Fracture performance study on Q460D steel and ER55-G welds after high temperature

Abstract

Uniaxial tensile tests were conducted on smooth round bar specimens made of Q460D high-strength steel base metal and ER55-G welds after a high temperature of 900 °C and natural cooling. Counterpart specimens at room temperature were also examined for comparison. The basic mechanical properties of each specimen were obtained, enabling quantification of the true stress-plastic strain curve of the material required for finite element analysis (FEA) in ABAQUS. The notched round bar specimens were heated up to high temperature of 900 °C, and then naturally cooled to room temperature. Uniaxial tensile tests were carried out on the notched round bar specimens. By combining test results with ABAQUS FEA and scanning electron microscope tests, the void growth model (VGM) parameters of Q460D high-strength steel and ER55-G welds after high temperature of 900 °C and natural cooling were calibrated. Finally, the calibrated VGM model was adopted as a fracture criterion in the ABAQUS subroutine VUMAT to simulate the uniaxial tensile tests on notched round bar specimens of Q460D steel base metal and ER55-G welds after high temperature of 900 °C and natural cooling. It is indicated that in most cases, the post-fracture path and the whole force-deformation curve can be simulated through the FEA with subroutine VUMAT with reasonable accuracy.