As the most widely applied material in the world, steel has been well studied for over hundred years. Many processing methods have been applied to improve its structure and properties. To control the properties of steels, the cold work such such as rolling and drawing was performed together with other treatments. However, the grain size of such treated steels is generally at the range of micrometers. It is expected that further improvement of steels can be achieved by obtaining nanostructure by heavy cold work, e.g. ball milling of powders.
The present study is devoted to the obtaining nanocrystalline structure in ball milled powders of various steels. For carbon steels the formation of nanoferrite and dissolution of carbides was observed. The obtained nanoferrite was characterized by grain size, strain and lattice parameter calculations. In the case of austenitic stainless steel subjected to ball milling, strain-induced transformation leading to the martensite formation was observed. The thermal stability of the obtained nanostructures was also studied.