A stray arc can cause which type of weld imperfection?

A stray arc can cause which type of weld imperfection?

• A. Metallurgical notch
• B. Porosity
• C. Hydrogen embrittlement
• D. Lamellar tearing

Answer: (A)

Stray arc changes heat input where you don’t intend it, altering the microstructure in the weld and heat-affected zone near the toe. That abrupt, localized metallurgical change creates a stress‑concentrating region—a metallurgical notch—that weakens toughness and can become a crack initiation site under load. Porosity comes from gas entrapment in the weld metal, hydrogen embrittlement from hydrogen within steel, and lamellar tearing from welds in thick, restrained plates; these defects arise from different mechanisms and aren’t directly caused by stray arc wandering. So the stray arc most directly leads to a metallurgical notch.