一(yi).配料

　　鈦合金(jin)根據下述原則(ze)確定(ding)合金(jin)元素(su)的配料比例：

　　(1)合金元素和雜質含(han)量允(yun)許(xu)的波動范圍及合金最佳(jia)性能所要求的最佳(jia)成分范圍;

　　(2) 熔(rong)煉(lian)方(fang)法及熔(rong)煉(lian)次(ci)數;

　　(3) 合(he)金元素(su)在真空白耗熔(rong)煉過(guo)程中的燒損率和蒸發率;

　　(4) 合(he)金元素的(de)加入方(fang)式及物理性質。

　　一(yi)般情況下，燒損率大、容易揮發的元素，配料比例接近上限(xian)或超過(guo)上限(xian)，不(bu)易揮發損失的元素按要求范圍的中(zhong)限(xian)配料。。

　　二.電(dian)極塊的壓(ya)制(zhi)

　　自耗(hao)熔煉對電極(ji)的要求主要是：

　　(1)足夠的強(qiang)度;

　　(2)足夠的導(dao)電(dian)性;

　　(3) 平(ping)直度;

　　(4) 合金元素在電極中的分布合理;

　　(5) 不受(shou)潮、不污染。

　　單塊電(dian)極的制(zhi)(zhi)備方法(fa)有壓(ya)制(zhi)(zhi)(又(you)分(fen)立壓(ya)和橫壓(ya))和擠制(zhi)(zhi)(又(you)分(fen)臥(wo)式和立式)兩(liang)類，較常用的是(shi)壓(ya)制(zhi)(zhi)法(fa)。

　　電(dian)極(ji)(ji)塊的密度與(yu)被壓(ya)(ya)制的原料有關(guan)。圖8—27所示(shi)為單(dan)位壓(ya)(ya)力與(yu)電(dian)極(ji)(ji)密度的關(guan)系。一般地(di)說，電(dian)極(ji)(ji)塊的密度大于3.2 g/cm3就(jiu)可以滿足熔(rong)煉要求。一般使用(yong)壓(ya)(ya)力達(da)到300～500MPa的壓(ya)(ya)機。電(dian)極(ji)(ji)的組焊

　　電極(ji)(ji)的組焊(han)(han)是(shi)將壓好的單塊(kuai)電極(ji)(ji)塊(kuai)組焊(han)(han)成自耗電弧熔煉所需截面和長度的電極(ji)(ji)。工業上(shang)，常采用(yong)(yong)氬氣(qi)保護等(deng)離子(zi)焊(han)(han)、真空(kong)等(deng)離子(zi)焊(han)(han)和電子(zi)束焊(han)(han)。為了防止混入高比重夾(jia)雜(za)，一般不(bu)使用(yong)(yong)鎢(wu)極(ji)(ji)氬弧焊(han)(han)接。焊(han)(han)接用(yong)(yong)氬氣(qi)純度為99.99﹪。

　　三(san)(san).從(cong)開(kai)始(shi)送電(dian)熔(rong)(rong)(rong)(rong)(rong)煉(lian)(lian)(lian)至爐(lu)(lu)料(liao)(liao)(liao)全部(bu)熔(rong)(rong)(rong)(rong)(rong)化(hua)(除熔(rong)(rong)(rong)(rong)(rong)池(chi)上方的(de)(de)固體(ti)拱橋(qiao)外)完畢稱為(wei)(wei)爐(lu)(lu)料(liao)(liao)(liao)熔(rong)(rong)(rong)(rong)(rong)化(hua)階段(duan)。熔(rong)(rong)(rong)(rong)(rong)煉(lian)(lian)(lian)剛開(kai)始(shi)時，新加(jia)入的(de)(de)爐(lu)(lu)料(liao)(liao)(liao)比(bi)電(dian)阻(zu)較大(da)，電(dian)極與爐(lu)(lu)料(liao)(liao)(liao)直接(jie)接(jie)觸，依靠爐(lu)(lu)料(liao)(liao)(liao)電(dian)阻(zu)熱(re)(re)加(jia)熱(re)(re)爐(lu)(lu)料(liao)(liao)(liao)，此時輸入電(dian)流(liu)雖小(xiao)但比(bi)較穩(wen)定(ding)，此段(duan)期(qi)(qi)間電(dian)阻(zu)熱(re)(re)占主導地位。但這(zhe)段(duan)時間不(bu)長，當電(dian)極下方爐(lu)(lu)料(liao)(liao)(liao)熔(rong)(rong)(rong)(rong)(rong)化(hua)形(xing)成(cheng)三(san)(san)個”坩(gan)(gan)蝸熔(rong)(rong)(rong)(rong)(rong)池(chi)”后(hou)，電(dian)極與”坩(gan)(gan)堝(guo)熔(rong)(rong)(rong)(rong)(rong)池(chi)”間產生(sheng)電(dian)弧(hu)熱(re)(re)加(jia)熱(re)(re)爐(lu)(lu)料(liao)(liao)(liao)使(shi)熔(rong)(rong)(rong)(rong)(rong)池(chi)逐漸(jian)向外擴張，直至形(xing)成(cheng)一(yi)個溝通(tong)三(san)(san)電(dian)極的(de)(de)”大(da)熔(rong)(rong)(rong)(rong)(rong)池(chi)”。從(cong)”坩(gan)(gan)堝(guo)熔(rong)(rong)(rong)(rong)(rong)池(chi)”向”大(da)熔(rong)(rong)(rong)(rong)(rong)池(chi)”的(de)(de)過(guo)渡期(qi)(qi)間，由于未熔(rong)(rong)(rong)(rong)(rong)化(hua)爐(lu)(lu)料(liao)(liao)(liao)部(bu)分被還原(yuan)，其比(bi)電(dian)阻(zu)逐漸(jian)變小(xiao)，所以爐(lu)(lu)料(liao)(liao)(liao)電(dian)阻(zu)熱(re)(re)逐漸(jian)減少;而(er)(er)(er)電(dian)極與”坩(gan)(gan)堝(guo)熔(rong)(rong)(rong)(rong)(rong)池(chi)”間的(de)(de)電(dian)弧(hu)熱(re)(re)所出比(bi)例逐漸(jian)上升。從(cong)熔(rong)(rong)(rong)(rong)(rong)煉(lian)(lian)(lian)開(kai)始(shi)經過(guo)約半小(xiao)時后(hou)電(dian)弧(hu)熱(re)(re)便(bian)占主導地位。上述的(de)(de)”過(guo)渡期(qi)(qi)”為(wei)(wei)熔(rong)(rong)(rong)(rong)(rong)煉(lian)(lian)(lian)高鈦渣的(de)(de)不(bu)穩(wen)定(ding)時期(qi)(qi)，一(yi)是因(yin)為(wei)(wei)電(dian)流(liu)經過(guo)的(de)(de)線路(電(dian)極→坩(gan)(gan)堝(guo)熔(rong)(rong)(rong)(rong)(rong)池(chi)→未化(hua)爐(lu)(lu)料(liao)(liao)(liao)→坩(gan)(gan)堝(guo)熔(rong)(rong)(rong)(rong)(rong)池(chi)→電(dian)極)的(de)(de)電(dian)阻(zu)隨時間而(er)(er)(er)變化(hua);二是”坩(gan)(gan)堝(guo)熔(rong)(rong)(rong)(rong)(rong)池(chi)”上方的(de)(de)固體(ti)料(liao)(liao)(liao)經常會陷(xian)落至熔(rong)(rong)(rong)(rong)(rong)池(chi)引起激烈的(de)(de)反應而(er)(er)(er)使(shi)渣沸騰，而(er)(er)(er)且這(zhe)種”塌(ta)料(liao)(liao)(liao)—渣沸騰”現象是無規律的(de)(de)。