In order to obtain the damage coefficient of Cyclic Void Growth Model (CVGM) and Degraded Significant Plastic Strain (DSPS) model for Steel Q235B widely used in China

taking four types of steel Q235B materials extracted from the hot-rolled seamless pipe and the matrix

heat affected zone as well as welded zone of cold-welding pipe respectively

twelve smooth specimens and eight notched specimens were machined. A series of low-frequency cyclic loading material tests were carried out to acquire the combined hardening parameters. The UVARM subroutines of CVGM model and DSPS model were developed in FORTRAN language and embedded in ABAQUS. The calibration of the damage degradation coefficients of CVGM model and DSPS model of four kinds of steel materials was performed. Based on the UVARM subroutine and identified damage coefficients

fracture initiation for the notched specimens can be predicted and simulation results match well with experimental results.