| 摘要 |
PURPOSE:To obtain an ultra-high strength steel product having excellent durability by subjecting a steel material containing specific proportions of C, Si, Mn, P, etc., in addition to Fe to a solution heat treatment, cooling, a shot peening treatment, and an aging treatment in order under specific conditions. CONSTITUTION:A steel material, containing 0.03% or less C, 0.10% or less Si, 0.10% or less Mn, 0.010% or less P, 0.010% or less S, 15.0-25.0% Ni, 6-17% Co, 3-10% Mo, 0.03-1.6% Ti, 0.03-1.6% Al, and Fe and inevitable impurities, is subjected to a solution heat treatment at 800-950 deg.C for 30min-5hr and then cooled at a cooling rate faster than air-colling. Then, the steel material is subjected to a shot peening treatment using a metal sphere of HRC of about 30 and then to an antificial aging treatment at 450-540 deg.C for 1-15hr. Thus, an ultra-high strength steel product having excellent ductility and excellent toughness can be obtained. |
