共查询到18条相似文献,搜索用时 156 毫秒
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过高的温度会影响医疗器械机架激光焊效果,为解决这一问题,提出医疗器械机架激光焊变形分析及控制方法。在分析医疗器械机架激光焊变形前,优先分析激光焊参数对产生焊接变形的影响,将其作为信息基础进一步获取医疗器械机架激光焊的变形量。结合Ansys软件模拟机架激光焊温度场变化结果,分析医疗器械机架激光焊变形情况;基于分析结果将机架焊缝变形量作为模型建立依据,构建超声波激振控制模型,利用该模型减小机架激光焊后的残余应力,达到降低焊接变形的目的,实现焊接变形控制。试验结果表明,通过对该方法弯曲挠度值测试和控制效果测试,验证了该方法的有效性。 相似文献
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针对2 mm的316L薄板单面密集焊缝结构,采用数值模拟的方法分析了两种焊接方案下的薄板焊接弯曲变形. 利用高度测量装置建立了薄板弯曲变形测量方法,进行了两种焊接方案的工艺试验,对焊后弯曲变形进行了测量. 在此基础上,对数值模拟和工艺试验的结果进行了对比. 结果表明,薄板单面密集焊缝结构焊接后呈船形变形,拉通焊弯曲变形中心接近于板中心,而两端向中间焊弯曲变形中心偏向板的先焊位置. 两端向中间焊在长度方向弯曲变形量小于拉通焊,两端向中间焊的焊接方案较优. 相似文献
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首先对50mm厚TA15钛合金平板分别采用堆焊和对焊两种方法进行电子束焊接,然后采用盲孔法测量了热处理和未热处理情况下焊接试件残余应力的分布情况.测量发现,对接焊和堆焊试件上表面纵向应力在焊缝和热影响区呈现较大的拉应力,且对接焊试件的纵向应力大于堆焊试件;上表面横向残余应力幅值较低,且整体呈现压应力分布.下表面的横纵应力整体上为压应力,且横纵应力的分布和大小非常接近.结果表明,热处理工艺造成各试板的横纵应力趋于一致,整个试板上的应力趋于均匀化,且堆焊试件的均匀化程度更明显. 相似文献
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为研究电渣焊接头焊接残余应力的分布规律及变形特征,基于有限元分析软件MSC. Marc,开发了用于模拟电渣焊接头温度场、残余应力与焊接变形的热-弹-塑性有限元计算方法. 在所开发的计算方法中,采用全椭球等密度体积移动热源模型来模拟电渣焊的热输入,并以生死单元技术考虑焊缝成形,数值模拟了箱型柱中的腹板与隔板处电渣焊接头的焊接残余应力与变形. 同时,采用试验方法实测了电渣焊接头的横向收缩及角变形. 结果表明,横向收缩和角变形的计算结果都与试验值比较吻合,验证了所开发的数值计算方法的妥当性. 此外,利用数值模拟方法详细研究了电渣焊接头焊接残余应力的分布特征. 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):453-458
AbstractThis paper investigates a trailing heat sink, which was designed and applied to friction stir welding (FSW) in order to control the residual stresses and welding distortion. Residual stresses, residual plastic strains and welding distortion of 2024-T3 and 5083-H321 Al sheets welded by FSW with and without the trailing heat sink were compared. The optimal placement of the heat sink was discussed. The results revealed that the reductions in peak tensile stresses were 66% for 2024-T3 and 58% for 5083-H321 by application of the trailing heat sink in FSW. In addition, the welding distortion could be reduced drastically by this method. The 5083-H321 sheet with a size of 1000×100×3·5 mm welded by this method was very flat and had almost no distortion. This method achieved in-process control of stresses and welding distortion, without additional complicated work before or after welding operation. 相似文献
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Nobuhisa Ochi Shigetaka Okano Masahito Mochizuki Junji Shimamura Nobuyuki Ishikawa 《Welding International》2013,27(3):174-183
In recent years, in order to reduce the costs of transportation and construction of pipelines, which are often constructed using multiple-electrode submerged arc welding (SAW), higher joint performance is required. Therefore, there has arisen the need to understand theoretically and control appropriately metallurgical and mechanical characteristics in heat-affected zone (HAZ), which has a significant influence on the strength and toughness of welded joints. Commonly, metallurgical phenomena in HAZ are evaluated based on the highest temperature and the cooling rate. Therefore, in order to control metallurgical and mechanical characteristics in HAZ by means of the welding conditions, evaluating the temperature distribution and the temperature history near the melted zone is essential. However, a detailed investigation of the temperature distribution for multiple-electrode SAW has not yet been carried out enough. In this study, in order to investigate the temperature distribution and histories during multiple-electrode SAW, the experimental results are compared with the theoretical results. In the theoretical analysis, the temperature rise equation in multiple heat sources welding is developed using the method of summation. Furthermore, on temperature distribution during welding, the effects of multiple heat sources, such as the number of heat sources and the distance between each electrodes, are considered quantitatively through the thermal conduction theoretical analysis. As the result, the distance between lead heat source and final heat source primally influences the area with the difference between a single heat source welding and multiple heat sources welding. Based on the results, it is expected to control temperature distribution near melted zone by more appropriate heat input characteristics, which is depended on heat source arrangement. 相似文献
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由于认为焊缝存在加热过程和忽视熔化现象的存在,导致传统观点认为的焊缝存在压缩塑性应变的错误.传统观点尚不能解释液化裂纹出现于熔合线处和裂纹很短的现象,用作者给出的高温应变分布图可很好解释.消除焊接残余应力并不是一定要去除固有应变源,有时不去除固有应变源仍可消除残余应力.消除残余应力的过程实质上都是将残余弹性应变转变为塑性应变的过程. 相似文献