目前采用的(de)有三種芯棒(bang)操(cao)作(zuo)方式。早期(qi)的(de)三輥軋管機(ji)均采用全(quan)浮(fu)芯棒(bang)，即使在今天，仍有一部(bu)分機(ji)組采用全(quan)浮(fu)芯棒(bang)操(cao)作(zuo)。但(dan)是，全(quan)浮(fu)芯棒(bang)操(cao)作(zuo)方式有如(ru)下(xia)缺點：
（1）軋制特厚(hou)壁管時(shi)不易脫(tuo)棒；
（2）對各種(zhong)尺(chi)寸的毛管均(jun)需要配置再(zai)加熱爐(lu)；
（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(san)種不同芯棒操作方式(shi)的簡(jian)述。
1. 全浮芯棒(bang)
采(cai)用(yong)(yong)全浮芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)操作(zuo)(zuo)方式時，荒(huang)(huang)(huang)(huang)管(guan)(guan)被撥入(ru)(ru)(ru)到(dao)荒(huang)(huang)(huang)(huang)管(guan)(guan)推(tui)(tui)入(ru)(ru)(ru)機(ji)(ji)前(qian)的人口臺，落到(dao)和(he)軋(ya)(ya)機(ji)(ji)中(zhong)心線一(yi)(yi)(yi)致的U形槽里。氣動壓管(guan)(guan)器壓在(zai)荒(huang)(huang)(huang)(huang)管(guan)(guan)上(shang)，將其夾(jia)緊，芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)(ru)機(ji)(ji)將芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)穿入(ru)(ru)(ru)荒(huang)(huang)(huang)(huang)管(guan)(guan)內。一(yi)(yi)(yi)旦芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)完全穿入(ru)(ru)(ru)，壓管(guan)(guan)器就(jiu)松開(kai)，于是，荒(huang)(huang)(huang)(huang)管(guan)(guan)連同芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)一(yi)(yi)(yi)并(bing)向軋(ya)(ya)輥(gun)方向送(song)去。如果荒(huang)(huang)(huang)(huang)管(guan)(guan)不(bu)易喂(wei)入(ru)(ru)(ru)軋(ya)(ya)機(ji)(ji)，就(jiu)用(yong)(yong)荒(huang)(huang)(huang)(huang)管(guan)(guan)推(tui)(tui)入(ru)(ru)(ru)機(ji)(ji)在(zai)后(hou)(hou)(hou)面推(tui)(tui)下(xia)，以(yi)(yi)(yi)幫助荒(huang)(huang)(huang)(huang)管(guan)(guan)喂(wei)入(ru)(ru)(ru)。當荒(huang)(huang)(huang)(huang)管(guan)(guan)開(kai)始軋(ya)(ya)制時，荒(huang)(huang)(huang)(huang)管(guan)(guan)推(tui)(tui)入(ru)(ru)(ru)機(ji)(ji)和(he)芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)(ru)機(ji)(ji)便返回到(dao)初(chu)始位置。但是，當采(cai)用(yong)(yong)小直(zhi)徑芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)軋(ya)(ya)管(guan)(guan)時，荒(huang)(huang)(huang)(huang)管(guan)(guan)推(tui)(tui)入(ru)(ru)(ru)機(ji)(ji)可保留在(zai)前(qian)位，充當導衛，防(fang)止芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)抖動。荒(huang)(huang)(huang)(huang)管(guan)(guan)延伸(shen)后(hou)(hou)(hou)，荒(huang)(huang)(huang)(huang)管(guan)(guan)和(he)芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)一(yi)(yi)(yi)起(qi)通(tong)過軋(ya)(ya)機(ji)(ji)向前(qian)移(yi)動軋(ya)(ya)制終(zhong)了(le)時，后(hou)(hou)(hou)臺輥(gun)子升起(qi)，將毛管(guan)(guan)及芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)送(song)到(dao)輸出(chu)輥(gun)道(dao)。然(ran)后(hou)(hou)(hou)，從輸出(chu)輥(gun)送(song)到(dao)脫(tuo)(tuo)(tuo)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)機(ji)(ji)，將芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)從毛管(guan)(guan)中(zhong)脫(tuo)(tuo)(tuo)出(chu)。脫(tuo)(tuo)(tuo)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)后(hou)(hou)(hou)，芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)先(xian)冷卻，再送(song)到(dao)軋(ya)(ya)管(guan)(guan)機(ji)(ji)前(qian)臺，以(yi)(yi)(yi)備再用(yong)(yong)。荒(huang)(huang)(huang)(huang)管(guan)(guan)則(ze)由輥(gun)道(dao)送(song)走(zou)，進行下(xia)一(yi)(yi)(yi)步(bu)加工。采(cai)用(yong)(yong)全浮棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)操作(zuo)(zuo)方式時，軋(ya)(ya)機(ji)(ji)生產率最高，因(yin)此，下(xia)一(yi)(yi)(yi)根(gen)芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)的前(qian)端實際上(shang)可以(yi)(yi)(yi)跟在(zai)正在(zai)軋(ya)(ya)制的前(qian)一(yi)(yi)(yi)根(gen)荒(huang)(huang)(huang)(huang)管(guan)(guan)的芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)的后(hou)(hou)(hou)面。這(zhe)是可能的，因(yin)為在(zai)前(qian)一(yi)(yi)(yi)根(gen)荒(huang)(huang)(huang)(huang)管(guan)(guan)軋(ya)(ya)完以(yi)(yi)(yi)前(qian)，后(hou)(hou)(hou)一(yi)(yi)(yi)根(gen)荒(huang)(huang)(huang)(huang)管(guan)(guan)可以(yi)(yi)(yi)放在(zai)前(qian)臺上(shang)、并(bing)穿好(hao)芯(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)(bang)。
2. 回退芯棒
回(hui)退(tui)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)操作(zuo)方式和浮動芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)一(yi)(yi)樣使(shi)用(yong)同(tong)一(yi)(yi)荒(huang)管(guan)(guan)(guan)推(tui)人機(ji)與芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)入(ru)機(ji)，但是芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)入(ru)機(ji)上加(jia)了一(yi)(yi)套裝(zhuang)置，可將芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)的(de)后端固定在(zai)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)入(ru)機(ji)上并使(shi)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)回(hui)轉(zhuan)。荒(huang)管(guan)(guan)(guan)在(zai)前(qian)(qian)臺(tai)的(de)初(chu)始(shi)位置和夾緊與全浮芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)操作(zuo)方式一(yi)(yi)樣。然而，在(zai)插入(ru)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)時，不僅(jin)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)頭部穿(chuan)(chuan)過荒(huang)管(guan)(guan)(guan)，而且(qie)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)要穿(chuan)(chuan)過軋(ya)機(ji)，伸出軋(ya)輥(gun)(gun)臺(tai)肩約3.5m。當(dang)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)到達(da)此(ci)位置后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)開始(shi)回(hui)轉(zhuan)，直到荒(huang)管(guan)(guan)(guan)接觸(chu)軋(ya)輥(gun)(gun)后一(yi)(yi)段時間才停(ting)止。當(dang)芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)入(ru)機(ji)到達(da)行(xing)程終(zhong)點時，壓管(guan)(guan)(guan)器松開，荒(huang)管(guan)(guan)(guan)推(tui)入(ru)機(ji)啟動前(qian)(qian)進(jin)。于是，荒(huang)管(guan)(guan)(guan)喂(wei)入(ru)軋(ya)機(ji)。軋(ya)制(zhi)開始(shi)后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)開始(shi)回(hui)退(tui)。其回(hui)退(tui)速(su)度與荒(huang)管(guan)(guan)(guan)的(de)行(xing)程長(chang)度及(ji)前(qian)(qian)進(jin)速(su)度有(you)關(guan)，以(yi)便在(zai)軋(ya)制(zhi)過程結束，當(dang)毛管(guan)(guan)(guan)離開軋(ya)輥(gun)(gun)時，芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)正好從荒(huang)管(guan)(guan)(guan)中抽出。見圖6-49。然后，毛管(guan)(guan)(guan)從軋(ya)機(ji)運走，進(jin)行(xing)下(xia)步(bu)加(jia)工，而芯(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)高速(su)返回(hui)其初(chu)始(shi)位置以(yi)備穿(chuan)(chuan)入(ru)下(xia)一(yi)(yi)根毛管(guan)(guan)(guan)。
3. 限動芯棒(bang)
限(xian)動芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)作法是全(quan)浮芯(xin)(xin)(xin)(xin)棒(bang)(bang)和回(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)作法的(de)折中方(fang)法。采用(yong)這種方(fang)法時，芯(xin)(xin)(xin)(xin)棒(bang)(bang)的(de)尾端固(gu)定(ding)在芯(xin)(xin)(xin)(xin)棒(bang)(bang)推入(ru)機上，并可(ke)回(hui)轉。這和回(hui)退芯(xin)(xin)(xin)(xin)棒(bang)(bang)操(cao)作方(fang)式一(yi)樣，不同的(de)是，鋼管(guan)(guan)(guan)軋(ya)(ya)制時芯(xin)(xin)(xin)(xin)棒(bang)(bang)向前(qian)(qian)移動。在軋(ya)(ya)制結束(shu)時，芯(xin)(xin)(xin)(xin)棒(bang)(bang)從毛管(guan)(guan)(guan)上脫(tuo)出。當(dang)荒(huang)(huang)(huang)管(guan)(guan)(guan)在前(qian)(qian)臺(tai)被夾(jia)緊(jin)時，穿(chuan)入(ru)芯(xin)(xin)(xin)(xin)棒(bang)(bang)，直到(dao)芯(xin)(xin)(xin)(xin)棒(bang)(bang)前(qian)(qian)端伸(shen)出軋(ya)(ya)輥(gun)(gun)臺(tai)肩約0.3m左右為(wei)止。插入(ru)芯(xin)(xin)(xin)(xin)棒(bang)(bang)時，芯(xin)(xin)(xin)(xin)棒(bang)(bang)開始回(hui)轉，直到(dao)荒(huang)(huang)(huang)管(guan)(guan)(guan)接(jie)觸軋(ya)(ya)輥(gun)(gun)后一(yi)段時間才(cai)停止。芯(xin)(xin)(xin)(xin)棒(bang)(bang)到(dao)位后，壓(ya)管(guan)(guan)(guan)器松開，荒(huang)(huang)(huang)管(guan)(guan)(guan)推入(ru)機將荒(huang)(huang)(huang)管(guan)(guan)(guan)推向軋(ya)(ya)輥(gun)(gun)，直到(dao)軋(ya)(ya)制過程開始為(wei)止。軋(ya)(ya)制過程中，芯(xin)(xin)(xin)(xin)捧以低(di)于毛管(guan)(guan)(guan)軸向輸出速(su)度(du)的(de)速(su)度(du)和軋(ya)(ya)件一(yi)起前(qian)(qian)進。軋(ya)(ya)制周期結束(shu)時，毛管(guan)(guan)(guan)從芯(xin)(xin)(xin)(xin)棒(bang)(bang)上脫(tuo)出，然后，芯(xin)(xin)(xin)(xin)棒(bang)(bang)高速(su)返(fan)回(hui)其初始位置。
三(san)種(zhong)芯(xin)(xin)(xin)(xin)棒(bang)操(cao)(cao)作方(fang)式的(de)比(bi)較。在采用(yong)回退(tui)芯(xin)(xin)(xin)(xin)棒(bang)與(yu)限動芯(xin)(xin)(xin)(xin)棒(bang)操(cao)(cao)作方(fang)式的(de)工廠，只有生產D/t小于(yu)7.5的(de)鋼(gang)管(guan)(guan)時(shi)(shi)才采用(yong)回退(tui)芯(xin)(xin)(xin)(xin)棒(bang)操(cao)(cao)作方(fang)式，而當(dang)生產D/t大于(yu)7.5的(de)鋼(gang)管(guan)(guan)時(shi)(shi)采用(yong)限動芯(xin)(xin)(xin)(xin)棒(bang)操(cao)(cao)作方(fang)式。顯(xian)然，采用(yong)回退(tui)和限動芯(xin)(xin)(xin)(xin)棒(bang)操(cao)(cao)作方(fang)式時(shi)(shi)，軋機產量比(bi)采用(yong)全(quan)浮(fu)芯(xin)(xin)(xin)(xin)棒(bang)時(shi)(shi)低，因為，下一(yi)根(gen)荒管(guan)(guan)撥入(ru)到(dao)前臺之前，在用(yong)的(de)芯(xin)(xin)(xin)(xin)棒(bang)必須返回其初始位置(zhi)。同時(shi)(shi)，芯(xin)(xin)(xin)(xin)棒(bang)的(de)冷卻不充分，芯(xin)(xin)(xin)(xin)棒(bang)壽命不長。
