本文選題：冷金屬過渡焊(CMT) + 鋁合金薄板��； 參考：《中國民航大學(xué)》2017年碩士論文

【摘要】：汽車的車身板件多采用電阻點焊工藝進(jìn)行焊接,為了能夠保證車身結(jié)構(gòu)的整體氣密性,對于焊點之間的縫隙應(yīng)進(jìn)行焊接處理以獲得密封性。國產(chǎn)汽車生產(chǎn)制造廠家多運(yùn)用熔化極活性氣體保護(hù)焊(Metal Active-gas Arc Welding,MAG)的技術(shù)來實現(xiàn)點焊焊點之間的縫隙焊接。傳統(tǒng)焊接方式進(jìn)行作業(yè)時無控制、粗獷式的熱輸入方式往往產(chǎn)生大量飛濺,嚴(yán)重?fù)p壞車身鋁合金板材。同時,熔滴過渡時過大的短路電流會向熔池傳入過多熱量,引起車身鋁合金板材多度受熱變形。焊縫成型不均勻,局部可能出現(xiàn)燒穿、焊漏。有時需要對縫隙進(jìn)行二次焊接,大幅度降低車身生產(chǎn)效率�；谝陨仙a(chǎn)加工實際情況,本文采用冷金屬過渡焊接技術(shù)(Cold Metal Transfer,CMT)進(jìn)行鋁合金薄板對接形式的焊接。CMT冷金屬過渡焊接工藝是一種新型的熔化極氣體保護(hù)焊接方式,相對于普通的焊接方式,CMT焊接的特點是熱輸入量更低、焊接過程無飛濺、熔滴過渡方式溫和的特點。本文選取1mm厚度的6022牌號鋁合金薄板作為母材,以直徑Φ=1.2 mm ER4043鋁硅焊絲作為焊接的焊縫填充材料,來研究CMT鋁合金板件的對接焊接性。通過單因素水平對比試驗,研究了主要的焊接參數(shù):送絲速度、弧長修正系數(shù)、焊接速度對焊接接頭力學(xué)性能和微觀組織的影響。利用激光共聚焦顯微鏡、蔡斯顯微鏡、掃描電子顯微鏡(SEM)觀察微觀形貌;采用能譜掃描儀分析接頭成分組成;通過萬能拉伸試驗機(jī),和顯微硬度儀確定了焊縫熔合區(qū),熱影響區(qū)(HAZ,Heat-affected Zone)的范圍。1.試驗表明,鋁合金薄板CMT焊縫表面成型均勻,沒有明顯的可見缺陷,焊后母材平整幾乎無變形,焊縫熔合區(qū)域組織致密。2.鋁合金薄板對接焊縫成型良好。母材硬度高于焊縫區(qū)硬度,鋁合金薄板對接接頭截面不同位置的顯微硬度結(jié)果的峰值標(biāo)示了熱影響區(qū)的范圍。對接接頭的拉伸強(qiáng)度比焊接母材低20%,觀察拉伸試驗斷口,主要為熱影響區(qū)HAZ韌斷模式。3.焊縫宏觀形貌參數(shù)主要包括熔深、熔寬和深寬比。焊縫宏觀形貌參數(shù)與焊絲輸送速度、弧長修正系數(shù)成正相關(guān),與焊槍行走速度數(shù)值成負(fù)相關(guān)。焊接送絲速度、弧長修正系數(shù)和焊接速度共同決定了焊接線能量大小。4.冷金屬過渡焊接工藝(CMT)代替?zhèn)鹘y(tǒng)焊接方式,鋁合金薄板焊接接頭的宏觀成型和力學(xué)性能達(dá)到要求。經(jīng)過試驗數(shù)據(jù)統(tǒng)計分析,得到6022牌號1mm鋁合金薄板CMT焊接的最佳工藝參數(shù):送絲速度為8m/min.、弧長修正系數(shù)為5%、焊接速度為540mm/min.。
[Abstract]:In order to ensure the overall airtightness of the body structure, the welding of the cracks between the solder joints should be carried out in order to obtain sealing. Domestic automobile manufacturers often use metal Active-gas Arc welding technology to realize gap welding between spot welding joints. The traditional welding method has no control, and the rough heat input often produces a lot of spatter, which seriously damages the aluminum alloy plate of the body. At the same time, the excessive short circuit current will transmit too much heat to the molten pool during droplet transfer, which will cause many thermal deformation of aluminum alloy sheet. Weld formation is not uniform, local may be burn-through, welding leakage. Sometimes it is necessary to weld the cracks twice, which greatly reduces the production efficiency of the body. Based on the actual production and processing, the cold metal transfer welding technology, Cold Metal transfer (CMT), is a new type of gas shielded welding process for aluminum alloy sheet welding. Compared with conventional welding method, CMT welding is characterized by lower heat input, no spatter and mild droplet transfer mode. In this paper, 6022 grade aluminum alloy sheet with 1mm thickness is selected as base metal, and diameter 桅 1.2mm ER4043 aluminum silicon wire is used as weld filling material to study the butt weldability of CMT aluminum alloy plate. The effects of main welding parameters, such as wire feeding speed, arc length correction coefficient and welding speed, on the mechanical properties and microstructure of welded joints were studied by single factor horizontal contrast test. Laser confocal microscope, Chase microscope, scanning electron microscope (SEM) were used to observe the microstructure, energy spectrum scanner (EDS) was used to analyze the composition of the joints, and the weld fusion zone was determined by universal tensile tester and microhardness tester. The range of HAZA Heat-affected Zone1. The results show that the CMT weld surface of the aluminum alloy sheet is uniform, without obvious visible defects, the base metal is flat and almost no deformation after welding, and the microstructure of the weld fusion zone is dense. 2. The butt weld of aluminum alloy sheet is well formed. The hardness of base metal is higher than that of weld zone. The peak value of microhardness of aluminum alloy sheet butt joint at different positions indicates the range of heat affected zone. The tensile strength of the butt joint was 20% lower than that of the welding base metal. The tensile test fracture was observed mainly in the heat affected zone (HAZ) HAZ fracture mode. 3. The macroscopic morphology parameters of weld include penetration width and aspect ratio. The macroscopic appearance parameters of the weld are positively correlated with the wire conveying speed and arc length correction coefficient, and negatively correlated with the walking speed of the welding torch. Welding wire feeding speed, arc length correction coefficient and welding speed together determine the welding line energy. 4. Cold metal transition welding process (CMT) instead of conventional welding method, aluminum alloy sheet welding joint macro forming and mechanical properties meet the requirements. Through statistical analysis of test data, the optimum technological parameters for CMT welding of 6022 grade 1mm aluminum alloy sheet are obtained: wire feeding speed is 8 m / min., arc length correction coefficient is 5 and welding speed is 540 mm / min.
【學(xué)位授予單位】：中國民航大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG457.14;U466

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 孫春華;;汽車消費(fèi)市場對汽車產(chǎn)業(yè)布局影響的實證研究[J];技術(shù)經(jīng)濟(jì)與管理研究;2016年06期

2 張德芬;譚蓋;劉璐;楊陽;陳孝文;陳宇;;熱處理對6061鋁合金組織與性能的影響[J];金屬熱處理;2015年11期

3 范子杰;桂良進(jìn);蘇瑞意;;汽車輕量化技術(shù)的研究與進(jìn)展[J];汽車安全與節(jié)能學(xué)報;2014年01期

4 王利;陸匠心;;汽車輕量化及其材料的經(jīng)濟(jì)選用[J];汽車工藝與材料;2013年01期

5 張洪濤;馮吉才;胡樂亮;;CMT能量輸入特點與熔滴過渡行為[J];材料科學(xué)與工藝;2012年02期

6 王巖;湯小紅;;鋁合金焊接應(yīng)力與變形數(shù)值分析綜述[J];焊接技術(shù);2012年01期

7 黃政艷;;焊接技術(shù)與裝備在汽車行業(yè)的應(yīng)用及發(fā)展趨勢[J];裝備制造技術(shù);2011年04期

8 李瑞;張洪發(fā);;鋁合金壓鑄件在汽車上的應(yīng)用[J];金屬加工(熱加工);2010年23期

9 劉西洋;孫鳳蓮;王旭友;王威;雷振;;Nd:YAG激光+CMT電弧復(fù)合熱源橫焊工藝參數(shù)對焊縫成形的影響[J];焊接學(xué)報;2010年09期

10 孔淑華;賈磊;袁宗杰;周學(xué)鑫;;激光焊接技術(shù)在一汽-大眾白車身焊接中的應(yīng)用[J];電焊機(jī);2010年05期

相關(guān)博士學(xué)位論文 前1條

1 侯志剛;薄板結(jié)構(gòu)焊接變形的預(yù)測與控制[D];華中科技大學(xué);2005年

，

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