Theoretical and experimental study on formability of laser seamed tube hydroforming

摘要

As an effective method to evaluate the tube hydro-formability, forming limit curve (FLC) has been widely applied on the hydroforming process design. This paper mainly focuses on the study of evaluation of laser seamed tube hydro-formability. Based on the test methods of free bulging and elliptical bulging, hydroforming limit tests of the laser welded tube and the electric resistance welded tube (ERW) have been carried out. The cracking failure characteristics of the seamed tube above during hydroforming are analyzed, and then a new theoretical model which reflects the heterogeneity of material and the non-uniformity of curvature during seamed tube hydroforming is developed to predict FLC for seamed tube hydroforming. The comparison results show that the predicted FLCs are in agreement with the test data. The FLC analysis demonstrates that the laser welded tube exhibits a better hydro-formability than that of the ERW tube with the same size and tubular material, and that the hydro-formability of seamed tube is affected by its diameter and thickness.