目前采(cai)用(yong)的有(you)(you)三種芯棒(bang)操作(zuo)方式(shi)。早期的三輥(gun)軋(ya)管(guan)機均(jun)采(cai)用(yong)全(quan)浮(fu)芯棒(bang)，即使在今(jin)天，仍有(you)(you)一部分(fen)機組采(cai)用(yong)全(quan)浮(fu)芯棒(bang)操作(zuo)。但是，全(quan)浮(fu)芯棒(bang)操作(zuo)方式(shi)有(you)(you)如下缺(que)點(dian)：

（1）軋制(zhi)特厚(hou)壁管(guan)時不易脫棒；

（2）對(dui)各種尺寸的毛管均(jun)需要配置(zhi)再加(jia)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(xia)是三種不(bu)同芯(xin)棒(bang)操作方(fang)式的簡(jian)述。

1. 全(quan)浮(fu)芯棒

  采(cai)用全(quan)浮(fu)芯(xin)(xin)棒(bang)操作方式時，荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)被撥入(ru)(ru)(ru)到(dao)(dao)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)前(qian)(qian)的(de)(de)人(ren)口臺，落到(dao)(dao)和(he)軋(ya)(ya)(ya)機(ji)(ji)(ji)中(zhong)心(xin)線(xian)一(yi)致的(de)(de)U形槽里。氣動(dong)(dong)壓(ya)管(guan)(guan)(guan)(guan)(guan)器(qi)壓(ya)在荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)上，將(jiang)其(qi)夾緊，芯(xin)(xin)棒(bang)推入(ru)(ru)(ru)機(ji)(ji)(ji)將(jiang)芯(xin)(xin)棒(bang)穿入(ru)(ru)(ru)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)內。一(yi)旦芯(xin)(xin)棒(bang)完全(quan)穿入(ru)(ru)(ru)，壓(ya)管(guan)(guan)(guan)(guan)(guan)器(qi)就松開，于是，荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)連同芯(xin)(xin)棒(bang)一(yi)并向軋(ya)(ya)(ya)輥方向送(song)去。如果(guo)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)不易(yi)喂(wei)入(ru)(ru)(ru)軋(ya)(ya)(ya)機(ji)(ji)(ji)，就用荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)在后(hou)(hou)(hou)面(mian)推下，以幫助(zhu)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)喂(wei)入(ru)(ru)(ru)。當(dang)(dang)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)開始軋(ya)(ya)(ya)制時，荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)和(he)芯(xin)(xin)棒(bang)推入(ru)(ru)(ru)機(ji)(ji)(ji)便返回到(dao)(dao)初始位置。但是，當(dang)(dang)采(cai)用小直徑(jing)芯(xin)(xin)棒(bang)軋(ya)(ya)(ya)管(guan)(guan)(guan)(guan)(guan)時，荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)可(ke)(ke)保(bao)留在前(qian)(qian)位，充(chong)當(dang)(dang)導衛，防(fang)止(zhi)芯(xin)(xin)棒(bang)抖動(dong)(dong)。荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)延伸后(hou)(hou)(hou)，荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)和(he)芯(xin)(xin)棒(bang)一(yi)起(qi)通(tong)過軋(ya)(ya)(ya)機(ji)(ji)(ji)向前(qian)(qian)移動(dong)(dong)軋(ya)(ya)(ya)制終了時，后(hou)(hou)(hou)臺輥子升起(qi)，將(jiang)毛管(guan)(guan)(guan)(guan)(guan)及(ji)芯(xin)(xin)棒(bang)送(song)到(dao)(dao)輸(shu)出(chu)輥道。然后(hou)(hou)(hou)，從輸(shu)出(chu)輥送(song)到(dao)(dao)脫棒(bang)機(ji)(ji)(ji)，將(jiang)芯(xin)(xin)棒(bang)從毛管(guan)(guan)(guan)(guan)(guan)中(zhong)脫出(chu)。脫棒(bang)后(hou)(hou)(hou)，芯(xin)(xin)棒(bang)先冷卻，再送(song)到(dao)(dao)軋(ya)(ya)(ya)管(guan)(guan)(guan)(guan)(guan)機(ji)(ji)(ji)前(qian)(qian)臺，以備再用。荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)則由輥道送(song)走，進行(xing)下一(yi)步加工。采(cai)用全(quan)浮(fu)棒(bang)操作方式時，軋(ya)(ya)(ya)機(ji)(ji)(ji)生產率最高，因此，下一(yi)根(gen)(gen)芯(xin)(xin)棒(bang)的(de)(de)前(qian)(qian)端實際上可(ke)(ke)以跟在正(zheng)在軋(ya)(ya)(ya)制的(de)(de)前(qian)(qian)一(yi)根(gen)(gen)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)的(de)(de)芯(xin)(xin)棒(bang)的(de)(de)后(hou)(hou)(hou)面(mian)。這(zhe)是可(ke)(ke)能(neng)的(de)(de)，因為在前(qian)(qian)一(yi)根(gen)(gen)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)軋(ya)(ya)(ya)完以前(qian)(qian)，后(hou)(hou)(hou)一(yi)根(gen)(gen)荒(huang)(huang)(huang)(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)可(ke)(ke)以放在前(qian)(qian)臺上、并穿好(hao)芯(xin)(xin)棒(bang)。

2. 回退芯棒(bang)

  回(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)操(cao)作(zuo)方式和浮(fu)動芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)一(yi)樣使(shi)(shi)用同一(yi)荒(huang)(huang)(huang)管(guan)推(tui)(tui)人(ren)機(ji)(ji)(ji)與(yu)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)(ji)，但(dan)是芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)(ji)上加(jia)了一(yi)套裝置(zhi)，可將芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)的(de)后端固定(ding)在(zai)(zai)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)(ji)上并(bing)使(shi)(shi)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)回(hui)轉。荒(huang)(huang)(huang)管(guan)在(zai)(zai)前臺的(de)初始(shi)位(wei)置(zhi)和夾緊(jin)與(yu)全(quan)浮(fu)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)操(cao)作(zuo)方式一(yi)樣。然(ran)而，在(zai)(zai)插入(ru)(ru)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)時(shi)，不(bu)僅(jin)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)頭部穿過荒(huang)(huang)(huang)管(guan)，而且(qie)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)要(yao)穿過軋(ya)(ya)機(ji)(ji)(ji)，伸出軋(ya)(ya)輥(gun)臺肩約3.5m。當芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)到達(da)此位(wei)置(zhi)后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)開始(shi)回(hui)轉，直到荒(huang)(huang)(huang)管(guan)接(jie)觸軋(ya)(ya)輥(gun)后一(yi)段時(shi)間(jian)才停(ting)止。當芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)(ji)(ji)到達(da)行程(cheng)終點(dian)時(shi)，壓管(guan)器松開，荒(huang)(huang)(huang)管(guan)推(tui)(tui)入(ru)(ru)機(ji)(ji)(ji)啟動前進。于是，荒(huang)(huang)(huang)管(guan)喂入(ru)(ru)軋(ya)(ya)機(ji)(ji)(ji)。軋(ya)(ya)制開始(shi)后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)開始(shi)回(hui)退。其(qi)回(hui)退速度與(yu)荒(huang)(huang)(huang)管(guan)的(de)行程(cheng)長(chang)度及前進速度有關，以便在(zai)(zai)軋(ya)(ya)制過程(cheng)結束，當毛(mao)管(guan)離開軋(ya)(ya)輥(gun)時(shi)，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)正好從荒(huang)(huang)(huang)管(guan)中抽出。見圖(tu)6-49。然(ran)后，毛(mao)管(guan)從軋(ya)(ya)機(ji)(ji)(ji)運走，進行下(xia)(xia)步加(jia)工，而芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)高速返回(hui)其(qi)初始(shi)位(wei)置(zhi)以備穿入(ru)(ru)下(xia)(xia)一(yi)根毛(mao)管(guan)。

3. 限動芯棒

  限動芯(xin)棒(bang)(bang)(bang)操作(zuo)法(fa)是全浮芯(xin)棒(bang)(bang)(bang)和回(hui)(hui)退芯(xin)棒(bang)(bang)(bang)操作(zuo)法(fa)的(de)折中方法(fa)。采用(yong)這種(zhong)方法(fa)時(shi)，芯(xin)棒(bang)(bang)(bang)的(de)尾端(duan)固定(ding)在芯(xin)棒(bang)(bang)(bang)推入(ru)(ru)機(ji)上(shang)，并可回(hui)(hui)轉。這和回(hui)(hui)退芯(xin)棒(bang)(bang)(bang)操作(zuo)方式一樣，不(bu)同的(de)是，鋼管(guan)(guan)軋(ya)(ya)制(zhi)時(shi)芯(xin)棒(bang)(bang)(bang)向前(qian)移(yi)動。在軋(ya)(ya)制(zhi)結(jie)束時(shi)，芯(xin)棒(bang)(bang)(bang)從(cong)毛管(guan)(guan)上(shang)脫(tuo)出。當荒(huang)(huang)管(guan)(guan)在前(qian)臺被夾(jia)緊時(shi)，穿入(ru)(ru)芯(xin)棒(bang)(bang)(bang)，直到芯(xin)棒(bang)(bang)(bang)前(qian)端(duan)伸(shen)出軋(ya)(ya)輥(gun)(gun)臺肩約0.3m左右為(wei)止(zhi)(zhi)。插(cha)入(ru)(ru)芯(xin)棒(bang)(bang)(bang)時(shi)，芯(xin)棒(bang)(bang)(bang)開(kai)始回(hui)(hui)轉，直到荒(huang)(huang)管(guan)(guan)接觸軋(ya)(ya)輥(gun)(gun)后(hou)一段時(shi)間才停止(zhi)(zhi)。芯(xin)棒(bang)(bang)(bang)到位(wei)后(hou)，壓(ya)管(guan)(guan)器松開(kai)，荒(huang)(huang)管(guan)(guan)推入(ru)(ru)機(ji)將(jiang)荒(huang)(huang)管(guan)(guan)推向軋(ya)(ya)輥(gun)(gun)，直到軋(ya)(ya)制(zhi)過程開(kai)始為(wei)止(zhi)(zhi)。軋(ya)(ya)制(zhi)過程中，芯(xin)捧以低于毛管(guan)(guan)軸向輸出速(su)度(du)的(de)速(su)度(du)和軋(ya)(ya)件(jian)一起前(qian)進。軋(ya)(ya)制(zhi)周期結(jie)束時(shi)，毛管(guan)(guan)從(cong)芯(xin)棒(bang)(bang)(bang)上(shang)脫(tuo)出，然后(hou)，芯(xin)棒(bang)(bang)(bang)高速(su)返回(hui)(hui)其(qi)初始位(wei)置(zhi)。

  三種芯(xin)(xin)棒(bang)(bang)操(cao)作方(fang)(fang)式(shi)的(de)(de)比較。在采(cai)(cai)用(yong)回(hui)退芯(xin)(xin)棒(bang)(bang)與限(xian)(xian)動芯(xin)(xin)棒(bang)(bang)操(cao)作方(fang)(fang)式(shi)的(de)(de)工廠，只有(you)生產(chan)D/t小于7.5的(de)(de)鋼管(guan)時(shi)才采(cai)(cai)用(yong)回(hui)退芯(xin)(xin)棒(bang)(bang)操(cao)作方(fang)(fang)式(shi)，而(er)當生產(chan)D/t大于7.5的(de)(de)鋼管(guan)時(shi)采(cai)(cai)用(yong)限(xian)(xian)動芯(xin)(xin)棒(bang)(bang)操(cao)作方(fang)(fang)式(shi)。顯然，采(cai)(cai)用(yong)回(hui)退和限(xian)(xian)動芯(xin)(xin)棒(bang)(bang)操(cao)作方(fang)(fang)式(shi)時(shi)，軋機產(chan)量比采(cai)(cai)用(yong)全浮芯(xin)(xin)棒(bang)(bang)時(shi)低，因為(wei)，下一根荒管(guan)撥入到前(qian)臺之前(qian)，在用(yong)的(de)(de)芯(xin)(xin)棒(bang)(bang)必須返回(hui)其初始位置。同時(shi)，芯(xin)(xin)棒(bang)(bang)的(de)(de)冷卻(que)不充分，芯(xin)(xin)棒(bang)(bang)壽命不長。