Which condition prohibits welding due to surface condition?

Which condition prohibits welding due to surface condition?

• A. Inclement weather
• B. Ambient temperature
• C. Base metal is wet
• D. Good lighting

Answer: (C)

Welding relies on a clean, dry surface. When the base metal is wet, the moisture can turn to steam in the heat of the weld and release hydrogen into the molten metal. The hydrogen can become trapped as porosity or cause hydrogen-induced cracking as the weld cools, weakening the joint. Because of this surface condition, welding should not be performed on a wet base metal. Environmental factors like weather or lighting don’t describe the metal’s surface condition in the same way, so they don’t inherently prohibit welding for surface-related quality reasons.

Welding relies on a clean, dry surface. When the base metal is wet, the moisture can turn to steam in the heat of the weld and release hydrogen into the molten metal. The hydrogen can become trapped as porosity or cause hydrogen-induced cracking as the weld cools, weakening the joint. Because of this surface condition, welding should not be performed on a wet base metal. Environmental factors like weather or lighting don’t describe the metal’s surface condition in the same way, so they don’t inherently prohibit welding for surface-related quality reasons.