AWS Certified Welding Inspector — FundamentalsWelding ProcessesEasy
A welding inspector is reviewing a weld procedure specification (WPS) for a structural steel project. The WPS specifies using Gas Metal Arc Welding (GMAW) with a short-circuit transfer mode. Which of the following is a primary limitation of the short-circuit transfer mode that the inspector should be aware of?
- ALimited to thin materials and prone to lack of fusion on thick sections.
- BHigh heat input, leading to excessive distortion.
- CSignificant spatter generation, requiring extensive post-weld cleaning.
- DInability to weld in out-of-position applications.
Show answer & explanationAnswer & explanation
Correct answer: A. Limited to thin materials and prone to lack of fusion on thick sections.
Short-circuit GMAW is characterized by low heat input and is generally suitable for thin materials. Its low penetration makes it prone to lack of fusion when used on thick sections, which is a critical limitation for structural applications.
Why the other options are wrong
- B. Short-circuit GMAW is known for its low heat input, not high, which helps in minimizing distortion.
- C. While spatter can occur, it is not the primary limitation compared to penetration issues, and other transfer modes can also generate spatter.
- D. Short-circuit GMAW is actually well-suited for out-of-position welding due to its controlled puddle and low heat input.
GMAW Short-Circuit Transfer Limitations
Short-circuit Gas Metal Arc Welding (GMAW-S) is a low heat input process where the consumable electrode repeatedly contacts the weld puddle, causing a short circuit. Its primary limitation is its suitability for thin materials and susceptibility to lack of fusion on thicker sections due to shallow penetration.
- Low heat input process.
- Electrode repeatedly shorts to the weld puddle.
- Limited to thin materials.
- Prone to lack of fusion on thick sections.
- Good for out-of-position welding.
Memory trick: Spray is fast and hot, Globular is messy and big, Short-circuit is cool and thin.