How can you determine if your GMAW settings are producing adequate throat thickness?

• A. By inspecting penetration and bead size with a weld gauge or cross-section checks against the joint design
• B. By measuring arc length with a ruler
• C. By the color of the weld pool
• D. By the time elapsed during welding

Answer: (B)

Throat thickness is checked by looking at the actual weld cross-section to see how much material the weld has deposited and how deeply it has fused into the joint. The reliable way to know if you’ve met the required throat is to inspect penetration and bead size against the joint design, typically with a weld gauge or by cutting a sample and cross-sectioning it. Arc length, measured with a ruler, isn’t a direct or reliable indicator of how thick the throat is, because it affects heat input and bead shape but doesn’t guarantee the cross-sectional thickness. The color of the weld pool and the overall welding time don’t provide dependable information about throat thickness either. The goal is to ensure the minimum throat dimension specified for the joint is met, which is best confirmed through cross-section inspection or appropriate nondestructive testing.