Ferritic-austenitic stainless steels are normally regarded as readily weldable by common arc processes. However, cases of weld metal hydrogen cracking have been reported, principally at joints produced using shielded metal arc (SMA) welding; the present study was carried out to examine conditions under which the problem was likely to occur.

First, a procedure was derived for hydrogen analysis of ferritic-austenitic SMA weld metals, based on the vacuum hot extraction method. Second, self-retrained single run and multipass weld cracking tests were performed, with consumables varying in deposit hydrogen potential and phase balance. Weld metal cracking was found to occur only at high ferrite contents and hydrogen levels. The results were correlated with other published information, and a diagram was produced relating cracking to the consumable hydrogen content determined under standard conditions and the deposit phase balance. From this correlation, the risk of hydrogen cracking in practice is expected to be low, given adoption of normal welding procedure guidelines.