Aluminum, chromium, vanadium and molybdenum in traditional alloy steel are very helpful for nitriding. At nitriding temperature, these elements will form stable nitrides when they contact with the primary nitrogen atoms. In particular, molybdenum is not only used to form nitride element, but also to reduce brittleness at nitriding temperature. Other elements in alloy steel, such as nickel, copper, silicon and manganese, do not contribute much to nitriding properties.

Generally speaking, if the steel contains one or more nitride forming elements, the effect of nitriding is better. Aluminum is a strong nitride element, containing 0.85 ~ 1.5% aluminum. In the case of chromium containing steel, if there is enough content, it can also get good results. However, carbon steel without alloy is not suitable for nitriding steel because of its brittle nitriding layer and easy peeling off.