Which flame type is produced when acetylene is in excess in an oxy-acetylene flame?

Which flame type is produced when acetylene is in excess in an oxy-acetylene flame?

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

Answer: (D)

Excess acetylene creates a carburizing flame because there isn’t enough oxygen to fully burn all the fuel. When fuel burns with insufficient oxidizer, combustion is incomplete and carbon-rich byproducts (soot and carbon monoxide) build up in the flame. That carbon-rich environment deposits carbon onto the workpiece, which is why this flame type is called carburizing. In welding or heating, a neutral flame (balanced oxygen and acetylene) is usually preferred, while an oxidizing flame comes from excess oxygen and a cleaner, hotter burn; the carburizing flame specifically arises from too much fuel.

Excess acetylene creates a carburizing flame because there isn’t enough oxygen to fully burn all the fuel. When fuel burns with insufficient oxidizer, combustion is incomplete and carbon-rich byproducts (soot and carbon monoxide) build up in the flame. That carbon-rich environment deposits carbon onto the workpiece, which is why this flame type is called carburizing. In welding or heating, a neutral flame (balanced oxygen and acetylene) is usually preferred, while an oxidizing flame comes from excess oxygen and a cleaner, hotter burn; the carburizing flame specifically arises from too much fuel.