| 摘要 |
PURPOSE:To obtain the steel excellent in strength, ductility, and toughness by a procedure in which an 18Ni type maraging steel composed of specific components, e.g., Ni, Co, etc., is subjected to solution heat treatment and then to cold plastic processing, reverse transformation treatment, aging treatment, etc., by given methods. CONSTITUTION:The 18Ni type maraging steel, composed of 16-20% Ni, 6-13% Co, 2-6% Mo, 0.1-2% Ti, 2% Al, and the balance Fe, is subjected to the usual solution heat treatment, to cold plastic processing by cooling it to room temperature, for example, in a martensitic state, to transformation heat treatment to form reverse transformed austenite in its partial part, to a recold treatment in two- phase mixed state consisting of a martensite phase and an austenite phase, and then to an usual aging treatment. Thus, a steel which is excellent in strength, ductility, and toughness can be obtained, which could not ogtained by the conventional heat treating method. |
