本文關鍵詞：X90管線鋼的柔性生產工藝研究　出處：《遼寧科技大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： X90管線鋼 奧氏體晶粒 針狀鐵素體 控軋控冷工藝

【摘要】：“十二五”以來我國能源戰(zhàn)略的調整推動了石油、天然氣工業(yè)的全面發(fā)展�！拔鳉鈻|輸”工程中我國已經掌握了X70和X80管線技術,為進一步提效降本,管線鋼的升級換代是必然趨勢,因此有必要對X90管線鋼進行更多的實驗研究。本文從柔性軋制工藝同系列產品工藝優(yōu)化升級軋制思想出發(fā),以X90管線鋼為研究對象,首先在不同加熱溫度和保溫時間條件下進行回溶實驗,通過金相觀察研究了實驗鋼顯微組織變化規(guī)律;通過熱模擬實驗和金相觀察研究了實驗鋼的連續(xù)冷卻相變規(guī)律和顯微組織;在此基礎上,通過熱模擬實驗研究了不同工藝參數對實驗鋼組織的影響,根據實驗結果最優(yōu)工藝參數范圍。主要研究結果如下:1.加熱過程中,隨著加熱溫度升高、保溫時間延長,X90管線鋼的奧氏體晶粒逐漸長大。根據實驗數據的非線性回歸得出了加熱過程中X90管線鋼奧氏體晶粒長大模型:綜合考慮微合金元素充分固溶和工業(yè)生產需要細小均勻的原始奧氏體晶粒兩方面,加熱溫度選擇在1140~1200℃范圍,保溫時間選擇30~40 min左右。2.連續(xù)冷卻實驗結果表明,未變形條件下冷速在5~15℃/s之間,主要是粒狀貝氏體相變,高于15℃/s后,組織以貝氏體鐵素體為主。熱變形使CCT曲線向左上方平移,擴大相變溫度區(qū)間的同時提高了相變的開始溫度,細化了組織。在變形條件下,冷速3℃/s時已相變生成了粒狀貝氏體,變形促進了針狀鐵素體形成。隨著冷速加快,M-A島組織含量增加且更細小、彌散,由粒狀逐漸變?yōu)獒槧罨虮∧睢90管線鋼在控制軋制后,采用不低于20℃/s的冷速可以得到高韌性的針狀鐵素體,且含有細小M-A島的理想組織。3.高的粗軋溫度不利于組織細化;降低精軋溫度有利于得到細小均勻的粒狀貝氏體;增大精軋變形量有利于組織細化且可以得到針狀鐵素體,但精軋變形量過大會使相變溫度升高導致出現高溫相變產物;終冷溫度在350~400℃范圍內有利于得到典型的粒狀貝氏體組織,終冷溫度的降低也有益于組織細化。4.根據實驗結果得出優(yōu)化參數范圍:奧氏體化加熱溫度1140~1200℃,保溫30~40 min;在奧氏體再結晶區(qū)粗軋,溫度1000~1050℃,變形量25%;在奧氏體未再結晶區(qū)精軋,溫度800~830℃,變形量30~40%;終冷溫度在300~350℃范圍內,軋后采用20~25℃/s的冷卻速度快速冷卻。
[Abstract]:Since the 12th Five-Year Plan, the adjustment of China's energy strategy has promoted the overall development of the oil and natural gas industry. In the "West-to-East Gas Transmission" project, China has mastered the X70 and X80 pipeline technologies to further improve the efficiency and reduce the cost. The upgrading of pipeline steel is an inevitable trend, so it is necessary to do more experimental research on X90 pipeline steel. Taking X90 pipeline steel as the research object, the resolution experiment was carried out under different heating temperature and holding time, and the microstructure of the experimental steel was studied by metallographic observation. The continuous cooling phase transformation and microstructure of the experimental steel were studied by thermal simulation and metallographic observation. On this basis, the influence of different process parameters on the structure of experimental steel was studied by thermal simulation experiment, and the optimal range of technological parameters was obtained according to the experimental results. The main results were as follows: 1. During heating process. With the increase of heating temperature, the holding time is prolonged. The austenitic grain growth model of X90 pipeline steel during heating is obtained by nonlinear regression of experimental data. Both the solid solution of microalloyed elements and the need of fine and uniform primary austenite grains in industrial production are considered. The heating temperature is in the range of 1 140 ~ 1 200 鈩，

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