高强铝合金机器人双面双弧自动焊接工艺研究

发布时间：2018-03-18 01:24

  本文选题：7A52　切入点：双面双TIG弧　出处：《南京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：课题以20mm7A52铝合金板为研究对象,确定了以机器人双面双TIG弧自动焊接打底,双脉冲MIG填充焊方法。搭建机器人双面双弧焊接工作站,双机器人可协调运动,自动化焊接。开展了机器人双面双TIG弧自熔焊和填丝焊同轴打底焊接工艺试验,掌握了焊接速度、线能量等工艺参数对焊缝成形、缺陷形成的影响规律,自熔打底焊线能量在约5KJ/cm到10KJ/cm的范围内,降低焊速和提高线能量有助于减少气孔缺陷,气孔率从1.12个/mm2下降到0个/mm2,截面形状发生窄腰X型→宽腰X型→方形腰转变。试验研究了三种坡口形式机器人双面双弧自熔打底焊工艺,得出6mm钝边、凸台型坡口是双面双TIG弧的最佳坡口形式,具有焊接过程稳定、热输入小、后续填充面积较小等显著特点。试验表明：20mm厚板7A52铝合金双面双TIG弧打底焊接易出现气孔、热裂纹、未熔合、焊穿等缺陷,特别是焊穿缺陷,极易导致“边缘热切割效应”,造成焊缝大面积坍塌。进行了DSAW打底焊自熔焊和填丝焊对比,结果表明：自熔焊比填丝焊更简单高效、气孔倾向小。自熔焊缝的硬度约比母材低8HV、比填丝焊缝高11HV,自熔焊接头成分从母材到焊缝变化稳定。填丝焊接头成分从母材到焊缝中心,Mg ↑、Zn ↓,强化相MgZn2数量不如自熔焊。两者接头组织组成总体一致,但填丝焊组织出现分层现象,导致力学性能不均匀。自熔焊拉伸试件断裂在母材,焊缝系数71.7%；填丝焊断裂在焊缝处,焊缝系数44.7%,自熔焊拉伸性能优于填丝焊。完成了双脉冲MIG填充试验,填充焊缝的主要组成相为α(A1)和Mg2A13。自熔打底焊试件填充和填丝打底焊试件填充焊缝的组织除了在打底焊道和填充焊道结合处有差别外,大体相似。显微硬度(75HV左右)和拉伸性能(焊缝系数42%左右)也总体处于同一水平,前者机械性能略好于后者。
[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，

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