Sulphide stress cracking behaviour of the coarse-grained heat-affected zone in X100 pipeline steel under different heat inputs
By Han, Y. D.; Wang, R. Z.; Jing, H. Y.; Zhao, L.; Xu, L. Y.; Xin, P.
Published in International Journal of Hydrogen Energy
2020
Abstract
The sulphide stress cracking (SSC) behaviour of a simulated coarse-grained heat-affected zone was investigated under different heat inputs. The microstructure and fracture surfaces were observed. SSC susceptibility was dominated by hydrogen embrittlement (HE) and, to a lesser extent, anodic corrosion. Heat input had a critical effect on the microstructure and material properties. When t8/5 (time taken to cool from 800 °C to 500 °C) was 30 s, the microstructure was mixed lath bainite/granular, with low HE and high SSC resistance. When t8/5 was 100 s, the microstructure was granular bainite, with high corrosion current density and low SSC resistance. The results provide guidance for development of SCC resistant welding procedures.