In the designation E7018-R, the R indicates compliance with what specific test?

• A. Radiographic testing
• B. Magnetic particle testing
• C. Absorbed moisture testing
• D. Ultrasonic testing

Answer: (C)

In this electrode designation, suffixes tell you extra handling or performance requirements for the electrode itself, not the weld you’ll produce. The R signal means the electrode has passed absorbed moisture testing. This test checks how much moisture the electrode material or coating can absorb, which is crucial because moisture can release hydrogen during welding and cause hydrogen-induced cracking in the weld metal. By meeting absorbed moisture requirements, the electrode is kept at a low hydrogen level when used, helping to ensure sound welds on susceptible steels. The other options describe tests used to inspect a completed weld (radiographic, magnetic particle, ultrasonic), not criteria applied to the electrode’s moisture characteristics.