Nitralloy

the generic name of a group of structural steels used to manufacture nitrided parts. The main alloying elements of nitralloys are aluminum, chromium, molybdenum, and vanadium, which form fine-crystalline hard nitrides that impart a high hardness (Vickers hardness, up to 1200) and wear resistance to the nitrided surface layer. The most common nitralloys in the USSR are 38KhMIuA and 38KhIu steels. Type 38KhMIuA steel, which is used in the manufacture of critical parts, contains 0.15–0.25 percent molybdenum, in addition to aluminum and chromium. The molybdenum increases hardenability, moderately improves the ultimate strength of the core of the part, and prevents the development of temper brittleness during nitriding.