| 摘要 |
The invention concerns a method for making a strip or a workpiece cut out from a cold rolled maraging steel strip and hardened by a hardening heat treatment, which consists, prior to the heat treatment, in subjecting the strip or the workpiece to cold plastic deformation with a rate of strain hardening more than 30 % and in subjecting the strip or the workpiece to a recrystallization annealing so as to obtain a fine grain of ASTM index more than 8. The maraging steel composition comprises, by weight: 12 % <= Ni <= 24.5 %; 2.5 % <= Mo <= 12 %; 4.17 % <= Co <= 20 %; Al <= 0.15 %; Ti <= 0. 1 %; N <= 0.003 %; Si <= 0.1 %; Mn <= 0.1 %; C <= 0.005 %; S <= 0.001 %; P <= 0.005 %; H <= = 0.0003 %; O <= 0.001 %; the rest being iron and impurities resulting from preparation of the composition, the composition further satisfying the following relationships: 20 % <= Ni + Mo <= 27 %; 50 <= Co x Mo <= 200<; Ti x N <= 2 x 10-4. The invention also concerns the resulting strip.
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