目(mu)前采用的有(you)三種芯(xin)棒操(cao)作(zuo)(zuo)方式(shi)。早期的三輥軋管機均采用全浮(fu)芯(xin)棒，即使在今天，仍有(you)一部(bu)分機組采用全浮(fu)芯(xin)棒操(cao)作(zuo)(zuo)。但是，全浮(fu)芯(xin)棒操(cao)作(zuo)(zuo)方式(shi)有(you)如下缺點：

（1）軋制特厚壁(bi)管時不易脫棒；

（2）對各種(zhong)尺寸的毛管均需(xu)要配(pei)置再加熱爐；

（3）軋制薄壁管時易產生的金屬扭曲和表面缺陷。由于存在上述問題導致限動芯棒和回退芯棒操作方式的開發。

以下是三種不同芯(xin)棒操作方式的簡述。

1. 全(quan)浮(fu)芯棒

  采用(yong)全(quan)浮(fu)芯(xin)(xin)棒(bang)(bang)操作方式(shi)時(shi)，荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)被撥入(ru)到(dao)(dao)(dao)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推(tui)入(ru)機前(qian)(qian)(qian)(qian)的人口臺(tai)，落到(dao)(dao)(dao)和軋(ya)(ya)機中(zhong)(zhong)心線(xian)一(yi)(yi)致的U形槽里(li)。氣動(dong)壓管(guan)(guan)(guan)(guan)(guan)器壓在(zai)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)上，將(jiang)其夾緊，芯(xin)(xin)棒(bang)(bang)推(tui)入(ru)機將(jiang)芯(xin)(xin)棒(bang)(bang)穿(chuan)(chuan)入(ru)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)內(nei)。一(yi)(yi)旦芯(xin)(xin)棒(bang)(bang)完(wan)全(quan)穿(chuan)(chuan)入(ru)，壓管(guan)(guan)(guan)(guan)(guan)器就松開(kai)(kai)，于是，荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)連同芯(xin)(xin)棒(bang)(bang)一(yi)(yi)并向軋(ya)(ya)輥方向送(song)(song)去。如果荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)不易喂入(ru)軋(ya)(ya)機，就用(yong)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推(tui)入(ru)機在(zai)后面(mian)推(tui)下(xia)，以(yi)幫助荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)喂入(ru)。當(dang)(dang)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)開(kai)(kai)始軋(ya)(ya)制(zhi)時(shi)，荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推(tui)入(ru)機和芯(xin)(xin)棒(bang)(bang)推(tui)入(ru)機便返回到(dao)(dao)(dao)初始位置。但是，當(dang)(dang)采用(yong)小(xiao)直徑(jing)芯(xin)(xin)棒(bang)(bang)軋(ya)(ya)管(guan)(guan)(guan)(guan)(guan)時(shi)，荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推(tui)入(ru)機可(ke)保留在(zai)前(qian)(qian)(qian)(qian)位，充當(dang)(dang)導(dao)衛(wei)，防止芯(xin)(xin)棒(bang)(bang)抖動(dong)。荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)延伸后，荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)和芯(xin)(xin)棒(bang)(bang)一(yi)(yi)起通過軋(ya)(ya)機向前(qian)(qian)(qian)(qian)移動(dong)軋(ya)(ya)制(zhi)終了時(shi)，后臺(tai)輥子升(sheng)起，將(jiang)毛(mao)管(guan)(guan)(guan)(guan)(guan)及芯(xin)(xin)棒(bang)(bang)送(song)(song)到(dao)(dao)(dao)輸出(chu)輥道。然后，從(cong)輸出(chu)輥送(song)(song)到(dao)(dao)(dao)脫(tuo)棒(bang)(bang)機，將(jiang)芯(xin)(xin)棒(bang)(bang)從(cong)毛(mao)管(guan)(guan)(guan)(guan)(guan)中(zhong)(zhong)脫(tuo)出(chu)。脫(tuo)棒(bang)(bang)后，芯(xin)(xin)棒(bang)(bang)先冷卻(que)，再(zai)送(song)(song)到(dao)(dao)(dao)軋(ya)(ya)管(guan)(guan)(guan)(guan)(guan)機前(qian)(qian)(qian)(qian)臺(tai)，以(yi)備(bei)再(zai)用(yong)。荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)則由輥道送(song)(song)走，進行(xing)下(xia)一(yi)(yi)步加工。采用(yong)全(quan)浮(fu)棒(bang)(bang)操作方式(shi)時(shi)，軋(ya)(ya)機生產率(lv)最(zui)高，因此，下(xia)一(yi)(yi)根(gen)芯(xin)(xin)棒(bang)(bang)的前(qian)(qian)(qian)(qian)端實際上可(ke)以(yi)跟在(zai)正在(zai)軋(ya)(ya)制(zhi)的前(qian)(qian)(qian)(qian)一(yi)(yi)根(gen)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)的芯(xin)(xin)棒(bang)(bang)的后面(mian)。這(zhe)是可(ke)能的，因為(wei)在(zai)前(qian)(qian)(qian)(qian)一(yi)(yi)根(gen)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)軋(ya)(ya)完(wan)以(yi)前(qian)(qian)(qian)(qian)，后一(yi)(yi)根(gen)荒(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)可(ke)以(yi)放在(zai)前(qian)(qian)(qian)(qian)臺(tai)上、并穿(chuan)(chuan)好芯(xin)(xin)棒(bang)(bang)。

2. 回退芯棒(bang)

  回(hui)(hui)退(tui)芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方式和浮動芯(xin)(xin)棒(bang)(bang)一(yi)樣使用同一(yi)荒(huang)管(guan)(guan)推(tui)(tui)人機(ji)(ji)與芯(xin)(xin)棒(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)，但是芯(xin)(xin)棒(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)上(shang)加了一(yi)套裝(zhuang)置(zhi)，可將芯(xin)(xin)棒(bang)(bang)的(de)(de)后端(duan)固定在(zai)芯(xin)(xin)棒(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)上(shang)并使芯(xin)(xin)棒(bang)(bang)回(hui)(hui)轉(zhuan)。荒(huang)管(guan)(guan)在(zai)前(qian)臺的(de)(de)初始(shi)位(wei)置(zhi)和夾緊與全浮芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方式一(yi)樣。然而(er)，在(zai)插入(ru)(ru)芯(xin)(xin)棒(bang)(bang)時(shi)，不僅芯(xin)(xin)棒(bang)(bang)頭部穿過(guo)(guo)荒(huang)管(guan)(guan)，而(er)且芯(xin)(xin)棒(bang)(bang)要穿過(guo)(guo)軋(ya)機(ji)(ji)，伸出軋(ya)輥(gun)臺肩約3.5m。當芯(xin)(xin)棒(bang)(bang)到達此(ci)位(wei)置(zhi)后，芯(xin)(xin)棒(bang)(bang)開(kai)始(shi)回(hui)(hui)轉(zhuan)，直到荒(huang)管(guan)(guan)接(jie)觸軋(ya)輥(gun)后一(yi)段時(shi)間才停止。當芯(xin)(xin)棒(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)到達行程(cheng)(cheng)終點時(shi)，壓管(guan)(guan)器(qi)松開(kai)，荒(huang)管(guan)(guan)推(tui)(tui)入(ru)(ru)機(ji)(ji)啟動前(qian)進。于是，荒(huang)管(guan)(guan)喂入(ru)(ru)軋(ya)機(ji)(ji)。軋(ya)制(zhi)開(kai)始(shi)后，芯(xin)(xin)棒(bang)(bang)開(kai)始(shi)回(hui)(hui)退(tui)。其(qi)回(hui)(hui)退(tui)速度與荒(huang)管(guan)(guan)的(de)(de)行程(cheng)(cheng)長度及前(qian)進速度有關(guan)，以(yi)便在(zai)軋(ya)制(zhi)過(guo)(guo)程(cheng)(cheng)結束，當毛管(guan)(guan)離開(kai)軋(ya)輥(gun)時(shi)，芯(xin)(xin)棒(bang)(bang)正好從荒(huang)管(guan)(guan)中抽出。見圖(tu)6-49。然后，毛管(guan)(guan)從軋(ya)機(ji)(ji)運走(zou)，進行下步加工，而(er)芯(xin)(xin)棒(bang)(bang)高速返回(hui)(hui)其(qi)初始(shi)位(wei)置(zhi)以(yi)備穿入(ru)(ru)下一(yi)根毛管(guan)(guan)。

3. 限(xian)動芯(xin)棒

  限動芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)作(zuo)法是(shi)全浮(fu)芯(xin)(xin)(xin)(xin)棒(bang)(bang)和(he)回(hui)(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)作(zuo)法的(de)(de)折中(zhong)方法。采(cai)用這(zhe)種方法時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)的(de)(de)尾端固定在芯(xin)(xin)(xin)(xin)棒(bang)(bang)推(tui)入機(ji)上(shang)，并(bing)可回(hui)(hui)轉。這(zhe)和(he)回(hui)(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方式(shi)一樣，不(bu)同的(de)(de)是(shi)，鋼管(guan)軋(ya)(ya)制(zhi)時(shi)(shi)芯(xin)(xin)(xin)(xin)棒(bang)(bang)向前(qian)移動。在軋(ya)(ya)制(zhi)結(jie)束(shu)時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)從毛管(guan)上(shang)脫出。當荒(huang)管(guan)在前(qian)臺被夾(jia)緊時(shi)(shi)，穿入芯(xin)(xin)(xin)(xin)棒(bang)(bang)，直到芯(xin)(xin)(xin)(xin)棒(bang)(bang)前(qian)端伸出軋(ya)(ya)輥臺肩約0.3m左(zuo)右為(wei)止。插入芯(xin)(xin)(xin)(xin)棒(bang)(bang)時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)開始(shi)(shi)回(hui)(hui)轉，直到荒(huang)管(guan)接觸軋(ya)(ya)輥后一段時(shi)(shi)間才停止。芯(xin)(xin)(xin)(xin)棒(bang)(bang)到位后，壓管(guan)器松開，荒(huang)管(guan)推(tui)入機(ji)將(jiang)荒(huang)管(guan)推(tui)向軋(ya)(ya)輥，直到軋(ya)(ya)制(zhi)過程(cheng)開始(shi)(shi)為(wei)止。軋(ya)(ya)制(zhi)過程(cheng)中(zhong)，芯(xin)(xin)(xin)(xin)捧以低于毛管(guan)軸向輸出速度的(de)(de)速度和(he)軋(ya)(ya)件一起前(qian)進(jin)。軋(ya)(ya)制(zhi)周期結(jie)束(shu)時(shi)(shi)，毛管(guan)從芯(xin)(xin)(xin)(xin)棒(bang)(bang)上(shang)脫出，然后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)高速返回(hui)(hui)其(qi)初始(shi)(shi)位置。

  三種芯(xin)棒(bang)(bang)(bang)操(cao)作方式(shi)(shi)的(de)(de)比較(jiao)。在采用(yong)回(hui)退(tui)芯(xin)棒(bang)(bang)(bang)與限(xian)動芯(xin)棒(bang)(bang)(bang)操(cao)作方式(shi)(shi)的(de)(de)工廠，只(zhi)有生產D/t小于7.5的(de)(de)鋼管時(shi)(shi)才(cai)采用(yong)回(hui)退(tui)芯(xin)棒(bang)(bang)(bang)操(cao)作方式(shi)(shi)，而(er)當生產D/t大(da)于7.5的(de)(de)鋼管時(shi)(shi)采用(yong)限(xian)動芯(xin)棒(bang)(bang)(bang)操(cao)作方式(shi)(shi)。顯然，采用(yong)回(hui)退(tui)和(he)限(xian)動芯(xin)棒(bang)(bang)(bang)操(cao)作方式(shi)(shi)時(shi)(shi)，軋機產量比采用(yong)全浮芯(xin)棒(bang)(bang)(bang)時(shi)(shi)低，因為，下一根荒管撥入到前臺之前，在用(yong)的(de)(de)芯(xin)棒(bang)(bang)(bang)必須(xu)返回(hui)其初始位置。同時(shi)(shi)，芯(xin)棒(bang)(bang)(bang)的(de)(de)冷卻不(bu)充分，芯(xin)棒(bang)(bang)(bang)壽命不(bu)長。