Patent ID: 7323070

Claim:
A process for producing a maraging steel excellent in fatigue characteristics which comprises: melting steel having a composition consisting essentially of, in % by weight: C: 0.01% or less, Ni: 8-19%, Co: 8-20%, Mo: 2-9%, Ti: 0.1-2%, Al: 0.15% or less, N: 0.003% or less, O: 0.0015% or less, and the balance Fe; casting the molten steel to obtain a steel ingot; hot forging the steel ingot at a forging ratio of at least 4 to obtain a forged piece; then submitting said forged piece to soaking treatment by keeping the forged piece one or more times at a temperature range of 1100-1280° C. for a total hot holding time of 10-100 hours, to make the Ti component segregation ratio and the Mo component segregation ratio in a structure of said forged piece be 1.3 or less each; and then plastic working the forged piece.