Under what circumstances should extra low hydrogen electrodes be used during welding on in-service equipment?

Using extra low hydrogen electrodes during welding on in-service equipment is critical when the carbon equivalent is greater than .43%. The presence of higher carbon equivalents in the base material can increase the risk of hydrogen-induced cracking, particularly in high-strength steels. Extra low hydrogen electrodes are formulated to minimize the amount of hydrogen that can be introduced into the weld metal, therefore significantly reducing the probability of cracking and ensuring the integrity of the weld.

In applications involving materials with higher carbon equivalents, careful control of hydrogen levels becomes paramount. The use of these electrodes provides a safeguard against potential defects that might arise, ensuring that the welding process is not only efficient but also produces durable and reliable welds that are essential for in-service operations.