Optimizing Hydrogen Embrittlement Resistance Via Controlling Reversed Austenite Content and Stability in Ultra-High-Strength Multi-Alloyed Steel

Abstract

In this study, we investigated the role of “lamellarization” on the fraction, distribution, and stability of reversed austenite on NiCrMoV/Nb high-strength multi-alloyed steel subjected to a quenching-lamellarization-tempering (QLT) treatment. The effect of reversed austenite (RA) on hydrogen embrittlement (HE) behavior was investigated. The increase in the fraction of reversed austenite was able to reduce the effective diffusion coefficient and HE susceptibility. Moreover, an appropriate heat treatment can from 6.7% filmy and stable reversed austenite, hinder the hydrogen diffusion, reduce local hydrogen concentration, and finally achieves the optimization of the strength and HE resistance. However, the interface of RA and matrix is a preferred site for crack initiation.

Keywords: Multi-alloyed steel, Lamellarization, Reversed austenite, Heat treatment, Hydrogen embrittlement