Role of Coalesced Bainite in Hydrogen Embrittlement of Tempered Martensitic Steels

The role of coalesced bainite in hydrogen embrittlement of tempered martensitic steels was investigated. Results showed that the coalesced bainite significantly enhanced the hydrogen embrittlement resistance by restricting hydrogen accumulation at the prior austenite grain boundaries, thus shifting the hydrogen-assisted failure mode from intergranular to transgranular fracture.