Finite element modelling of seamed tube NC bending process and its application

The weld and heat affected zone (HAZ) have a significant effect on the stress and strain distributions of the seamed tube in the numerical control (NC) bending process. To reveal these characteristics, a three-dimensional (3D) finite element (FE) model for the process is developed based on ABAQUS/Explicit code. In FE modelling, the geometry partitions of the seamed tube and their mesh densities are addressed in accordance with the microhardness results. After the validation of the model, the effects of geometry partitions and weld position on the stress and strain distributions are studied. The results show that: (1) the weld and HAZ have a great influence on the stress across the weld area but little influence on the strain distribution; (2) the tangent tensile and compressive stress reach the largest when the weld is at the extrados and intrados, respectively; by changing weld position, the maximum tangent tensile and compressive stresses change by 22 and 21% respectively.