圆管件锥面型冲压缩口中一些重要参数的确定

为给工艺设计人员制订工艺、设计模具提供依据，对薄壁圆管件锥面型冲压缩口工艺进行了分析．在工件材料为理想刚塑性材料的假设下，应用考虑厚度变化的轴对称塑性薄壳理论并通过数据拟合，得出了不同锥角及库仑摩擦系数情况下工件缩口变形区应力的变化规律与分布模式，据此推导出了工件成形阶段最大应力、缩口力与最终壁厚、弧面曲率半径、所需管坯长度及小锥角时极限缩口系数的计算式，这些公式均易于推广应用到变形强化材料圆管件的分析中．

Determination of Some Important Parameters in the Stamping-necking Process of the Cone Type for Cylindrical-tube Workpiece

In order to provide technologists with some guidelines for process-planning and die-designing, the stamping-necking process of the cone type for thin-walled cylindrical-tube workpiece was analyzed. Then, based on the thickness-changeable axisymmetric plastic thin-shell theory and the assumption that the workpiece material is perfectly rigid-plastic, the variation law and distribution patterns of the stress in the necking deformation zone with different cone-angles and Coulomb's coefficients of friction were formulated by means of data fitting. Many formulas were finally deduced for determining the maximum stress and the necking force during the necking-forming stage, the final thickness, the arc-surface curvature radius, the needed tube-blank length as well as the minimum necking coefficient of the workpiece. These formulas can be easily applied to the analyses of the cylindrical-tube workpieces produced with deformation-hardening material.