Surface porosity in a weld is caused by insufficient current.

Surface porosity in a weld is caused by insufficient current.

• A. True
• B. False
• C. Porosity is caused by shielding gas flow
• D. Porosity is caused by poor workpiece cleanliness

Answer: (B)

Porosity forms when gas is trapped in the molten weld metal as it solidifies. The shield protecting the weld pool is supposed to keep atmospheric gases out. If shielding gas coverage is inadequate (flow too low, leaks, improper nozzle distance, or drafts) or the workpiece surface is contaminated (oil, dirt, rust, moisture), gas pockets can remain in the bead and show up as surface porosity. Upstream heat input from welding current primarily affects how deeply the metal melts and the bead shape; insufficient current tends to cause lack of fusion or a weak bead rather than creating porosity. So surface porosity is not caused by insufficient current; it’s typically due to shielding gas issues or surface contamination. To prevent it, ensure clean, dry surfaces and proper shielding gas flow and coverage.