Post-welding heat treatment method for 1,100MPa-grade low-alloy heat treatment steel rail

Abstract

The invention relates to the technical field of railway steel rail manufacturing, and discloses a post-welding heat treatment method for a 1,100MPa-grade low-alloy heat treatment steel rail. The method comprises the following steps that (1) first-stage cooling is performed on a steel rail welded joint which is formed by welding and has the residual temperature of 1,150-1,300 DEG C, so that the surface temperature of the steel rail welded joint is dropped to 580-640 DEG C; (2) the steel rail welded joint is subjected to second-stage cooling, so that the surface temperature of the steel rail welded joint is dropped to 410-470 DEG C; and (3) the steel rail welded joint is subjected to third-stage cooling, so that the surface temperature of the steel rail welded joint is dropped to 10-30 DEG C. According to the method, welding waste heat is used for heat treatment without reheating, so that the heat treatment process is simplified, and the cost is lowered; and the percentage content of a martensite structure possibly appearing in a metallographic structure of the steel rail welded joint can be controlled to be smaller than or equal to 3%, and meanwhile the physical fatigue life of thesteel rail joint can reach 2,500,000 times.

Description

technical field [0001] The invention relates to the technical field of railway rail manufacturing, in particular to a post-weld heat treatment method for 1100MPa grade low-alloy heat-treated rails. Background technique [0002] With the continuous improvement of my country's high-speed railway network, the existing mixed passenger and freight trunk lines will gradually implement heavy-duty transformation. Large capacity, large axle load, and high density are the development direction of heavy-duty railways in the future. The rapid development of railways puts forward higher requirements on the service performance of steel rails, and ordinary carbon steel rails have been difficult to meet the needs of railway speed-up and heavy-duty transportation. [0003] There are usually two ways to strengthen rails: heat treatment and alloying. Heat treatment is the most economical and effective way to improve the performance of rails. The advantage of alloying is that the production p...

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Problems solved by technology

[0009] The purpose of the present invention is to overcome the problems of complicated operation process and high cost of heat treatment method for rail welded joints in the prior art, poor mechanical properties of welded joints after heat treatment, and short physical fatigue life of rail joints, and to provide a A post-weld heat treatment method for 1100MPa low-alloy heat-treated rails. This method heat-treats welded joints of 1100MPa-level low-alloy heat-treated rails. The cost of heat treatment is low, and the mechanical properties of welded joints after heat treatment are good.

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