Bainite type rail excellent in surface fatigue damage resistance and wear resistance

Abstract

High-strength bainitic steel rails have improved resistances to surface fatigue failures and wear required of the head of rails for heavy-load service railroads. The high-strength bainitic steels rails having excellent resistances to surface fatigue failures and wear contain constituents of specific ranges and consisting of bainitic structures at least in part are characterized in that the total area occupied by carbides whose longer axes are 100 to 1000 nm in a given cross section of said bainitic structures accounts for 10 to 50 percent thereof.

Description

field of invention [0001] The invention relates to a high-strength bainitic steel rail, which has good surface fatigue damage resistance, wear resistance and metal plastic deformation, and the rail head used for the railway guide rail in the heavy operation system needs to have these properties. Background of the invention [0002] Heavy-running railway systems abroad have been increasing train speeds and wagon load capacity as a measure to improve the efficiency of the freight transport system. This improvement in performance was achieved through a more stringent operating environment, which in turn required further improvements in rail quality. In such an environment, particularly rails used in curved sections of railways, their gauge bends and their head sides quickly wear out, and this wear seriously affects the operating life of the rails. However, the strengthening heat treatment technology developed in recent years, which will be described below, can be used to prepa...

AI Technical Summary

Problems solved by technology

The study reveals that when the area occupied by hard carbides of ideal size on a given section is smaller than a certain limit value, hard carbides important for the wear resistance of bainitic steels are difficult to Build up under the rolling surface, thus reducing wear resistance

On the other hand, when the number of hard carbides with the desired size exceeds a certain limit, the toughness of the bainite structure decreases and the chance of spalling and other delamination damage may increase

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