| 摘要 |
<p>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.</p> |
