For low hydrogen electrodes with designators higher than E49 that are to be re-baked, what is the temperature range and minimum time?

• A. 370-430 C for 30 minutes
• B. 200-250 C for 2 hours
• C. 500-600 C for 2 hours
• D. 370-430 C for at least 1 hour

Answer: (D)

Moisture in low-hydrogen electrodes is a major reason for hydrogen-induced cracking in welds, so re-baking is used to drive the moisture out and restore the electrode’s low-hydrogen characteristics. For electrodes with designators higher than E49, the recommended bake is in the range of 370–430 C for a minimum of one hour. This temperature band is hot enough to desorb moisture from the coating and core without risking damage to the electrode’s flux or coating, which could alter weld metal behavior. Baking at a lower temperature won’t remove moisture effectively, while baking much hotter (like 500–600 C) could degrade the electrode. A bake time shorter than one hour may not allow sufficient moisture to diffuse out, so the one-hour minimum ensures adequate drying. After baking, store or use the electrodes promptly in a dry environment to maintain their low-hydrogen characteristics.