Patent ID: 7695576
Filing Date: 2010-04-13
Classification: C21D,C22C

Abstract:
1. A low alloy high speed tool steel, which consists essentially of, by weight %, C: 0.50-0.75%, Si: 0.02-2.00%, Mn: 0.1-3.0%, P: up to 0.050%, S: up to 0.010%, Cr: 5.0-6.0%, W: 0.5-2.0%, V: 0.70-1.25%, Al: up to 0.1%, O: up to 0.01% and N: up to 0.04%, Mo in an amount satisfying the relationship [Mo+0.5W](Mo-eq.) is 2.5-5.0%, and the balance of Fe, wherein Mo-eq./V is 2-4, the steel contains carbides of, in the annealed state, [MC+M the steel has a 10R Charpy impact value equal to or greater than about 120 J/cm the steel has a hardness (HRC) equal to or greater than about 58, and a difference between hardness by oil quenching and hardness by controlled quenching of the steel is less than or equal to 0.5.