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Postweld heat treatment method of hypereutectoid steel rail and eutectoid steel rail welding joint

A technology for post-weld heat treatment and welded joints, which is applied in the field of post-weld heat treatment for welded joints of hypereutectoid steel rails and eutectoid steel rails, can solve problems such as high cost, complicated operation and implementation process, and achieve improved wear and early fatigue Fracture effect

Active Publication Date: 2018-10-16
CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The dissimilar rail welded joints obtained by this method can meet the test requirements for fatigue, tensile, impact and static bending tests in the current domestic railway industry standard TB / T1632.2-2014 "Rail Welding Part 2: Flash Welding"; but The above-mentioned invention involves post-weld normalizing heat treatment of rails, which requires the use of post-weld heat treatment equipment to locally heat the welded joints of the rails. The operation and implementation process is complicated and the cost is relatively high.

Method used

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  • Postweld heat treatment method of hypereutectoid steel rail and eutectoid steel rail welding joint
  • Postweld heat treatment method of hypereutectoid steel rail and eutectoid steel rail welding joint
  • Postweld heat treatment method of hypereutectoid steel rail and eutectoid steel rail welding joint

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Embodiment 1

[0039] After the rail has completed upsetting and push-out during the mobile flash welding process, the welded joint is subjected to post-weld heat treatment. 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 4.0 °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 0.4 °C / s is used for the second-stage cooling to reduce the surface temperature of the rail head of the rail joint to 450 °C, and finally the third cooling rate of 0.4 °C / s is used for the third-stage cooling of the rail joint 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 welded joint of the rail after heat treatment after welding of the present invention;

[0040] In the post-weld heat treatment process, the firs...

Embodiment 2

[0047] After the rail has completed upsetting and push-out during the mobile flash welding process, the welded joint is subjected to post-weld heat treatment. Firstly, the rail joint with a residual temperature of 1000 °C after welding is cooled in the first stage at the first cooling rate of 5.0 °C / s to reduce the surface temperature of the rail head of the rail joint to 610 °C, and then the rail joint is cooled at 2.2 °C The second cooling rate of / s is used for second-stage cooling to reduce the surface temperature of the rail head of the rail joint to 440 °C, and finally the third cooling rate of 0.10 °C / s is used for the third-stage cooling of the rail joint 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 invention;

[0048] In the post-weld heat treatment process, the first coolin...

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Abstract

The invention discloses a postweld heat treatment method of a hypereutectoid steel rail and eutectoid steel rail welding joint, and belongs to the technical field of steel rail welding. In order to solve the technical problems that in the steel rail on-track service process, due to the fact that the hardness of a welding area is low, or a microstructure of the joint is abnormal, the steel rail welding joint saddle-shaped wear and early fatigue breakage are caused, the invention provides the postweld heat treatment method of the hypereutectoid steel rail and eutectoid steel rail welding joint.The steel rail welding joint is sequentially subject to operation of the first cooling stage, the second cooling stage and the third cooling stage, the cooling speed and the temperature of each stageare controlled, and the problems that in the steel rail on-track service process, due to the low welding area hardness or the abnormal joint microstructure, steel rail welding joint saddle-shaped wearand early fatigue breakage are caused are solved.

Description

technical field [0001] The invention belongs to the technical field of rail welding, and in particular relates to a post-weld heat treatment method for welded joints of hypereutectoid steel rails and eutectoid steel rails. Background technique [0002] At present, eutectoid pearlitic steel rails are mostly used in heavy-duty railway lines at home and abroad. The carbon content of such steel rails is usually in the range of 0.72-0.82 wt%. Moderate features. With the rapid development of railways, heavy-duty and heavy-duty lines put forward higher requirements for the service performance of rails, and the comprehensive mechanical properties and welding properties of traditional pearlitic rails have almost reached their limits. In this case, hypereutectoid steel rails with higher strength levels and comprehensive properties such as good wear resistance and contact fatigue have emerged as the times require. The carbon content of such steel rails is usually in the range of 0.90-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/50
CPCC21D9/505C21D2211/009
Inventor 白威李大东王若愚邓健
Owner CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD