Which statement correctly describes cleaning steel prior to TIG welding?

• A. Grinder or acetone wipe
• B. Water washing only
• C. Sanding with a file only
• D. Air-drying with no cleaner

Answer: (A)

Cleaning the steel surface thoroughly before TIG welding is essential to remove oils, grease, moisture, and oxide films that can cause porosity and weak welds. Using a grinder helps physically remove oxide scales and contaminants, giving a fresh, clean metal surface. Following that with an acetone wipe dissolves oils and grease and evaporates quickly, leaving a clean, dry surface ready for welding. Water washing is not suitable because moisture can be trapped and introduce hydrogen-related porosity; sanding with a file may not fully remove oxides or grease and can leave scratches or embedded particles; air-drying with no cleaner leaves oils and moisture that can contaminate the weld.