材料期刊网

为了研究扩展腔结构和定径带长度对模具出口处金属流动的影响，从而优化扩展腔及模具的结构，采用有限元数值模拟方法对扩展腔结构参数以及定径带长度进行正交实验，并对挤压过程中模具入口处的金属流速、应变场和温度场进行有限元分析．结果表明：当扩展腔采用中间宽、边部窄的结构时，其模具出口处的金属流速比扩展腔厚度方向更均匀；影响模具出口处金属流速的扩展腔结构参数中，扩展腔中间厚度（ H）最为显著，扩展腔中间宽度（ l）的影响次之，其两边厚度h的影响较不明显．本实验条件下生产3 mm×100 mm的扁排，扩展腔组合结构的最佳方案如下：扩展腔中间宽度（ l）为62 mm，中间出口厚度（ H）为38 mm，两侧厚度（ h）为24 mm．在其他条件不变的情况下，选择7 mm的定径带不仅有利于金属成形，还有利于提高扁排质量．

The effect of the extending cavity structure and the calibrating strap length on the uniformity of metal flow were studied by numerical simulation. The metal flow velocity of die inlet, the strain field and the temperature field during the extrusion process was simulated by finite element method. The purpose is to research the effect of extending cavity structure and calibrating strap length on uniformity of metal flow, and then to optimize the structure of extending cavity and die. The results indicate that the extending cavity with a structure of a wide middle part and narrow sides exhibit a more uniform metal flow velocity of die inlet than that with a uniform thickness. Among three structure factors of the extending cavity on the metal flow velocity, the middle?thick of the extending cavity "H" is more significant than the middle width "l" and the thickness of the edge "h" has no significant effect. For the current experimental conditions, the optimum processing parameter of the extending cavity for fabricating the copper strap of 3 mm×100 mm is 62 mm in l, 38 mm in H and 24 mm in h. For the case of fixing the other processing parameters, the 7 mm calibrating strap length can benefit the metal forming, and improve the quality of the copper strap.