C-Masteralloy An Innovative Approach To Introduce Carbon In PM-steels

The standard process to introduce carbon into PM-steels is to admix fine graphite to the base powder. Prealloying is usually not an option since compressibility of the powder would suffer extremely. However, it has been shown in previous work that the masteralloy approach is an interesting alternative to the use of graphite. As the Fe-C-masteralloy is designed to have comparable density to the base powder, the problems of powder segregation during mixing, dusting during the filling process and formation of secondary porosity due to the low density of the graphite can be avoided.

The new method of ultra-high pressure water atomization opens the possibility to produce Fe-C masteralloys in the desired size and shape. The present paper compares the behaviour of Fe-0.6%C produced by standard techniques with the master alloy approach. It is shown that although the compressibility differs slightly the material properties reach the same level for both approaches.