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Post-weld heat treatment method for rail

A technology for post-weld heat treatment and steel rails, applied in heat treatment furnaces, heat treatment equipment, furnaces, etc., can solve the problems of complex operation and high cost

Active Publication Date: 2020-07-07
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

[0004] The technical problem to be solved by the present invention is that the operation of the prior art is complicated and the cost is relatively high

Method used

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  • Post-weld heat treatment method for rail

Examples

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Effect test

Embodiment 1

[0041] After the hypereutectoid steel rail and eutectoid pearlitic steel rail with a specification of 75kg / m are upset and pushed during the moving flash welding process, post-weld heat treatment is performed on the welded joint. Firstly, the rail joint with residual temperature of 1100 °C obtained by welding is cooled in the first stage at the first cooling rate of 4.9 °C / s to reduce the surface temperature of the rail head of the rail joint to 630 °C, and then the rail joint is cooled at 2.0 °C 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 220°C, and finally the rail joint is subjected to the third-stage cooling at a third cooling rate of 0.4°C / s to reduce the temperature of the rail joint The temperature of the surface layer of the rail head is lowered to the room temperature of 25° C., thereby obtaining the welded joint of the rail with post-weld heat treatment of the present invent...

Embodiment 2

[0049] After the hypereutectoid steel rail and eutectoid pearlitic steel rail with a specification of 60kg / m are upset and pushed during the moving flash welding process, post-weld heat treatment is performed on the welded joint. Firstly, the rail joint with residual temperature of 1000 °C obtained by welding is cooled in the first stage at the first cooling rate of 4.2 °C / s to reduce the surface temperature of the rail head of the rail joint to 620 °C, and then the rail joint is cooled at 2.3 °C 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 185°C, and finally the rail joint is subjected to the third-stage cooling at a third cooling rate of 0.10°C / s to reduce the temperature of the rail joint The temperature of the surface layer of the rail head is lowered to room temperature of 25° C., thereby obtaining the post-weld heat-treated rail welded joint of dissimilar materials of the present...

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Abstract

The invention provides a post-weld heat treatment method for steel rails, belonging to the field of steel rail welding. The objective of the invention is to overcome the technical problems of complexoperation and high cost in the prior art. The method of the invention comprises the following steps: carrying out first-stage cooling on a to-be-cooled welded joint obtained after the welding of steelrail made of dissimilar material rails so as to allow the surface temperature of the railhead of the steel rail welded joint to drop to 570-640 DEG C; then carrying out second-stage cooling on the welded joint to allow the surface temperature of the railhead of the steel rail welded joint to drop to 170-230 DEG C; and finally, carrying out third-stage cooling on the welded joint to allow the surface temperature of the railhead of the steel rail welded joint to drop to 10 to 30 DEG C. The method of the invention can improve the saddle wear of the steel rail welded joint caused by the low hardness of a welded area during the service of a steel rail, and controls the percentage content of the martensite structure of the steel rail joint to be within 3%, which is beneficial for ensuring the safety of railway operation.

Description

technical field [0001] The invention belongs to the technical field of rail welding, and in particular relates to a post-welding heat treatment method for rails. Background technique [0002] At present, eutectoid pearlitic steel rails are mostly used in domestic and foreign heavy-duty railway lines. The carbon content of such steel rails is usually in the range of 0.72-0.82% by weight. The metallographic structure is pearlite, which has good strength and toughness matching, and comprehensive mechanical properties. The indicators are moderate in characteristics. With the rapid development of railways, heavy-duty lines with large axle loads put forward higher requirements on the performance of rails. Since the comprehensive mechanical properties and welding properties of traditional pearlitic rails have almost reached their limits, under this circumstance, hypereutectoid rails with higher strength levels and comprehensive properties such as good wear resistance and contact f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D9/50
CPCC21D9/505
Inventor 白威李大东王若愚邓健
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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