Which type of flame is produced when there is an excess of fuel gas in the mixture?

A carburizing flame is produced when there is an excess of fuel gas in the mixture. This type of flame is characterized by a yellowish or luminous appearance and is commonly used in processes that require a reducing environment. It occurs when the amount of fuel exceeds the amount of oxygen available for combustion, leading to incomplete combustion.

This flame is particularly useful for tasks such as welding certain materials that require a specific heat and reducing atmosphere, preventing oxidation of the material being worked on. The carburizing flame provides additional carbon to the weld area, which can alter the properties of certain metals beneficially.

In contrast, a neutral flame contains a balanced ratio of fuel gas and oxygen, an oxidizing flame has an excess of oxygen leading to a hotter and more intense flame, while a flame-cutting flame is specifically designed for cutting materials, usually using a combination of gases. Thus, the identification of a carburizing flame distinctly reflects the presence of surplus fuel gas in the combustion mixture.