本文選題：TC4鈦合金 + 焊接工藝��； 參考：《內(nèi)蒙古工業(yè)大學(xué)》2017年碩士論文

【摘要】：TC4鈦合金作為一種典型的α+β雙相鈦合金,由于其具有良好的強度、塑性、耐腐蝕性等,被廣泛的用于制造高性能飛機的機身以及各種的承力構(gòu)件,在一些大型的機構(gòu)中如壓力容器、發(fā)動機、發(fā)動機支架等部件,鈦合金的用量也急劇上漲,并且在軍工方面的用量也不斷提高。據(jù)統(tǒng)計發(fā)現(xiàn)鈦合金在航天航空領(lǐng)域的實際使用量已經(jīng)高達80%以上,并且在一些關(guān)鍵的部位都采用了TC4鈦合金焊接結(jié)構(gòu)。隨著其在各個領(lǐng)域的應(yīng)用不斷提高,TC4鈦合金的焊接方法也日趨成熟。已有研究表明在使用高能束焊接時TC4鈦合金均能獲得性能較好的焊接接頭,但針對TC4鈦合金等離子弧焊的研究則相對較少。本文采用等離子弧焊對3mm厚TC4鈦合金進行焊接。分別以焊接接頭抗拉強度以及彎曲強度為評價指標(biāo),通過響應(yīng)曲面法確定較優(yōu)焊接參數(shù),確定各焊接參數(shù)對評價指標(biāo)的影響程度順序,并對較優(yōu)參數(shù)下獲得的焊接接頭的組織性能進行分析。通過觀察TC4鈦合金自熔焊以及對焊的焊縫成形情況,確定了響應(yīng)曲面的參數(shù)范圍。通過響應(yīng)曲面分析得到較優(yōu)參數(shù):當(dāng)焊接速度為14mm·s~(-1)、焊接電流為160A、離子氣流量為3L·min~(-1)時,TC4鈦合金等離子弧焊焊接接頭抗拉強度為1080MPa;當(dāng)焊接速度為14.4mm·s~(-1)、離子氣流量為3.8 L·min~(-1)、焊接電流為161A時,TC4鈦合金等離子弧焊焊接接頭彎曲強度為1426MPa。通過響應(yīng)曲面分析方法分別確定出擬合程度較好回歸方程H_1和H_2,發(fā)現(xiàn)在較優(yōu)參數(shù)下獲得的TC4鈦合金等離子弧焊焊接接頭抗拉強度的實測值與預(yù)測值相當(dāng),焊接接頭彎曲強度的實測值與預(yù)測值誤差僅為2.983%。其中,回歸方程H1中的一次項中C_1(焊接速度)、C_3(焊接電流)是差異顯著,二次項C_3~2(焊接電流2)是極差異顯著,在交互項中C_1C_2(焊接速度·離子氣流量)也是極差異顯著的�；貧w方程H_2的一次項中C_1(焊接速度)、C_2(離子氣流量)、C_3(焊接電流)都是極差異顯著,二次項C_22(離子氣流量2)是極差異顯著,在交互項中C_1C_3(焊接速度·焊接電流)是極差異顯著的。顯著性分析后可知一次項中焊接速度為顯著性較高的焊接參數(shù),因此以焊接速度為單一變量對焊接接頭組織性能分析發(fā)現(xiàn):當(dāng)焊接電流為160A、離子氣流量為3L·min~(-1)、焊接速度范圍為14mm·s~(-1)~16mm·s~(-1)時,焊接接頭性能較為理想;焊縫中心顯微組織由“網(wǎng)藍狀”分布的α′相組成,臨近焊縫中心處熱影響區(qū)的顯微組織是由原始的α相與針狀α′相構(gòu)成,臨近母材熱影響區(qū)的顯微組織由原始α相、原始β相與針狀α′相構(gòu)成。
[Abstract]:As a typical 偽 尾 dual phase titanium alloy, TC4 titanium alloy is widely used in the manufacture of high performance aircraft fuselage and various load-bearing components because of its good strength, plasticity, corrosion resistance and so on. In some large organizations, such as pressure vessels, engine support and other components, the amount of titanium alloy also increased sharply, and the amount of military industry is also increasing. According to statistics, it is found that the actual usage of titanium alloy in aerospace field has reached more than 80%, and TC4 titanium alloy welding structure has been adopted in some key parts. With its application in various fields, the welding method of TC4 titanium alloy is becoming more and more mature. It has been shown that TC4 titanium alloy can be welded with better performance when high energy beam welding is used, but the research on plasma arc welding of TC4 titanium alloy is relatively rare. In this paper, 3mm thick TC4 titanium alloy is welded by plasma arc welding. Taking the tensile strength and bending strength of welded joints as evaluation indexes, the optimal welding parameters are determined by response surface method, and the order of influence of each welding parameter on the evaluation index is determined. The microstructure and properties of welded joints obtained under optimum parameters were analyzed. The parameter range of the response surface was determined by observing the weld formation of TC4 titanium alloy in self-fusion welding and butt welding. The optimum parameters are obtained by response surface analysis: when the welding speed is 14mm s-1, the welding current is 160 A, the ion flow rate is 3 L min ~ (-1), the tensile strength of plasma arc welding joint of TC4 titanium alloy is 1080 MPA, the welding speed is 14.4mm s ~ (-1), the ion gas flow rate is 3.8 L min ~ (-1). When the welding current is 161A, the bending strength of plasma arc welding joint of TC4 titanium alloy is 1426MPa. According to the response surface analysis method, the regression equations H _ (1) and H _ (2) of fitting degree are determined respectively. It is found that the tensile strength of plasma arc welding joint of TC4 titanium alloy obtained under the better parameters is equal to the predicted value. The error between the measured and predicted bending strength of welded joints is only 2.983. Among them, there are significant differences in the first term of regression equation H1 (welding speed) and C _ S _ 3 (welding current), the second term C _ 3O _ 2 (welding current 2) is extremely different, and in the interactive term C _ 1C _ S _ 2 (welding velocity ion gas flow) is also very different. In the first term of the regression equation H2, there is a very significant difference between C _ 1 (welding speed) and C _ S _ 2 (ion gas flow) and C _ (3) (welding current) for C _ (1) C _ (2), and for C _ (1) C _ (2) (welding current), there is a significant difference between C _ (1) C _ (2) and C _ (1) C _ (3) (welding current) in the interaction. After significant analysis, it was found that the welding speed of one item was higher than that of other welding parameters. It is found that when welding current is 160 A, ion flow rate is 3 L min ~ (-1), and welding speed range is 14mm s ~ (-1) ~ (16 mm s ~ (-1), the welded joint properties are better. The microstructure in the center of the weld is composed of 偽 'phase of "net blue" distribution, the microstructure of the heat-affected zone near the center of the weld is composed of the original 偽 phase and the needle-like 偽' phase, and the microstructure near the heat-affected zone of the base metal is composed of the original 偽 phase. The original 尾 phase is composed of acicular 偽 'phase.
【學(xué)位授予單位】：內(nèi)蒙古工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG457.19

【參考文獻】

相關(guān)期刊論文 前10條

1 李坤;王威;單際國;王旭友;陳武柱;;TC4鈦合金光纖激光擺動焊抑制小孔型氣孔的原因分析[J];焊接學(xué)報;2016年11期

2 張美娟;南海;鞠忠強;高富輝;郄喜望;朱郎平;;航空鑄造鈦合金及其成型技術(shù)發(fā)展[J];航空材料學(xué)報;2016年03期

3 高福洋;廖志謙;熊進輝;李士凱;;船用鈦合金焊接接頭精細組織表征[J];焊接學(xué)報;2016年04期

4 侯繼軍;董俊慧;張啟良;;TC4鈦合金激光焊接頭顯微組織及斷口分析[J];熱加工工藝;2016年03期

5 韓志勇;秦川;雷娟娟;賈鵬;;TC4鈦合金微束等離子弧堆焊接頭成形研究[J];焊接技術(shù);2015年08期

6 金和喜;魏克湘;李建明;周建宇;彭文靜;;航空用鈦合金研究進展[J];中國有色金屬學(xué)報;2015年02期

7 崔常京;楊t，

本文編號：2057131