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、斜軋穿孔
自1885年發明二輥斜軋(ya)穿(chuan)(chuan)孔(kong)(kong)(kong)機(ji)以來,斜軋(ya)穿(chuan)(chuan)孔(kong)(kong)(kong)至今(jin)仍是(shi)最廣泛應(ying)用的穿(chuan)(chuan)孔(kong)(kong)(kong)設備。主要斜軋(ya)穿(chuan)(chuan)孔(kong)(kong)(kong)機(ji)的類型(xing)有:桶形輥穿(chuan)(chuan)孔(kong)(kong)(kong)機(ji)、狄塞爾(er)穿(chuan)(chuan)孔(kong)(kong)(kong)機(ji)、錐形輥穿(chuan)(chuan)孔(kong)(kong)(kong)機(ji)及三輥穿(chuan)(chuan)孔(kong)(kong)(kong)機(ji)。
1. 桶形(xing)輥穿(chuan)孔機
二(er)輥(gun)斜(xie)(xie)軋(ya)穿(chuan)孔(kong)機由德國的(de)(de)曼(man)乃(nai)斯(si)曼(man)(R.&M.Mannesmann)兄弟(di)發明,經(jing)瑞士工(gong)程師斯(si)蒂弗爾(R.C Stiefeil)加(jia)以完善。它的(de)(de)工(gong)作運(yun)動情況(kuang)如圖3-1所(suo)示,左右兩個(ge)(ge)軋(ya)輥(gun)同向旋轉(zhuan),上下垂直布(bu)置(zhi)的(de)(de)兩個(ge)(ge)導(dao)板固定不(bu)(bu)(bu)動,中間(jian)一(yi)(yi)個(ge)(ge)隨動頂(ding)頭,軋(ya)輥(gun)軸線(xian)和軋(ya)制(zhi)(zhi)線(xian)相(xiang)交成一(yi)(yi)個(ge)(ge)傾斜(xie)(xie)角(jiao)。軋(ya)輥(gun)左右布(bu)置(zhi),導(dao)板上下布(bu)置(zhi)的(de)(de)為(wei)臥式(shi)穿(chuan)孔(kong)機,相(xiang)反為(wei)立(li)式(shi)穿(chuan)孔(kong)機。二(er)輥(gun)斜(xie)(xie)軋(ya)穿(chuan)孔(kong)方法的(de)(de)優點是對(dui)心性好,毛(mao)管(guan)的(de)(de)壁厚較均勻;一(yi)(yi)次延伸(shen)系數較大(da),一(yi)(yi)般在(zai)1.25~4.5之間(jian),可以直接從實心圓(yuan)坯(pi)穿(chuan)制(zhi)(zhi)成較薄(bo)的(de)(de)毛(mao)管(guan)。主要(yao)(yao)缺點是這種加(jia)工(gong)方法變(bian)形復雜,容易在(zai)毛(mao)管(guan)內外表面產(chan)生和擴大(da)缺陷,所(suo)以對(dui)管(guan)坯(pi)質(zhi)量要(yao)(yao)求(qiu)(qiu)較高(gao),一(yi)(yi)般皆采用鍛、軋(ya)坯(pi)。由于對(dui)鋼(gang)(gang)管(guan)表面質(zhi)量要(yao)(yao)求(qiu)(qiu)的(de)(de)不(bu)(bu)(bu)斷提高(gao),合金(jin)鋼(gang)(gang)比重的(de)(de)不(bu)(bu)(bu)斷增長,尤(you)其是連鑄圓(yuan)坯(pi)的(de)(de)推廣使用,現在(zai)這種喂入角(jiao)小于13°的(de)(de)二(er)輥(gun)斜(xie)(xie)軋(ya)機,已不(bu)(bu)(bu)能滿足(zu)不(bu)(bu)(bu)銹(xiu)鋼(gang)(gang)管(guan)生產(chan)中對(dui)生產(chan)率(lv)和鋼(gang)(gang)管(guan)質(zhi)量的(de)(de)要(yao)(yao)求(qiu)(qiu),因而新結構的(de)(de)斜(xie)(xie)軋(ya)穿(chuan)孔(kong)機相(xiang)繼出(chu)現。

2. 狄塞爾穿孔機
狄(di)塞爾穿孔機(ji)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)毛管(guan)精度,進行(xing)了(le)一(yi)系列的技術改進。如(ru)頂桿采用線外循環冷(leng)卻(que)(que),在機架出口,向一(yi)側循環運送冷(leng)卻(que)(que),冷(leng)卻(que)(que)后(hou)送回(hui)穿(chuan)孔(kong)(kong)軋制線,由于是線外脫出穿(chuan)孔(kong)(kong)毛管(guan)送往下(xia)道工(gong)序,避免了(le)頂桿小(xiao)車的往復運動,縮短(duan)穿(chuan)孔(kong)(kong)周期,提(ti)高了(le)效率。如(ru)機后(hou)采用多組定心抱輥,增加頂桿的穩定性,提(ti)高壁厚精度。
3. 錐形輥穿(chuan)孔機
20世(shi)紀(ji)80年(nian)代又在(zai)狄塞爾穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji)結構特點的(de)(de)基礎上(shang),出現了主(zhu)動(dong)旋(xuan)轉導盤、大(da)喂入角的(de)(de)錐形(xing)(xing)(xing)(xing)輥(gun)(gun)兩(liang)輥(gun)(gun)斜(xie)軋(ya)(ya)(ya)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji),如(ru)圖3-3所示(shi)。它與狄塞爾穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji)最大(da)的(de)(de)不(bu)同是(shi)軋(ya)(ya)(ya)輥(gun)(gun)的(de)(de)形(xing)(xing)(xing)(xing)狀由桶形(xing)(xing)(xing)(xing)改為錐形(xing)(xing)(xing)(xing),這種輥(gun)(gun)形(xing)(xing)(xing)(xing)對(dui)斜(xie)軋(ya)(ya)(ya)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji)的(de)(de)適應性(xing)來說(shuo),優于桶形(xing)(xing)(xing)(xing)輥(gun)(gun)。因為在(zai)這種穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji)上(shang),錐形(xing)(xing)(xing)(xing)輥(gun)(gun)的(de)(de)直徑沿穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)變(bian)(bian)形(xing)(xing)(xing)(xing)區是(shi)逐(zhu)漸增(zeng)加的(de)(de),因此(ci),在(zai)很(hen)大(da)程(cheng)度上(shang)減少(shao)(shao)管(guan)(guan)(guan)坯(pi)(pi)變(bian)(bian)形(xing)(xing)(xing)(xing)過程(cheng)中的(de)(de)切(qie)向(xiang)(xiang)剪切(qie)應力,抑制(zhi)旋(xuan)轉橫(heng)鍛效(xiao)應,改善(shan)了毛管(guan)(guan)(guan)內(nei)外表面質量,使得許多(duo)難穿(chuan)(chuan)(chuan)的(de)(de)高合金(jin)鋼管(guan)(guan)(guan)坯(pi)(pi)都可以(yi)在(zai)這種軋(ya)(ya)(ya)機(ji)(ji)(ji)(ji)上(shang)順利軋(ya)(ya)(ya)制(zhi)。錐形(xing)(xing)(xing)(xing)輥(gun)(gun)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)效(xiao)率(lv)高,有(you)(you)(you)報道(dao)稱最大(da)出口速度可達(da)1.5m/s,有(you)(you)(you)利于高生(sheng)產率(lv)機(ji)(ji)(ji)(ji)組(zu)選用(yong);軋(ya)(ya)(ya)輥(gun)(gun)軸線(xian)與軋(ya)(ya)(ya)制(zhi)線(xian)間除了有(you)(you)(you)10°左(zuo)右的(de)(de)喂入角α外,還(huan)有(you)(you)(you)一個15°左(zuo)右的(de)(de)輾軋(ya)(ya)(ya)角γ,這樣可使該(gai)類型穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)軸向(xiang)(xiang)滑動(dong)系(xi)數(shu)達(da)到了0.9,最大(da)延(yan)伸系(xi)數(shu)可達(da)6.0,在(zai)變(bian)(bian)形(xing)(xing)(xing)(xing)量的(de)(de)分配(pei)(pei)上(shang),可承擔較大(da)變(bian)(bian)形(xing)(xing)(xing)(xing),從而(er)減少(shao)(shao)了軋(ya)(ya)(ya)管(guan)(guan)(guan)機(ji)(ji)(ji)(ji)的(de)(de)變(bian)(bian)形(xing)(xing)(xing)(xing);穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)擴徑量達(da)到30%~40%,這就不(bu)僅可提(ti)供薄壁(bi)毛管(guan)(guan)(guan),還(huan)可以(yi)減少(shao)(shao)管(guan)(guan)(guan)坯(pi)(pi)規格范圍,簡化生(sheng)產管(guan)(guan)(guan)理。錐形(xing)(xing)(xing)(xing)輥(gun)(gun)穿(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)(ji)(ji)既(ji)有(you)(you)(you)配(pei)(pei)備導盤的(de)(de),也有(you)(you)(you)配(pei)(pei)備導板的(de)(de),目前已(yi)建、在(zai)建新(xin)的(de)(de)軋(ya)(ya)(ya)管(guan)(guan)(guan)機(ji)(ji)(ji)(ji)組(zu)上(shang)兩(liang)種配(pei)(pei)置均(jun)有(you)(you)(you)使用(yong)。

狄塞爾穿(chuan)孔(kong)機和錐形輥穿(chuan)孔(kong)機都是當代廣為(wei)采用(yong)的新型穿(chuan)孔(kong)機,穿(chuan)孔(kong)效(xiao)率高(gao)及產品(pin)精度高(gao),適于連鑄(zhu)坯穿(chuan)孔(kong)。其中錐形輥穿(chuan)孔(kong)機具有(you)更大的發展前途。
二(er)、壓力(li)穿孔
不銹鋼管坯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(xie)軋(ya)相(xiang)比,這種加(jia)工(gong)方法的(de)(de)坯料中(zhong)(zhong)心(xin)(xin)處于不(bu)等軸(zhou)全向壓應力狀(zhuang)態,外表面承受著較大的(de)(de)徑向壓力,因內、外表面在(zai)加(jia)工(gong)過程中(zhong)(zhong)不(bu)會產生(sheng)缺(que)陷,對來料沒(mei)有(you)(you)苛(ke)刻(ke)要(yao)求,可用于鋼(gang)錠(ding)(ding)、連鑄方坯和低(di)(di)塑性材料的(de)(de)穿孔。此(ci)法加(jia)工(gong)主要(yao)是中(zhong)(zhong)心(xin)(xin)變(bian)形(xing),特別有(you)(you)利于鋼(gang)錠(ding)(ding)中(zhong)(zhong)心(xin)(xin)的(de)(de)粗大疏(shu)松組織致密化,雖然最大延(yan)伸(shen)系數只有(you)(you)1.1,但中(zhong)(zhong)心(xin)(xin)部(bu)分的(de)(de)變(bian)形(xing)效(xiao)果相(xiang)當于外部(bu)加(jia)工(gong)效(xiao)果的(de)(de)5倍。主要(yao)缺(que)點(dian)是生(sheng)產率(lv)(lv)低(di)(di),成材率(lv)(lv)低(di)(di),偏(pian)心(xin)(xin)率(lv)(lv)較大。
三、對穿孔毛管的質量(liang)要求
1. 對穿孔工藝要求
不銹鋼(gang)管(guan)(guan)坯(pi)穿(chuan)孔(kong)(kong)是(shi)熱軋(ya)無縫鋼(gang)管(guan)(guan)生(sheng)產(chan)中最重要的(de)(de)(de)變形工(gong)(gong)序(xu)之一,它將(jiang)實(shi)心(xin)的(de)(de)(de)管(guan)(guan)坯(pi)變為(wei)空心(xin)坯(pi),穿(chuan)孔(kong)(kong)后的(de)(de)(de)空心(xin)坯(pi)通常(chang)被稱(cheng)作(zuo)毛管(guan)(guan)。我們(men)可以視穿(chuan)孔(kong)(kong)工(gong)(gong)序(xu)為(wei)定(ding)(ding)型工(gong)(gong)序(xu),即(ji)將(jiang)軋(ya)件的(de)(de)(de)橫截面(mian)定(ding)(ding)為(wei)圓(yuan)環(huan)狀的(de)(de)(de)工(gong)(gong)序(xu)。穿(chuan)孔(kong)(kong)后毛管(guan)(guan)質(zhi)(zhi)量的(de)(de)(de)好壞(huai)直接關系到(dao)下(xia)道工(gong)(gong)序(xu)的(de)(de)(de)工(gong)(gong)藝(yi)是(shi)否(fou)能正(zheng)常(chang)執行以及最終(zhong)(zhong)產(chan)品(pin)質(zhi)(zhi)量的(de)(de)(de)高(gao)低。為(wei)此(ci)對穿(chuan)孔(kong)(kong)工(gong)(gong)藝(yi)提出如下(xia)幾(ji)(ji)點要求:首先要保(bao)證(zheng)穿(chuan)制(zhi)(zhi)的(de)(de)(de)毛管(guan)(guan)壁(bi)厚(hou)均勻,螺(luo)旋線較淺、橢圓(yuan)度(du)(du)小(xiao)(xiao),幾(ji)(ji)何尺(chi)寸精(jing)度(du)(du)高(gao),當毛管(guan)(guan)尺(chi)寸偏小(xiao)(xiao)、芯(xin)棒同毛管(guan)(guan)間隙過(guo)小(xiao)(xiao)時,毛管(guan)(guan)的(de)(de)(de)溫降快,軋(ya)制(zhi)(zhi)過(guo)程(cheng)中容易產(chan)生(sheng)壁(bi)厚(hou)不均、拉凹、孔(kong)(kong)洞等缺陷;其次(ci),毛管(guan)(guan)的(de)(de)(de)內(nei)外表面(mian)要光滑,不得有結疤、折疊、劃傷(shang)、裂(lie)紋、凹凸不平等缺陷;最后要有相應的(de)(de)(de)穿(chuan)孔(kong)(kong)速度(du)(du)和(he)軋(ya)制(zhi)(zhi)周期,以適應整個機組(zu)的(de)(de)(de)生(sheng)產(chan)節奏(zou),使(shi)毛管(guan)(guan)溫度(du)(du)比較均勻、終(zhong)(zhong)軋(ya)溫度(du)(du)能夠滿足軋(ya)管(guan)(guan)機的(de)(de)(de)工(gong)(gong)藝(yi)要求。
2. 確保(bao)毛管質量的技術措(cuo)施
為(wei)了滿(man)足上(shang)述工(gong)藝要求,除了確定(ding)正確的穿孔工(gong)藝參(can)數(包括(kuo)管坯(pi)加熱溫度、穿孔溫度、穿孔速度、軋(ya)輥(gun)轉速和喂入角的大小(xiao))及調整參(can)數(輥(gun)距(ju)、導板(ban)/導盤距(ju)、頂頭前(qian)伸量(liang))外(wai),穿孔機組還應用了如下(xia)技(ji)術:
a. 穿(chuan)孔機架:軋(ya)輥垂直布置,使(shi)得更換和檢查導(dao)盤/導(dao)板的時間(jian)很短,可確(que)保毛管外(wai)表面質量;
b. 出(chu)口(kou)部(bu)分:頂(ding)(ding)(ding)頭(tou)(tou)/頂(ding)(ding)(ding)桿(gan)(gan)從(cong)毛管中抽出(chu)后(hou)頂(ding)(ding)(ding)頭(tou)(tou)或頂(ding)(ding)(ding)頭(tou)(tou)/頂(ding)(ding)(ding)桿(gan)(gan)的(de)(de)冷(leng)卻(que)(que)(que)在線外進行(xing)。設(she)置頂(ding)(ding)(ding)頭(tou)(tou)或頂(ding)(ding)(ding)頭(tou)(tou)/頂(ding)(ding)(ding)桿(gan)(gan)線外冷(leng)卻(que)(que)(que)循(xun)環(huan)系(xi)統,可(ke)縮短周期(qi)時(shi)間(jian),更容易(yi)檢查、更換頂(ding)(ding)(ding)頭(tou)(tou),另(ling)外如(ru)采用線外用回轉式冷(leng)卻(que)(que)(que)裝置進行(xing)頂(ding)(ding)(ding)桿(gan)(gan)(帶(dai)頂(ding)(ding)(ding)頭(tou)(tou))冷(leng)卻(que)(que)(que),還可(ke)確保頂(ding)(ding)(ding)桿(gan)(gan)的(de)(de)直度較(jiao)好(hao),為毛管的(de)(de)壁厚均勻提供(gong)了保證;頂(ding)(ding)(ding)頭(tou)(tou)的(de)(de)循(xun)環(huan)使用,因冷(leng)卻(que)(que)(que)時(shi)間(jian)充分,使冷(leng)卻(que)(que)(que)效果(guo)得到保證,從(cong)而可(ke)以提高頂(ding)(ding)(ding)頭(tou)(tou)的(de)(de)使用壽命,確保毛管內表面的(de)(de)光滑;
c. 頂(ding)桿及(ji)毛(mao)管導向:有多組定心(xin)輥(gun),第一組定心(xin)輥(gun)裝在(zai)機架內,使其盡(jin)量靠近穿(chuan)(chuan)孔(kong)變形區,以減小頂(ding)頭/頂(ding)桿的(de)(de)懸臂(bei)長度、提(ti)高(gao)頂(ding)桿的(de)(de)剛度,可(ke)更好地限(xian)制頂(ding)桿/頂(ding)頭及(ji)軋件在(zai)穿(chuan)(chuan)孔(kong)過程(cheng)中的(de)(de)徑(jing)向抖動(dong),確保(bao)穿(chuan)(chuan)出的(de)(de)毛(mao)管壁厚均勻;
d. 采用(yong)頂(ding)桿預旋轉(zhuan)技術,頂(ding)頭(tou)能(neng)自動(dong)(dong)對正(zheng)管(guan)坯的(de)(de)中心,以提高毛(mao)管(guan)頭(tou)部的(de)(de)壁(bi)厚精度(du),并可降(jiang)低(di)二次咬(yao)入時因頂(ding)頭(tou)/頂(ding)桿轉(zhuan)動(dong)(dong)慣量的(de)(de)阻(zu)力轉(zhuan)矩(ju)而發生不咬(yao)入(前卡)故障(zhang)的(de)(de)概率。
3. 特殊(shu)的工(gong)藝要求
為(wei)滿足連(lian)軋(ya)管(guan)(guan)工(gong)藝的特(te)殊性(xing),對(dui)于(yu)專(zhuan)供連(lian)續軋(ya)管(guan)(guan)機使(shi)用的毛(mao)(mao)管(guan)(guan),還有兩項重(zhong)(zhong)要(yao)的質量(liang)指標要(yao)求:一(yi)是(shi)毛(mao)(mao)管(guan)(guan)尾(wei)(wei)(wei)部的橢圓度要(yao)小,因為(wei)毛(mao)(mao)管(guan)(guan)尾(wei)(wei)(wei)部橢圓度過大將(jiang)影響軋(ya)管(guan)(guan)前穿(chuan)芯(xin)棒(bang)的順利(li)進行,輕者(zhe)刮掉(diao)(diao)芯(xin)棒(bang)表面(mian)(mian)的潤滑(hua)劑,使(shi)軋(ya)制過程中(zhong)震動較大,降低荒管(guan)(guan)的壁(bi)厚精度和(he)芯(xin)棒(bang)的使(shi)用壽命并損傷(shang)設備,重(zhong)(zhong)者(zhe)芯(xin)棒(bang)可能會(hui)頂彎毛(mao)(mao)管(guan)(guan),致(zhi)使(shi)生(sheng)(sheng)產(chan)(chan)中(zhong)斷,這就要(yao)求在調整時注意保證穿(chuan)孔(kong)過程即將(jiang)結束時,毛(mao)(mao)管(guan)(guan)尾(wei)(wei)(wei)部的歸圓效(xiao)果(guo);二是(shi)毛(mao)(mao)管(guan)(guan)尾(wei)(wei)(wei)部不得存(cun)在尾(wei)(wei)(wei)部鐮(lian)刀(非環狀(zhuang)連(lian)續體部分的俗(su)稱,見圖3-5)缺陷,當(dang)毛(mao)(mao)管(guan)(guan)尾(wei)(wei)(wei)部存(cun)在尾(wei)(wei)(wei)部鐮(lian)刀缺陷時,穿(chuan)芯(xin)棒(bang)過程中(zhong)容易將(jiang)毛(mao)(mao)管(guan)(guan)尾(wei)(wei)(wei)部不連(lian)續的部分金(jin)(jin)屬(shu)(shu)(shu)碰掉(diao)(diao),一(yi)旦(dan)這些溫(wen)度較低的金(jin)(jin)屬(shu)(shu)(shu)被帶到毛(mao)(mao)管(guan)(guan)中(zhong),軋(ya)制時將(jiang)硌(luo)傷(shang)軋(ya)件而(er)產(chan)(chan)生(sheng)(sheng)孔(kong)洞(dong)管(guan)(guan),若這些較硬的金(jin)(jin)屬(shu)(shu)(shu)掉(diao)(diao)在軋(ya)輥(gun)上,將(jiang)硌(luo)傷(shang)軋(ya)輥(gun)輥(gun)面(mian)(mian)而(er)造成(cheng)鋼管(guan)(guan)外表面(mian)(mian)缺陷等嚴重(zhong)(zhong)的質量(liang)事故。

如果是向(xiang)限動芯棒連續軋管(guan)(guan)(guan)(guan)(guan)(guan)機提(ti)供毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan),還須向(xiang)毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)噴吹(chui)氮氣(qi)和(he)硼(peng)(peng)砂(sha)(sha),以(yi)起到去(qu)除毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)表(biao)面(mian)的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)化(hua)鐵皮、減(jian)小芯棒與軋件間的(de)(de)(de)(de)(de)(de)摩擦力、防(fang)止(zhi)軋制過程(cheng)(cheng)中抖動的(de)(de)(de)(de)(de)(de)作(zuo)用。其過程(cheng)(cheng)為:抽出頂桿(gan)后的(de)(de)(de)(de)(de)(de)毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan),送到吹(chui)硼(peng)(peng)砂(sha)(sha)站,由(you)一(yi)特制的(de)(de)(de)(de)(de)(de)噴嘴向(xiang)毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)部(bu)噴入硼(peng)(peng)砂(sha)(sha)和(he)氮氣(qi),吹(chui)掉(diao)毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)部(bu)的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)化(hua)鐵皮,清(qing)除原來的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)化(hua)物(硼(peng)(peng)砂(sha)(sha)使管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)壁的(de)(de)(de)(de)(de)(de)氧(yang)(yang)(yang)化(hua)層脫氧(yang)(yang)(yang),高(gao)溫(wen)下(xia)的(de)(de)(de)(de)(de)(de)硼(peng)(peng)砂(sha)(sha)呈熔融態(tai),均勻地附著在毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)表(biao)面(mian)上(shang)可(ke)起到潤滑(hua)劑的(de)(de)(de)(de)(de)(de)作(zuo)用,氮氣(qi)能(neng)保持毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)表(biao)面(mian)不再被氧(yang)(yang)(yang)化(hua));另外,硼(peng)(peng)砂(sha)(sha)在高(gao)溫(wen)狀態(tai)下(xia)生成霧狀氣(qi)體,充滿管(guan)(guan)(guan)(guan)(guan)(guan)內(nei),以(yi)防(fang)止(zhi)在隨后的(de)(de)(de)(de)(de)(de)運動中空(kong)氣(qi)進入,減(jian)少內(nei)表(biao)面(mian)產生二次氧(yang)(yang)(yang)化(hua)的(de)(de)(de)(de)(de)(de)可(ke)能(neng)。這就要求軋管(guan)(guan)(guan)(guan)(guan)(guan)前盡量避免毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)(de)(de)(de)軸(zhou)向(xiang)移(yi)動,以(yi)防(fang)止(zhi)毛(mao)管(guan)(guan)(guan)(guan)(guan)(guan)內(nei)表(biao)面(mian)產生二次氧(yang)(yang)(yang)化(hua),從(cong)而確保軋制過程(cheng)(cheng)的(de)(de)(de)(de)(de)(de)穩定和(he)軋出荒(huang)管(guan)(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)(de)(de)(de)質量。
限(xian)動芯棒連續軋管機組是(shi)否(fou)能正(zheng)常(chang)運轉(zhuan),是(shi)否(fou)能生產出(chu)高質(zhi)(zhi)量的(de)(de)不(bu)銹(xiu)鋼(gang)管,與(yu)毛(mao)管的(de)(de)各項質(zhi)(zhi)量指標(包括溫(wen)度的(de)(de)均勻性、外徑(jing)/壁厚幾(ji)何(he)尺寸的(de)(de)精度、內(nei)外表面(mian)的(de)(de)光滑程(cheng)度等)有很(hen)大關系特別是(shi)與(yu)毛(mao)管尾部的(de)(de)質(zhi)(zhi)量狀況(內(nei)徑(jing)尺寸偏(pian)差和是(shi)否(fou)存(cun)在尾部鐮刀)以及(ji)為清(qing)除毛(mao)管內(nei)表面(mian)氧化(hua)物、防止毛(mao)管內(nei)表面(mian)二次氧化(hua)所采(cai)取的(de)(de)上述(shu)工藝措施的(de)(de)效(xiao)果是(shi)密(mi)切相關的(de)(de)。

