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Construction method for heat treatment of bainite steel rail joint after welding

A construction method and bainite technology, applied in heat treatment furnaces, heat treatment equipment, manufacturing tools, etc., can solve problems such as the question of heat treatment effect, and achieve the effect of avoiding wear and eliminating accumulation factors.

Inactive Publication Date: 2019-07-16
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

In this invention, the joint is air-cooled directly after the bainitic rail is welded, and there is no heating process after the rail is welded, and the effect of heat treatment is open to question

Method used

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  • Construction method for heat treatment of bainite steel rail joint after welding
  • Construction method for heat treatment of bainite steel rail joint after welding
  • Construction method for heat treatment of bainite steel rail joint after welding

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Effect test

Embodiment

[0039] According to conventional methods, after welding of heat-treated bainitic rails, there are phenomena such as low tread hardness and poor toughness in the welded area, and normalizing heat treatment is usually required to improve joint performance. However, after normalizing, the welded joint has low hardness and widened softening zone, which is easy to cause "saddle-shaped" wear of the welded joint during service, resulting in poor service performance. Based on this, the work of the present invention finds and designs a post-weld heat treatment method for heat-treated bainite rails, which ensures the service life of rail joints while ensuring the hardness of the joint tread.

[0040] Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

[0041] In the present ...

Embodiment 1

[0059] 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. Firstly, the rail joint with residual temperature of 1100 °C after welding is cooled in the first stage at the first cooling rate of 4.5 °C / s to reduce the surface temperature of the rail head of the rail joint to 700 °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 200 °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 the room temperature of 25° C., thereby obtaining the welded joint of the rail with post-weld heat treatment of the present invention. Among them, the first cooling ...

Embodiment 2

[0067] After the rails with a specification of 60kg / m have completed upsetting and push-out during the mobile flash welding process, the welded joints are subjected to post-weld heat treatment. Firstly, the rail joint with residual temperature of 1200 °C obtained by welding is cooled in the first stage at the first cooling rate of 4.5 °C / s to reduce the surface temperature of the rail head of the rail joint to 650 °C, and then the rail joint is cooled at 2.5 °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 180°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 the room temperature of 25° C., thereby obtaining the welded joint of the rail with post-weld heat treatment of the present invention. Among them, the first cooling...

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Abstract

The invention discloses a construction method, in particular relates to a construction method for heat treatment of a bainite steel rail joint after welding, and belongs to the technical field of a production process for steel rail rolling. The invention provides the construction method for heat treatment of the bainite steel rail joint after welding, which can control the tread hardness of the bainite steel rail welded joint in a reasonable range. Based on the bainite steel rail welded joint with the temperature not less than 1100 DEG C obtained by welding, the construction method completes the heat treatment after welding of the bainite steel rail welded joint by cooling successively in a sequence of three cooling speeds gradually slowing down, wherein the final cooling temperature of secondary cooling is 150 ~ 210 DEG C, and the temperature is also the starting cooling temperature of tertiary cooling.

Description

technical field [0001] The invention relates to a construction method, in particular to a construction method for heat treatment of welded joints of bainite rails, and belongs to the technical field of rail rolling production technology. Background technique [0002] Bainitic steel rail has been a research hotspot in the world in recent decades. It is expected to replace traditional pearlitic steel rail due to its high strength, toughness, wear resistance and long service life. Radius curve segment. At this stage, rail seamlessness has become an inevitable trend. As an important process in the seamless link of rails, the quality of rail welding is directly related to the service life of railway lines and even the safety of traffic. During the service process of rails, due to the influence of welding quality and the complexity of the actual operating conditions of the line, most of the fractures of welded long rails occur on the welded joints, so the welded joints have beco...

Claims

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Application Information

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IPC IPC(8): C21D9/50C21D9/04
CPCC21D9/04C21D9/505
Inventor 白威李大东邓健陆鑫
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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