Carburizing is a common heat treatment process that is used to increase the depth and surface of a component’s hardness. During the carburizing process, carbon is added to the surface of a more ductile metal (such as steel) which causes it to become harder and more wear resistant. This process is used in a variety of industries, from automotive and aerospace to medical devices and tooling.
The carburizing process begins by heating the component and exposing it to carbon-rich atmosphere. The atmosphere is typically created within a carburizing furnace, or it may be delivered in a controlled manner from a cohesive or gaseous source. The type of atmosphere selected is typically determined by the desired results. Carbon can be added from a carbon monoxide, carbon dioxide, or other sources.
During the carburizing process, the carbon diffuses into the surface of the metal and penetrates the metal’s grain boundaries. The increased carbon concentrations within the surface microstructure alters the properties of the steel, causing it to be more wear resistant and increase its hardness, toughness, and ductility while decreasing its machinability.
Once the carburizing process is complete, the part is typically quenched in oil, water, air, or other cooling mediums to increase their hardness. After the part is quenched and cooled, it is typically tempered. Tempering is accomplished by reheating the part to a temperature below the critical range. This further increases the steel’s toughness without sacrificing hardness.
While the carburizing process itself does not require much in the way of tooling, the quenching and tempering steps do. This can include furnaces for heating and cooling, quenching tanks, tempering ovens and protective cooling systems. Additionally, proper analysis of the components throughout the process can be performed using hardness testing tools, optical microscopes and other metallurgical methods.
Overall, carburizing is a very useful heat treatment process for steels. It can be used to increase a part’s wear resistance, hardness and toughness. In addition, it can also be used to decrease a part’s machinability. However, while this heat treatment process can deliver great results, it is important to keep in mind that proper tooling and analysis is needed in order to ensure quality parts and results.
