AK Steel 439 Ultra Form (UF) has oxidation resistance and corrosion resistance superior to Type 409. The alloy also has an equiaxed microstructure and improved formability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming and joining. Filing Code: SS-877. Producer or source: AK Steel Corporation.