NITRODUR 8523 (40CrMoV13-9, 1.8523) is one of the Nitrodur family of nitriding steels that are used where high surface hardness and good fatigue strength are required and the material is also subjected to high temperatures. Nitrided surfaces maintain their hardness and strength at operating temperatures of up to approximately 500–550 deg C (932–1022 deg F). This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as casting. Filing Code: SA-806. Producer or source: Schmolz + Bickenbach Group.