聯箱(xiang)(xiang)材質為12Cr1MoV,如圖5-22所示。采用焊(han)條電弧焊(han)打底和埋弧自動焊(han)蓋面，用定(ding)位(wei)(wei)塊(kuai)將聯箱(xiang)(xiang)筒節固定(ding)在一起，沿圓周每隔(ge)200~300mm裝一塊(kuai)定(ding)位(wei)(wei)塊(kuai)，并(bing)均勻分(fen)布；定(ding)位(wei)(wei)塊(kuai)焊(han)接時(shi)，工件應預熱至250℃.

  嚴格控制坡口(kou)鈍邊厚度和(he)裝配(pei)間(jian)隙(xi)。鈍邊過大、間(jian)隙(xi)過小，易產生未(wei)焊(han)(han)(han)(han)(han)(han)透；鈍邊過小、間(jian)隙(xi)過大，則易產生燒(shao)穿。聯(lian)箱放(fang)在滾(gun)輪(lun)架(jia)上，采(cai)用(yong)火焰(yan)或感應加熱法，將焊(han)(han)(han)(han)(han)(han)口(kou)預熱至(zhi)300℃.打底焊(han)(han)(han)(han)(han)(han)時(shi)，從時(shi)針十(shi)點半位置開(kai)(kai)始(shi)進(jin)(jin)行下坡焊(han)(han)(han)(han)(han)(han)，焊(han)(han)(han)(han)(han)(han)接電(dian)流比立焊(han)(han)(han)(han)(han)(han)略小一些(xie)，ф3.2mm焊(han)(han)(han)(han)(han)(han)條選(xuan)(xuan)用(yong)電(dian)流100~110A,ф4mm焊(han)(han)(han)(han)(han)(han)條選(xuan)(xuan)用(yong)電(dian)流130~140A,隨時(shi)對熔(rong)(rong)池觀察，判斷(duan)熔(rong)(rong)透情(qing)況，并以合適的運條方法保證根部焊(han)(han)(han)(han)(han)(han)透。第2層起，可在時(shi)針十(shi)一點四十(shi)五(wu)分(fen)位置開(kai)(kai)始(shi)進(jin)(jin)行下坡焊(han)(han)(han)(han)(han)(han)，一直到10mm焊(han)(han)(han)(han)(han)(han)縫為(wei)止，隨后再進(jin)(jin)行埋弧自(zi)動焊(han)(han)(han)(han)(han)(han)。

  埋弧(hu)自動焊的(de)焊絲位置見(jian)表5-39.焊絲直(zhi)徑(jing)?4mm,焊接(jie)電(dian)流450~500A,電(dian)弧(hu)電(dian)壓28~30V,焊接(jie)速度28~30m/h.

  焊(han)后(hou)經外觀、表面磁粉和射線(xian)或超聲(sheng)波檢查合格(ge)，進(jin)行710~750℃的焊(han)后(hou)回火。