Investigation on heat-affected zone hydrogen-induced cracking of high-strength naval steels using the Granjon implant test HENRY GRANJON PRIZE 2014 Winner Category B: Materials Behaviour and Weldability

The implant test was used to study the heat-affected zone (HAZ) hydrogen-induced cracking (HIC) susceptibility of a recently developed blast-resistant steel BlastAlloy 160 (BA-160) and two existing naval steels, HY-100 and HSLA-100. It was found that the coarsegrained HAZ (CGHAZ) is the most susceptible to HIC in the entire HAZ. Therefore, phase transformation behavior in the CGHAZ was investigated and continuous cooling transformation (CCT) diagrams for the CGHAZ of the three steels were developed. The new BA-160 steel was compared with the current steels HY-100 and HSLA-100 with respect to inherent resistance to HIC and sensitivity to diffusible hydrogen level based on the implant test results. Fracture surfaces of the implant specimens were also studied, which supports the implant test results when comparing the three steels. Different performance of the three steels is a result of the formation of different microstructures in the CGHAZ. In addition, the effect of welding parameters on reducing HIC tendency of BA-160 was studied using the implant test, providing recommendations for welding BA-160 when HIC is a big concern.