Effect of tooling design on the cold pilgering behavior of zircaloy tube

Abstract

Cold pilgering is an incremental forming process through which the preliminary tube is formed to the final product between a mandrel and ring dies. The tooling (ring dies and mandrel) has a significant effect on the property and forming quality of tubes. In this paper, under ABAQUS/Explicit platform, a 3D elastic–plastic FE model of cold pilgering over the whole productive time was established and experimentally verified. A modified cumulative damage function (Lat&Co) was numerically implemented by user-defined material subroutine (VUMAT) in the ABAQUS. And the influence of top side relief on cold pilgering behavior of zircaloy tube, such as rolling force, strain ratio, and forming quality was explored. And the relationship between the strain ratio and texture revolution during cold pilgering was also revealed. It shows that ring dies with tangential side relief have advantage of preventing surface defects on the outer/inner zircaloy tube surface and lowering rolling force. The damage factor on inner surface of tube is slightly larger than which on outer surface. However, the top side relief of ring die has little influence on texture evolution.