在埋弧(hu)焊焊接過程中,維持電弧穩定燃燒,以及保持焊接參數基本不變是保證焊接接頭質量的基本要求。對此可通過以下兩種方法來實現。


1. 焊絲的送進按預選定的速度等速進入焊接區


  工(gong)作(zuo)原理(li)是采(cai)用(yong)機械方法(更換變(bian)速齒(chi)輪(lun))來(lai)調速。依靠電(dian)(dian)(dian)弧(hu)的(de)自身(shen)調節作(zuo)用(yong)來(lai)維持(chi)弧(hu)長相對穩定。當焊(han)(han)(han)接(jie)(jie)(jie)電(dian)(dian)(dian)弧(hu)受到(dao)外界干擾(rao)變(bian)長增加時,下降外特性電(dian)(dian)(dian)源供給的(de)焊(han)(han)(han)接(jie)(jie)(jie)電(dian)(dian)(dian)流減小,焊(han)(han)(han)絲熔(rong)化(hua)速度(du)減緩,電(dian)(dian)(dian)弧(hu)便會由長變(bian)短(duan),趨向給定值;反之,電(dian)(dian)(dian)弧(hu)變(bian)短(duan)時,焊(han)(han)(han)接(jie)(jie)(jie)電(dian)(dian)(dian)流增大,焊(han)(han)(han)絲熔(rong)化(hua)加快,弧(hu)長又(you)由短(duan)變(bian)長,趨向給定值。按這個工(gong)作(zuo)原理(li)制造的(de)等(deng)速送(song)絲埋弧(hu)焊(han)(han)(han)設備有MZ1-1000、MZ2-1500和MZ3-500等(deng)型號,焊(han)(han)(han)接(jie)(jie)(jie)電(dian)(dian)(dian)流可采(cai)用(yong)交、直電(dian)(dian)(dian)源。


2. 焊絲的送進速度(du)按電(dian)弧電(dian)壓的高低自動均勻調(diao)節


  電(dian)弧(hu)(hu)(hu)(hu)電(dian)壓(ya)調(diao)節原理是利用(yong)電(dian)弧(hu)(hu)(hu)(hu)電(dian)壓(ya)作為反(fan)饋信號(hao),經過控(kong)制調(diao)節系統(tong)改變送絲(si)(si)速度而保持(chi)弧(hu)(hu)(hu)(hu)長(chang)(chang)相對不變。當電(dian)弧(hu)(hu)(hu)(hu)受外界干擾變長(chang)(chang),電(dian)弧(hu)(hu)(hu)(hu)電(dian)壓(ya)升高(gao)時(shi)(shi),控(kong)制調(diao)節系統(tong)接到(dao)電(dian)壓(ya)反(fan)饋信號(hao)后將(jiang)送絲(si)(si)速度調(diao)快(kuai),弧(hu)(hu)(hu)(hu)長(chang)(chang)由(you)長(chang)(chang)變短,趨向穩定(ding)(ding)值;當電(dian)弧(hu)(hu)(hu)(hu)長(chang)(chang)度變短,電(dian)弧(hu)(hu)(hu)(hu)電(dian)壓(ya)下降時(shi)(shi),將(jiang)送絲(si)(si)速度調(diao)慢,弧(hu)(hu)(hu)(hu)長(chang)(chang)增(zeng)長(chang)(chang)趨向給(gei)定(ding)(ding)值。這種埋弧(hu)(hu)(hu)(hu)焊機的控(kong)制系統(tong)稍(shao)復雜,具(ju)體型號(hao)有MZ-1000和MZ-1-1000等(deng)型號(hao)。焊接電(dian)流可(ke)采(cai)用(yong)交、直流電(dian)源。


  按(an)工作(zuo)需要,埋弧(hu)焊機常見的構造形式(shi)有焊車式(shi)、懸(xuan)掛式(shi)、機床式(shi)、懸(xuan)臂式(shi)和門(men)架式(shi)等,如(ru)圖3-16所示(shi)。


16.jpg