| 摘要 |
The invention provides a process for the heat treatment of iron-based alloys, including irons and steels, such as carbon steels and low alloy steels, in a controlled oxidative environment, to modify the microstructure of the metal to obtain both improved mechanical properties and a protective surface oxide scale. In a first high-temperature treatment, a layer of wüstite (FeO) is formed on the surface of the material and austenite forms in the interior of the material. Rapid cooling follows the high temperature treatment so as to preserve the wüstite scale and to obtain at the same time an internal steel microstructure comprising martensite or bainite. In a second step of lower-temperature heat treatment, the scale is transformed so that it comprises an intermediate layer composed predominantly of wüstite (FeO), with a surface of predominantly magnetite (Fe3O4), while the mechanical properties of the material are tailored for specific applications. |
