The temperature of a neutral oxy-acetylene flame is approximately?

• A. 3,000 F
• B. 4,500 F
• C. 5,500 F
• D. 7,000 F

Answer: (C)

Neutral oxy-acetylene flame reaches its high temperature by balancing fuel and oxygen so there’s no excess of either gas. That balanced, or neutral, condition produces a flame ish around five and a half thousand degrees Fahrenheit (roughly 3,000 °C). That temperature range is what you’d expect for the neutral flame and is hot enough to weld most metals effectively without causing too much oxidation or carburization.

The cooler values shown would be too low for the neutral flame and wouldn’t provide the same welding performance, while the higher value sits above the typical neutral range and would imply a hotter condition or a different flame type. So, around 5,500 °F is the best approximation for a neutral oxy-acetylene flame.