What is the result of a stray arc?

• A. Metallurgical notch
• B. Porosity
• C. Weld toe crack
• D. Lack of fusion

Answer: (A)

When a stray arc occurs, heat is applied to areas outside the intended weld joint, especially near the weld toe. This localized heating changes the metal’s microstructure in the heat-affected zone, creating a sharp, notch-like discontinuity. That metallurgical notch becomes a stress concentrator, which weakens the joint and can be a source of failure under load. It’s different from porosity (gas pockets in the weld metal), lack of fusion (insufficient bonding to the base metal), or a weld toe crack (a crack that forms at the weld toe). So the stray arc most appropriately results in a metallurgical notch.