Abstract
Susceptibility of medium and high grades of supermartensitic stainless steels to hydrogen-assisted stress cracking was evaluated by performing constant slow strain rate tests on smooth tensile specimens at 20 oC. These two grades have the same Cr content but differ mainly in their contents of Ni and Mo. Test results showed that these grades were susceptible to hydrogen-assisted stress cracking under the investigated conditions. SEM examination showed that the fractured surfaces of charged specimens exhibited mixed transgranular and intergranular cracking. Average crack-propagation rates in hydrogen charged medium and high grades were determined at the tested strain rates.
