CARPENTER O-1 is a nondeforming die steel that can be oil hardened safely even in intricate sections. It is made from billets that are 100% acid-disc inspected and ultrasonically tested to insure sound metal in the finished bars. It may be classified as a general-purpose tool and die steel. Among its many uses are dies for a variety of purposes, master tools, broaches and thread gages. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, and deformation. It also includes information on forming, heat treating, machining, and surface treatment. Filing Code: TS-333. Producer or source: Carpenter.