AWS Certified Welding Inspector — FundamentalsWelding ProcessesMedium
A CWI is evaluating a Weld Procedure Specification (WPS) for the repair of heavy machinery components using Shielded Metal Arc Welding (SMAW). The WPS specifies the use of E7018 electrodes. What is the most critical handling and storage requirement for E7018 electrodes to ensure weld quality?
- AThey must be kept in an electrode oven at a minimum temperature of 250°F (121°C) after opening.
- BThey should be used within 24 hours of opening the hermetically sealed container.
- CThey must be stored in a cool, dry place away from direct sunlight.
- DThey require re-baking if exposed to the atmosphere for extended periods to remove absorbed moisture.
Show answer & explanationAnswer & explanation
Correct answer: A. They must be kept in an electrode oven at a minimum temperature of 250°F (121°C) after opening.
E7018 electrodes are low-hydrogen electrodes, meaning their flux coating is designed to minimize hydrogen content in the weld. To maintain this low hydrogen characteristic, they must be stored in heated electrode ovens (holding ovens) at specified temperatures after the hermetically sealed container is opened, to prevent moisture absorption.
Why the other options are wrong
- B. While some specifications might have time limits, the most critical and continuous requirement is heated storage to prevent moisture absorption, which is key to their low-hydrogen characteristic.
- C. While generally good practice for all electrodes, it is insufficient for the specific low-hydrogen requirements of E7018.
- D. Re-baking is required if they absorb moisture, but the primary preventative measure after opening is continuous storage in a heated oven.
E7018 Electrode Handling
E7018 electrodes are low-hydrogen electrodes requiring strict moisture control. After opening, they must be stored in heated holding ovens to prevent hydrogen-induced cracking.
- Low-hydrogen type electrode.
- Susceptible to moisture absorption from the atmosphere.
- Moisture introduces hydrogen into the weld, causing hydrogen-induced cracking.
- Requires storage in heated holding ovens (250-300°F) after opening.
- Re-baking at higher temperatures (700-800°F) is needed if moisture absorbed.
Memory trick: Low-hydrogen electrodes crave heat, keeping moisture at bay, preventing cracks from a bad day.