共查询到20条相似文献,搜索用时 62 毫秒
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材料轻量化是汽车制造业的发展趋势,而铝合金材料的应用则是材料轻量化的重要途径之一,介绍了铝合金焊接的技术特点、车身焊接方法的选择、焊前表面准备和铝合金点焊工艺、以及点焊质量的检查、试验。 相似文献
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电阻点焊质量决定了车身强度和车辆安全。超声无损检测方法常用于焊后抽检,但车身焊装完成后,结构内部诸多焊点难以触及,无法检测。针对上述问题,将超声检测技术应用于焊接过程监测,基于脉冲-回波超声探头与特征信号分析技术,研究点焊过程工件内部超声场瞬态分布情况;设计了新型内置超声波探头电极结构,将超声探头嵌入电极动臂水冷腔,进行脉冲电阻点焊超声在线监测试验,分析超声时程、焊接过程超声回波特征;利用声学信号实时记录焊核熔化和凝固过程,并研究点焊典型焊接缺陷虚焊的超声回波图特征,分析基于回波的虚焊焊点鉴别方法。研究结果表明,通过观察C扫描图像特征与A扫描信号的变化,能够很好地划分点焊接头的热影响区、熔合区、熔核区以及焊接缺陷。通过C扫描图像特征对虚焊焊点进行快速识别,进而实现点焊缺陷检测和熔核尺寸测量。 相似文献
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Kenji Miyamoto Shigeyuki Nakagawa Chika Sugi Tomo Ogura Akio Hirose 《Welding International》2016,30(9):675-687
This research concerns a dissimilar metal joining of steel and aluminium (Al) alloys by means of zinc (Zn) insertion. The authors propose a joining concept for achieving strong bonded joints between Zn-coated steel and Al alloys. A eutectic reaction between Zn in the Zn coating and uniform Al–Fe intermetallic compound (IMC) layer at the joint interface, leading to a strong bonded joint. The ultimate aim of this research was to apply this joining concept in the resistance spot welding process for manufacturing vehicle bodies. As a practical issue characteristic to joints of dissimilar metals, anticorrosion measures against electrochemical corrosion must be undertaken. If there is moisture near a joint interface of dissimilar metals, electrochemical erosion will progress. Therefore, a sealing function that could prevent moisture intrusion is required. By applying the above-mentioned welding process to a set of metals with thermosetting resin spread in between, we realized seal spot welding, which not only prevented moisture intrusion but also retained high tensile strength. In this research, first, a cyclic corrosion test was performed on the seal spot-welded joint of galvanized (GI) steel, a steel grade widely distributed in Japan, and Al alloy was bonded by seal spot welding, and the following topics are discussed. Complete removal of sealant from the joint interface is the key to realizing the high tensile stress joint, because remaining sealant will lead to reduction in tensile strength. Therefore, heat generation at the interface was monitored by measuring electrical current and potential difference between the two electrodes, and a precise temperature control was performed. Moreover, the bonding process was clarified by stepwise analysis of the joint interface using optical microscopy, and a guideline for producing strong joints was proposed. And finally, a TEM observation also confirmed that the interface structure of the seal spot-welded joint was the same as joints without the resin; a thin and uniform Al–Fe IMC layer was formed and a strong metallurgical bonding was achieved. 相似文献
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AA754和AA6082是两种具有不同强化机制的铝合金材料,在电阻点焊加热过程中,两种铝合金材料的组织会发生不同类型的转变.通过采用不同的计算模型,使用有限元软件对两种铝合金点焊后不同焊接组织的分布进行了模拟和预测.通过焊接试验研究,对两种铝合金的点焊组织的形态和分布进行了观察.结果表明,所采用的两种计算模型可以有效的预测和反映出两种铝合金点焊组织变化过程中的一些现象.仿真结果和试验结果都显示出两种铝合金的点焊组织有着明显不同的特征. 相似文献
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AA5754 aluminium alloy was resistance spot welded (RSW) to produce 27 different joint stack-ups with differing process parameters and corresponding weld quality. Quasi-static joint strength was evaluated for three test geometries; lap-shear, coach-peel and cross-tension. The results derived from over 1000 samples demonstrate various fundamental relationships. For lap-shear strength, a strong relationship with weld nugget diameter was observed; whilst discrete strength levels were found for coach-peel test geometry, depending on the governing metal thickness of the parent sheet for the various stack-ups. For cross-tension strength; there is a relationship with nugget diameter; but data are sensitive to nugget periphery defects. These fundamental relationships provide a set of generalised design guidelines for RSW of aluminium that will have significant relevance to manufacturing communities. 相似文献
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A friction stir spot welding process, in which a rotating tool without a probe was employed, was applied to a lap joint of an aluminium plate to a low carbon steel plate. The thicknesses of both plates were 0.5 mm. In this process, the rotating tool of 5 mm diameter, rotating at 18,000 rpm, was plunged into the aluminium plate at a rate of 2 mm/s, and then kept at a maximum plunged depth of 0.05–0.35 mm for 0–2 s (dwell time). In the weld obtained by this process, a hole due to the impression of the penetrated tool probe was not formed, although a slight depression by the tool plunging remained. At tool plunge depths of 0.1 mm or over, it was possible to weld the two plates. The maximum tensile failure load of 454 N was obtained at a plunge depth of 0.1 mm and a dwell time of 1.5 s. Its joint was fractured at an almost constant load along the periphery of the depression, leaving a part of the aluminium plate on the steel plate surface. Based on the observation of the weld interface microstructure and metal flow of aluminium in the weld, controlling factors of the joint strength were discussed. 相似文献
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铝合金具有导电导热性好、质量轻、抗腐蚀、易成形等优点,提高其焊接生产率和质量,减少焊接缺陷已成为实际生产的迫切要求;重点介绍了近年来发展的激光-电弧复合焊、激光等离子焊、等离子电弧焊、电子束-等离子弧焊、TIG-MAC焊、激光搅拌-摩擦焊等多种铝合金焊接工艺的特点度应用情况。 相似文献
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为了提高镁合金电阻点焊接头的力学性能,采用光学显微镜、激光共聚焦扫描显微镜、x射线衍射仪研究了接头的微观组织和相组成.结果表明,接头主要由熔核和热影响区(HAZ)所构成.熔核一般包括两种不同的组织形态,即熔核边缘的胞状树枝晶和熔核中心的等轴树枝晶.熔核是由大量的α-Mg相和少量的β-Mg17Al12相所组成.相对于未熔化的母材晶粒,热影响区晶粒变粗,并伴随晶界熔化.当焊接电流为23 kA,焊接时间为8个周波,电极力为4.5 kN时,熔核边缘的胞状树枝晶细化,而熔核中心的等轴树枝晶有向等轴晶转化的倾向,且平均晶粒尺寸为12.96μm. 相似文献
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对铝合金薄板激光单光点和双光点焊接(包括不填丝和填丝)的焊缝成形、对接间隙和准直度容许裕度以及气孔状况进行了比较,并分析了双光点能量分布的激光对铝合金焊接的影响.结果表明,与激光单光点焊接相比,激光双光点焊接铝合金所得焊缝表面质量更好,焊缝熔宽更大,对接间隙和准直度容许裕度明显放宽.激光双光点焊接铝合金可以显著减少焊缝中大气孔的数量,但对焊缝中小气孔数量的影响不明显.此外,填加焊丝可以进一步改善焊缝表面质量并放宽对接间隙和准直度容许裕度,但将增大焊缝产生大气孔的倾向,采用激光双光点焊接仍可使焊缝中大气孔的数量明显减少. 相似文献