Methane

A colourless and odourless gas with the formula CH4.

It is widely known as natural gas because it is the main constituent (80/95%) of the naturally occurring hydrocarbon gasses often found in association with crude oil and is also emitted by swamps owing to the decomposition of vegetation under the water.

Methane reacts with steel at temperatures above 800oC and imparts carbon into its surface and so is frequently used as one of the additions to heat treatment atmospheres to control their carbon potential. Being highly flammable, it is also used as the fuel for heating furnaces.