The cutting oxygen valve is opened when?

The cutting oxygen valve is opened when?

• A. As the cutting tip is brought near to the base metal
• B. When the base metal begins to melt or reaches its ignition point
• C. When the metal turns a near-white color
• D. When tip angle and distance are correct

Answer: (B)

In oxy-fuel cutting, you open the cutting oxygen when the base metal has been heated to a temperature where oxidation will sustain itself—essentially when the metal begins to melt or reaches its ignition point. At that moment, the oxygen jet can maintain the burning and blow away the molten oxide to create a clean cut. Opening the valve too early won’t sustain the cut and can cause instability, while waiting until ignition ensures the reaction continues smoothly once cutting starts. Flame angle and distance matter for getting to that ignition-ready state, but the critical trigger is having the metal hot enough to ignite.

In oxy-fuel cutting, you open the cutting oxygen when the base metal has been heated to a temperature where oxidation will sustain itself—essentially when the metal begins to melt or reaches its ignition point. At that moment, the oxygen jet can maintain the burning and blow away the molten oxide to create a clean cut. Opening the valve too early won’t sustain the cut and can cause instability, while waiting until ignition ensures the reaction continues smoothly once cutting starts. Flame angle and distance matter for getting to that ignition-ready state, but the critical trigger is having the metal hot enough to ignite.