NASCLA Accredited Commercial General ContractorMetalsMedium
A welding inspector is reviewing a Welding Procedure Specification (WPS) for a structural steel project. The WPS specifies the use of Shielded Metal Arc Welding (SMAW) with E7018 electrodes. What is the primary characteristic of E7018 electrodes that makes them a common choice for structural steel applications, especially where ductility, toughness, and good weldability in all positions are required?
- AThey are specifically designed for high-speed, flat-position welding.
- BThey are suitable only for thin-gauge metals due to their fast-freezing slag.
- CThey produce a high deposition rate with minimal slag.
- DThey are low-hydrogen electrodes, offering excellent mechanical properties and crack resistance.
Show answer & explanationAnswer & explanation
Correct answer: D. They are low-hydrogen electrodes, offering excellent mechanical properties and crack resistance.
E7018 electrodes are 'low-hydrogen' type, which means they produce welds with very low hydrogen content. This characteristic is crucial for structural steel as it significantly reduces the risk of hydrogen-induced cracking, leading to welds with excellent ductility, toughness, and impact strength, even in all welding positions.
Why the other options are wrong
- A. E7018 are excellent all-position electrodes, not limited to flat position, and while efficient, 'high-speed' is not their defining characteristic.
- B. E7018 electrodes are widely used for heavy structural steel and can be used on thicker sections, not just thin-gauge metals, and their slag is not fast-freezing in the same way as, for example, E6010.
- C. While E7018 can have good deposition, their primary appeal isn't minimal slag or highest deposition rate, which is often associated with flux-cored or submerged arc welding.
E7018 Electrodes
A type of low-hydrogen SMAW electrode commonly used for structural steel. The '70' indicates 70,000 psi tensile strength, '1' indicates all-position, and '8' denotes low-hydrogen flux.
- Low-hydrogen characteristic prevents hydrogen-induced cracking.
- Provides excellent ductility, toughness, and impact strength.
- Suitable for all welding positions and heavy sections.
Memory trick: E7018: Excellent Toughness, Low Hydrogen, All-Positions.