Effect of hydrogen charging on the tensile and constant load properties ofan austenitic stainless steel weldment

The effect of cathodic hydrogen charging on the tensile and constant load p roperties was determined for an austenitic stainless steel weldment compris ing a 304L steel in the solution treated condition as a base metal and a 30 8L filler steel as a weld metal. Part of the 304L solution treated steel wa s separately given additional sensitization treatment to simulate the micro structure that would develop in the heat affected zone. Tests were performe d at room temperature on notched round bar specimens. Hydrogen charging res ulted in a pronounced embrittlement of the tested materials. This was manif ested mainly as a considerable loss in the ductility of tensile specimens a nd a decrease in the time to failure and threshold stress of constant load specimens. The 308L weld metal exhibited the highest, and the 304L solution treated steel the lowest, resistance to hydrogen embrittlement. Hydrogen e mbrittlement was associated with the formation of strain induced martensite as well as a transition from brittle to ductile fracture morphology onward s the centre of the specimens.