When piercing steel plate with a cutting torch, the cutting oxygen valve should be opened during the preheating of the base metal to provide more heat.

When piercing steel plate with a cutting torch, the cutting oxygen valve should be opened during the preheating of the base metal to provide more heat.

• A. True
• B. False
• C. Only after preheating
• D. Only during piercing

Answer: (B)

In oxy-fuel cutting, you want to heat the metal to its ignition temperature using a fuel-gas flame before you start the actual cut. The cutting oxygen is what drives the oxidation that creates the cut, so it should be reserved for the moment you begin cutting, not used during preheating. If the cutting oxygen is opened during preheating, the metal would start to burn in an uncontrolled way, making the heating heatup hard to control and likely producing excessive heat, rough edges, or excessive kerf. Keep the cutting oxygen off or at a very low level during preheating, and open it only to start and maintain the cut once the base metal has reached ignition temperature.

In oxy-fuel cutting, you want to heat the metal to its ignition temperature using a fuel-gas flame before you start the actual cut. The cutting oxygen is what drives the oxidation that creates the cut, so it should be reserved for the moment you begin cutting, not used during preheating. If the cutting oxygen is opened during preheating, the metal would start to burn in an uncontrolled way, making the heating heatup hard to control and likely producing excessive heat, rough edges, or excessive kerf. Keep the cutting oxygen off or at a very low level during preheating, and open it only to start and maintain the cut once the base metal has reached ignition temperature.