Hydrogen contributes to delayed weld and/or heat affected zone cracking. Hydrogen combined with high residual stresses and crack-sensitive steel may result in cracking hours or days after the welding has been completed.

High strength steels, thick sections, and heavily restrained parts are more susceptible to hydrogen cracking. On these materials, we recommend using a low hydrogen process and consumable, and following proper preheat, interpass, and postheat procedures. Also, it is important to keep the weld joint free of oil, rust, paint, and moisture as they are sources of hydrogen. "