本文選題：7A52　切入點(diǎn)：雙面雙TIG弧　出處：《南京理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：課題以20mm7A52鋁合金板為研究對(duì)象,確定了以機(jī)器人雙面雙TIG弧自動(dòng)焊接打底,雙脈沖MIG填充焊方法。搭建機(jī)器人雙面雙弧焊接工作站,雙機(jī)器人可協(xié)調(diào)運(yùn)動(dòng),自動(dòng)化焊接。開展了機(jī)器人雙面雙TIG弧自熔焊和填絲焊同軸打底焊接工藝試驗(yàn),掌握了焊接速度、線能量等工藝參數(shù)對(duì)焊縫成形、缺陷形成的影響規(guī)律,自熔打底焊線能量在約5KJ/cm到10KJ/cm的范圍內(nèi),降低焊速和提高線能量有助于減少氣孔缺陷,氣孔率從1.12個(gè)/mm2下降到0個(gè)/mm2,截面形狀發(fā)生窄腰X型→寬腰X型→方形腰轉(zhuǎn)變。試驗(yàn)研究了三種坡口形式機(jī)器人雙面雙弧自熔打底焊工藝,得出6mm鈍邊、凸臺(tái)型坡口是雙面雙TIG弧的最佳坡口形式,具有焊接過程穩(wěn)定、熱輸入小、后續(xù)填充面積較小等顯著特點(diǎn)。試驗(yàn)表明：20mm厚板7A52鋁合金雙面雙TIG弧打底焊接易出現(xiàn)氣孔、熱裂紋、未熔合、焊穿等缺陷,特別是焊穿缺陷,極易導(dǎo)致“邊緣熱切割效應(yīng)”,造成焊縫大面積坍塌。進(jìn)行了DSAW打底焊自熔焊和填絲焊對(duì)比,結(jié)果表明：自熔焊比填絲焊更簡(jiǎn)單高效、氣孔傾向小。自熔焊縫的硬度約比母材低8HV、比填絲焊縫高11HV,自熔焊接頭成分從母材到焊縫變化穩(wěn)定。填絲焊接頭成分從母材到焊縫中心,Mg ↑、Zn ↓,強(qiáng)化相MgZn2數(shù)量不如自熔焊。兩者接頭組織組成總體一致,但填絲焊組織出現(xiàn)分層現(xiàn)象,導(dǎo)致力學(xué)性能不均勻。自熔焊拉伸試件斷裂在母材,焊縫系數(shù)71.7%；填絲焊斷裂在焊縫處,焊縫系數(shù)44.7%,自熔焊拉伸性能優(yōu)于填絲焊。完成了雙脈沖MIG填充試驗(yàn),填充焊縫的主要組成相為α(A1)和Mg2A13。自熔打底焊試件填充和填絲打底焊試件填充焊縫的組織除了在打底焊道和填充焊道結(jié)合處有差別外,大體相似。顯微硬度(75HV左右)和拉伸性能(焊縫系數(shù)42%左右)也總體處于同一水平,前者機(jī)械性能略好于后者。
[Abstract]:Taking the 20mm 7A52 aluminum alloy plate as the research object, the method of automatic bottom welding and double pulse MIG filling welding of robot with double TIG arc is determined. The workstation of double side and double arc welding of robot is built, and the dual robot can coordinate movement. Automatic welding. The experiments of robot double-side double-#en0# arc self-fusion welding and coaxial bottom welding were carried out, and the influence of welding speed, wire energy and other technological parameters on the formation of weld and defects was mastered. In the range of about 5KJ / cm to 10KJ / cm, the decrease of welding speed and the increase of line energy can help to reduce the porosity, the porosity decreases from 1.12 / mm2 to 0 / mm2, and the shape of section is narrow waist X type. 鈫扺ide waist X type. 鈫扴quare waist transformation. Three kinds of groove form robot double-side double-arc self-fluxing bottom welding technology is studied. It is concluded that 6mm obtuse edge, convex platform groove is the best groove form of double-sided double-#en0# arc, the welding process is stable and the heat input is small. The test results show that the double TIG arc bottom welding of 7A52 aluminum alloy with 20 mm thick plate is prone to porosity, hot crack, non-fusion, weld penetration and so on, especially the weld penetration defect. It is easy to cause "edge hot cutting effect" and cause large area collapse of weld seam. The comparison of DSAW bottom welding and filler wire welding shows that self-fusion welding is simpler and more efficient than filler wire welding. The hardness of the self-melting weld is about 8HVV lower than that of the base metal, which is 11HVV higher than that of the wire filler weld, and the composition of the weld joint changes steadily from the base metal to the weld seam. The composition of the filler wire welding joint changes from the base metal to the center of the weld. 鈫，

本文編號(hào)：1627388