What is the most common residue left from Oxy Cutting?

• A. Soot
• B. Scale
• C. Dross
• D. Slag

Answer: (D)

Oxy cutting leaves slag as the common residue because the flame’s oxygen rapidly oxidizes the metal, producing iron oxide that becomes molten and flows away from the cut. This molten oxide then solidifies along the kerf as a layer of slag, which is the typical byproduct you see after a cut. Soot would indicate incomplete combustion and isn’t the characteristic residue of the cutting process. Scale refers to oxide already formed on the hot surface and isn’t the distinctive byproduct carried away from the cut. Dross is more associated with melting operations where impurities float on molten metal, not with the typical slag formed during oxy-fuel cutting. So the residue you most commonly deal with after oxy cutting is slag.