A kind of high-strength anti-delayed fracture hot-rolled steel rail and its preparation method

Abstract

The invention relates to the technical field of rail preparation, and discloses a high-strength delayed-fracture-resistant hot-rolled rail and a preparation method thereof. The method includes converter or electric furnace smelting, aluminum-free deoxidation, LF refining, RH or VD vacuum treatment, continuous casting, continuous cooling, furnace heating, on-line rolling and post-treatment; the continuous cooling process of steel billet includes: (1) the surface temperature Perform the first-stage cooling for the billet at 830-900°C, and cool the billet to a surface temperature of 350-500°C at a cooling rate of 0.3-1.3°C / s; Cool the billet to a surface temperature of 150-250°C at a cooling rate of ‑1°C / s; (3) Perform a third-stage cooling of the billet and cool the billet to a surface temperature of 50 at a cooling rate of 0.1‑0.8°C / s ‑150°C. The delayed fracture resistance of the hot-rolled rail obtained by the invention is significantly improved.

Description

technical field [0001] The invention relates to the technical field of rail preparation, in particular to a high-strength delayed-fracture-resistant hot-rolled rail and a preparation method thereof. Background technique [0002] The development of high-speed and heavy-haul railways has put forward higher requirements for the comprehensive service performance of rails. With the further requirements for driving safety, abnormal fatigue, excessive wear and sudden fracture of rails in service have been strictly restricted. my country's existing high-speed railways mainly use pearlitic hot-rolled steel rails. In the fiercely competitive existing technologies, manufacturers mainly use micro-alloying, controlled rolling and controlled cooling to improve the comprehensive performance of pearlitic steel rails. However, through There are few reports on the continuous cooling of continuous casting slabs on-line to improve the delayed fracture resistance of hot-rolled rails. [0003] T...

AI Technical Summary

Problems solved by technology

my country's existing high-speed railways mainly use pearlitic hot-rolled steel rails. In the fiercely competitive existing technologies, manufacturers mainly use micro-alloying, controlled rolling and controlled cooling to improve the comprehensive performance of pearlitic steel rails. However, through On-line continuous cooling of continuous casting slabs to improve the delayed fracture resistance of hot-rolled rails has rarely been reported

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