Bainite steel rail and preparation method thereof

Abstract

The invention relates to the field of steel rail materials and discloses a bainite steel rail and a preparation method thereof. On the basis of the weight of the bainite steel rail, the content of a bainite ferrite strip in a microscopic structure of a fillet part on a rail head of the bainite steel rail is more than or equal to 90wt% and the width of the bainite ferrite strip is 0.3-0.8 mu m; the content of a film-shaped retained austenite is less than or equal to 5wt% and the width of the film-shaped retained austenite is less than 0.1 mu m; the content of martensite is less than or equal to 5wt%; the chemical components of the billet steel of the acquired bainite steel rail meet the following conditions: on the basis of the weight of the bainite steel rail, the billet steel contains 0.20-0.30wt% of C, 1.40-1.60wt% of Si, 1.85-2.05wt% of Mn, 1.00-1.25wt% of Cr, 0.30-0.50wt% of Mo and 0.07-0.09wt% of V, wherein Mn+Cr is more than or equal to 3.1wt% but less than or equal to 3.3wt%. The bainite steel rail has excellent toughness performance and service safety.

Description

technical field [0001] The invention relates to rail materials, in particular to a bainite rail and a preparation method thereof. Background technique [0002] The continuous improvement of the axle load and transportation volume of railways has put forward higher requirements for the service performance of steel rails. Heavy-duty railways with an annual transportation volume of more than 200 million tons, especially small curve radius sections, have become the hardest hit areas for rail damage. Rail service The service life usually does not exceed 3 years, and some road sections with harsh conditions are even less than one year, which is difficult to match with adjacent straight sections and large-radius curved road sections. Frequent replacement of rails not only greatly increases the maintenance cost of the line and the labor intensity of workers, but also causes rapid damage Development also brings serious hidden dangers to traffic safety. After more than 100 years of d...

AI Technical Summary

Problems solved by technology

[0002] The continuous improvement of the axle load and transport volume of railways has put forward higher requirements for the service performance of steel rails. Heavy-duty railways with an annual transport volume of more than 200 million tons, especially small curve radius sections, have become the hardest hit areas for rail damage. Rail service The service life usually does not exceed 3 years, and some road sections with harsh conditions are even less than one year, which is difficult to match with adjacent straight sections and large-radius curved road sections. Frequent replacement of rails not only greatly increases the maintenance cost of the line and the labor intensity of workers, but also causes rapid damage Development also brings serious hidden dangers to traffic safety

Studies have shown that although this production method is beneficial to the performance of the steel rail, the content of alloying elements such as Ni, V, and Nb in the steel is relatively high, resulting in a substantial increase in the production cost of the steel rail; The difference in cooling rate between the surface layer and the core of the rail, especially the rail head, will lead to bending of the rail and a substantial increase in residual stress. Even through subsequent isothermal and tempering treatments, ideal stress indicators cannot be obtained; Quenching, one isothermal treatment and one tempering treatment, the production cycle of the rail is significantly extended and the cost of energy consumption increases

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