Latrobe BR-4 is a high-vanadium, high-chromium tool and die steel of the air hardening and nondeforming type. In the hardened condition it is extremely abrasion resistant. This datasheet provides information on composition and hardness as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: TS-1. Producer or source: Latrobe Steel Company.