共查询到20条相似文献,搜索用时 125 毫秒
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在焊工考试中要想焊出美观、质量优良的熔化极气体保护焊焊接接头,在练习过程中需要严格按照对接试件评分标准要求自己,并经过严格反复练习。文中从对接试件表面评分标准、内部质量评分标准、焊前准备、打底层施焊、填充层施焊、盖面层施焊及接头处理等方面进行了阐述。根据焊接实践,焊接之前深入了解在焊接技能等级考试中对焊接试件表面及内部评分标准要求,了解容易出现焊接缺欠的种类及位置,并提出对应的避免措施。阐述了熔化极气体保护焊单面焊双面成形过程中每一步操作要点及操作技巧,对焊接出优质、美观的焊缝具有一定的指导作用。 相似文献
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文中以LGA器件焊接质量问题为对象,针对该类器件封装的特殊性,通过对影响焊接质量的因素进行分析,从印制焊盘设计、焊盘作非阻焊层限定(NSMD)设计、印制板加工、焊膏量控制、器件贴装压力控制及再流焊温度曲线设置等方面,提出了优化及改进方案。通过试验,验证了改进措施的可行性和有效性,获得最优的焊接效果,保证LGA器件焊接质量满足标准要求。 相似文献
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着重分析了焊接工艺对自动焊焊接质量的影响,给出了各工艺参数在不同焊接位置合适的范围,对自动焊与手工焊的成本及效率进行了对比分析。成功地对5台1000m^3精丙烯球罐进行了全位置自动焊。 相似文献
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电子束焊接是近年来飞速进步、蓬勃发展的一种先进连接技术,随着技术工艺的日益成熟,其在工业领域的竞争力也日渐增强,已为工业部门所广泛接受.文中综述了电子束焊接在高温钛合金、高温合金、难熔金属、金属间化合物等先进材料与各类互相固溶的、难以互溶的异种材料连接方面的研究现状,对国内外在焊接缺陷控制、焊接工艺优化、焊接机理研究等方面取得的典型研究成果进行了简要介绍,并从中概括总结了先进材料与异种材料电子束焊接的具体问题,归纳阐述了先进材料与异种材料电子束焊接中所采用的能量控制与冶金调控等特色技术方法. 相似文献
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孙咸 《机械制造文摘:焊接分册》2013,(4):17-22
分析了珠光体钢与奥氏体钢异种钢的焊接性,介绍了焊接材料的选用原则、材料种类、工艺及工程中的应用.结果表明:该类异种钢焊接材料的选择原则是,尽量选用接近或高于奥氏体钢的高合金成分,而不是接近珠光体钢的成分;尽量避免焊缝中马氏体组织形成,保证接头获得良好的使用性能和焊接性.可供该类异种钢选用的焊接材料种类较多,工艺方法各具特色.三个典型应用案例表明,这类异种钢焊接质量的有效控制,取决于焊接材料的合理选用及正确的工艺方法.新型、高效、自动化焊接材料是颇具推广应用前景的焊接新材料. 相似文献
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《Science & Technology of Welding & Joining》2013,18(7):558-565
AbstractPrevious research within friction stir welding (FSW) has demonstrated that online control of welding parameters can improve the mechanical properties and is necessary for certain applications to guarantee a consistent weld quality. One approach to control the process is by adapting the heat input to maintain a stable welding temperature, within the specified operating boundaries. This requires accurate in-process temperature measurements. This paper presents a novel method to measure the temperature at the interface of the FSW tool and workpiece. The method is based on the thermoelectric effect between dissimilar materials. The measurements are compared to thermocouple measurements and to a physical model and show good correspondence to each other. Experiments demonstrate that the method can quickly detect temperature variations, due to geometrical variations of the workpiece or due to parameter changes. This allows use of the method for online control of robotic FSW. 相似文献
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阐述了紫铜与16Mn R钢异种金属材料焊接在柳钢3#高炉紫铜水冷壁修复中的应用。针对紫铜与16Mn R钢异种金属材料的焊接特点,在制造车间将新紫铜冷却水箱与炉壳等厚的16Mn R钢板(δ=40 mm)焊接制成一个组合工件,在高炉施工现场由组合工件与高炉炉壳直接焊接。加工适当的焊接坡口,选择合理的焊接工艺,成功解决了紫铜与16Mn R钢异种金属材料的焊接问题,按质、按期完成紫铜冷却水箱的更换,获得甲方的一致好评。 相似文献
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《Science & Technology of Welding & Joining》2013,18(4):279-286
AbstractWhen fusion welding is conducted on the dissimilar materials between a reduced activation ferritic/martensitic steel F82H steel and an austenite stainless steel SUS 316 steel, δ ferrite is generally formed and inevitably deteriorates the weld properties. In this study, dissimilar welding of F82H to SUS 316 steel was successfully achieved by friction stir lap welding technique. It revealed that the shape and microstructure of the joint interface can be controlled by controlling the welding temperature, in another word, by changing the applied load. By controlling the welding temperature at ~710°C, a sound dissimilar joint can be obtained with a smooth joint interface and no mixed microstructure, despite the relative overlapping position of the steel plates. All the dissimilar joints showed high shear tensile strength and fracture in the base metal of F82H steel plate, which has lower strength than the SUS 316 steel plate at room temperature. 相似文献
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研究了T91与10CrMo910钢的异质焊接工艺,确定出预热和层间温度,选择了焊接材料,制订出相应的工艺参数和焊接、热处理工艺。通过焊接工艺试验评定表明:此焊接工艺选择适当,焊接接头的力学性能、显微组织满足要求,可以保证工程焊口质量。 相似文献
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文中基于SYSWELD有限元分析软件对Q345/316L异种钢焊接过程的瞬态温度分布、残余应力及变形进行了数值模拟,并通过试验对其模拟结果进行了验证. 试验测量结果与数值模拟结果吻合良好,证明了利用SYSWELD模拟异种钢焊接的可靠性. 结果表明,异种钢焊接温度场呈不对称分布,Q345侧的高温区域范围更大. 不论是横向残余应力还是纵向残余应力,沿焊缝方向均呈帽状分布且在焊缝中部位置存在最大残余应力;在垂直于焊缝中央截面上,纵向残余应力与横向残余应力在焊缝和焊缝附近区域分布是不连续的,存在较大的应力梯度且应力状态也较复杂,而最大残余应力出现在Q345侧的熔合线处. 不同的热输入下模拟结果表明,在保证焊接接头质量的前提下,最好采用小热输入的焊接工艺. 相似文献
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S J. Lee H. Nakamura Y. Kawahito S. Katayama 《Science & Technology of Welding & Joining》2014,19(2):111-118
Conventional fusion welding of aluminium and copper dissimilar materials is difficult because of poor weldability arising from the formation of brittle intermetallic compounds on the weld zone as well as different chemical, mechanical and thermal properties of welded joints. Joining of Al and Cu plates or sheets offers a metallurgical challenge due to unavoidable formation of brittle intermetallic compounds. Therefore, it is necessary to effectively suppress the formation and growth of Al–Cu intermetallic compounds. For welding of dissimilar Al and Cu sheets, no systematic work has been conducted to reduce these defects. Thus, this paper focuses on the effect of welding speed on the quality of a lap weld joint in the Al and Cu sheets with a single mode fibre laser. It was found that consequently sound strong weld joints could be produced by suppressing the formation of intermetallic compounds in the interface zone at extremely high speeds. 相似文献
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Refi ll friction stir spot welding, also known as friction spot welding(FSpW), is a solid-state welding process suitable for spot joining of lightweight materials. Through the eff orts of improving joint quality for similar and dissimilar materials, for example, aluminum and magnesium, this joining technology is well developed. The joining mechanism and process characteristics of FSpW have been widely studied. However, the application of FSpW in industry has not been entirely successful. In this review article, the research of similar and dissimilar material joints, such as, Al/Cu, Al/Ti, Al/Mg and Al/Steel, is summarized. The microstructural features and mechanical properties of the joints, welding tool and the application development are discussed in detail. 相似文献
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Aude Simar Marie-Noëlle Avettand-Fènoël 《Science & Technology of Welding & Joining》2017,22(5):389-403
Friction stir welding is a rather recent welding process (patented in 1991 by Thomas et al., ‘Improvements to friction welding’ UK patent application no. 9125978.8, US Patent 5460317, 1995) that has shown great potential for welding dissimilar materials even of different metallic nature, e.g. Al to steel, Mg to steel, Al to Ti, Mg to Ti, Al to Cu, Al to Mg. This review presents the specific microstructural features and mechanical properties, in particular tensile strength, of such welds. A focus will be on the material flow and welding defects, on the intermetallic compounds, on constitutional liquation, on particularities related to dissimilar lap welding and finally on process modifications to improve dissimilar friction stir weldability. 相似文献