| 摘要 |
PURPOSE:To provide superior wear resistance to a usual rail by strongly cooling the austenitized rail head with water; removing water adhered; and transforming the structure of the rail surface layer into fine pearlite after heat recuperation. CONSTITUTION:The rail head is heated to above the Ac3 point and strongly cooled to 600 deg.C- above the Ms point at the rail surface by mist jet cooling under control so that ferrite or bainite transformation does not occur at a predetermined depth position under the rail surface layer. The cooled head is sprayed with hot steam to remove water adhered by the mist jet cooling as well as to carry out slow cooling. After heat recuperation the structure of the rail surface layer is isothermal-transformed into fine pearlite in the temp. range of 420-600 deg.C. By this method quenching end point and slow cooling can be controlled, and a fine pearlite transformation region can be determined assuredly, resulting in a rail with superior wear resistance. |
