Role of Microstructure in Susceptibility of X70 Pipeline Steel to Hydrogen Embrittlement
In order to investigate the susceptibility of steels to hydrogen embrittlement as a function of their microstructure X70 steel was chosen in different conditions: normalized transfer bar, as-received hot rolled strip and heat affected zone (HAZ). Notched and fatigue pre-cracked samples were subjected to electrochemical hydrogen charging to achieve 2 ppm hydrogen content. Three point bend tests were conducted on as-received and hydrogen charged samples. The results showed that HAZ samples are more susceptible to hydrogen embrittlement than the others. This was supported by fracture surface observations.
Jian-Feng Nie and Allan Morton
D. Hejazi et al., "Role of Microstructure in Susceptibility of X70 Pipeline Steel to Hydrogen Embrittlement", Materials Science Forum, Vols. 654-656, pp. 162-165, 2010