Aldur 550 steels (minimum yield strength of 550 MPa, or 80 ksi, for thicknesses up to 50 mm, or 2 in.) are a part family of water-quenched, high-strength, fine-grained steels that have excellent toughness at low temperatures. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on low temperature performance. Filing Code: SA-851. Producer or source: Voestalpine Grobblech GmbH.