuan)絲和頂絲現象，造成飛濺和根部燒穿、保護(hu)不好等(deng)缺陷。當焊(han)(han)(han)接(jie)中斷需要再次(ci)接(jie)頭時，起弧點必(bi)須(xu)在(zai)(zai)熔(rong)池(chi)的(de)前端5~8mm處，此時在(zai)(zai)坡口一(yi)側引弧，當電弧穩(wen)定(ding)燃(ran)燒時快速將焊(han)(han)(han)絲拉到熔(rong)池(chi)內開始正常焊(han)(han)(han)接(jie)。
②. 熔池的控制
在(zai)正常焊(han)(han)(han)接過程中，必須(xu)保(bao)證要有(you)(you)一定的熔(rong)(rong)(rong)(rong)(rong)深。當(dang)(dang)熔(rong)(rong)(rong)(rong)(rong)深達到一定程度時(shi)，能夠(gou)保(bao)證背面焊(han)(han)(han)縫(feng)焊(han)(han)(han)透。操作時(shi)要及(ji)時(shi)觀察焊(han)(han)(han)接熔(rong)(rong)(rong)(rong)(rong)池前端的熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)，熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)尺寸始終保(bao)持(chi)在(zai)大于間(jian)隙0.5~1mm.當(dang)(dang)發現(xian)(xian)熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)尺寸逐(zhu)漸增大時(shi)，說(shuo)明(ming)背面焊(han)(han)(han)縫(feng)在(zai)逐(zhu)步增高，再繼續(xu)下去將會導致(zhi)焊(han)(han)(han)瘤或(huo)燒(shao)穿(chuan)現(xian)(xian)象，此時(shi)應放慢(man)速度，將焊(han)(han)(han)絲往坡口兩邊運(yun)送或(huo)壓(ya)在(zai)熔(rong)(rong)(rong)(rong)(rong)池后(hou)面運(yun)行，直到熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)尺寸恢復原狀，再繼續(xu)進行正常送絲焊(han)(han)(han)接。如果發現(xian)(xian)熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)尺寸逐(zhu)漸減小直至沒(mei)有(you)(you)熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)，說(shuo)明(ming)背面焊(han)(han)(han)縫(feng)過低甚(shen)至出現(xian)(xian)未焊(han)(han)(han)透，此時(shi)應加快前進速度，焊(han)(han)(han)絲壓(ya)在(zai)熔(rong)(rong)(rong)(rong)(rong)池的前半部或(huo)直線運(yun)絲，直到打(da)開熔(rong)(rong)(rong)(rong)(rong)孔(kong)(kong)(kong)為正常尺寸，再進行正常的焊(han)(han)(han)接。
在蓋(gai)面焊(han)過(guo)程中，由于在大電流下(xia)熔(rong)滴過(guo)渡屬于射流過(guo)渡，此時(shi)把握(wo)不當會(hui)出現熔(rong)寬(kuan)增加(jia)、熔(rong)深減小、咬邊(bian)、焊(han)縫表(biao)面不規則(ze)等缺陷(xian)。
③. 導電嘴距離的控制
操作時應注(zhu)意導(dao)電嘴(zui)與(yu)焊縫表面的距離。導(dao)電嘴(zui)距離過(guo)(guo)低：第一，會(hui)影(ying)焊工視線；第二，使(shi)過(guo)(guo)渡金屬受保護氣(qi)(qi)體(ti)的壓(ya)縮后沖擊熔池(chi)，使(shi)熔池(chi)產生(sheng)較大的波(bo)動而造成焊縫表面的不平；第三(san)，氣(qi)(qi)體(ti)保護過(guo)(guo)近易(yi)造成紊流產生(sheng)氣(qi)(qi)孔(kong)。導(dao)電嘴(zui)距離過(guo)(guo)高會(hui)使(shi)氣(qi)(qi)體(ti)保護效(xiao)果變差，也容(rong)易(yi)產生(sheng)氣(qi)(qi)孔(kong)、飛濺、咬邊等缺陷。
合理的(de)方法是，導電(dian)嘴距離焊縫(feng)表面(mian)8~10mm,焊接時中間快(kuai)，兩邊(bian)停(ting)留，尤其在兩邊(bian)停(ting)留時，應控制(zhi)導電(dian)嘴的(de)高(gao)度，否則易(yi)出現咬邊(bian)缺陷(xian)。
④. 焊槍角(jiao)度(du)的控制
焊(han)縫表面(mian)的(de)(de)余高(gao)、熔(rong)寬(kuan)與焊(han)槍(qiang)角(jiao)度有著(zhu)很(hen)大的(de)(de)關系，焊(han)槍(qiang)前(qian)傾角(jiao)越小或(huo)垂直于(yu)工件（圖4-22(a)),得到(dao)的(de)(de)是窄而(er)高(gao)的(de)(de)焊(han)縫，前(qian)傾角(jiao)大得到(dao)的(de)(de)是平而(er)寬(kuan)的(de)(de)焊(han)縫（圖4-22(b))。
