熱軋無縫不銹鋼管產涉及軋鋼的幾種形式,根據軋件變形原理,一般將軋鋼分為以下三種形式:
a. 縱軋
縱(zong)軋(ya)是軋(ya)件的運(yun)行(xing)方向(軸(zhou)線)與軋(ya)輥軸(zhou)線垂直,軋(ya)件做直線運(yun)動。型鋼、板(ban)材生產及無縫鋼管的連軋(ya)等都屬(shu)于縱(zong)軋(ya);
b. 橫(heng)軋(ya)
橫(heng)軋(ya)(ya)(ya)是(shi)軋(ya)(ya)(ya)件的運(yun)行方(fang)向(軸線)與軋(ya)(ya)(ya)輥(gun)軸線平行,軋(ya)(ya)(ya)件做(zuo)回轉運(yun)動。機(ji)車輪轂、自行車軸等的生產屬(shu)于橫(heng)軋(ya)(ya)(ya);
c. 斜軋
斜(xie)(xie)軋(ya)(ya)(ya)(ya)是軋(ya)(ya)(ya)(ya)件的(de)運(yun)行(xing)方向(xiang)(軸(zhou)線)與軋(ya)(ya)(ya)(ya)輥軸(zhou)線既(ji)不垂直也不平(ping)行(xing),軋(ya)(ya)(ya)(ya)件除(chu)了前進運(yun)動(dong)外,還有(you)繞其本身軸(zhou)線旋(xuan)(xuan)轉,做螺旋(xuan)(xuan)前進運(yun)動(dong)。最(zui)常見的(de)無縫鋼管二輥、三(san)輥穿(chuan)(chuan)孔(kong)(kong)(推軋(ya)(ya)(ya)(ya)穿(chuan)(chuan)孔(kong)(kong)、擠壓穿(chuan)(chuan)孔(kong)(kong)除(chu)外)生產屬于斜(xie)(xie)軋(ya)(ya)(ya)(ya);Assel 和 Accu-Roll軋(ya)(ya)(ya)(ya)管也是斜(xie)(xie)軋(ya)(ya)(ya)(ya)。
熱軋(ya)無縫不銹鋼(gang)管的(de)(de)生(sheng)(sheng)產工(gong)(gong)(gong)藝流程包括坯(pi)料軋(ya)前準備、管坯(pi)加熱、穿孔、軋(ya)制、定減徑、鋼(gang)管冷(leng)卻、鋼(gang)管切頭尾、分段(duan)、矯(jiao)直、探傷、人工(gong)(gong)(gong)檢查、噴標打(da)印、打(da)捆包裝(zhuang)等基本(ben)工(gong)(gong)(gong)序。當今熱軋(ya)無縫鋼(gang)管生(sheng)(sheng)產一(yi)般主要變形工(gong)(gong)(gong)序有三個:穿孔、軋(ya)管和(he)定減徑,其(qi)各自的(de)(de)工(gong)(gong)(gong)藝目的(de)(de)和(he)要求如下。
1. 穿孔
穿孔是將實心(xin)的管坯(pi)穿制成空心(xin)的毛管,其設(she)備(bei)被稱為穿孔機。對穿孔工藝的要求是:
①. 要保證穿出的毛管(guan)壁厚均(jun)勻,橢圓(yuan)度小(xiao),幾何(he)尺寸精度高;
②. 毛管(guan)的內外(wai)表面較光(guang)滑,不得有(you)結疤、折疊、裂紋等缺陷;
③. 要(yao)有相應的穿孔(kong)速度和軋(ya)制周期,以適應整個機組的生產節奏(zou),使毛管(guan)的終軋(ya)溫度能(neng)滿足軋(ya)管(guan)機的要(yao)求(qiu)。
2. 軋管
軋(ya)管(guan)(guan)(guan)(guan)是將穿孔(kong)后(hou)的厚壁(bi)毛管(guan)(guan)(guan)(guan)軋(ya)成薄壁(bi)的荒(huang)管(guan)(guan)(guan)(guan),以達到成品管(guan)(guan)(guan)(guan)所要求的熱(re)尺(chi)寸和均勻性。即根據后(hou)續工序減徑量和經(jing)驗公式確定(ding)本工序荒(huang)管(guan)(guan)(guan)(guan)的壁(bi)厚值進行(xing)壁(bi)厚的加工,該設備被稱為(wei)軋(ya)管(guan)(guan)(guan)(guan)機。對軋(ya)管(guan)(guan)(guan)(guan)工藝的要求是:
①. 將厚壁毛管變成薄壁荒管(減壁延伸)時首先要保證荒管具有較高的壁厚均勻度;
②. 荒管具有良好的內外表面質量。軋管機的選型及其與穿孔工序之間變形量的合理匹配,是決定機組產品質量、產量和技術經濟指標好壞的關鍵。
3. 定減徑(包括(kuo)張減)
定(ding)減(jian)(jian)徑(jing)(jing)主要作用(yong)是(shi)(shi)消除前(qian)道工序軋(ya)制過程中造(zao)成的(de)荒(huang)管(guan)外徑(jing)(jing)不一(yi),以提高熱軋(ya)成品管(guan)的(de)外徑(jing)(jing)精度和(he)真圓度。減(jian)(jian)徑(jing)(jing)是(shi)(shi)將大管(guan)徑(jing)(jing)縮(suo)減(jian)(jian)到(dao)要求(qiu)的(de)規格尺寸和(he)精度。張力(li)減(jian)(jian)徑(jing)(jing)是(shi)(shi)在前(qian)后機(ji)架張力(li)的(de)作用(yong)下進行減(jian)(jian)徑(jing)(jing),同(tong)時(shi)進行減(jian)(jian)壁。定(ding)減(jian)(jian)徑(jing)(jing)使用(yong)的(de)設備為定(ding)(減(jian)(jian))徑(jing)(jing)機(ji)。對(dui)定(ding)減(jian)(jian)徑(jing)(jing)工藝的(de)要求(qiu)是(shi)(shi):
①. 在一定的總減徑率和較小的單機架減徑率條件下來達到定徑目的;
②. 可實現使用一種規格管坯生產多種規格成品管的任務;
③. 進一步改善不銹鋼管的外表面質量。
20世紀80年代末(mo),曾有試圖取消軋(ya)(ya)管(guan)(guan)(guan)(guan)工序的(de)(de)(de)傾向,僅(jin)使用(yong)穿(chuan)孔加定減(jian)徑(jing)的(de)(de)(de)方(fang)法(fa)生產無縫不(bu)(bu)(bu)銹(xiu)鋼管(guan)(guan)(guan)(guan)的(de)(de)(de)工藝(yi)(yi),簡稱CPS(即斜(xie)軋(ya)(ya)穿(chuan)孔和張減(jian)的(de)(de)(de)英文Cross-roll Piercing,Stretch-reducing 縮寫(xie)),并(bing)于1990年3月(yue)~1991年7月(yue)在(zai)南非的(de)(de)(de)不(bu)(bu)(bu)銹(xiu)鋼管(guan)(guan)(guan)(guan)廠(chang)進行了工業試驗,生產外徑(jing)φ33.4~?179.8mm,壁厚3.4~25mm的(de)(de)(de)不(bu)(bu)(bu)銹(xiu)鋼管(guan)(guan)(guan)(guan),其中定徑(jing)最小外徑(jing)為(wei)101.6mm.經過實踐(jian)檢驗,該工藝(yi)(yi)在(zai)生產壁厚大于10mm的(de)(de)(de)鋼管(guan)(guan)(guan)(guan)時(shi)質(zhi)(zhi)(zhi)量(liang)尚(shang)可,但在(zai)生產壁厚小于8mm的(de)(de)(de)鋼管(guan)(guan)(guan)(guan)時(shi)通過定徑(jing)、張減(jian)不(bu)(bu)(bu)能(neng)完全(quan)消除穿(chuan)孔毛管(guan)(guan)(guan)(guan)的(de)(de)(de)螺旋線,影響了不(bu)(bu)(bu)銹(xiu)鋼管(guan)(guan)(guan)(guan)的(de)(de)(de)外觀質(zhi)(zhi)(zhi)量(liang)。在(zai)隨后的(de)(de)(de)改(gai)造中不(bu)(bu)(bu)得不(bu)(bu)(bu)在(zai)穿(chuan)孔機(ji)與定減(jian)徑(jing)機(ji)之間增設了一臺MINI-MPM(4機(ji)架)連(lian)續軋(ya)(ya)管(guan)(guan)(guan)(guan)機(ji)來(lai)確保產品質(zhi)(zhi)(zhi)量(liang),MINI-MPM 于1993年4月(yue)投產。