Characteristics of Susceptible Microstructure for Hydrogen-Induced Cracking in the Coarse-Grained Heat-Affected Zone of Carbon Steel

Abstract

Hydrogen-induced cracking (HIC) susceptibility of the coarse-grained heat-affected zone (CGHAZ) of carbon steel was evaluated using implant tests and the characteristics of susceptible microstructure to HIC was investigated. Three types of carbon steel with different alloying elements were employed as base metals to vary the microstructure of the CGHAZ and implant test assemblies were prepared using an automatic shielded metal arc welding process. A clear difference in microstructure was observed between the CGHAZs of steel with high and low HIC susceptibility; the formation of the primary ferrite in the CGHAZ of carbon steel plays an important role in decreasing the HIC susceptibility.