Abstract:  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 cylindrica- l 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 Coulombʾs 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 ra-dius‚the needed tube-blank length as well as the minimum necking coefficient of the workpiece．These formulas can be eas-ily applied to the analyses of the cylindrica- l tube workpieces produced with deformation-hardening material。

Key words:  cylindrica- l tube workpiece, stamping-necking, cone type, stress, necking force, size