不銹鋼管軋制過程中，受制于特殊的環形斷面形狀，使得軋制的工藝、設備具有特殊性和復雜性。同時在成型過程中存在擠壓、扭轉、拉伸等多種形變方式，因此實現變形溫度與變形量匹配的控制靈活性非常小。在此條件的制約下，軋制成型的控制思想往往也只能是在高溫環境變形抗力較小的條件下盡快完成熱變形過程。顯然，這種“無奈之舉”與控制軋制的通過對加熱溫度、軋制溫度、變形制度等工藝參數的匹配控制，進而基于“低溫軋制”實現對奧氏體及相變產物組織狀態的調控機制相違背，最終在改善性能方面無能為力。因此，在不實際改變高溫熱軋成型條件的背景下，如何實現奧氏體的調控進而為后續相變提供理想奧氏體狀態成為不銹鋼管組織進一步細化的突破口。

  通(tong)過(guo)(guo)對第(di)二(er)(er)相(xiang)粒(li)子的(de)(de)(de)(de)(de)(de)(de)適當(dang)控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)，可在實現釘扎(zha)奧(ao)氏體(ti)(ti)晶(jing)(jing)界的(de)(de)(de)(de)(de)(de)(de)同時利用第(di)二(er)(er)相(xiang)誘導(dao)晶(jing)(jing)內鐵素(su)體(ti)(ti)形(xing)(xing)(xing)核(he)(he)機制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)，獲(huo)得(de)一(yi)(yi)定程(cheng)度細(xi)(xi)(xi)化(hua)的(de)(de)(de)(de)(de)(de)(de)奧(ao)氏體(ti)(ti)并為后(hou)續(xu)相(xiang)變(bian)(bian)提(ti)供豐富(fu)的(de)(de)(de)(de)(de)(de)(de)相(xiang)變(bian)(bian)形(xing)(xing)(xing)核(he)(he)點。該組(zu)(zu)(zu)(zu)織(zhi)(zhi)調控(kong)(kong)(kong)(kong)思想(xiang)目前(qian)廣泛應用于(yu)大線(xian)能(neng)(neng)量(liang)焊接用鋼(gang)材的(de)(de)(de)(de)(de)(de)(de)開發(fa)中，其核(he)(he)心機理是通(tong)過(guo)(guo)引入適當(dang)氧(yang)(yang)化(hua)物和(he)析出(chu)相(xiang)實現釘扎(zha)熱(re)(re)影(ying)響(xiang)區奧(ao)氏體(ti)(ti)晶(jing)(jing)界并促(cu)進(jin)晶(jing)(jing)內鐵素(su)體(ti)(ti)形(xing)(xing)(xing)成，進(jin)而細(xi)(xi)(xi)化(hua)相(xiang)變(bian)(bian)組(zu)(zu)(zu)(zu)織(zhi)(zhi)，改善熱(re)(re)影(ying)響(xiang)區組(zu)(zu)(zu)(zu)織(zhi)(zhi)性能(neng)(neng)。顯(xian)然，這種熱(re)(re)影(ying)響(xiang)區內的(de)(de)(de)(de)(de)(de)(de)奧(ao)氏體(ti)(ti)狀態與不(bu)銹鋼(gang)管高(gao)(gao)(gao)溫(wen)形(xing)(xing)(xing)變(bian)(bian)下的(de)(de)(de)(de)(de)(de)(de)粗大奧(ao)氏體(ti)(ti)組(zu)(zu)(zu)(zu)織(zhi)(zhi)十分吻合。因此，第(di)二(er)(er)相(xiang)誘導(dao)相(xiang)變(bian)(bian)形(xing)(xing)(xing)核(he)(he)成為熱(re)(re)軋(ya)(ya)(ya)(ya)(ya)(ya)無縫鋼(gang)管在線(xian)組(zu)(zu)(zu)(zu)織(zhi)(zhi)性能(neng)(neng)調控(kong)(kong)(kong)(kong)，特別是組(zu)(zu)(zu)(zu)織(zhi)(zhi)細(xi)(xi)(xi)化(hua)和(he)提(ti)高(gao)(gao)(gao)強韌性能(neng)(neng)的(de)(de)(de)(de)(de)(de)(de)一(yi)(yi)種有(you)效途徑，即可在熱(re)(re)軋(ya)(ya)(ya)(ya)(ya)(ya)不(bu)銹鋼(gang)管高(gao)(gao)(gao)溫(wen)變(bian)(bian)形(xing)(xing)(xing)的(de)(de)(de)(de)(de)(de)(de)條件下，實現板(ban)材領域低溫(wen)軋(ya)(ya)(ya)(ya)(ya)(ya)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)具備(bei)的(de)(de)(de)(de)(de)(de)(de)“控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)軋(ya)(ya)(ya)(ya)(ya)(ya)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)”組(zu)(zu)(zu)(zu)織(zhi)(zhi)細(xi)(xi)(xi)化(hua)效果(guo)。基(ji)于(yu)這一(yi)(yi)思路以及對鋼(gang)中第(di)二(er)(er)相(xiang)粒(li)子析出(chu)行(xing)為的(de)(de)(de)(de)(de)(de)(de)研究，東北大學研究團(tuan)隊進(jin)一(yi)(yi)步提(ti)出(chu)了(le)(le)“第(di)二(er)(er)相(xiang)控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)＋高(gao)(gao)(gao)溫(wen)熱(re)(re)軋(ya)(ya)(ya)(ya)(ya)(ya)＋控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)冷(leng)(leng)卻”的(de)(de)(de)(de)(de)(de)(de)在線(xian)形(xing)(xing)(xing)變(bian)(bian)／相(xiang)變(bian)(bian)一(yi)(yi)體(ti)(ti)化(hua)組(zu)(zu)(zu)(zu)織(zhi)(zhi)調控(kong)(kong)(kong)(kong)路線(xian)。針對典型碳錳(meng)鋼(gang)，通(tong)過(guo)(guo)復合脫氧(yang)(yang)工(gong)藝控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)，在鋼(gang)中引入具有(you)高(gao)(gao)(gao)熱(re)(re)穩定性的(de)(de)(de)(de)(de)(de)(de)氧(yang)(yang)化(hua)物后(hou)，充分發(fa)揮第(di)二(er)(er)相(xiang)粒(li)子的(de)(de)(de)(de)(de)(de)(de)誘導(dao)晶(jing)(jing)內形(xing)(xing)(xing)核(he)(he)作用，在1100℃高(gao)(gao)(gao)溫(wen)軋(ya)(ya)(ya)(ya)(ya)(ya)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)和(he)控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)冷(leng)(leng)卻條件下獲(huo)得(de)了(le)(le)微細(xi)(xi)(xi)的(de)(de)(de)(de)(de)(de)(de)晶(jing)(jing)內鐵素(su)體(ti)(ti)組(zu)(zu)(zu)(zu)織(zhi)(zhi)，實驗鋼(gang)的(de)(de)(de)(de)(de)(de)(de)強、韌性能(neng)(neng)均顯(xian)著提(ti)高(gao)(gao)(gao)（如圖(tu)6-68所示），在不(bu)實施低溫(wen)軋(ya)(ya)(ya)(ya)(ya)(ya)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)的(de)(de)(de)(de)(de)(de)(de)控(kong)(kong)(kong)(kong)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)軋(ya)(ya)(ya)(ya)(ya)(ya)制(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)(zhi)前(qian)提(ti)下，實現了(le)(le)類(lei)同于(yu)“控(kong)(kong)(kong)(kong)軋(ya)(ya)(ya)(ya)(ya)(ya)控(kong)(kong)(kong)(kong)冷(leng)(leng)”的(de)(de)(de)(de)(de)(de)(de)良(liang)好組(zu)(zu)(zu)(zu)織(zhi)(zhi)細(xi)(xi)(xi)化(hua)效果(guo)。

  針(zhen)(zhen)對“第二相(xiang)控(kong)制(zhi)＋高溫熱軋(ya)＋控(kong)制(zhi)冷卻”工藝下的(de)低碳(tan)鋼(gang)組織演(yan)變(bian)(bian)(bian)(bian)行(xing)(xing)(xing)為(wei)進行(xing)(xing)(xing)了系統研(yan)究。采用質(zhi)量分數為(wei)0.07C-0.06Si-1.5Mn-0.01P-0.006S成分的(de)實驗(yan)鋼(gang)，進行(xing)(xing)(xing)鈦(tai)脫氧(yang)(yang)處理(li)，引(yin)入氧(yang)(yang)化(hua)(hua)鈦(tai)型第二相(xiang)粒子，考察了不(bu)(bu)同變(bian)(bian)(bian)(bian)形(xing)(xing)(xing)和(he)冷速條(tiao)件下的(de)連續冷卻轉變(bian)(bian)(bian)(bian)行(xing)(xing)(xing)為(wei)，如圖6-69和(he)圖6-70所示。結果表明，含氧(yang)(yang)化(hua)(hua)鈦(tai)實驗(yan)鋼(gang)在1.5～15℃／s冷速范圍內可獲(huo)得明顯的(de)針(zhen)(zhen)狀鐵素體組織，并(bing)且在1050℃以上高的(de)變(bian)(bian)(bian)(bian)形(xing)(xing)(xing)溫度(du)(du)下有利于組織的(de)細(xi)化(hua)(hua)。根據實驗(yan)結果，為(wei)了達到組織細(xi)化(hua)(hua)的(de)目的(de)，在不(bu)(bu)銹(xiu)鋼(gang)管高溫變(bian)(bian)(bian)(bian)形(xing)(xing)(xing)條(tiao)件下，需結合控(kong)制(zhi)冷卻技術(shu)進行(xing)(xing)(xing)鋼(gang)管軋(ya)后冷卻路徑的(de)控(kong)制(zhi)，從(cong)而(er)發(fa)揮(hui)細(xi)晶(jing)組織對強度(du)(du)和(he)韌(ren)性同時(shi)改(gai)善的(de)作用。

  目前，控制冷卻技術在熱軋不銹鋼管中的工業應用研究尚處于起步階段，特別是結合管材成分特點的組織性能在線調控機理機制研究還落后于板帶材等領域。熱軋鋼管形變／相變在線組織一體化調控技術研究取得一定進展，后續依據“第二相控制＋高溫熱軋＋控制冷卻”的組織調控思路，深入研究變形一冷卻一相變的協同控制機制，實現鋼管領域產品的“控軋控冷”組織調控工藝效果，構建基于在線控制冷卻工藝的全新熱軋不銹鋼管組織性能調控平臺。基于形變／相變在線組織調控技術，進一步地通過成分設計一熱軋成型一控制冷卻一熱處理的全流程工藝一體化控制，實現細晶強化、相變強化及析出強化的綜合強韌化，開發出高品質、低成本的熱軋不銹鋼管產品是進一步研發的重點。這對促進我國鋼鐵行業以“資源節約型、節能減排型”等綠色制造為特征的熱軋不(bu)銹(xiu)鋼管產品的開發與生產，具有重要意義。