Which gas is used as the oxidizer in cutting torch operations?

• A. Argon
• B. Nitrogen
• C. Oxygen
• D. Hydrogen

Answer: (C)

In oxy-fuel cutting, the oxidizer is the gas that provides oxygen to support the combustion that actually enables the cut. Oxygen is used because it readily reacts with the hot metal to produce a very high flame temperature, which melts or oxidizes the steel and allows the cut to form. Argon and nitrogen are inert or shielding gases and don’t promote the cutting reaction. Hydrogen is a fuel gas, not the oxidizer, so it wouldn’t supply the needed oxygen for the cutting process. That's why oxygen is the oxidizer used.