本文選題：熱絲TIG + 焊接工藝　； 參考：《西南石油大學(xué)》2017年碩士論文

【摘要】：熱絲TIG焊擁有優(yōu)于一般手工鎢極氬弧焊的焊接質(zhì)量和自動化焊接帶來的高效率,研發(fā)出一套耐酸性介質(zhì)腐蝕的碳鋼及低合金鋼管道熱絲TIG焊接工藝技術(shù),作為酸性氣田地面建設(shè)的重要技術(shù)儲備,滿足工程建設(shè)實際生產(chǎn)需求。本文采用振動送絲半自動熱絲TIG焊接設(shè)備,試驗滿足酸性介質(zhì)服役條件的L245、L360級別鋼管進行焊接接頭設(shè)計、焊接參數(shù)開發(fā)、焊接工藝措施制定、焊接接頭力學(xué)性能試驗和焊縫組織分析、焊接接頭耐蝕性能研究,并對焊接質(zhì)量控制措施和焊接工效進行了分析。通過以上分析研究得到以下結(jié)論:選用V型有間隙坡口時,鈍邊高度和對口間隙是控制根部成型的主要參數(shù),適當(dāng)增加鈍邊高度有助于提高焊縫根部的電流承載力,將間隙控制在2.5±0.2mm有助于提高焊接速度和根部成型。選用U型無間隙坡口時,鈍邊高度是控制無間隙對口焊縫根部成型的關(guān)鍵,鈍邊高度宜控制在2.5至3.0mm。將V型坡口角度設(shè)計為60°±5°,U型坡口角度設(shè)計24°±5°,便于根焊操作。大坡口多層多道焊接能顯著提高沖擊韌性,所有試驗焊縫硬度均滿足驗收要求,當(dāng)熱絲TIG焊最大填蓋焊接線能量從1.22KJ/mm降低至0.99KJ/mm,坡口角度從24°加大至60℃,焊縫硬度逐漸降低。焊縫金屬組織為F+P,隨線能量的升高和單道焊縫厚度變大逐漸出現(xiàn)M/A組元,組織均勻度逐漸變差。熱絲TIG焊縫組織較手工鎢極氬弧焊+焊條電弧焊組織均勻度較好,晶粒更致密,非金屬夾雜物含量更低。熱絲TIG焊縫試樣滿足90%實際屈服強度應(yīng)力條件下的抗硫化氫應(yīng)力腐蝕開裂要求和抗氫致開裂要求。手工鎢極氬弧焊+焊條電弧焊的焊縫自腐蝕電流密度為7.1829×10~(-5),熱絲TIG焊接的焊縫自腐蝕電流密度為4.8473×10~(-5),熱絲TIG焊縫耐電化學(xué)腐蝕性能優(yōu)于手工鎢極氬弧焊+焊條電弧焊焊縫。未焊透、內(nèi)凹是焊縫根部主要缺陷,根部焊接時應(yīng)控制鎢極與熔池間距,鎢極與焊道夾角成約45°至60°,控制合理的坡口鈍邊尺寸和電弧吹力,保證熔池流動性和熔透能力是避免根部缺陷的主要措施。未熔合是熱焊及填充焊主要缺陷,應(yīng)注意焊道成型,采用多道焊接方式及減少單層焊接厚度是避免未熔合缺陷的主要措施。采用U型坡口時比V形坡口焊接效率高100%至150%,填蓋焊接效率高38%至40%。采用V型坡口時,熱絲TIG的焊材耗量比手工焊減少約45%,焊接效率高約15%,在采用U型坡口時比采用氬電焊接的焊材減少約66%,焊接效率高約42%。
[Abstract]:Hot wire TIG welding has better welding quality than manual TIG welding and high efficiency brought by automatic welding. A set of hot wire TIG welding technology for acid medium corrosion resistant carbon steel and low alloy steel pipeline has been developed. As an important technical reserve for surface construction of acid gas field, it meets the actual production demand of engineering construction. In this paper, the semi-automatic hot-wire TIG welding equipment for vibrating wire feeding is used to test the welding joint design, welding parameter development and welding process measures of L245 and L360 grade steel pipe, which meet the service conditions of acid medium. The mechanical property test, weld microstructure analysis and corrosion resistance of welded joint were studied. The welding quality control measures and welding efficiency were analyzed. The conclusions are as follows: when V type groove with clearance is selected, the height of the obtuse edge and the corresponding gap are the main parameters to control the forming of the root, and the proper increase of the height of the obtuse edge is helpful to improve the current bearing capacity of the weld root. Controlling the gap at 2. 5 鹵0.2mm is helpful to improve the welding speed and the forming of the root. When U type gap free groove is selected, the height of the blunt edge is the key to control the root forming of the weld seam without clearance, and the height of the obtuse edge should be controlled between 2.5 and 3.0 mm. The V-groove angle is designed to be 60 擄鹵5 擄U groove angle 24 擄鹵5 擄, which is convenient for root welding. The impact toughness can be significantly improved by multi-layer and multi-pass welding of large groove, and the hardness of all test welds can meet the acceptance requirements. When the maximum welding line energy of hot wire TIG welding decreases from 1.22KJ/mm to 0.99KJ / mm and the groove angle increases from 24 擄to 60 鈩，

本文編號：1788207