In oxy-acetylene welding, what flame type results from an acetylene-rich mixture?

In oxy-acetylene welding, what flame type results from an acetylene-rich mixture?

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

Answer: (C)

When you adjust the ratio of oxygen to acetylene, the type of flame changes. If you have more acetylene than oxygen, not all the fuel can burn, and the flame becomes carburizing (a reducing flame). This condition introduces carbon to the metal surface, can leave a sooty flame, and may cause carbon pickup in the weld. That’s why an acetylene-rich mixture yields a carburizing flame. An oxidizing flame comes from excess oxygen and tends to oxidize the surface, a neutral flame is balanced for clean welding, and the invisible flame isn’t the typical result described for acetylene-rich conditions.

When you adjust the ratio of oxygen to acetylene, the type of flame changes. If you have more acetylene than oxygen, not all the fuel can burn, and the flame becomes carburizing (a reducing flame). This condition introduces carbon to the metal surface, can leave a sooty flame, and may cause carbon pickup in the weld. That’s why an acetylene-rich mixture yields a carburizing flame. An oxidizing flame comes from excess oxygen and tends to oxidize the surface, a neutral flame is balanced for clean welding, and the invisible flame isn’t the typical result described for acetylene-rich conditions.