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采用铅试料,用网格法实验观测连续变断面循环挤压法挤压时金属的流动特征。研究表明,正挤压时,金属在模腔中延伸变形成圆台体,受模具形状影响,变形程度从顶端向底端逐渐减小;圆台体镦粗时金属在高度方向从顶端至底端各层沿径向流动逐渐减小,依次连续变形成圆柱体。这种变形特点使试料在变形过程中逐渐渗透达到累积的效果,并且未出现圆柱体镦粗时的鼓形现象,也未出现因失稳导致的界面叠层。
Lead samples were used to observe the flow characteristics of metals during the extrusion process with continuous variable cross-section by grid method. The results show that when the steel is being extruded, the metal will be deformed and deformed into a circular truncated cone in the cavity. The shape of the metal will decrease gradually from the top to the bottom due to the shape of the mold. In upsetting, Layer flow along the radial decreases, followed by continuous deformation into a cylinder. The deformation characteristics of the sample gradually penetrate the deformation process to achieve the cumulative effect, and does not appear when the cylinder upset drum phenomenon, nor because of instability caused interface stack.