本文選題：5Cr管線鋼　切入點：焊接性　出處：《華僑大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：目前石油管道的運輸、儲藏主要采用耐蝕合金類鋼種,但是此類鋼種的大量應(yīng)用會提高油田的開發(fā)成本。研究出一種新材料,并開發(fā)出新的制造方法和工藝成了業(yè)內(nèi)關(guān)注的焦點,目前有人提出低鉻新鋼種的利用和開發(fā)是一個重要途徑,本文針對5Cr管線鋼這一新鋼種,采用試驗和數(shù)值模擬的方法,進行焊接性研究,并分析其使用性能。對5Cr鋼焊接過程的溫度場進行有限元數(shù)值模擬分析,研究了溫度場分布及熱循環(huán)曲線。通過研究其焊接條件下連續(xù)冷卻組織轉(zhuǎn)變,預(yù)測其焊接熱影響區(qū)的組織、性能和硬度。結(jié)果表明:5Cr鋼在較寬的冷速范圍內(nèi)能夠獲得含有鐵素體的組織類型,具有較高的強度和良好的力學(xué)性能。分析所選焊絲與母材的匹配性,分別對三種接頭進行成型性分析和抗裂性分析。結(jié)果表明:硬面堆焊藥芯焊絲YC-YD450焊縫成型性良好,表面光亮,不銹鋼焊絲ER308焊縫平整光亮,有輕微變形。低碳鋼焊絲H08Mn2SiA焊接平板變形不大�？沽研栽囼灲Y(jié)果表明,在預(yù)熱60℃和100℃的情況下,三種焊絲對應(yīng)的焊接接頭均沒有發(fā)現(xiàn)裂紋。對這三種焊接接頭分別進行力學(xué)性能測試以及微觀組織觀察發(fā)現(xiàn):三種焊絲焊接接頭熔合良好,未出現(xiàn)缺陷。藥芯焊絲焊縫區(qū)組織以粒狀貝氏體為主,其接頭平均抗拉強度為533.52Mpa,普通焊絲焊縫區(qū)主要為少量馬氏體和羽毛狀貝氏體,接頭平均抗拉強度為580.16Mpa,不銹鋼焊絲焊縫區(qū)主要為鐵素體和貝氏體,接頭平均抗拉強度為547.75Mpa。三種接頭斷口形貌均表現(xiàn)韌窩,塑性和韌性良好。普通焊絲接頭能承受的平均載荷達到17kN,不銹鋼焊絲接頭平均載荷達到12kN,藥芯焊絲接頭平均載荷為8kN,彎曲角度大且均未發(fā)生斷裂,說明三種接頭抗彎性能均良好。三種接頭沖擊試驗結(jié)果表明,沖擊韌性均接近于母材。三種接頭的硬度分布規(guī)律一致,焊縫中心區(qū)較熱影響區(qū)大,整體母材最低。腐蝕試驗發(fā)現(xiàn)藥芯焊絲平均腐蝕速率為0.0397mm/a,普通焊絲平均腐蝕速率為0.07675mm/a,不銹鋼焊絲的平均腐蝕速率為0.0496mm/a,腐蝕形貌也可以看出:藥芯焊絲和不銹鋼焊絲由于焊縫區(qū)Cr元素高于母材而腐蝕不明顯,普通焊絲焊縫區(qū)腐蝕嚴(yán)重。整體密閉性研究和耐壓試驗表明:在試驗壓力3.2MPa、5MPa、10MPa下保持10min,結(jié)果發(fā)現(xiàn)壓力損失率均小于10%,焊縫未見滲水現(xiàn)象,表明圓筒焊縫致密,密閉性良好。三種接頭的X射線衍射探傷結(jié)果顯示,普通焊絲和藥芯焊絲接頭均未出現(xiàn)夾雜、氣孔、裂紋等缺陷。本文研究成果將為5Cr新鋼種的結(jié)構(gòu)化應(yīng)用提供理論依據(jù),節(jié)約石油工業(yè)的生產(chǎn)開發(fā)成本,為實際生產(chǎn)提供了重大的指導(dǎo)。
[Abstract]:At present, the transportation and storage of oil pipelines are mainly made of corrosion-resistant alloy steel, but the extensive application of this kind of steel will increase the development cost of oil fields. The development of new manufacturing methods and processes has become the focus of attention in the industry. At present, it has been proposed that the utilization and development of new low chromium steel is an important way. In this paper, the method of test and numerical simulation is adopted for 5Cr pipeline steel, which is a new kind of steel. The weldability of 5Cr steel was studied and its performance was analyzed. The temperature field distribution and thermal cycle curve of 5Cr steel during welding process were studied by finite element numerical simulation, and the continuous cooling microstructure transformation under welding condition was studied. The microstructure, properties and hardness of the HAZ were predicted. The results showed that the microstructure containing ferrite could be obtained in a wide range of cooling rates. It has high strength and good mechanical properties. The matching between the wire and the base metal is analyzed. The forming property and crack resistance of the three kinds of joints are analyzed respectively. The results show that the YC-YD450 welding seam of hard surfacing flux-cored wire is good. The surface is bright, the ER308 weld of stainless steel wire is smooth and bright, and the welding plate of low carbon steel welding wire H08Mn2SiA is not much deformed. The results of crack resistance test show that, under the condition of preheating at 60 鈩，

本文編號：1569083