Advances in Hydrogen Management for High Strength Steel

Diffusible hydrogen content in high strength low alloy steels welding can be better managed with modifications to the low hydrogen welding consumables. The welding consumable alloy content needs to allow the weld metal to transform from austenite to ferrite/martensite at slightly higher temperature than the base metal does. This practice will allow for the best dispersal of hydrogen from the weld deposit and minimizing the tendency of localizing the hydrogen in the heat affected zone at the fusion line. The use of weld metal hydrogen traps will both reduce the total diffusible hydrogen content and also minimize the hydrogen distribution near the fusion line. The use of complex metal fluorides in the welding consumable to achieve small but sufficient amounts of fluorine to the welding plasma can produce hydrogen fluoride, thus reducing the amount of hydrogen source available for the weld pool or the resulting the weld deposit. Also, the presence of retained austenite was found to influence the ability to control weld metal hydrogen in high strength low alloy steels. Presented at the Ninth CF/DRDC Meeting on Naval Applications of Materials Technology, Dartmouth, Nova Scotia, Canada, 5-7 June 2001.