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在准静态条件下,采用理论和实验方法研究圆形金属坯加工成类杯形样品的成形工艺(以Teflon为衬垫)。实验中,通过Teflon为衬垫的模具及刚性冲头之间的挤压操作将圆形金属坯挤压成预先设计的形状。为了研究不同参数对样品变形过程的影响,选用不同尺寸的12个刚性冲头、板厚分别为0.6、1.1和1.5 mm金属铝和镀锌铁坯料及聚氯乙烯和聚氨酯两种填充料进行实验。在进行理论分析时,引入金属坯料和Teflon填料的变形模型。基于能量方法,计算出金属坯和Teflon填料的吸附能,从而推导出用于预测变形过程所需总能量的理论模型。在金属坯和Teflon填料变形的计算模型中考虑了不同的能量吸附机理。将模型预测值与对应的实验值进行比较以验证模型的正确性。理论和实验结果反映了变形能随板材厚度的变化规律。变形实验结果表明,当刚性冲头对于水平方向的外锥角增加时,变形能呈线性增加;当刚性冲头圆形部分的高度增加时,试样断裂的几率增大。此外,实验结果显示,金属坯料的变形能与其流变应力密切相关。相对于以聚氨脂为填料的工艺,以聚氯乙烯(PVC)为填料加工金属坯的变形能较高且其发生起皱现象的几率较低,这是采用PVC为填料相对于以聚氨脂为填料的优点所在。
Under quasi-static conditions, theoretical and experimental methods are used to study the forming process of round billet into cup-like samples (with Teflon liner). In the experiment, the circular blank was extruded into a pre-designed shape by a squeezing operation between a Teflon-lined die and a rigid punch. In order to study the influence of different parameters on the deformation process of the sample, twelve rigid punches with different sizes were used, the aluminum, galvanized iron billets with thickness of 0.6, 1.1 and 1.5 mm respectively and two kinds of filler, polyvinyl chloride and polyurethane, were tested. In the theoretical analysis, the deformation model of metal blank and Teflon filler was introduced. Based on the energy method, the adsorption energy of the metal billet and the Teflon filler was calculated to derive a theoretical model for predicting the total energy required for the deformation process. Different energy adsorption mechanisms have been considered in the calculation model of metal billet and Teflon packing deformation. The model predictive value is compared with the corresponding experimental value to verify the correctness of the model. The theoretical and experimental results show the variation of deformation energy with the thickness of the slab. The results of deformation experiment show that the deformation energy increases linearly when the external taper angle of the rigid punch increases, and the probability of specimen rupture increases when the height of the circular part of the rigid punch increases. In addition, the experimental results show that the deformation of metal billet can be closely related to its flow stress. Relative to the process of polyurethane as a filler, polyvinyl chloride (PVC) as a filler metal processing deformation of the metal billet and the lower the risk of wrinkling phenomenon, which is the use of PVC as a filler relative to polyurethane Advantages of grease for the filler.