Development on technique of tube reducing in double 3-roll dies

Based on the experiments, a new technique of reducing tube with two linked 3-roll roller dies was developed. The external friction conditions, velocity and the non-uniform deformation of metal were distinctly improved, and the friction between metal and tool was decreased. Corrosion strip layers and photo-elastic coatings methods were adopted in the experiment for measuring residual stress, and the residual stresses in the drawn tube with 3-roll dies are reduced.