An application of a simple numerical model for hydrogen diffusion in multipass submerged arc welds in C-Mn steels

TWI Industrial Member Report Summary 473/1993

By S D Smith and F J Blunt

Background

Previous work has shown that, in contrast to the HAZ situation, weld metal hydrogen cracking risk can increase at higher arc energy. This may stem from the resultant larger weld bead retaining a higher proportion of the original hydrogen on cooling to room temperature than with lower arc energy deposits.

A description is given of a finite element model to predict hydrogen diffusion and final hydrogen distributions in single and multipass CMn steel welds. The modelling procedure was applied to a single pass gapped bead-on-plate specimen (G-BOP) and to a seven pass (5kJ/mm) weld and a 14 pass (3kJ/mm) weld.