共查询到18条相似文献,搜索用时 218 毫秒
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利用DEFORM-3D有限元软件建立了其三维刚塑性有限元模型,通过仿真与实验相结合的方法,分析展宽角、成形角、断面收缩率对GH4169合金成形过程中力能参数的影响规律。结果表明在展宽段有:随着成形角的增大,径向力、横向力和轧制力矩均减小,轴向力略增大,但增大幅度不明显;随着展宽角的增大,径向力、横向力和轧制力矩均增大,轴向力减小;随着断面收缩率的增大,径向力、横向力和轧制力矩先增大后减小,轴向力增大。采用无量纲影响因子法,综合分析获得了工艺参数对力能参数影响的主次顺序。在此基础上,进行了1∶1楔横轧GH4169合金实验,得到轧制力矩与数值模拟结果相对误差在10%以内。研究结果为GH4169合金轴类件楔横轧成形合理选取工艺参数和轧机设计力能参数确定提供参考。 相似文献
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二辊楔横轧工艺参数的研究 总被引:1,自引:0,他引:1
从理论上导出了二辊楔横轧的旋转条件以及不产生缩颈的极限条件和不产生中心疏松或裂纹的条件,得出了成形角、展宽角以及断面收缩率之间的关系。这些关系对于参数的选择和模具设计具有一定的实用价值。 相似文献
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采用有限元软件DEFORM-3D对楔横轧厚壁空心轴进行热力耦合数值模拟,得到了工艺参数对楔横轧厚壁空心轴不圆度的影响规律。结果表明,在成形角35°~45°、展宽角4°~7°、断面收缩率35%~65%、轧制温度900℃~1100℃时,轧件不圆度与成形角及断面收缩率的变化成反比,与展宽角及轧制温度变化成正比。采用H630楔横轧机进行轧制实验验证了有限元模型的正确性。模拟与实验结果证明,轧件横截面失圆是楔横轧成形厚壁空心轴类件常见的质量问题;变形区金属沿轴向的流动受到未变形金属的阻碍,是造成不圆度在轧件的对称面上最大并沿轴向逐渐减小的原因。研究结果为确定楔横轧厚壁空心轴的工艺参数提供了理论依据。 相似文献
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就二辊楔横轧工艺从理论上导出了旋转条件以及不产生缩颈的极限条件和不产生中心疏松或裂纹的条件,提出了成形角,展宽角以及断面收缩率之间的关系,这些关系对于参数的选择和模具设计具有一定的实用价值。 相似文献
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The internal void of cross wedge rolling (CWR) part can be treated as porous material due to their similar physical property and deformation characteristics. Aiming at the CWR process of aluminum alloy 7075 workpiece, the numerical simulation model for internal void was established by means of the rigid-plastic FEM method for the porous material. The relative density was used to research the influence of three primary parameters on the internal void in CWR process, including the forming angle α1, the stretching angle β and the area reduction ΔA. The experimental results show that the expansion of internal void occurs in the stretching zone, and the knifing zone just has a little influence on it. The stretching angle has a great influence on the internal void, while the area reduction has a small influence on it. The size of internal voids decreases with the increase of area reduction, stretching angle and forming angle. When designing the CWR tool geometry and operating conditions, to prevent the internal void, the area reduction is suggested to be 55%–65%, the stretching angle to be 8°–10°, and the forming angle to be 29°–32°. 相似文献
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《Journal of Materials Processing Technology》2000,97(1-3):44-53
Friction and slip between the workpiece and the tool in metal forming processes are important issues in tool design and product development. This paper characterizes the tool–workpiece interfacial slip in a flat-wedge cross-wedge rolling process (CWR) using an explicit dynamic finite element method. An experimentally validated finite-element model of CWR is used to investigate the effects of the friction coefficient, the forming angle, and the area reduction on the tool–workpiece interfacial slip. A total of 14 rolling conditions are analyzed. An analytical CWR model for the workpiece rotational condition, which predicts the onset of rotation, is derived. Using this model, the critical area reduction and friction coefficient are compared with the failure conditions that occurred in the finite-element modeling and the prototype experiments. The variation of interfacial slip with CWR design parameters is found to provide insight regarding the CWR process design. 相似文献
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采用120°角度尺等简单自制工辅具,实现了对曲拐空间相位角度和偏心量的控制,减少三拐曲轴工艺重量、降低材料成本,成功整体锻造了隔膜泵三拐曲轴,实现了自由锻无错移大偏心曲拐成形,降低了加工周期,外形尺寸及内部质量均符合技术要求。 相似文献
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Ti-6Al-4V钛合金的激光弯曲成形特性 总被引:4,自引:1,他引:4
以Ti-6Al-4V薄板材料为研究对象,研究了激光弯曲成形技术在钛合金上的应用特征.通过实验描述了不同扫描参数对弯曲角的影响规律,并对多次扫描下的板材弯曲动态特性进行了研究.结果表明:弯曲角随扫描次数呈近似的线性增加关系;在扫描次数一定的情况下,存在一个最优的累积线能量使弯曲角达到最大;不同的材料状态在加热和冷却过程呈现出不同的弯曲动态特性.此外,对激光弯曲后的材料微观组织、力学性能进行了测量和分析.结果表明:扫描参数的选择对发生相变的区域形状与相变区组织有较大影响;多次扫描后,加热区材料的强度与硬度均增加,塑性降低. 相似文献
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Using rigid-plastic finite element DEFORM-2D and -3D software, this study simulates the plastic deformation of metal sheets at the roll gap during the sheet rolling process. The study focuses specifically upon the deformation of porous metal sheets containing internal void defects. The present numerical analysis investigates the relative density distributions, the void closure behavior, the deformation mechanisms and the stress–strain distributions around the internal voids for various rolling conditions. The influences on the dimensions of the final void of the thickness reduction, the initial internal void dimensions, the friction factors and the relative density are systematically discussed. The critical rolling conditions also investigated. A series of sheet rolling experiments are performed in order to verify the validity of the simulation results. The current numerical results provide a valuable source of reference for the design of pass schedules for porous metals undergoing rolling processes. 相似文献
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Ghislaine Bertrand Pierre Bertrand Catherine Rio 《Surface & coatings technology》2008,202(10):1994-2001
Life and thermal properties of plasma sprayed TBCs - widely used in gas turbine engines - are closely related to the microstructure of the ceramic top coating. Especially, the thermal behaviour of this coating is induced by the void shapes and networks which are in turn determined by both the spraying conditions and the feedstock material.A specific hollow yttria partially stabilised zirconia powder was produced in a one-step process by spray drying and an experimental statistical design study was conducted to investigate the influence of spraying variables (primary and secondary gas flow rates, arc current, spraying distance, spraying angle and traverse speed) on structure and properties of resulting plasma sprayed coatings. The coatings were characterized with respect to deposition efficiency, roughness, porosity and thermal conductivity. A reduction of 25% of the thermal conductivity was achieved by improving the spray and powder parameters. A quantitative characterization of the porous structure using image analysis of polished cross-sections was implemented. The parameters that have relevant influence on the coating porous structure were identified, and their relative importance was determined. An attempt was made to identify morphological criteria of the porous network (coarse/fine porosity ratio, cracks total length, cracks orientation) correlating with the thermal conductivity values. 相似文献