Jessair is a manganese, chromium, molybdenum alloy steel combining the deep harding characteristics of air-hardening steels with the simplicity of low temperature heat treatment possible in many oil-hardening steels. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and bend strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: TS-157. Producer or source: Jessop Steel Company.