A post-weld heat treatment method for 1300mpa low-alloy heat-treated rails

A post-weld heat treatment, low-alloy technology, applied in heat treatment furnaces, heat treatment equipment, rails, etc., can solve the problems of short fatigue life of rail joints, poor mechanical properties of welded joints, complicated operation process, etc., to simplify the heat treatment process, improve Abrasion and safety effect

Active Publication Date: 2022-07-19
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the problems of complicated operation process, high cost, poor mechanical properties of welded joints after heat treatment, and short physical fatigue life of rail joints in the prior art, and to provide a A post-weld heat treatment method for 1300MPa low-alloy heat-treated rails, the method is low in cost and has good mechanical properties of welded joints after heat treatment, and is suitable for post-weld heat treatment of 1300MPa low-alloy heat-treated rails

Method used

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  • A post-weld heat treatment method for 1300mpa low-alloy heat-treated rails
  • A post-weld heat treatment method for 1300mpa low-alloy heat-treated rails
  • A post-weld heat treatment method for 1300mpa low-alloy heat-treated rails

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Embodiment 1

[0085] After the rail with a specification of 68kg / m has completed the upsetting and push-out during the mobile flash welding process, the welded joint is subjected to post-weld heat treatment. First, the rail joint obtained by welding with a residual temperature of 1080°C was subjected to the first-stage cooling at a first cooling rate of 5.5°C / s to reduce the surface temperature of the rail head of the rail joint to 710°C, and then the rail joint was cooled at 2.2°C / s. The second cooling rate of s is used for the second stage cooling to reduce the surface temperature of the rail head of the rail joint to 530°C, and finally the rail joint is subjected to the third stage cooling at the third cooling rate of 0.55°C / s to cool the rail head surface of the rail joint. The temperature is lowered to a room temperature of 25° C., thereby obtaining a rail welded joint that has undergone post-weld heat treatment. In the post-weld heat treatment process, the first stage of cooling is na...

Embodiment 2

[0093]After the upsetting and push-out during the mobile flash welding process of the rail with a specification of 60kg / m is completed, the welded joint is subjected to post-weld heat treatment. First, the rail joint obtained by welding with a residual temperature of 1000°C was subjected to the first-stage cooling at a first cooling rate of 5.8°C / s to reduce the surface temperature of the rail head of the rail joint to 680°C, and then the rail joint was cooled at 2.5°C / s. The second cooling rate of s performs the second stage cooling to reduce the surface temperature of the rail head of the rail joint to 490°C, and finally the rail joint is carried out at the third cooling rate of 0.6°C / s. The temperature is lowered to a room temperature of 25° C., thereby obtaining a rail welded joint that has undergone post-weld heat treatment. In the post-weld heat treatment process, the first cooling is natural cooling in the air; during the second and third stages of cooling, the rail hea...

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Abstract

The invention relates to the technical field of railway steel rail manufacturing, and discloses a post-weld heat treatment method for a 1300 MPa grade low-alloy heat-treated steel rail. The method includes: (1) first-stage cooling of the rail welded joint formed by welding with a residual temperature of 900-1100°C, so that the surface temperature of the welded joint is reduced to 650-720°C; (2) second-stage cooling of the rail welded joint Stage cooling to reduce the surface temperature of the welded joint to 480‑550℃; (3) The third stage cooling of the rail welded joint is carried out to reduce the surface temperature of the welded joint to 10‑30℃. The invention utilizes the residual heat of welding for heat treatment, and does not need to be reheated during the heat treatment process, thus simplifying the heat treatment process and reducing the cost; At the same time, the fatigue life of rail joints can reach 3 million times, which helps to ensure the safety of railway operation.

Description

technical field [0001] The invention relates to the technical field of railway steel rail manufacturing, in particular to a post-weld heat treatment method for a 1300 MPa grade low-alloy heat-treated steel rail. Background technique [0002] my country is a country dominated by railway transportation. The rapid development of the national economy requires railways to increase the transportation density by further increasing the running speed, increasing the axle load of the locomotive, and shortening the running interval, which in turn puts forward higher requirements for the steel rails, while the ordinary carbon steel rails have been unable to meet the requirements of railway speed-up and heavy-duty transportation. need. [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 process is simple, and it...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D9/50C21D9/04C21D6/00C22C38/02C22C38/04C22C38/24
CPCC21D9/505C21D9/04C21D6/005C21D6/008C21D6/002C22C38/02C22C38/04C22C38/24B23K35/3053B23K2103/04B23K2101/26
Inventor 白威李大东王若愚邓健
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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