| 摘要 |
Stainless steel (I) and method of making it are claimed. It comprises (by wt.) 25-35 (esp. 28.5-30.5)% Cr, 3.6-5.6 (esp. 3.75- 4.75)% Mo, less than 3% Ni, less than 2% Mn, less than 2% Si, less than 0.5% Al, less than 0.5% Cu, less than 0.05% P, less than 0.05% S, less than 0.01% C, less than 0.02% N, the sum of C and N being less than 0.025%, 0.05-0.5 (esp. 0.05-0.2)% Nb, and/or Ti, balance Fe. It is hot rolled, annealed, air cooled and then cold rolled to produce a steel with a charpy impact transition temp. of below O deg.F as cold rolled to a thickness of 0.062 ins. The Nb and/or Ti improve the toughness of the steel when the max. achievable cooling rate is limited.
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