Hydrogen Response of 304 SS and Ti Weld Realised by Explosion

Abstract

Welds of thick plates (304 SS) cladded with Ti of commercial purity both in as received state and subsequently heat treated (HT, 600°C/1.5 h/air), charged by hydrogen, were investigated after fatigue tests (tension-pressure) with amplitude of 20 Hz. Simultaneously, samples of above mentioned welds were also exposed in H2S in accord with NACE Standard TM0284-2011 to find hydrogen induced cracking (HIC) response. Charged welds after the HT showed by 15 MPa higher threshold level than the welds without the HT. The HIC tests generally demonstrated favourable results both after as weld state and after subsequent HT. Short and thin cracks were observed, exclusively located in intermetallic phase areas, where approx. 16-20 wt. % of Ti was revealed. Fracture surfaces of fatigue bars showed maximal failure in areas with 42-97 wt. % of Ti.