Suppression of hydrogen embrittlement by formation of a stable austenite layer in metastable austenitic stainless steel

Solution nitriding was applied to a metastable austenitic stainless steel plate (Fe-18Cr-8Ni alloy) to stabilize the austenite near the plate surface. After cold rolling, the interior austenite almost entirely transformed to martensite, but the stabilized surface austenite remained unchanged. The interior deformation-induced martensite contributes to the material's high strength and the surface stable austenite-layer plays an important role in preventing hydrogen permeation. As a result, the resistance to hydrogen embrittlement was significantly improved for the cold-rolled specimen. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.