共查询到17条相似文献,搜索用时 125 毫秒
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《塑性工程学报》2017,(5)
铝合金微通道扁管热挤压成形中温度变化对成形质量有重要的影响。通过Gleeble热压缩试验,研究了AA3102铝合金的流变应力关系,并基于带线性软化项的修正的Voce硬化模型建立了该合金的本构关系。基于此模型,利用Qform-Extrusion软件平台建立了微通道扁管挤压成形的有限元模型,并通过与现场生产试验对比验证了模型的准确性。利用验证的有限元模型,以峰值挤压力和模孔出口处产品温度为目标变量,进行了仿真模拟正交试验研究。研究结果表明,峰值挤压力随着坯料温度梯度的增大而增大,模孔出口处扁管峰值温度随着挤压速度的增大而增大,调整挤压速度可以减小扁管温差。 相似文献
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焊合室深度及焊合角对方形管分流模挤压成形质量的影响 总被引:2,自引:0,他引:2
基于Deform-3D有限元分析平台,采用所开发的焊合过程网格重构技术,分析方形管分流模双孔挤压时焊合室深度及焊合角对成形质量的影响。结果表明:焊合面平均静水压力、分流桥底部等效应力及模芯最大偏移量随焊合室深度的增加而增加;综合考虑焊合质量、模具应力集中及型材尺寸精度等因素,分流模合适的焊合室深度为10~16mm;随着焊合角的增加,焊合室内死区体积及挤压力均增大,而模芯最大变形偏移量呈减小趋势;综合考虑焊合角对挤压过程死区大小、模芯的稳定性及挤压力大小的影响,分流模合适的焊合角为30?~45?。实验结果和模拟结果在金属流动景象、死区位置、死区形状等方面吻合较好。 相似文献
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微型微通道管产品具有孔道数量多、孔道尺寸小、壁厚薄、尺寸精度要求高等特点,制备加工难度很大。采用连续挤压制备方法,通过采取双槽挤压方式、增加金属导流板等措施,对模具结构与加工方法、挤压工艺进行优化设计,明显改善了微型微通道管产品挤压成形时金属在产品宽度方向的流动均匀性、孔道部位的有效填充及焊合质量,解决了挤压过程中模具模芯强度不足导致的尺寸超差与失效问题和溢料过多导致产品无法挤出等问题。最终成功试制了厚度为2.2 mm、宽度为45 mm的52孔微型微通道管产品,产品外形尺寸和组织结构均满足设计要求。 相似文献
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分流模挤压焊合区域的氧化物分布及焊合组织分析(英文) 总被引:1,自引:0,他引:1
利用有限元分析、扫描电子显微镜及金相实验研究分流模的锭接锭挤压条件下,型材纵、横向焊合区域的氧化物分布及焊缝微观组织。结果表明:氧化物仅存在于型材基体与横向焊合区域结合面;纵向焊缝表现为深色条纹状组织,包含在强剪切变形及高温条件下形成的粗大再结晶晶粒中;横向焊缝组织表现为晶粒度略小的等轴再结晶晶粒。 相似文献
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采用FEM方法对分流焊合模成形管材的挤压变形过程进行了三维模拟,给出了管材挤压过程中铝合金的应力、应变及流动速度等的分布和变化。 相似文献
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平面分流焊合模在有色金属型材挤压中得到较多的采用,结合金属流动的数值模拟结论和对MB2合金实际单位挤压力的研究结果,给出了平面分流焊合挤压力的工程简化计算方法,与实际相比,工程相对误差小于10%,可供实际参考。 相似文献
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针对微通道换热器用扁管与集流管连接处炉中钎焊焊接工艺进行了研究,根据相关钎焊理论及试验数据,对现有扁管槽结构进行了改良。采用改良的扁管槽结构,焊接质量得到了显著提高,扁管基本不再紧贴扁管槽一侧,降低了焊缝尾部缺陷率,平均缺陷率由20%降低为:中间段焊缝缺陷率小于等于2%,固定端焊缝缺陷率不高于5%。焊缝成形良好,降低了泄漏风险,保障了焊接品质。此外,在焊接试验的基础上,对焊接缺陷产生原因及改良机理进行了分析。 相似文献
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Qingqing Zhang Ding Tang Dayong Li Yinghong Peng 《Journal of Materials Processing Technology》2010,210(14):1876-1884
Microchannel aluminum flat tubes have attracted more and more attention in recent years, especially in ACR (air conditioning and refrigeration) industry. Rotary-draw bending is a versatile and precise method in forming of tubes. Compared with traditional out-of-plane bending method, in-plane bending can cause different forming defects. During the process, wall thinning, sectional distortion, wrinkling, and channel shape degradation are the main defects that affect tube quality in industrial applications. In this paper, an experimental apparatus for flat tube in-plane bending is manufactured, and experiments are performed to examine the forming quality of tubes. Considering the characteristics of the bending process, based on the LS-DYNA software environment, a 3D elastic–plastic finite element model is established and validated by experiment. Using the validated FE model, the forming quality of microchannel flat tube bending process is evaluated quantitively. Furthermore, the influence mechanism of process parameters, such as bending radius, tool–tube clearance, and channel diameter, has been revealed. The results indicate that the degradation of the tube channels is relatively small under common process conditions; bending radius is the main factor which influences the forming quality of the flat tube; the tool–tube clearance mainly affects the wrinkling of the flat tubes; channel diameter has little effect on the formability of tube. 相似文献
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《Science & Technology of Welding & Joining》2013,18(5):325-333
AbstractIn the present work, a software system is developed that can simulate and predict welding solidification cracks, based on previous work on welding solidification crack simulation in stainless steels. First, it assists users in discretising the welding workpiece, calculating welding heat input distribution, inputting material properties, and generating input data cards. Second, the system runs commercial finite element calculation software on the basis of input data cards. Third, the system performs data treatment to provide the user with simulated results in the form of contours, three-dimensional plots, and featured curves such as welding temperature cycles and strain - stress cycles. Next, the system carries out regression analysis on experimental data from transverse Varestraint testing to determine the resistance of the material to welding solidification cracking. Finally, the system calculates the curves of strain evolution with temperature at the trailing edge of the mushy region in the weld pool to obtain the driving force for welding solidification cracking. Consequently, the system can predict welding solidification cracking by presenting users with the driving force and resistance curves in one figure. The software package is developed mainly using Visual Basic and its graphical functions are achieved with the assistance of the Matlab software packages. 相似文献
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