| 摘要 |
The invention relates to a method for producing martensitic steel that comprises a content of other metals such that the steel can be hardened by an intermetallic compound and carbide precipitation, with an Al content of between 0.4% and 3%, comprising the following steps: (a) heating the entirety of the steel above its austenizing temperature, (b) cooling said steel approximately to ambient temperature, (c) placing said steel in a cryogenic medium. The temperature T1 is substantially lower than the martensitic transformation temperature Mf, and the time t during which said steel is kept in said cryogenic medium at a temperature T1 from the moment when the hottest part of the steel reaches a temperature lower than the martensitic transformation temperature Mf is at least equal to a non-zero time t1, the temperature T1 (in ° C.) and the time t1 (in hours) being linked by the equation T1=ƒ(t1), the first derivative of the function f relative to t, ƒ′(t), being positive, and the second derivative of ƒ relative to t, ƒ″(t), being negative. |
