隨著國家產業發展戰略對資源節約和可持續發展要求的提高,以及市場競爭的加劇,無縫鋼管生產企業越來越需要高性能、節約能源、成本低的無縫鋼管生產技術。因此,控制軋制和控制冷卻(簡稱控軋控冷,英文縮寫TMCP)技術在無縫鋼管生產中越來越受重視。
控(kong)(kong)(kong)(kong)軋(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)(leng)技術(shu)(shu)作為一(yi)種降(jiang)低合金消耗、減少生產(chan)成本的(de)(de)(de)有效手段(duan),在(zai)熱軋(ya)帶鋼(gang)(gang)、中厚板、棒(bang)線(xian)材(cai)及H型鋼(gang)(gang)工業生產(chan)中應用廣泛(fan)。與(yu)板帶的(de)(de)(de)控(kong)(kong)(kong)(kong)軋(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)(leng)技術(shu)(shu)相比,由于受鋼(gang)(gang)管幾何形(xing)(xing)狀、軋(ya)制工藝(yi)、軋(ya)制設備等因素(su)的(de)(de)(de)限制,無(wu)縫(feng)鋼(gang)(gang)管在(zai)生產(chan)過程中的(de)(de)(de)可(ke)控(kong)(kong)(kong)(kong)、可(ke)變(bian)因素(su)相對(dui)較少;因此(ci),控(kong)(kong)(kong)(kong)軋(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)(leng)技術(shu)(shu)在(zai)無(wu)縫(feng)鋼(gang)(gang)管生產(chan)中的(de)(de)(de)應用在(zai)一(yi)定程度(du)(du)上受到制約,仍處于探索(suo)發展(zhan)階段(duan)。雖然(ran)無(wu)縫(feng)鋼(gang)(gang)管控(kong)(kong)(kong)(kong)軋(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)(leng)技術(shu)(shu)不能從變(bian)形(xing)(xing)溫度(du)(du)、變(bian)形(xing)(xing)量(liang)、變(bian)形(xing)(xing)道次、變(bian)形(xing)(xing)間隙時間、終軋(ya)溫度(du)(du)以及終軋(ya)后的(de)(de)(de)冷(leng)(leng)(leng)卻工藝(yi)等方面形(xing)(xing)成一(yi)套完整的(de)(de)(de)控(kong)(kong)(kong)(kong)軋(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)(leng)方案,但(dan)是目(mu)前無(wu)縫(feng)鋼(gang)(gang)管的(de)(de)(de)控(kong)(kong)(kong)(kong)軋(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)(leng)技術(shu)(shu)也形(xing)(xing)成了包括(kuo)在(zai)線(xian)常化、在(zai)線(xian)淬火和(he)在(zai)線(xian)快速(su)冷(leng)(leng)(leng)卻等多(duo)種工藝(yi),呈多(duo)樣(yang)化發展(zhan)。
在(zai)線常(chang)(chang)化(hua)是(shi)一(yi)(yi)種熱(re)(re)處(chu)(chu)(chu)理(li)工(gong)(gong)(gong)藝(yi),亦稱在(zai)線正(zheng)火(huo),是(shi)在(zai)熱(re)(re)軋(ya)生產(chan)(chan)線上軋(ya)管工(gong)(gong)(gong)序(xu)之(zhi)后(hou),使鋼管在(zai)奧氏體相(xiang)區(qu)內(nei)空冷或強(qiang)制(zhi)冷卻后(hou),得到(dao)均(jun)勻(yun)金相(xiang)組(zu)(zu)織(zhi)的(de)工(gong)(gong)(gong)藝(yi)。該工(gong)(gong)(gong)藝(yi)將熱(re)(re)處(chu)(chu)(chu)理(li)過(guo)程與(yu)軋(ya)制(zhi)變(bian)形過(guo)程結合在(zai)軋(ya)鋼連續生產(chan)(chan)環節,其(qi)工(gong)(gong)(gong)藝(yi)特點既包(bao)含相(xiang)變(bian),又包(bao)含軋(ya)制(zhi)變(bian)形,因而屬于現代軋(ya)制(zhi)新工(gong)(gong)(gong)藝(yi)的(de)一(yi)(yi)種。通過(guo)在(zai)線常(chang)(chang)化(hua)工(gong)(gong)(gong)藝(yi),既可(ke)(ke)以使鋼材組(zu)(zu)織(zhi)均(jun)勻(yun),晶(jing)粒(li)細(xi)化(hua),為進(jin)一(yi)(yi)步熱(re)(re)處(chu)(chu)(chu)理(li)做好(hao)準備(bei),又可(ke)(ke)以改善(shan)無縫鋼管的(de)綜合力(li)學性(xing)能。
無(wu)縫鋼(gang)管(guan)在線淬(cui)火(huo)工藝的應(ying)用包括奧氏體不銹鋼(gang)在線固(gu)溶處理(li)和碳(tan)鋼(gang)、低合金鋼(gang)管(guan)在線淬(cui)火(huo)熱處理(li)。
無(wu)(wu)縫(feng)鋼管在(zai)線快(kuai)(kuai)速冷(leng)卻(que)(que)(que)(que)工(gong)(gong)藝是基(ji)于超快(kuai)(kuai)速冷(leng)卻(que)(que)(que)(que)技(ji)(ji)術(shu)為核心的(de)新一代(dai)控(kong)(kong)軋(ya)控(kong)(kong)冷(leng)技(ji)(ji)術(shu)在(zai)無(wu)(wu)縫(feng)鋼管生產中的(de)新工(gong)(gong)藝。超快(kuai)(kuai)速冷(leng)卻(que)(que)(que)(que)技(ji)(ji)術(shu)是指在(zai)精軋(ya)機后(hou)(hou)利用軋(ya)制(zhi)后(hou)(hou)余熱直(zhi)接進行熱處(chu)理的(de)工(gong)(gong)藝,其控(kong)(kong)制(zhi)原理是對軋(ya)制(zhi)后(hou)(hou)的(de)奧氏體施以強化(hua)(hua)冷(leng)卻(que)(que)(que)(que),使金屬在(zai)很短時(shi)間內迅速冷(leng)卻(que)(que)(que)(que)到鐵素體相變溫度附(fu)近(jin),從而抑制(zhi)奧氏體晶粒長(chang)大,盡量保(bao)持奧氏體的(de)硬(ying)化(hua)(hua)狀態。目前,無(wu)(wu)縫(feng)鋼管在(zai)線快(kuai)(kuai)速冷(leng)卻(que)(que)(que)(que)工(gong)(gong)藝主要受到無(wu)(wu)縫(feng)鋼管沿長(chang)度方向冷(leng)卻(que)(que)(que)(que)均勻(yun)性(xing)和內外表面性(xing)能一致性(xing)的(de)限(xian)制(zhi)。
控軋控冷裝置的(de)完善:
1)在(zai)線(xian)常化(hua)工藝(yi):需(xu)主要關(guan)注合理選擇(ze)常化(hua)鏈床(chuang)長度(du)、鏈床(chuang)運行(xing)速度(du)、冷卻方式(shi)、增加水冷環以及(ji)再加熱爐的工藝(yi)參數設定(ding)等。
2)在(zai)線(xian)淬(cui)火(huo)(含在(zai)線(xian)固溶處理)工藝:需主要關注冷卻方式的(de)選擇(ze),應盡量選擇(ze)“內噴+外淋(lin)、鋼管夾(jia)持旋轉(zhuan)”或“鋼管旋轉(zhuan)的(de)同時(shi)浸入水槽、內表面(mian)軸(zhou)流噴水”的(de)淬(cui)火(huo)方式,后者還可變換為鋼管沿水槽軸(zhou)向前進或水基液(ye)淬(cui)火(huo)。
3)在線快速冷卻(que)工藝:需(xu)主要關注增(zeng)加水冷環控(kong)制起(qi)始溫度、冷卻(que)裝置長度的合(he)理設(she)計、無縫(feng)鋼管旋轉機構的合(he)理配置以及冷卻(que)器(qi)噴頭進行合(he)理改進。
控(kong)軋(ya)(ya)控(kong)冷技(ji)(ji)術(shu)(shu)在我國無(wu)縫鋼(gang)管生(sheng)產(chan)(chan)(chan)中(zhong),既(ji)有成(cheng)功的(de)(de)經(jing)驗(yan),也有尚需摸索的(de)(de)領(ling)域。作為一種節(jie)約能源的(de)(de)應(ying)用技(ji)(ji)術(shu)(shu),控(kong)軋(ya)(ya)控(kong)冷技(ji)(ji)術(shu)(shu)在國內無(wu)縫鋼(gang)管生(sheng)產(chan)(chan)(chan)企業中(zhong)越來越受(shou)到(dao)重視。對(dui)控(kong)軋(ya)(ya)控(kong)冷技(ji)(ji)術(shu)(shu)的(de)(de)應(ying)用體現在兩方面(mian):一方面(mian)是通過生(sheng)產(chan)(chan)(chan)線的(de)(de)改造對(dui)已(yi)成(cheng)功使用的(de)(de)在線常(chang)化(hua)、在線固(gu)溶(rong)、在線快速(su)冷卻工(gong)(gong)藝(yi)(yi)合理利用并不(bu)斷優化(hua);在另一方面(mian)是對(dui)未進行大(da)規模工(gong)(gong)業化(hua)生(sheng)產(chan)(chan)(chan)的(de)(de)在線淬火工(gong)(gong)藝(yi)(yi)不(bu)斷地摸索并最(zui)終應(ying)用于工(gong)(gong)業生(sheng)產(chan)(chan)(chan)。控(kong)軋(ya)(ya)控(kong)冷技(ji)(ji)術(shu)(shu)必(bi)將成(cheng)為今后無(wu)縫鋼(gang)管生(sheng)產(chan)(chan)(chan)技(ji)(ji)術(shu)(shu)發展的(de)(de)新增(zeng)長點。