鈦合金板材的超塑性成形方法介紹!
材的(de)(de)超塑(su)性成(cheng)(cheng)形(xing)(xing)(xing)(xing)方(fang)法大致(zhi)可(ke)分(fen)為下列(lie)三種(zhong):(1)真(zhen)空(kong)成(cheng)(cheng)形(xing)(xing)(xing)(xing);(2)氣壓成(cheng)(cheng)形(xing)(xing)(xing)(xing)(吹塑(su)成(cheng)(cheng)形(xing)(xing)(xing)(xing));(3)模壓成(cheng)(cheng)形(xing)(xing)(xing)(xing)(偶合(he)模成(cheng)(cheng)形(xing)(xing)(xing)(xing))。前兩種(zhong)是塑(su)料(或(huo)玻璃)制品成(cheng)(cheng)形(xing)(xing)(xing)(xing)常用的(de)(de)方(fang)法。鈦(tai)板超塑(su)性成(cheng)(cheng)形(xing)(xing)(xing)(xing)因(yin)屬于粘性或(huo)半粘性流動變形(xing)(xing)(xing)(xing),所(suo)以可(ke)以利(li)用低(di)壓成(cheng)(cheng)形(xing)(xing)(xing)(xing)。氣壓成(cheng)(cheng)形(xing)(xing)(xing)(xing)還可(ke)同真(zhen)空(kong)成(cheng)(cheng)形(xing)(xing)(xing)(xing)結合(he)起來應用。
1、真空成形法
真空成形法又可分為兩種:凸模(mo)法與凹模(mo)法。
凸模(mo)(mo)法(fa)是(shi)把經過加熱(re)后的(de)毛(mao)料(liao),吸(xi)附在具有零件(jian)(jian)內(nei)形(xing)(xing)的(de)凸模(mo)(mo)上(shang)的(de)成(cheng)(cheng)形(xing)(xing)方(fang)(fang)法(fa),用來成(cheng)(cheng)形(xing)(xing)要求內(nei)側尺寸精度高的(de)零件(jian)(jian)。凹模(mo)(mo)法(fa)則是(shi)把加熱(re)過的(de)毛(mao)料(liao),吸(xi)附在具有零件(jian)(jian)外(wai)形(xing)(xing)的(de)凹模(mo)(mo)上(shang)的(de)成(cheng)(cheng)形(xing)(xing)方(fang)(fang)法(fa),用于要求外(wai)形(xing)(xing)尺寸精度高的(de)零件(jian)(jian)成(cheng)(cheng)形(xing)(xing)。一般說來,前者用于較深容器(qi)的(de)成(cheng)(cheng)形(xing)(xing),后者用于較淺容器(qi)的(de)成(cheng)(cheng)形(xing)(xing)。
真空(kong)成(cheng)(cheng)形(xing)也(ye)是(shi)一(yi)種氣(qi)壓成(cheng)(cheng)形(xing),只是(shi)成(cheng)(cheng)形(xing)壓力只能是(shi)一(yi)個大(da)氣(qi)壓。故對(dui)鈦板(ban)來(lai)說(shuo),只能成(cheng)(cheng)形(xing)厚(hou)度薄、形(xing)狀(zhuang)簡單、曲率度化和緩的零(ling)件,不適于成(cheng)(cheng)形(xing)厚(hou)度較(jiao)(jiao)厚(hou)、形(xing)狀(zhuang)較(jiao)(jiao)復雜和變形(xing)較(jiao)(jiao)劇(ju)的零(ling)件。
2、氣壓成形法(吹塑成形法)
這是(shi)一種特殊的脹形工藝。
傳統的(de)脹形(xing)(xing)工藝是用機械、液壓脹形(xing)(xing)或用爆炸脹形(xing)(xing)的(de)方(fang)法實(shi)現的(de),使用的(de)壓力與(yu)(yu)能(neng)量(liang)都比較高,并且由(you)(you)于(yu)材料塑(su)性的(de)限制,變(bian)形(xing)(xing)量(liang)一般都不太大。吹(chui)塑(su)成(cheng)(cheng)形(xing)(xing)則是一種(zhong)(zhong)用低(di)能(neng)、低(di)壓可(ke)以獲得大變(bian)形(xing)(xing)量(liang)的(de)成(cheng)(cheng)形(xing)(xing),是—種(zhong)(zhong)與(yu)(yu)傳統工藝概(gai)念(nian)不同的(de)板料成(cheng)(cheng)形(xing)(xing)技術。由(you)(you)于(yu)金(jin)屬(shu)在變(bian)形(xing)(xing)過(guo)程(cheng)中是自由(you)(you)的(de),因此,幾乎(hu)全部(bu)動力都消(xiao)耗在變(bian)形(xing)(xing)功上,摩擦(ca)損(sun)失(shi)很小(xiao)(對于(yu)自由(you)(you)吹(chui)塑(su)成(cheng)(cheng)形(xing)(xing)來說,則沒有摩擦(ca)損(sun)失(shi)),這與(yu)(yu)其(qi)它(ta)沖壓成(cheng)(cheng)形(xing)(xing)有著本質的(de)區別。
吹塑(su)成形(xing)(xing)(xing)(xing)可(ke)分(fen)為自由吹塑(su)成形(xing)(xing)(xing)(xing)和模(mo)(mo)具(ju)吹塑(su)成形(xing)(xing)(xing)(xing)兩類(lei)。模(mo)(mo)具(ju)吹塑(su)成形(xing)(xing)(xing)(xing)的(de)特(te)點為半(ban)模(mo)(mo)成形(xing)(xing)(xing)(xing),與真空成形(xing)(xing)(xing)(xing)類(lei)似(si)之處,也分(fen)為凸模(mo)(mo)成形(xing)(xing)(xing)(xing)和凹模(mo)(mo)成形(xing)(xing)(xing)(xing)兩種;其不同之處是成形(xing)(xing)(xing)(xing)壓力(li)可(ke)大于一個大氣壓,還對(dui)通過氣源系(xi)統對(dui)壓力(li)進行調節,因而可(ke)以制造形(xing)(xing)(xing)(xing)狀(zhuang)復雜,曲率(lv)變(bian)化大的(de)零件。
(1)自由吹塑成(cheng)形法
這是(shi)(shi)Z簡單的一種吹(chui)塑成(cheng)形(xing)。其(qi)特點(dian)是(shi)(shi)不用模具,吹(chui)制的典型零件(jian)是(shi)(shi)球形(xing)零件(jian)。
(2)凸模成形法
此法是(shi)使鈦板毛(mao)料(liao)的外(wai)側,形(xing)成一封閉的壓力空間,鈦板加(jia)熱到超塑性(xing)溫度(du)(du)(du)后,在壓縮氣體的氣壓作用下,毛(mao)料(liao)產生(sheng)超塑性(xing)變形(xing),逐(zhu)漸向模(mo)(mo)具型(xing)面(mian)靠近,直(zhi)到同(tong)模(mo)(mo)具完(wan)全(quan)貼合,做(zuo)出與(yu)(yu)模(mo)(mo)具型(xing)面(mian)相同(tong)的零件(jian)。成形(xing)零件(jian)的內表面(mian)尺寸精度(du)(du)(du)高,形(xing)狀準確,深(shen)度(du)(du)(du)與(yu)(yu)寬度(du)(du)(du)之(zhi)比較(jiao)(jiao)(jiao)大,模(mo)(mo)具加(jia)工也較(jiao)(jiao)(jiao)易,但脫(tuo)模(mo)(mo)較(jiao)(jiao)(jiao)困難,原材料(liao)也較(jiao)(jiao)(jiao)費。用該法成形(xing)的零件(jian)底部較(jiao)(jiao)(jiao)四(si)周為(wei)厚(hou)。
(3)凹(ao)模成形法
與凸模成(cheng)(cheng)(cheng)形法(fa)不同的是(shi),在成(cheng)(cheng)(cheng)形過程中使鈦板毛料(liao)內側形成(cheng)(cheng)(cheng)一(yi)封閉(bi)的壓(ya)力空間。成(cheng)(cheng)(cheng)形零(ling)件外表面尺寸精度(du)高,形狀(zhuang)準確,零(ling)件脫(tuo)模較(jiao)易,原(yuan)材料(liao)較(jiao)省,但深度(du)與寬度(du)比較(jiao)小,模具加工也較(jiao)困(kun)難。用(yong)該法(fa)成(cheng)(cheng)(cheng)形的零(ling)件底部較(jiao)四周為(wei)薄(bo)。
3、模壓成形法
采用偶(ou)合模。與普(pu)通壓型不(bu)同的是溫度(du)高,模壓速度(du)慢得多。
由(you)于鈦板超塑性溫度的(de)(de)金屬偶(ou)合模(mo)具制造困難(nan),配合精度難(nan)以保證(特別對復雜形(xing)狀的(de)(de)模(mo)具),故鈦板超塑性成形(xing)少用(yong)。