The paper presents the procedure and different types of nitration as well as properties and application of nitride layers. Nitration is defined as a chemical procedure of modification of the surface whereby the surface layer of steel is enriched with nitrogen with the aim of enhancing hardness and dynamic solidity as well as wear resistance and corrosion resistance. There are three types of nitration processes: gas nitration, aromatic nitration and plasma nitration. The paper exhibits the exact course of procedure along with the crucial parameters (time, temperature etc.), the process of inserting nitrogen into the surface layers of steel including the properties of steel after the nitration process for each of the nitration procedures. All types of steel can be subdued to the nitration process depending on their application and characteristics. However, it is preferable to choose the type which contains substances that form nitrides easily. In addition, further explanation of the control properties of nitride surfaces will be provided. It is of outmost importance to determine ne depth of the nitrated layer along with the hardness of the surface layer of steel in order to be able to properly test its features and determine whether steel has developed wanted properties through the nitration process. At the end of the paper, in the experimental part, a procedure for testing microstructure and hardness on cold working steel 40CrMnMo7.