| 摘要 |
PROBLEM TO BE SOLVED: To enable utilization of contained elements restraining the micro- segregation and improving the strength by applying a working having >=5% plastic deforming ratio in the austenitic range to a continuously cast bloom completing the solidification, heating to a prescribed temp. add rolling to a target shape. SOLUTION: Since the steel cast bloom after the continuous casting is cooled to the austenitic developing temp. zone and held to apply the plastic working havxng >=5% plastic deforming ratio, the working strain is effectively added. Thereafter, since this blank is heated to the hot-rolling temp. of 1100-1300 deg.C and rolled to a rail-shape, the micro-segregation of the elements, can effectively be restrained by promoting the diffusion the elements according to the hot- rolling, and the elements of strengthening elements of the rail, such as C, Si, Cr, Mo, can efficiently be utilized. In the production of the high strength rail, the cooling is executed at 2-6 deg.C/sec after hot-rolling to the shape of the rail, and thus, the rail is formed as fine pearlite structure or bainite structure and the high strength and high hardness can be obtd. |
