目前采用的有三種芯(xin)棒操作方(fang)式。早期(qi)的三輥軋(ya)管(guan)機均采用全(quan)(quan)(quan)浮芯(xin)棒，即使在今天(tian)，仍有一部分機組采用全(quan)(quan)(quan)浮芯(xin)棒操作。但是(shi)，全(quan)(quan)(quan)浮芯(xin)棒操作方(fang)式有如下缺點：
（1）軋制特厚(hou)壁管時不易脫棒；
（2）對各種尺寸的毛管(guan)均需要配置再加(jia)熱爐；
（3）軋制薄壁(bi)管(guan)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(shi)三種不同芯棒操作方式的簡述。
1. 全浮芯(xin)棒
采用(yong)全浮(fu)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)操作方式時，荒(huang)(huang)(huang)管(guan)(guan)(guan)被撥入(ru)到荒(huang)(huang)(huang)管(guan)(guan)(guan)推(tui)(tui)入(ru)機(ji)(ji)(ji)(ji)前(qian)(qian)(qian)的(de)人(ren)口臺，落到和(he)(he)軋(ya)(ya)機(ji)(ji)(ji)(ji)中心(xin)線一(yi)(yi)致的(de)U形槽里。氣動(dong)壓管(guan)(guan)(guan)器壓在(zai)(zai)(zai)荒(huang)(huang)(huang)管(guan)(guan)(guan)上，將其(qi)夾(jia)緊，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)推(tui)(tui)入(ru)機(ji)(ji)(ji)(ji)將芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)穿(chuan)入(ru)荒(huang)(huang)(huang)管(guan)(guan)(guan)內。一(yi)(yi)旦芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)完(wan)全穿(chuan)入(ru)，壓管(guan)(guan)(guan)器就(jiu)松開，于是(shi)，荒(huang)(huang)(huang)管(guan)(guan)(guan)連同芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)一(yi)(yi)并向軋(ya)(ya)輥方向送去(qu)。如果荒(huang)(huang)(huang)管(guan)(guan)(guan)不(bu)易(yi)喂入(ru)軋(ya)(ya)機(ji)(ji)(ji)(ji)，就(jiu)用(yong)荒(huang)(huang)(huang)管(guan)(guan)(guan)推(tui)(tui)入(ru)機(ji)(ji)(ji)(ji)在(zai)(zai)(zai)后(hou)(hou)面推(tui)(tui)下，以(yi)(yi)幫助(zhu)荒(huang)(huang)(huang)管(guan)(guan)(guan)喂入(ru)。當荒(huang)(huang)(huang)管(guan)(guan)(guan)開始軋(ya)(ya)制(zhi)時，荒(huang)(huang)(huang)管(guan)(guan)(guan)推(tui)(tui)入(ru)機(ji)(ji)(ji)(ji)和(he)(he)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)推(tui)(tui)入(ru)機(ji)(ji)(ji)(ji)便返回到初(chu)始位置。但(dan)是(shi)，當采用(yong)小(xiao)直徑芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)軋(ya)(ya)管(guan)(guan)(guan)時，荒(huang)(huang)(huang)管(guan)(guan)(guan)推(tui)(tui)入(ru)機(ji)(ji)(ji)(ji)可保(bao)留在(zai)(zai)(zai)前(qian)(qian)(qian)位，充當導衛，防止芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)抖動(dong)。荒(huang)(huang)(huang)管(guan)(guan)(guan)延伸后(hou)(hou)，荒(huang)(huang)(huang)管(guan)(guan)(guan)和(he)(he)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)一(yi)(yi)起通過軋(ya)(ya)機(ji)(ji)(ji)(ji)向前(qian)(qian)(qian)移動(dong)軋(ya)(ya)制(zhi)終(zhong)了(le)時，后(hou)(hou)臺輥子(zi)升起，將毛(mao)管(guan)(guan)(guan)及芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)送到輸出輥道(dao)。然后(hou)(hou)，從輸出輥送到脫棒(bang)(bang)(bang)(bang)機(ji)(ji)(ji)(ji)，將芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)從毛(mao)管(guan)(guan)(guan)中脫出。脫棒(bang)(bang)(bang)(bang)后(hou)(hou)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)先冷卻，再送到軋(ya)(ya)管(guan)(guan)(guan)機(ji)(ji)(ji)(ji)前(qian)(qian)(qian)臺，以(yi)(yi)備再用(yong)。荒(huang)(huang)(huang)管(guan)(guan)(guan)則由輥道(dao)送走(zou)，進行下一(yi)(yi)步加工(gong)。采用(yong)全浮(fu)棒(bang)(bang)(bang)(bang)操作方式時，軋(ya)(ya)機(ji)(ji)(ji)(ji)生產率(lv)最高，因此，下一(yi)(yi)根(gen)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)的(de)前(qian)(qian)(qian)端實(shi)際上可以(yi)(yi)跟(gen)在(zai)(zai)(zai)正在(zai)(zai)(zai)軋(ya)(ya)制(zhi)的(de)前(qian)(qian)(qian)一(yi)(yi)根(gen)荒(huang)(huang)(huang)管(guan)(guan)(guan)的(de)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)的(de)后(hou)(hou)面。這是(shi)可能的(de)，因為(wei)在(zai)(zai)(zai)前(qian)(qian)(qian)一(yi)(yi)根(gen)荒(huang)(huang)(huang)管(guan)(guan)(guan)軋(ya)(ya)完(wan)以(yi)(yi)前(qian)(qian)(qian)，后(hou)(hou)一(yi)(yi)根(gen)荒(huang)(huang)(huang)管(guan)(guan)(guan)可以(yi)(yi)放在(zai)(zai)(zai)前(qian)(qian)(qian)臺上、并穿(chuan)好(hao)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)。
2. 回退(tui)芯(xin)棒
回(hui)(hui)退(tui)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)操(cao)作(zuo)(zuo)方(fang)(fang)式和浮(fu)動芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)一(yi)樣使用(yong)同一(yi)荒(huang)管(guan)推(tui)人機(ji)(ji)與(yu)(yu)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)推(tui)入(ru)(ru)機(ji)(ji)，但是(shi)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)推(tui)入(ru)(ru)機(ji)(ji)上(shang)加了一(yi)套裝置(zhi)，可將芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)的后端固定在(zai)(zai)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)推(tui)入(ru)(ru)機(ji)(ji)上(shang)并使芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)回(hui)(hui)轉(zhuan)。荒(huang)管(guan)在(zai)(zai)前臺(tai)的初(chu)始(shi)位(wei)置(zhi)和夾緊(jin)與(yu)(yu)全浮(fu)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)操(cao)作(zuo)(zuo)方(fang)(fang)式一(yi)樣。然(ran)(ran)而，在(zai)(zai)插入(ru)(ru)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)時(shi)，不(bu)僅芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)頭部穿(chuan)過荒(huang)管(guan)，而且芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)要穿(chuan)過軋(ya)(ya)機(ji)(ji)，伸出軋(ya)(ya)輥臺(tai)肩約3.5m。當(dang)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)到達此(ci)位(wei)置(zhi)后，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)開(kai)(kai)始(shi)回(hui)(hui)轉(zhuan)，直到荒(huang)管(guan)接觸軋(ya)(ya)輥后一(yi)段時(shi)間才停止。當(dang)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)推(tui)入(ru)(ru)機(ji)(ji)到達行(xing)程終點時(shi)，壓管(guan)器松開(kai)(kai)，荒(huang)管(guan)推(tui)入(ru)(ru)機(ji)(ji)啟動前進。于是(shi)，荒(huang)管(guan)喂入(ru)(ru)軋(ya)(ya)機(ji)(ji)。軋(ya)(ya)制開(kai)(kai)始(shi)后，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)開(kai)(kai)始(shi)回(hui)(hui)退(tui)。其回(hui)(hui)退(tui)速度與(yu)(yu)荒(huang)管(guan)的行(xing)程長度及前進速度有關，以便在(zai)(zai)軋(ya)(ya)制過程結(jie)束，當(dang)毛(mao)管(guan)離開(kai)(kai)軋(ya)(ya)輥時(shi)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)正好從荒(huang)管(guan)中抽出。見圖6-49。然(ran)(ran)后，毛(mao)管(guan)從軋(ya)(ya)機(ji)(ji)運走，進行(xing)下(xia)步(bu)加工，而芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)高速返回(hui)(hui)其初(chu)始(shi)位(wei)置(zhi)以備(bei)穿(chuan)入(ru)(ru)下(xia)一(yi)根毛(mao)管(guan)。
3. 限動芯(xin)棒
限動(dong)芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)(cao)作法是全浮芯(xin)(xin)(xin)(xin)棒(bang)(bang)和(he)回(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)(cao)作法的(de)折中(zhong)方法。采用這種方法時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)的(de)尾端(duan)固定在(zai)(zai)芯(xin)(xin)(xin)(xin)棒(bang)(bang)推(tui)入(ru)機上(shang)，并可(ke)回(hui)轉。這和(he)回(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)(cao)作方式一樣(yang)，不同的(de)是，鋼管軋(ya)(ya)制(zhi)(zhi)時(shi)(shi)芯(xin)(xin)(xin)(xin)棒(bang)(bang)向前(qian)移動(dong)。在(zai)(zai)軋(ya)(ya)制(zhi)(zhi)結(jie)束時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)從毛(mao)管上(shang)脫出(chu)(chu)。當荒(huang)管在(zai)(zai)前(qian)臺(tai)被夾緊時(shi)(shi)，穿入(ru)芯(xin)(xin)(xin)(xin)棒(bang)(bang)，直(zhi)到芯(xin)(xin)(xin)(xin)棒(bang)(bang)前(qian)端(duan)伸出(chu)(chu)軋(ya)(ya)輥(gun)(gun)臺(tai)肩(jian)約0.3m左右為止(zhi)。插入(ru)芯(xin)(xin)(xin)(xin)棒(bang)(bang)時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)開始回(hui)轉，直(zhi)到荒(huang)管接觸軋(ya)(ya)輥(gun)(gun)后一段時(shi)(shi)間(jian)才停止(zhi)。芯(xin)(xin)(xin)(xin)棒(bang)(bang)到位后，壓管器(qi)松開，荒(huang)管推(tui)入(ru)機將(jiang)荒(huang)管推(tui)向軋(ya)(ya)輥(gun)(gun)，直(zhi)到軋(ya)(ya)制(zhi)(zhi)過(guo)程開始為止(zhi)。軋(ya)(ya)制(zhi)(zhi)過(guo)程中(zhong)，芯(xin)(xin)(xin)(xin)捧以低于毛(mao)管軸(zhou)向輸出(chu)(chu)速度的(de)速度和(he)軋(ya)(ya)件一起前(qian)進。軋(ya)(ya)制(zhi)(zhi)周期結(jie)束時(shi)(shi)，毛(mao)管從芯(xin)(xin)(xin)(xin)棒(bang)(bang)上(shang)脫出(chu)(chu)，然后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)高速返回(hui)其初始位置。
三種芯棒(bang)操(cao)作方(fang)(fang)(fang)式(shi)的(de)(de)比較。在(zai)采(cai)用(yong)(yong)回(hui)退芯棒(bang)與限動芯棒(bang)操(cao)作方(fang)(fang)(fang)式(shi)的(de)(de)工廠(chang)，只有生產(chan)D/t小于7.5的(de)(de)鋼管(guan)(guan)時才采(cai)用(yong)(yong)回(hui)退芯棒(bang)操(cao)作方(fang)(fang)(fang)式(shi)，而當生產(chan)D/t大于7.5的(de)(de)鋼管(guan)(guan)時采(cai)用(yong)(yong)限動芯棒(bang)操(cao)作方(fang)(fang)(fang)式(shi)。顯(xian)然(ran)，采(cai)用(yong)(yong)回(hui)退和限動芯棒(bang)操(cao)作方(fang)(fang)(fang)式(shi)時，軋機產(chan)量比采(cai)用(yong)(yong)全浮芯棒(bang)時低(di)，因為，下(xia)一(yi)根(gen)荒管(guan)(guan)撥(bo)入到(dao)前(qian)臺(tai)之前(qian)，在(zai)用(yong)(yong)的(de)(de)芯棒(bang)必須返回(hui)其初始位置(zhi)。同時，芯棒(bang)的(de)(de)冷卻不充分，芯棒(bang)壽命不長(chang)。
