What does a stray arc cause?

What does a stray arc cause?

• A. Metallurgical notch
• B. Crack
• C. Porosity
• D. Undercut

Answer: (A)

A stray arc introduces unintended, localized heat into the weld area, which disrupts the metal’s microstructure near the weld. That localized overheating and rapid cooling can create a small, notch-like irregularity in the heat-affected zone—a metallurgical notch. This type of defect acts as a stress concentrator and can weaken the joint, especially under cyclic loading. Porosity comes from gas entrapment, undercut from excessive heat or poor technique at the toe, and cracks come from tensile stresses or hydrogen-related cracking; these are not the direct result of a stray arc.

A stray arc introduces unintended, localized heat into the weld area, which disrupts the metal’s microstructure near the weld. That localized overheating and rapid cooling can create a small, notch-like irregularity in the heat-affected zone—a metallurgical notch. This type of defect acts as a stress concentrator and can weaken the joint, especially under cyclic loading.

Porosity comes from gas entrapment, undercut from excessive heat or poor technique at the toe, and cracks come from tensile stresses or hydrogen-related cracking; these are not the direct result of a stray arc.