Velocity Field and Variation of Wall Thickness During Tube Dieless Upsetting

Theoretical analyses show that the variation of wall thickness is in direct proportion to outer-diameter, inter-diameter, and,（1+Rs平方根）Rs(Rs is sectional increase ratio of tube), the theoretical calculated results of wall thickness during tube dieless upsetting are very approximate to the experimental one. As the width of deformation field increases, both the variation of wall thickness and the derivative of wall thickness variation to width of deformation field (tf/to） reduce.