共查询到19条相似文献,搜索用时 567 毫秒
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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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平面分流焊合成形力的工程简易算法 总被引:1,自引:0,他引:1
平面分流焊合模在有色金属型材挤压中得到较多的采用,本文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,给发流焊合挤压力的工程简化计算与实际相比,工程相对误差小于10%,可供实际参考。 相似文献
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采用作者等人开发的基于Deform-3D与Pro/Engineer的网格行重构技术,对典型大断面空心铝合金工业型材分流模挤压全过程(包括焊合过程)进行了模拟分析.结果表明,采用某企业的现行模具设计方案,挤压初始阶段,型材两侧焊合面率先产生焊合,中间部位焊合面的焊合相对滞后,导致挤出型材断面的中间位置金属流量不足,同时模芯出现弹性偏移,易造成壁厚超差;挤压稳态阶段,模孔附近型材的最高温度为520℃、焊合室内的静水压力约为A6005铝合金屈服强度的5~10倍、模芯弹性偏移量为0.43 mm,基本满足型材挤出温度、焊合质量及壁厚尺寸公差的要求. 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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以汽车某零件为研究对象,针对其初始挤压工艺方案产生焊缝焊合不良问题,采用数值模拟的方法,对其挤压过程进行了模拟,得到了挤压型材焊合不良焊合面的静水压力及材料流动应力分布规律。为提高挤压型材焊缝的焊合质量,采用K*参数对焊合质量进行定量表征,研究了不同模具结构和挤压工艺下焊合面焊合质量的变化情况。研究结果表明,K*值随焊合室高度的增加和分流比的增加而逐渐上升,随着坯料温度的升高、挤压速度的下降、坯料直径的增加而逐渐提高。根据模拟规律,对型材挤压工艺进行改进,改进后,纵向焊缝的焊合质量得到有效改善,与模拟结果吻合。 相似文献
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应用Hyper Xtrude软件对ZK60镁合金空心型材的挤压成形过程进行了有限元数值模拟研究,分别得到了型材在稳态挤压下的温度场、速度场、应变场和位移场,分析了金属流动情况、焊合室入口和出口处的压力。通过不同挤压速度下的稳态模拟分析,确定了合适的型材挤压速度为10 mm·s-1。在挤压温度为350℃和挤压速度为10 mm·s-1条件下进行实验验证,得到了形状外观均合格的产品。对比分析发现,模拟结果与实验结果的型材断面宏观组织形貌具有一致性,证明了应用Hyper Xtrude软件可以有效预测镁合金型材成形过程中的金属流动和焊合情况。 相似文献
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Ding Tang Qingqing ZhangDayong Li Yinghong Peng 《Journal of Materials Processing Technology》2014,214(11):2777-2783
Micro channel tube is a newly developed type of aluminum profiles with sub-millimeter-diameter ports in the cross-section designed for heat transfer enhancement. Micro channel tube is formed with porthole extrusion die, and the longitudinal seam welding problem is the key issue related to both the design of the delicate mandrel in the extrusion die and the pressure bearing capacity of the tube. This paper proposes a novel method to evaluate the seam welding strength of the micro channel tube at the stage of extrusion die design. First, a finite element (FE) simulation of the tube extrusion process is performed for the seam welding conditions in the die chamber and effect of the welding chamber height on hydrostatic pressure. Then, a thermo-mechanical experiment is carried out for a quantitative relationship between the welding strength and the weld condition parameters. Combining this relationship to the numerical results, the welding strength under different die design can be evaluated. Pressure bearing tests on the tube prove the reliability of this evaluation method. This study quantitatively connects the seam welding strength of the profile to the extrusion die parameters, which is helpful for optimizing the design of the extrusion process. 相似文献
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对于非对称断面、大壁厚且空心的复杂断面空心铝型材,采用常规分流模挤压时很难平衡金属流速,型材挤出后经常产生弯曲或扭拧现象。为此,提出了在常规分流模前增加一级分流模,使传统的分流-焊合-成形的3个阶段变为预分流-分流-焊合-成形的4个阶段,进而达到平衡金属流速目的。研究结果表明:双级分流模比常规分流模挤压时金属流动均匀性得到了改善;各孔金属流速平均值为6.41 mm·s-1,方差为0.2511且降低了65%;挤压温度场分布均匀,温差在7~12℃之间范围内,抵消了温差不均匀的影响;焊合室内静水压力平均值约为290 MPa,模芯周围静水压力分布均匀,模芯不易发生移动。 相似文献
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The simulation of the upsetting-extruding process ot dispersion strengthened copper welding electrode was carried out using Deform-2D finite element analysis software, and the characteristics of metal flow and the effect of different friction factors were analysed. The results show that the whole forming process consists of a forward extrusion and a backward extrusion. When the friction factor of the female die is 0.4, it is advantageous to the forward extrusion forming of the electrode work nose part, while the friction factor of the male die is only 0.1, it would be benefit to the backward extrusion forming of the electrode fit-up hole part. Addition of a scoop channel with 1.5 mm in depth and 4 mm in diameter at the bottom of the female die can avoid folds at the work nose. The rise in temperature is about 60℃ during the forming process. 相似文献
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H. H. Jo S. K. Lee S. B. Lee B. M. Kim 《International Journal of Machine Tools and Manufacture》2002,42(6):763
This paper describes a numerical analysis of non-steady state porthole die extrusion, which is useful for manufacturing long tubes with a hollow section. Materials divided through several portholes are gathered within a chamber and are then welded under high pressure. This weldability classifies the quality of tube products and is affected by process variables and die shapes. However, porthole die extrusion has been executed based on the experience of experts, due to the complicated die assembly and the complexity of metal flow. To better assist the design of die and to obtain improvement of productivity, non-steady 3D FE simulation for porthole die extrusion is required. Therefore, the objective of this study is to analyze the behavior of metal flow and to determine the welding pressure of hot extrusion products according to various billet temperatures, bearing length, and tube thickness by FE analysis. The results of FE analysis are compared with those of experiments. 相似文献
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提出了一种镁合金管材转角焊合室分流挤压新工艺,该工艺可在有效延长焊合室长度和焊合时间前提下保证舌针刚度,从而保证管材尺寸精度,并且可通过转角剪切变形机制增加预焊合金属变形量和动态再结晶程度,从而有利于提高管材性能和焊缝焊合性能。利用有限元法揭示了转角焊合室分流挤压成形过程中金属的流动特征,应变分布特征和焊合室内的静水压力分布特征。结果表明,整个挤压过程无金属折叠,从而保证管材的表面质量;流经转角后预焊合金属变形量明显增加,有利于提高管材质量和焊缝质量。最后,研究揭示了坯料初始温度,挤压速度和模具转角对焊合室内静水压力的影响规律。结果表明,随着挤压速度的增加和模具转角的增大,转角焊合室内静水压力增大;随着坯料预热温度的增加,转角焊合室内静水压力呈先增大后减小的趋势。 相似文献
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To solve the defects of bottom concave appearing in the extrusion experiments of complex hollow aluminium profiles, a 3D finite element model for simulating steady-state porthole die extrusion process was established based on HyperXtrude software using Arbitrary Lagrangian–Eulerian (ALE) algorithm. The velocity distribution on the cross-section of the extrudate at the die exit and pressure distribution at different heights in the welding chamber were quantitatively analyzed. To obtain an uniformity of metal flow velocity at the die exit, the porthole die structure was optimized by adding baffle plates. After optimization, maximum displacement in the Y direction at the bottom of profile decreases from 1.1 to 0.15 mm, and the concave defects are remarkably improved. The research method provides an effective guidance for improving extrusion defects and optimizing the metal flow of complex hollow aluminium profiles during porthole die extrusion. 相似文献
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截面变形是复杂空心型材挤压过程中经常遇到的难题,实际生产中需通过反复试模、修模才能得到合格的产品。针对6063铝合金空心型材截面内凹问题,采用数值模拟方法获得了挤压过程中不同方向上的金属流速及模具焊合室内不同高度的压力分布,分析与讨论了产生缺陷的原因,并优化了模具结构。模拟仿真结果表明,添加阻流块后挤压过程中型材不同位置和不同方向上的流动速度更加均匀,挤出型材向内凹的现象得到改善。实测结果显示,采用改进后的模具结构,挤压型材最大内凹量减小为0.15 mm,可以满足实际应用要求。 相似文献