BAINITIC RAIL EXCELLENT IN RESISTANCE TO ROLLING FATIGUE DAMAGE AND INTERNAL FATIGUE DAMAGE AND WELDED JOINT PROPERTIES, AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a bainitic rail in which rolling fatigue damage such as dark spot damage that has been a problem in the present rail steel of pearlitic structure is prevented and the occurrence of internal fatigue damage in a railhead is suppressed, and simultaneously, reduction of hardness in a welded-joint heat-affected zone and also a region thereof are reduced and local wear in a railhead surface part is suppressed.;SOLUTION: The rail has a composition consisting of, by mass, 0.15-0.55% C, 0.10-2.00% Si, 0.20-3.00% Mn, 0.20-3.00% Cr, 0.01-0.30% V, 0.01-0.50% Nb and the balance Fe with inevitable impurities and satisfying V+10×Nb=0.14 to 0.50. Moreover, at least the region within 20 mm from the surface of railhead corners and top part of railhead shows a baintic structure, and further, handness is HV 330 to 500 and the difference in hardness is ≤ HV 50.;COPYRIGHT: (C)2001,JPO