| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a maraging steel having an excellent fatigue resistance. SOLUTION: Before applying a hardening heat-treatment, a strip steel or a steel slab is subjectedc to a cold-plastic deformation at >30% cold-working ratio, and fine crystal particle having >8 ASTM index, is obtained and the chemical composition of a maraging steel is composed by wt.% of 12-24.5% Ni, 2.5-12% Mo, 4.17-20% Co,≤0.15% Al,≤0.1% Ti,≤0.0003% N,≤0.1% Si,≤0.1% Mn,≤0.005% C,≤0.001% S,≤0.005% P,≤0.0003% H,≤0.001% O and the balance Fe with impurities depending to the refining and further, the following chemical compositions satisfies the following relationships: 20%≤Ni+Mo≤27%, 50≤Co×Mo≤200, Ti×N≤20×10<SP>-4</SP>. COPYRIGHT: (C)2009,JPO&INPIT
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