摘要
鎂合金由于具有優(yōu)異的性能而成為備受關(guān)注的新型材料。迄今為止，鎂合金在汽車行業(yè)、電子設(shè)備、航空航天、自行車及日常生活等方面都得到了廣泛的應(yīng)用。 電磁作用焊接技術(shù)是近年才完善起來(lái)的一種新的焊接技術(shù)，應(yīng)用也日趨廣泛。由于其成本低、裝置簡(jiǎn)單而備受人們關(guān)注。
本課題以AZ31鎂合金為研究對(duì)象，采用TIG焊方法，在焊接過(guò)程中加入縱向磁場(chǎng)，研究了磁場(chǎng)對(duì)焊縫成型性及接頭顯微組織的影響規(guī)律，在交流磁場(chǎng)作用時(shí)，磁場(chǎng)頻率保持不變的情況下，增大磁場(chǎng)電流，熔寬增大。當(dāng)磁場(chǎng)電流保持不變的情況下，增大磁場(chǎng)頻率，熔寬也隨之增大，外加磁場(chǎng)對(duì)焊縫的成型性有影響。還
發(fā)現(xiàn)外加縱向磁場(chǎng)對(duì)焊接過(guò)程中電弧的形態(tài)、熔池液態(tài)金屬的流動(dòng)、熔池中晶粒的形核與長(zhǎng)大方式均有顯著作用，可以細(xì)化焊縫組織，降低化學(xué)不均勻性，減少熱裂紋的生成，全面提高鎂合金焊接接頭的質(zhì)量。


關(guān)鍵詞: 鎂合金，縱向磁場(chǎng)，鎢極氬弧焊
















Abstract
Magnesium alloy is concerned a lot for its excellent performance. Electromagnetism is applied to welding as a new welding technology in recent years. People are very interested in electromagnetism because of its low cost and simple equipment.
In this paper, AZ31 magnesium alloy is studied on TIG welding with applied longitudinal magnetic field. In the double inversion pulse magnetic field, with remains unchanged, the magnetic current increases, the melt-wide increase. When magnetic current remains unchanged, magnetic frequency increases, melt-wide will also increase. The effect of the longitudinal magnetic field on formability of welding seam and micro-structure in joint is studied and the relationship between mechanical property of joint and mechanical parameters; and it is discovered that longitudinal magnetic field can give an effective intervention to the shape of arc, flowing of molten bath metal, crystalline and nucleation of molten bath and the process of crystalline growth in welding process. The texture of welding seam is refined, the degree of segregation is reduced, the hot crack is decreased, quality of welding joint on magnesium alloy is increased.


Key Words: Magnesium Alloy, Longitudinal Magnetic Field, TIG welding

目錄
摘要 Ⅰ
Abstract Ⅱ
1緒論 1
1.1引言 1
1.2鎂及鎂合金的性能 1
1.2.1 鎂的性能 1
1.2.2 鎂合金的性能 2
1.3鎂合金的應(yīng)用及發(fā)展前景 2
1.4鎂合金焊接特點(diǎn) 3
1.5鎂合金焊接技術(shù)的發(fā)展 4
1.6電磁作用焊接技術(shù) 6
1.6.1電磁作用焊接技術(shù)的意義 6
1.6.2電磁作用焊接技術(shù)在國(guó)內(nèi)外的研究現(xiàn)狀 6
2實(shí)驗(yàn)材料、設(shè)備及方法 8
2．1實(shí)驗(yàn)材料 8
2．2實(shí)驗(yàn)設(shè)備 8
2．3實(shí)驗(yàn)方法及步驟 9
2.3.1焊前清理 9
2.3.2焊接工藝規(guī)范的確定 9
2.3.3磁場(chǎng)作用焊接試驗(yàn) 9
2.3.4力學(xué)性能的分析 10
2.3.5微觀組織的分析 10
3磁場(chǎng)作用焊接試驗(yàn) 11
3．1 基本焊接工藝參數(shù)的選擇 11
3.1.1氬氣的選擇 11
3.1.2焊接電流的選擇 11
3.1.3焊接速度的選擇 12
3.1.4鎢極外伸長(zhǎng)度和電弧長(zhǎng)度的選擇 12
3.1.5基本焊接工藝參數(shù)的確定 12
3．2交流磁場(chǎng)對(duì)鎂合金TIG焊接過(guò)程的影響 13
3.2.1磁場(chǎng)對(duì)焊縫成型性的影響 13
3.2.2磁場(chǎng)電流對(duì)焊接接頭顯微組織的影響 15
3.2.3磁場(chǎng)頻率對(duì)焊接接頭顯微組織的影響 18
3.2.4磁場(chǎng)對(duì)焊接接頭裂紋的影響 20
3.2.5磁場(chǎng)對(duì)焊接接頭力學(xué)性能的影響 21
4 結(jié)論 23
5 展望 24
致謝 25
參考文獻(xiàn) 26