ATHA PNEU is a shock resistant tool and die steel designed for applications requiring extreme toughness combined with good wear resistance and cutting properties. It conforms to AISI Type S1, SAE Type S1 and ASM Class III-D. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and machining. Filing Code: TS-76. Producer or source: Crucible Steel Company of America.