Why are low hydrogen SMAW electrodes baked before use?

• A. To dry moisture in the flux coating
• B. To increase weld speed
• C. To improve taste of fumes
• D. To reduce the size of slag

Answer: (A)

Low hydrogen SMAW electrodes have a flux coating that readily absorbs moisture from the air. If the coating is damp, water in the flux can release hydrogen into the weld as it heats, increasing hydrogen content in the weld metal and raising the risk of hydrogen cracking and porosity. Baking the electrodes before use dries out the flux, driving off the absorbed moisture and keeping hydrogen levels low in the weld. This is especially important for high-strength steels and critical joints. Baking temp and time are chosen to effectively remove moisture (typical ranges are around 250–350°F or 120–180°C for several hours), and the electrodes should be kept dry after baking. Baking does not affect weld speed, fumes taste, or slag size.