Decarburisierung

Decarburisation is a metallurgical process that involves the removal of carbon from the surface of a metal, typically steel. This phenomenon occurs when the metal is heated to high temperatures in the presence of an oxidizing atmosphere, such as air or steam. The carbon atoms at the surface react with the oxygen, forming gaseous carbon oxides (carbon monoxide or carbon dioxide) which then escape from the metal.

The depth and extent of decarburisation depend on several factors including temperature, time, the composition of the atmosphere, and the carbon content of the steel. Higher temperatures and longer exposure times generally lead to deeper decarburisation. The process can be detrimental to the mechanical properties of steel components, as it can reduce surface hardness and wear resistance. This is because the decarburised layer is softer and weaker than the bulk material.

To mitigate decarburisation, various strategies can be employed. These include heat treating steel in a non-oxidizing atmosphere, such as a vacuum or a controlled inert gas environment. Surface treatments, like plating or coating, can also act as a barrier to prevent oxidation. In some applications, such as tool steels, selective decarburisation might even be intentionally controlled to achieve specific surface characteristics. Understanding and controlling decarburisation is crucial in many manufacturing processes to ensure the integrity and performance of steel parts.