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冷挤压过程中凹模的强度条件历来是一个至关重要的问题。由于与此有关的影响因素相当多,仅用纯理论的方法是很难精确计算挤压时作用于凹模内壁的压力值及其分布规律的。为此,本项研究采用实验的方法进行测试,取得了良好的效果,从而使人们对冷挤压凹模内壁压力开始有了崭新的认识。实验中,采用六个压电石英测力传感器为测试元件,分别在变形程度(ε)为40％、45％、50％、55％、60％、65％以及凹模锥角(2α)为60°、90°、120°、150°、180°的各种组合情况下进行了实测。试样材料为铝。结果表明,作用于凹模内壁的压力是从凸模端面所处位置到凹模锥口逐渐增大的,最大值p凹_(max)发生在凹模锥口处,且P凹_(max)小于凸模最大单位压力p凹_(max),两者的比值K在0.56～0.99范围内,K的具体数值视所采用的ε及α而异。本文进一步利用逐步线性回归法,经过计算机处理,得到了p凹_(max)与ε、α之间关系的经验公式,并绘制了实用曲线。研究结果为今后冷挤凹模的设计提供了可靠依据。
The strength of the die during cold extrusion has historically been a crucial issue. Due to the considerable number of influencing factors, it is very difficult to accurately calculate the pressure value and its distribution on the inner wall of the die when using the purely theoretical method. To this end, this study using experimental methods to test and achieved good results, so that people on the cold extrusion die wall pressure began a new understanding. In the experiment, six piezoelectric quartz load cells were used as the test elements. The deformations (ε) were 40%, 45%, 50%, 55%, 60%, 65% and 2α 60 °, 90 °, 120 °, 150 °, 180 ° were measured under various combinations. The sample material is aluminum. The results show that the pressure acting on the inner wall of the die increases from the position of the die face to the taper of the die, and the maximum p concat occurs at the die taper, and P conc ) Is less than the maximum pressure of the punch p depression _ (max), the ratio of the two K in the range of 0.56 to 0.99, K specific values ?? depending on the use of ε and α vary. In this paper, we further use the stepwise linear regression method, through computer processing, we get the empiric formula of the relation between p concave max and ε, α, and draw the practical curve. The results provide a reliable basis for the design of cold extrusion die in the future.