Influence of weld relative strength on wrinkling and wall thickness distribution of thin-walled seamed tube in rotary draw bending process

In thin-walled seamed tube rotary draw bending, the relative strength of weld to base meal has an influence on the wrinkling and wall thickness distribution. In this study, a concept of weld relative strength factor S _f is proposed and its expression is deduced. A criterion is put forward to evaluate the wrinkling tendency of seamed tube. By employing FE simulation, the influence of weld relative strength factor on the wrinkling and wall thickness distribution of the seamed tube is studied. The results show that: 1) The wrinkling tendency increases marginally with the increasing of S _f, when the change of S _f is induced by weld strength coefficient; decreases with the increasing of S _f, when the change of S _f is caused by the weld strain hardening exponent or anisotropy exponent. 2) The wall thinning degree decreases with an increase in S _f. The S _f has the most significant influence on the wall thinning degree when the change of S _f is caused by the weld anisotropy exponent. The changing ratio of wall thinning degree is 37.61% (from 10.9% to 6.8%), when the S _f increases 0.89% (from 1.2788 to 1.2902).