JESSOP No. 9, super high tensile steel, is one of the toughest and most wear resistant steels of its class in existence. Primarily developed as a high tensile, non-magnetic armor plate, it has since been widely used for equipment subject to severe battering. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: SA-457. Producer or source: Jessop Steel Company.