抄録
We have proposed bainitic steel as the most suitable grade steel to prevent rails from initiating darkspots and extend their life based on the results of research and development of new type rails which eliminate contact fatigue layer, a possible start of damage, while promoting wear appropriately. From the field test results of the proposed bainitic rail, we have clarified that the most suitable hardness of the new type rail under the service conditions ranges from 260 HV to 295 HV, in view of wear amount and head check, and in order to diminish irregularity in welded parts of rail head, tolerable scattering range of hardness in manufacturing and so on. On the basis of the obtained test results, we propose a specification of bainitic rail for application. Furthermore, it has been clarified through laying tests in the field that bainitic rails can be welded in order to have practical applicable performance, though welding is more difficult than with standard carbon rails.
