ALMAR 300 Alloy is a vacuum-melted ultra-high-strength steel. The annealed structure of this alloy is essentially a carbon-free, iron-nickel martensite (a relatively soft Rockwell C 28) that can be strengthened by cold working and elevated-temperature (900-950 F) age hardening to useful yield strengths as high as 300,000 psi. The unique properties of this alloy make it suitable for a wide range of section sizes. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-349. Producer or source: Allegheny Ludlum Corporation.