穿孔是不銹鋼管生產的重要工序之一，對不銹鋼管的管坯成本、品種規格及成品質量有很大影響。根據穿孔機的結構和穿孔過程變形特點的不同，穿孔機可分為兩大類：一類為斜軋穿孔機，又根據軋輥形狀及導衛裝置的不同而演變出多種類型，如曼乃斯曼穿孔機、狄塞爾穿孔機等；另一類是壓力擠孔機和推軋穿孔機（PPM穿孔機）。目前應用最廣的是二輥斜軋穿孔機。
一、斜(xie)軋穿孔
自1885年發明二輥(gun)斜(xie)軋(ya)穿孔(kong)(kong)機以來，斜(xie)軋(ya)穿孔(kong)(kong)至今仍(reng)是最廣泛應(ying)用(yong)的穿孔(kong)(kong)設備。主要斜(xie)軋(ya)穿孔(kong)(kong)機的類(lei)型有：桶形(xing)(xing)輥(gun)穿孔(kong)(kong)機、狄塞爾穿孔(kong)(kong)機、錐形(xing)(xing)輥(gun)穿孔(kong)(kong)機及三輥(gun)穿孔(kong)(kong)機。
1. 桶形輥(gun)穿孔機
二輥(gun)(gun)斜(xie)(xie)軋(ya)(ya)穿(chuan)孔(kong)(kong)(kong)機由德國(guo)的(de)(de)(de)曼(man)乃(nai)斯曼(man)（R.&M.Mannesmann)兄弟發(fa)明，經(jing)瑞士(shi)工程師斯蒂(di)弗爾（R.C Stiefeil)加以完善(shan)。它的(de)(de)(de)工作運動(dong)(dong)情況如圖3-1所示，左(zuo)右兩個(ge)(ge)(ge)軋(ya)(ya)輥(gun)(gun)同向(xiang)旋轉，上下(xia)垂直布(bu)置(zhi)(zhi)的(de)(de)(de)兩個(ge)(ge)(ge)導板固定不(bu)(bu)動(dong)(dong)，中間一(yi)個(ge)(ge)(ge)隨動(dong)(dong)頂(ding)頭，軋(ya)(ya)輥(gun)(gun)軸(zhou)線和軋(ya)(ya)制(zhi)線相(xiang)交成一(yi)個(ge)(ge)(ge)傾斜(xie)(xie)角(jiao)。軋(ya)(ya)輥(gun)(gun)左(zuo)右布(bu)置(zhi)(zhi)，導板上下(xia)布(bu)置(zhi)(zhi)的(de)(de)(de)為臥(wo)式(shi)穿(chuan)孔(kong)(kong)(kong)機，相(xiang)反為立(li)式(shi)穿(chuan)孔(kong)(kong)(kong)機。二輥(gun)(gun)斜(xie)(xie)軋(ya)(ya)穿(chuan)孔(kong)(kong)(kong)方(fang)法的(de)(de)(de)優點是對(dui)心性好，毛管(guan)的(de)(de)(de)壁厚較(jiao)均勻(yun)；一(yi)次延(yan)伸(shen)系(xi)數較(jiao)大，一(yi)般在1.25~4.5之間，可以直接從實心圓坯穿(chuan)制(zhi)成較(jiao)薄的(de)(de)(de)毛管(guan)。主要(yao)缺點是這種(zhong)加工方(fang)法變形復雜，容(rong)易(yi)在毛管(guan)內外表(biao)面(mian)產(chan)生和擴(kuo)大缺陷，所以對(dui)管(guan)坯質(zhi)量(liang)要(yao)求較(jiao)高(gao)，一(yi)般皆采用鍛、軋(ya)(ya)坯。由于(yu)對(dui)鋼管(guan)表(biao)面(mian)質(zhi)量(liang)要(yao)求的(de)(de)(de)不(bu)(bu)斷提(ti)高(gao)，合金鋼比重的(de)(de)(de)不(bu)(bu)斷增長，尤其是連鑄(zhu)圓坯的(de)(de)(de)推廣使用，現(xian)在這種(zhong)喂入(ru)角(jiao)小(xiao)于(yu)13°的(de)(de)(de)二輥(gun)(gun)斜(xie)(xie)軋(ya)(ya)機，已不(bu)(bu)能滿(man)足不(bu)(bu)銹鋼管(guan)生產(chan)中對(dui)生產(chan)率和鋼管(guan)質(zhi)量(liang)的(de)(de)(de)要(yao)求，因而新結構的(de)(de)(de)斜(xie)(xie)軋(ya)(ya)穿(chuan)孔(kong)(kong)(kong)機相(xiang)繼出(chu)現(xian)。
2. 狄塞爾(er)穿(chuan)孔機(ji)
狄塞爾穿(chuan)孔(kong)機是主動旋轉導盤二輥桶形輥斜軋穿孔機，如圖3-2所示，1972年開始見于聯邦德國，是在二輥桶形輥穿孔機基礎上演變而來的。軋輥上下布置，每個軋輥由單獨的主電機通過萬向連接軸直接驅動；左右兩側的導板被兩主動旋轉導盤所替代，因導盤是傳動的，導盤旋轉的切線速度在變形區壓縮帶比軋輥切線速度在軋制軸線上的分量大20%~25%,給軋件施加一個軸向送進力，以減少軋件的軸向阻力。孔喉橢圓度可調近1.0,這樣使最大延伸系數達到5.0,軸向金屬滑動系數增加，毛管內外表面質量大為改善，從而提高了生產率，降低了單位能耗。狄塞爾穿孔機出口速度達1.2m/s,導盤磨損小，使用壽命長，不必經常更換，有利于作業率的提高。
圍繞提(ti)高穿(chuan)孔(kong)(kong)效率和穿(chuan)孔(kong)(kong)毛(mao)管精度，進行了一系(xi)列的技術(shu)改進。如(ru)頂(ding)桿(gan)采用線(xian)外循(xun)環冷卻，在(zai)機(ji)架(jia)出口，向一側循(xun)環運(yun)送(song)冷卻，冷卻后(hou)(hou)送(song)回穿(chuan)孔(kong)(kong)軋制線(xian)，由于(yu)是(shi)線(xian)外脫出穿(chuan)孔(kong)(kong)毛(mao)管送(song)往下道(dao)工序，避免了頂(ding)桿(gan)小車的往復運(yun)動，縮(suo)短穿(chuan)孔(kong)(kong)周(zhou)期(qi)，提(ti)高了效率。如(ru)機(ji)后(hou)(hou)采用多組定心抱(bao)輥(gun)，增加(jia)頂(ding)桿(gan)的穩定性，提(ti)高壁厚(hou)精度。
3. 錐形輥穿孔機(ji)
20世紀(ji)80年(nian)代又在(zai)(zai)狄塞爾穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)結(jie)構(gou)特點(dian)的(de)(de)(de)(de)(de)基礎上(shang)，出(chu)(chu)現了(le)(le)主(zhu)動旋轉(zhuan)導盤、大(da)(da)喂(wei)入角的(de)(de)(de)(de)(de)錐(zhui)(zhui)形(xing)(xing)輥(gun)(gun)(gun)(gun)(gun)兩輥(gun)(gun)(gun)(gun)(gun)斜(xie)軋(ya)(ya)(ya)穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)，如圖3-3所示。它與(yu)狄塞爾穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)最大(da)(da)的(de)(de)(de)(de)(de)不同(tong)是軋(ya)(ya)(ya)輥(gun)(gun)(gun)(gun)(gun)的(de)(de)(de)(de)(de)形(xing)(xing)狀(zhuang)由桶(tong)形(xing)(xing)改(gai)為(wei)錐(zhui)(zhui)形(xing)(xing)，這(zhe)種(zhong)輥(gun)(gun)(gun)(gun)(gun)形(xing)(xing)對斜(xie)軋(ya)(ya)(ya)穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)的(de)(de)(de)(de)(de)適應性來(lai)說，優于(yu)桶(tong)形(xing)(xing)輥(gun)(gun)(gun)(gun)(gun)。因(yin)為(wei)在(zai)(zai)這(zhe)種(zhong)穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)上(shang)，錐(zhui)(zhui)形(xing)(xing)輥(gun)(gun)(gun)(gun)(gun)的(de)(de)(de)(de)(de)直徑沿穿(chuan)(chuan)(chuan)孔(kong)(kong)變(bian)形(xing)(xing)區(qu)是逐漸增加(jia)的(de)(de)(de)(de)(de)，因(yin)此，在(zai)(zai)很(hen)大(da)(da)程度上(shang)減(jian)(jian)(jian)少(shao)管(guan)坯(pi)(pi)(pi)變(bian)形(xing)(xing)過程中的(de)(de)(de)(de)(de)切向(xiang)(xiang)剪切應力(li)，抑制(zhi)(zhi)旋轉(zhuan)橫(heng)鍛效(xiao)(xiao)應，改(gai)善了(le)(le)毛管(guan)內外(wai)表面質(zhi)量(liang)，使得許(xu)多難穿(chuan)(chuan)(chuan)的(de)(de)(de)(de)(de)高合金鋼(gang)管(guan)坯(pi)(pi)(pi)都可(ke)以(yi)在(zai)(zai)這(zhe)種(zhong)軋(ya)(ya)(ya)機(ji)(ji)(ji)上(shang)順利軋(ya)(ya)(ya)制(zhi)(zhi)。錐(zhui)(zhui)形(xing)(xing)輥(gun)(gun)(gun)(gun)(gun)穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)穿(chuan)(chuan)(chuan)孔(kong)(kong)效(xiao)(xiao)率高，有(you)(you)報(bao)道稱最大(da)(da)出(chu)(chu)口速度可(ke)達(da)1.5m/s,有(you)(you)利于(yu)高生產率機(ji)(ji)(ji)組(zu)選用；軋(ya)(ya)(ya)輥(gun)(gun)(gun)(gun)(gun)軸(zhou)線與(yu)軋(ya)(ya)(ya)制(zhi)(zhi)線間除了(le)(le)有(you)(you)10°左(zuo)右(you)的(de)(de)(de)(de)(de)喂(wei)入角α外(wai)，還(huan)有(you)(you)一(yi)個15°左(zuo)右(you)的(de)(de)(de)(de)(de)輾軋(ya)(ya)(ya)角γ,這(zhe)樣(yang)可(ke)使該類(lei)型穿(chuan)(chuan)(chuan)孔(kong)(kong)軸(zhou)向(xiang)(xiang)滑動系數(shu)達(da)到了(le)(le)0.9,最大(da)(da)延伸系數(shu)可(ke)達(da)6.0,在(zai)(zai)變(bian)形(xing)(xing)量(liang)的(de)(de)(de)(de)(de)分配上(shang)，可(ke)承擔較大(da)(da)變(bian)形(xing)(xing)，從(cong)而減(jian)(jian)(jian)少(shao)了(le)(le)軋(ya)(ya)(ya)管(guan)機(ji)(ji)(ji)的(de)(de)(de)(de)(de)變(bian)形(xing)(xing)；穿(chuan)(chuan)(chuan)孔(kong)(kong)擴徑量(liang)達(da)到30%~40%,這(zhe)就不僅可(ke)提供(gong)薄(bo)壁毛管(guan)，還(huan)可(ke)以(yi)減(jian)(jian)(jian)少(shao)管(guan)坯(pi)(pi)(pi)規格范圍，簡(jian)化生產管(guan)理。錐(zhui)(zhui)形(xing)(xing)輥(gun)(gun)(gun)(gun)(gun)穿(chuan)(chuan)(chuan)孔(kong)(kong)機(ji)(ji)(ji)既有(you)(you)配備(bei)導盤的(de)(de)(de)(de)(de)，也有(you)(you)配備(bei)導板(ban)的(de)(de)(de)(de)(de)，目前已建、在(zai)(zai)建新的(de)(de)(de)(de)(de)軋(ya)(ya)(ya)管(guan)機(ji)(ji)(ji)組(zu)上(shang)兩種(zhong)配置均有(you)(you)使用。
狄塞(sai)爾穿(chuan)(chuan)孔(kong)機(ji)和(he)錐(zhui)形輥穿(chuan)(chuan)孔(kong)機(ji)都是當(dang)代廣(guang)為采用的新型穿(chuan)(chuan)孔(kong)機(ji)，穿(chuan)(chuan)孔(kong)效率高及產(chan)品精度高，適于連鑄(zhu)坯穿(chuan)(chuan)孔(kong)。其中錐(zhui)形輥穿(chuan)(chuan)孔(kong)機(ji)具有更大的發(fa)展前途。
二、壓(ya)力(li)穿(chuan)孔
不銹鋼(gang)管(guan)坯(pi)壓力穿孔常在立式水壓機或液壓機（穿孔機）上進行，圖3-4為壓力穿孔（也稱壓力沖孔）操作過程示意圖。壓力穿孔于1891年問世，它是將方形或多邊形鋼錠放在擠壓缸中，擠成中空杯體，延伸系數為1.0~1.1,穿孔比（空心坯長度與內徑比）不大于7~10。
與二輥斜軋相比，這種加工(gong)方法(fa)的(de)(de)(de)坯(pi)料(liao)中(zhong)心(xin)處于(yu)(yu)不(bu)(bu)等軸全向壓應力狀(zhuang)態，外(wai)表面承受著較大(da)(da)的(de)(de)(de)徑向壓力，因內、外(wai)表面在(zai)加工(gong)過程中(zhong)不(bu)(bu)會(hui)產生缺(que)陷，對來料(liao)沒有苛刻(ke)要(yao)求，可(ke)用于(yu)(yu)鋼錠、連(lian)鑄方坯(pi)和低塑性(xing)材料(liao)的(de)(de)(de)穿孔。此法(fa)加工(gong)主要(yao)是(shi)(shi)中(zhong)心(xin)變(bian)(bian)形，特(te)別有利于(yu)(yu)鋼錠中(zhong)心(xin)的(de)(de)(de)粗(cu)大(da)(da)疏松組織(zhi)致密化，雖然最大(da)(da)延伸系(xi)數(shu)只有1.1,但中(zhong)心(xin)部分的(de)(de)(de)變(bian)(bian)形效(xiao)果(guo)(guo)相當于(yu)(yu)外(wai)部加工(gong)效(xiao)果(guo)(guo)的(de)(de)(de)5倍。主要(yao)缺(que)點是(shi)(shi)生產率(lv)低，成材率(lv)低，偏心(xin)率(lv)較大(da)(da)。
三、對穿孔(kong)毛管(guan)的質(zhi)量(liang)要求
1. 對穿孔(kong)工藝要(yao)求
不(bu)(bu)銹鋼管(guan)(guan)(guan)(guan)坯穿(chuan)孔(kong)(kong)(kong)(kong)是(shi)熱軋(ya)無縫鋼管(guan)(guan)(guan)(guan)生產中最重要的(de)變形工(gong)(gong)序(xu)(xu)之一，它將實心(xin)的(de)管(guan)(guan)(guan)(guan)坯變為(wei)空心(xin)坯，穿(chuan)孔(kong)(kong)(kong)(kong)后的(de)空心(xin)坯通(tong)常被稱作毛(mao)管(guan)(guan)(guan)(guan)。我們可以視穿(chuan)孔(kong)(kong)(kong)(kong)工(gong)(gong)序(xu)(xu)為(wei)定型(xing)工(gong)(gong)序(xu)(xu)，即(ji)將軋(ya)件的(de)橫截面定為(wei)圓環狀的(de)工(gong)(gong)序(xu)(xu)。穿(chuan)孔(kong)(kong)(kong)(kong)后毛(mao)管(guan)(guan)(guan)(guan)質量的(de)好(hao)壞(huai)直接關系到下(xia)道工(gong)(gong)序(xu)(xu)的(de)工(gong)(gong)藝(yi)是(shi)否能正常執行以及最終(zhong)產品質量的(de)高低。為(wei)此對(dui)穿(chuan)孔(kong)(kong)(kong)(kong)工(gong)(gong)藝(yi)提出如下(xia)幾點要求(qiu)：首(shou)先要保證(zheng)穿(chuan)制的(de)毛(mao)管(guan)(guan)(guan)(guan)壁(bi)厚(hou)均(jun)(jun)勻，螺旋線較淺、橢圓度(du)小，幾何(he)尺(chi)寸精度(du)高，當毛(mao)管(guan)(guan)(guan)(guan)尺(chi)寸偏小、芯(xin)棒同毛(mao)管(guan)(guan)(guan)(guan)間隙(xi)過(guo)小時(shi)，毛(mao)管(guan)(guan)(guan)(guan)的(de)溫降快，軋(ya)制過(guo)程中容易(yi)產生壁(bi)厚(hou)不(bu)(bu)均(jun)(jun)、拉凹、孔(kong)(kong)(kong)(kong)洞等(deng)缺陷(xian)(xian)；其次(ci)，毛(mao)管(guan)(guan)(guan)(guan)的(de)內外表(biao)面要光滑，不(bu)(bu)得(de)有結疤(ba)、折(zhe)疊、劃傷、裂紋、凹凸不(bu)(bu)平等(deng)缺陷(xian)(xian)；最后要有相應的(de)穿(chuan)孔(kong)(kong)(kong)(kong)速(su)度(du)和(he)軋(ya)制周期，以適(shi)應整個機組的(de)生產節奏，使毛(mao)管(guan)(guan)(guan)(guan)溫度(du)比較均(jun)(jun)勻、終(zhong)軋(ya)溫度(du)能夠滿(man)足軋(ya)管(guan)(guan)(guan)(guan)機的(de)工(gong)(gong)藝(yi)要求(qiu)。
2. 確保(bao)毛管質(zhi)量(liang)的技(ji)術措施(shi)
為了滿足上述工(gong)(gong)藝要求，除了確定正(zheng)確的(de)穿孔(kong)工(gong)(gong)藝參(can)數(shu)（包括管坯加熱(re)溫度、穿孔(kong)溫度、穿孔(kong)速度、軋輥(gun)(gun)轉(zhuan)速和喂入角的(de)大小(xiao)）及調整(zheng)參(can)數(shu)（輥(gun)(gun)距、導(dao)板／導(dao)盤距、頂頭前伸量）外，穿孔(kong)機組(zu)還應用(yong)了如下技術：
a. 穿孔機架：軋輥(gun)垂直布置，使得更換和檢查導盤(pan)／導板的時間很短，可確保毛管外(wai)表面質(zhi)量(liang)；
b. 出(chu)口部分：頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)／頂(ding)(ding)(ding)(ding)(ding)(ding)桿(gan)從毛(mao)管中抽(chou)出(chu)后頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)或頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)／頂(ding)(ding)(ding)(ding)(ding)(ding)桿(gan)的冷(leng)卻(que)在線外(wai)(wai)進行。設置頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)或頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)／頂(ding)(ding)(ding)(ding)(ding)(ding)桿(gan)線外(wai)(wai)冷(leng)卻(que)循環系統(tong)，可(ke)縮短周期時(shi)間，更容(rong)易(yi)檢(jian)查、更換頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)，另外(wai)(wai)如采(cai)用線外(wai)(wai)用回轉式冷(leng)卻(que)裝(zhuang)置進行頂(ding)(ding)(ding)(ding)(ding)(ding)桿(gan)（帶(dai)頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)）冷(leng)卻(que)，還可(ke)確保(bao)頂(ding)(ding)(ding)(ding)(ding)(ding)桿(gan)的直度較好，為毛(mao)管的壁(bi)厚(hou)均勻提供了(le)保(bao)證(zheng)(zheng)；頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)的循環使(shi)用，因冷(leng)卻(que)時(shi)間充分，使(shi)冷(leng)卻(que)效果得到保(bao)證(zheng)(zheng)，從而可(ke)以提高頂(ding)(ding)(ding)(ding)(ding)(ding)頭(tou)的使(shi)用壽命，確保(bao)毛(mao)管內表(biao)面的光滑；
c. 頂(ding)桿及毛管導向：有多組定心(xin)輥，第一組定心(xin)輥裝在機(ji)架內(nei)，使(shi)其盡量靠近(jin)穿(chuan)(chuan)孔變形區，以減小頂(ding)頭(tou)／頂(ding)桿的懸臂(bei)長度、提高頂(ding)桿的剛度，可更好地限制頂(ding)桿／頂(ding)頭(tou)及軋(ya)件(jian)在穿(chuan)(chuan)孔過程(cheng)中的徑向抖動，確(que)保穿(chuan)(chuan)出的毛管壁厚均勻；
d. 采用頂桿(gan)預旋轉(zhuan)技術(shu)，頂頭(tou)(tou)能自動對正管坯的中心，以(yi)提高毛(mao)管頭(tou)(tou)部的壁(bi)厚(hou)精度，并可降低二次咬入時因頂頭(tou)(tou)／頂桿(gan)轉(zhuan)動慣量(liang)的阻力(li)轉(zhuan)矩而發生不咬入（前卡(ka)）故障的概率。
3. 特殊的工(gong)藝要(yao)求
為滿(man)足連軋管(guan)(guan)(guan)(guan)(guan)(guan)工藝的(de)(de)(de)(de)特殊性，對于專供連續(xu)軋管(guan)(guan)(guan)(guan)(guan)(guan)機使用(yong)的(de)(de)(de)(de)毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)，還有(you)兩項重要(yao)的(de)(de)(de)(de)質量(liang)指標要(yao)求(qiu)：一是毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)的(de)(de)(de)(de)橢(tuo)圓度(du)要(yao)小，因(yin)為毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)橢(tuo)圓度(du)過大將影響軋管(guan)(guan)(guan)(guan)(guan)(guan)前穿(chuan)芯(xin)棒(bang)(bang)(bang)的(de)(de)(de)(de)順利(li)進行，輕(qing)者刮掉(diao)芯(xin)棒(bang)(bang)(bang)表面的(de)(de)(de)(de)潤滑劑，使軋制過程中(zhong)(zhong)震動(dong)較(jiao)(jiao)大，降低荒管(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)(de)壁(bi)厚精度(du)和芯(xin)棒(bang)(bang)(bang)的(de)(de)(de)(de)使用(yong)壽命并損傷(shang)設備，重者芯(xin)棒(bang)(bang)(bang)可(ke)能會頂彎毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)，致使生(sheng)產中(zhong)(zhong)斷，這就(jiu)要(yao)求(qiu)在調整時(shi)注意保證穿(chuan)孔過程即將結束(shu)時(shi)，毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)的(de)(de)(de)(de)歸圓效(xiao)果；二是毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)不(bu)得存(cun)在尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)鐮刀（非環(huan)狀連續(xu)體部(bu)(bu)(bu)(bu)(bu)分的(de)(de)(de)(de)俗(su)稱(cheng)，見圖3-5)缺陷(xian)，當毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)存(cun)在尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)鐮刀缺陷(xian)時(shi)，穿(chuan)芯(xin)棒(bang)(bang)(bang)過程中(zhong)(zhong)容易將毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)尾(wei)(wei)部(bu)(bu)(bu)(bu)(bu)不(bu)連續(xu)的(de)(de)(de)(de)部(bu)(bu)(bu)(bu)(bu)分金(jin)(jin)屬碰掉(diao)，一旦這些溫度(du)較(jiao)(jiao)低的(de)(de)(de)(de)金(jin)(jin)屬被帶到(dao)毛(mao)(mao)(mao)管(guan)(guan)(guan)(guan)(guan)(guan)中(zhong)(zhong)，軋制時(shi)將硌傷(shang)軋件(jian)而(er)產生(sheng)孔洞(dong)管(guan)(guan)(guan)(guan)(guan)(guan)，若這些較(jiao)(jiao)硬的(de)(de)(de)(de)金(jin)(jin)屬掉(diao)在軋輥上，將硌傷(shang)軋輥輥面而(er)造成鋼管(guan)(guan)(guan)(guan)(guan)(guan)外表面缺陷(xian)等嚴重的(de)(de)(de)(de)質量(liang)事故。
如果是(shi)向限動芯(xin)棒(bang)連續軋(ya)(ya)管(guan)(guan)機提(ti)供毛管(guan)(guan)，還須向毛管(guan)(guan)內(nei)(nei)(nei)(nei)噴(pen)(pen)吹氮(dan)氣(qi)(qi)和(he)硼砂(sha)，以起到去除(chu)毛管(guan)(guan)內(nei)(nei)(nei)(nei)表(biao)(biao)(biao)面(mian)(mian)的(de)(de)氧(yang)(yang)(yang)化(hua)(hua)鐵(tie)皮、減小芯(xin)棒(bang)與軋(ya)(ya)件(jian)間的(de)(de)摩擦力、防(fang)止(zhi)軋(ya)(ya)制(zhi)(zhi)過程中抖動的(de)(de)作(zuo)用。其過程為：抽(chou)出頂桿后的(de)(de)毛管(guan)(guan)，送(song)到吹硼砂(sha)站，由一(yi)特制(zhi)(zhi)的(de)(de)噴(pen)(pen)嘴(zui)向毛管(guan)(guan)內(nei)(nei)(nei)(nei)部噴(pen)(pen)入硼砂(sha)和(he)氮(dan)氣(qi)(qi)，吹掉(diao)毛管(guan)(guan)內(nei)(nei)(nei)(nei)部的(de)(de)氧(yang)(yang)(yang)化(hua)(hua)鐵(tie)皮，清除(chu)原(yuan)來的(de)(de)氧(yang)(yang)(yang)化(hua)(hua)物（硼砂(sha)使管(guan)(guan)內(nei)(nei)(nei)(nei)壁的(de)(de)氧(yang)(yang)(yang)化(hua)(hua)層脫(tuo)氧(yang)(yang)(yang)，高(gao)溫下(xia)的(de)(de)硼砂(sha)呈熔融態，均(jun)勻地附著在(zai)毛管(guan)(guan)內(nei)(nei)(nei)(nei)表(biao)(biao)(biao)面(mian)(mian)上可(ke)(ke)起到潤滑劑的(de)(de)作(zuo)用，氮(dan)氣(qi)(qi)能(neng)保(bao)(bao)持毛管(guan)(guan)內(nei)(nei)(nei)(nei)表(biao)(biao)(biao)面(mian)(mian)不再被氧(yang)(yang)(yang)化(hua)(hua)）；另(ling)外，硼砂(sha)在(zai)高(gao)溫狀(zhuang)態下(xia)生成(cheng)霧狀(zhuang)氣(qi)(qi)體，充滿管(guan)(guan)內(nei)(nei)(nei)(nei)，以防(fang)止(zhi)在(zai)隨(sui)后的(de)(de)運動中空(kong)氣(qi)(qi)進入，減少內(nei)(nei)(nei)(nei)表(biao)(biao)(biao)面(mian)(mian)產生二(er)次氧(yang)(yang)(yang)化(hua)(hua)的(de)(de)可(ke)(ke)能(neng)。這就要求(qiu)軋(ya)(ya)管(guan)(guan)前盡量(liang)(liang)避免(mian)毛管(guan)(guan)的(de)(de)軸向移(yi)動，以防(fang)止(zhi)毛管(guan)(guan)內(nei)(nei)(nei)(nei)表(biao)(biao)(biao)面(mian)(mian)產生二(er)次氧(yang)(yang)(yang)化(hua)(hua)，從而(er)確保(bao)(bao)軋(ya)(ya)制(zhi)(zhi)過程的(de)(de)穩定和(he)軋(ya)(ya)出荒管(guan)(guan)的(de)(de)質量(liang)(liang)。
限(xian)動(dong)芯棒連續軋管(guan)機組是(shi)(shi)否(fou)能正常運(yun)轉，是(shi)(shi)否(fou)能生(sheng)產出高質(zhi)(zhi)量(liang)的不銹鋼(gang)管(guan)，與毛管(guan)的各項(xiang)質(zhi)(zhi)量(liang)指標（包括(kuo)溫度的均(jun)勻性、外(wai)徑(jing)／壁厚幾何尺寸的精度、內外(wai)表面(mian)(mian)的光滑(hua)程度等）有(you)很(hen)大關系特別是(shi)(shi)與毛管(guan)尾(wei)部的質(zhi)(zhi)量(liang)狀況(kuang)（內徑(jing)尺寸偏差和(he)是(shi)(shi)否(fou)存在尾(wei)部鐮刀）以及為清除毛管(guan)內表面(mian)(mian)氧化物、防(fang)止毛管(guan)內表面(mian)(mian)二次氧化所采取的上述工(gong)藝措施的效(xiao)果(guo)是(shi)(shi)密切相關的。
