目(mu)前(qian)采用的有(you)三種芯棒操(cao)作方(fang)式(shi)。早期的三輥(gun)軋(ya)管機均采用全浮(fu)(fu)(fu)芯棒，即使(shi)在(zai)今天，仍有(you)一部分機組(zu)采用全浮(fu)(fu)(fu)芯棒操(cao)作。但是(shi)，全浮(fu)(fu)(fu)芯棒操(cao)作方(fang)式(shi)有(you)如下缺點：

（1）軋制特(te)厚壁(bi)管時不易脫棒；

（2）對各種尺寸的毛(mao)管(guan)均需要配(pei)置再加熱(re)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(zhong)不同芯棒操作方式的簡述。

1. 全浮芯(xin)棒

  采(cai)用(yong)全浮芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)操作方(fang)式(shi)時(shi)，荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)被撥入(ru)(ru)(ru)到荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)前(qian)(qian)的人口臺(tai)，落(luo)到和(he)軋(ya)(ya)機(ji)(ji)(ji)中心線一致的U形槽里。氣(qi)動壓(ya)管(guan)(guan)(guan)(guan)(guan)器(qi)壓(ya)在(zai)(zai)荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)上，將其夾緊，芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)推入(ru)(ru)(ru)機(ji)(ji)(ji)將芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)穿(chuan)(chuan)入(ru)(ru)(ru)荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)內(nei)。一旦芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)完(wan)全穿(chuan)(chuan)入(ru)(ru)(ru)，壓(ya)管(guan)(guan)(guan)(guan)(guan)器(qi)就(jiu)松開，于(yu)是(shi)，荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)連(lian)同(tong)芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)一并向軋(ya)(ya)輥(gun)(gun)方(fang)向送去。如果荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)不易喂入(ru)(ru)(ru)軋(ya)(ya)機(ji)(ji)(ji)，就(jiu)用(yong)荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)在(zai)(zai)后(hou)面推下(xia)(xia)，以幫助荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)喂入(ru)(ru)(ru)。當荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)開始軋(ya)(ya)制時(shi)，荒(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)(bang)(bang)(bang)(bang)推入(ru)(ru)(ru)機(ji)(ji)(ji)便(bian)返(fan)回到初始位置。但是(shi)，當采(cai)用(yong)小直(zhi)徑芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)軋(ya)(ya)管(guan)(guan)(guan)(guan)(guan)時(shi)，荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)推入(ru)(ru)(ru)機(ji)(ji)(ji)可(ke)(ke)(ke)保(bao)留在(zai)(zai)前(qian)(qian)位，充當導(dao)衛，防止芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)抖動。荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)延伸(shen)后(hou)，荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)和(he)芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)一起通過軋(ya)(ya)機(ji)(ji)(ji)向前(qian)(qian)移(yi)動軋(ya)(ya)制終了時(shi)，后(hou)臺(tai)輥(gun)(gun)子(zi)升起，將毛(mao)管(guan)(guan)(guan)(guan)(guan)及(ji)芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)送到輸出輥(gun)(gun)道(dao)。然(ran)后(hou)，從(cong)輸出輥(gun)(gun)送到脫(tuo)(tuo)棒(bang)(bang)(bang)(bang)(bang)機(ji)(ji)(ji)，將芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)從(cong)毛(mao)管(guan)(guan)(guan)(guan)(guan)中脫(tuo)(tuo)出。脫(tuo)(tuo)棒(bang)(bang)(bang)(bang)(bang)后(hou)，芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)先冷卻(que)，再送到軋(ya)(ya)管(guan)(guan)(guan)(guan)(guan)機(ji)(ji)(ji)前(qian)(qian)臺(tai)，以備再用(yong)。荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)則由(you)輥(gun)(gun)道(dao)送走(zou)，進行(xing)下(xia)(xia)一步加工(gong)。采(cai)用(yong)全浮棒(bang)(bang)(bang)(bang)(bang)操作方(fang)式(shi)時(shi)，軋(ya)(ya)機(ji)(ji)(ji)生(sheng)產率最高，因此，下(xia)(xia)一根(gen)芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)的前(qian)(qian)端(duan)實際上可(ke)(ke)(ke)以跟在(zai)(zai)正(zheng)在(zai)(zai)軋(ya)(ya)制的前(qian)(qian)一根(gen)荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)的芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)的后(hou)面。這是(shi)可(ke)(ke)(ke)能的，因為在(zai)(zai)前(qian)(qian)一根(gen)荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)軋(ya)(ya)完(wan)以前(qian)(qian)，后(hou)一根(gen)荒(huang)(huang)(huang)(huang)管(guan)(guan)(guan)(guan)(guan)可(ke)(ke)(ke)以放在(zai)(zai)前(qian)(qian)臺(tai)上、并穿(chuan)(chuan)好芯(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)。

2. 回退芯(xin)棒(bang)

  回(hui)(hui)退芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)操作方式和(he)(he)浮動芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)一(yi)(yi)樣使(shi)用同一(yi)(yi)荒(huang)(huang)管(guan)推(tui)(tui)人機(ji)與芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)，但是芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)上加了(le)一(yi)(yi)套裝置(zhi)(zhi)，可將芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)的(de)后(hou)端(duan)固定在芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)上并使(shi)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)回(hui)(hui)轉(zhuan)。荒(huang)(huang)管(guan)在前(qian)臺(tai)的(de)初始位(wei)置(zhi)(zhi)和(he)(he)夾(jia)緊與全(quan)浮芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)操作方式一(yi)(yi)樣。然而(er)，在插入(ru)(ru)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)時(shi)，不僅芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)頭部(bu)穿過(guo)荒(huang)(huang)管(guan)，而(er)且芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)要(yao)穿過(guo)軋(ya)(ya)(ya)機(ji)，伸出軋(ya)(ya)(ya)輥(gun)臺(tai)肩約3.5m。當芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)到(dao)達(da)此位(wei)置(zhi)(zhi)后(hou)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)開始回(hui)(hui)轉(zhuan)，直到(dao)荒(huang)(huang)管(guan)接觸(chu)軋(ya)(ya)(ya)輥(gun)后(hou)一(yi)(yi)段時(shi)間才停止。當芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)推(tui)(tui)入(ru)(ru)機(ji)到(dao)達(da)行程(cheng)(cheng)終點時(shi)，壓管(guan)器松開，荒(huang)(huang)管(guan)推(tui)(tui)入(ru)(ru)機(ji)啟動前(qian)進。于是，荒(huang)(huang)管(guan)喂(wei)入(ru)(ru)軋(ya)(ya)(ya)機(ji)。軋(ya)(ya)(ya)制開始后(hou)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)開始回(hui)(hui)退。其回(hui)(hui)退速(su)度(du)與荒(huang)(huang)管(guan)的(de)行程(cheng)(cheng)長度(du)及前(qian)進速(su)度(du)有關(guan)，以便在軋(ya)(ya)(ya)制過(guo)程(cheng)(cheng)結束，當毛(mao)管(guan)離(li)開軋(ya)(ya)(ya)輥(gun)時(shi)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)正好從荒(huang)(huang)管(guan)中抽出。見(jian)圖6-49。然后(hou)，毛(mao)管(guan)從軋(ya)(ya)(ya)機(ji)運走，進行下步加工，而(er)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)高速(su)返回(hui)(hui)其初始位(wei)置(zhi)(zhi)以備穿入(ru)(ru)下一(yi)(yi)根(gen)毛(mao)管(guan)。

3. 限(xian)動芯棒

  限動(dong)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)操作法(fa)是(shi)全浮芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)和回(hui)退芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)操作法(fa)的折中方(fang)法(fa)。采用這種方(fang)法(fa)時(shi)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)的尾端固定在芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)推(tui)入(ru)機(ji)上，并可(ke)回(hui)轉。這和回(hui)退芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)操作方(fang)式(shi)一(yi)(yi)樣，不(bu)同的是(shi)，鋼管(guan)(guan)軋(ya)制(zhi)時(shi)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)向(xiang)前移動(dong)。在軋(ya)制(zhi)結束時(shi)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)從(cong)毛管(guan)(guan)上脫出。當荒(huang)管(guan)(guan)在前臺被(bei)夾緊時(shi)，穿(chuan)入(ru)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)，直到芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)前端伸出軋(ya)輥(gun)臺肩約(yue)0.3m左(zuo)右為止。插(cha)入(ru)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)時(shi)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)開始回(hui)轉，直到荒(huang)管(guan)(guan)接觸軋(ya)輥(gun)后(hou)一(yi)(yi)段時(shi)間(jian)才停(ting)止。芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)到位后(hou)，壓(ya)管(guan)(guan)器(qi)松(song)開，荒(huang)管(guan)(guan)推(tui)入(ru)機(ji)將荒(huang)管(guan)(guan)推(tui)向(xiang)軋(ya)輥(gun)，直到軋(ya)制(zhi)過程開始為止。軋(ya)制(zhi)過程中，芯(xin)(xin)(xin)(xin)(xin)(xin)捧以低于毛管(guan)(guan)軸(zhou)向(xiang)輸出速度的速度和軋(ya)件一(yi)(yi)起前進。軋(ya)制(zhi)周期(qi)結束時(shi)，毛管(guan)(guan)從(cong)芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)上脫出，然后(hou)，芯(xin)(xin)(xin)(xin)(xin)(xin)棒(bang)(bang)(bang)(bang)(bang)(bang)高速返回(hui)其(qi)初始位置。

  三種(zhong)芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方(fang)(fang)式(shi)的(de)(de)(de)比(bi)較。在采用回退芯(xin)(xin)棒(bang)(bang)與限動(dong)芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方(fang)(fang)式(shi)的(de)(de)(de)工廠，只有生產(chan)D/t小于(yu)7.5的(de)(de)(de)鋼(gang)管時(shi)才(cai)采用回退芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方(fang)(fang)式(shi)，而當(dang)生產(chan)D/t大于(yu)7.5的(de)(de)(de)鋼(gang)管時(shi)采用限動(dong)芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方(fang)(fang)式(shi)。顯然，采用回退和限動(dong)芯(xin)(xin)棒(bang)(bang)操(cao)作(zuo)方(fang)(fang)式(shi)時(shi)，軋機產(chan)量(liang)比(bi)采用全浮芯(xin)(xin)棒(bang)(bang)時(shi)低，因(yin)為，下一(yi)根荒管撥入到前臺之前，在用的(de)(de)(de)芯(xin)(xin)棒(bang)(bang)必(bi)須返回其初(chu)始位(wei)置(zhi)。同(tong)時(shi)，芯(xin)(xin)棒(bang)(bang)的(de)(de)(de)冷卻不(bu)(bu)充分，芯(xin)(xin)棒(bang)(bang)壽命不(bu)(bu)長。