Fracture toughness calculation method amendment of the dissimilar steel welded joint based on 3D XFEM

Abstract

The dissimilar steel welded joint is divided into three pieces, parent material-weld metal-parent material, by the integrity identification of BS7910-2013. In reality, the undermatched welded joint geometry is different: parent material-heat affected zone (HAZ)-fusion line-weld metal. A combination of the CF62 (parent material) and E316L (welding rod) was the example undermatched welded joint, whose geometry was divided into four pieces to investigate the fracture toughness of the joint by experiments and the extended finite element method (XFEM) calculation. The experimental results were used to change the fracture toughness of the undermatched welded joint, and the XFEM results were used to amend the fracture toughness calculation method with a new definition of the crack length. The research results show that the amendment of the undermatched welded joint geometry expresses more accuracy of the fracture toughness of the joint. The XFEM models were verified as valid by the experiment. The amendment of the fracture toughness calculation method expresses a better fit by the new definition of the crack length, in accordance with the crack route simulated by the XFEM. The results after the amendment coincide with the reality in engineering.