Excess acetylene in an oxy-acetylene flame most directly leads to which flame?

Excess acetylene in an oxy-acetylene flame most directly leads to which flame?

• A. Oxidizing flame
• B. Neutral flame
• C. Carburizing flame
• D. Invisible flame

Answer: (C)

In oxy-fuel flames, the ratio of fuel to oxygen determines the flame type: oxidizing, neutral, or carburizing. When acetylene is in excess, there isn’t enough oxygen to burn all the fuel completely. The unburned carbon-containing species build up as soot and carbon monoxide, creating a reducing, carbon-rich environment near the work surface. That environment is what we call a carburizing flame, and it can deposit carbon on the metal, changing its surface properties. So excess acetylene directly produces a carburizing flame.

In oxy-fuel flames, the ratio of fuel to oxygen determines the flame type: oxidizing, neutral, or carburizing. When acetylene is in excess, there isn’t enough oxygen to burn all the fuel completely. The unburned carbon-containing species build up as soot and carbon monoxide, creating a reducing, carbon-rich environment near the work surface. That environment is what we call a carburizing flame, and it can deposit carbon on the metal, changing its surface properties. So excess acetylene directly produces a carburizing flame.