The role of induced α′-martensite on the hydrogen-assisted fatigue crack growth of austenitic stainless steels

• Fatigue crack growth rates of 301, 304L and 310S stainless steels were measured.
• Metastable 301 and 304L SSs were susceptible to hydrogen-accelerated crack growth.
• The 310S SS was resistant to hydrogen-assisted crack growth even in the cold rolled state.
• The α′-martensite was formed within a narrow region ahead of fatigue crack tip.
• Cracking along α′-martensite resulted in hydrogen-assisted fatigue crack growth.

The effects of rolling on the hydrogen-assisted fatigue crack growth characteristics of AISI 301, 304L and 310S stainless steels (SSs) were investigated. In hydrogen, cold rolled specimens with a 20% thickness reduction were found to increase the fatigue crack growth rates (FCGRs) in the 301 and 304L SSs, and to a much lesser extent in the 310S SS. However, enhanced slip was observed for the 310S specimen in hydrogen. Hydrogen-accelerated FCGRs of the 301 and 304L SSs were related with the crack growth through the strain-induced martensite formed in the plastic zone ahead of the crack tip.