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Post-welding thermal treatment method for channel type steel rail flash welding head

A technology of post-weld heat treatment and grooved rails, applied in heat treatment furnaces, heat treatment equipment, furnace types, etc., can solve the problems of low impact toughness and low hardness of rail head profile

Inactive Publication Date: 2019-02-19
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

[0006] The technical problem solved by the invention is that the air-cooled impact toughness of the grooved rail flash welding joint is low, and the hardness of the longitudinal section of the rail head after post-welding heat treatment is relatively low

Method used

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  • Post-welding thermal treatment method for channel type steel rail flash welding head
  • Post-welding thermal treatment method for channel type steel rail flash welding head
  • Post-welding thermal treatment method for channel type steel rail flash welding head

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Air-cool the welded joints of channel rails obtained by flash welding at a temperature of 1400°C. When the joints are cooled from 1400°C to 150°C, use medium-frequency induction profiling electric heating coils to heat the entire section of the welded joints of channel rails. Stop heating when the rail head longitudinal section temperature of the rail reaches 900°C, then immediately spray the heated rail welded joint to 520°C, and finally air-cool the welded joint to room temperature (25°C), thereby obtaining the process of the present invention Channel rail welded joints with post-weld heat treatment. The longitudinal section hardness data at the position 5mm below the rail head tread of the welded joint is shown in Table 1, and the distribution of the longitudinal section hardness is as follows figure 2 shown.

[0047] Table 1

[0048]

[0049] From Table 1 and figure 1 It can be seen that when the post-weld heat treatment method provided by the present inventi...

Embodiment 2

[0051] The trough-shaped rail welded joints obtained by flash welding at a temperature of 1300 °C were air-cooled. When the joints were cooled from 1300 °C to 50 °C, the medium-frequency induction profiling electric heating coil was used to heat the entire section of the rail welded joint area. Stop heating when the rail head longitudinal section temperature of the rail reaches 920°C, then immediately cool the obtained rail welded joint to 500°C, and finally air-cool the welded joint to room temperature (25°C), thereby obtaining the welded joint of the present invention Post-heat-treated channel rail welded joints. The longitudinal section hardness data at the position 5mm below the rail head tread of the welded joint is shown in Table 2, and the distribution of the longitudinal section hardness is as follows image 3 shown.

[0052] Table 2

[0053]

[0054] From Table 2 and figure 2 It can be seen that when the post-weld heat treatment method provided by the present i...

Embodiment 3

[0056] The trough rail welded joint obtained by flash welding at a temperature of 1400 °C was air-cooled. When the welded joint was cooled from 1400 °C to 40 °C, the entire section of the rail welded joint area was heated with an oxy-acetylene flame profiling heater. Stop heating when the rail head longitudinal section temperature of the rail reaches 900°C, then spray the welded joints of the rails to 430°C, and finally air-cool the welded joints to room temperature (25°C), thereby obtaining the post-weld heat treatment of the present invention Channel rail welded joints. The longitudinal section hardness data at the position 5mm below the rail head tread of the welded joint is shown in Table 3, and the distribution of the longitudinal section hardness is as follows Figure 4 shown.

[0057] table 3

[0058]

[0059] From Table 3 and image 3 It can be seen that when the post-weld heat treatment method provided by the present invention is used to treat the welded joints ...

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Abstract

The invention relates to a post-welding thermal treatment method for a channel type steel rail flash welding head, belongs to the technical field of railway steel rail welding, and aims to solve the technical problems that the channel type steel rail flash welding head is low in impact toughness through air-cooling, and the hardness of the longitudinal section of the post-welded thermally-treatedrail head is low. According to the technical scheme adopted by the invention, the post-welding thermal treatment method comprises the following steps of: performing first-time cooling on a channel type steel rail welding joint until a temperature lower than 200 DEG C, stopping heating while heating the joint to a temperature of 850-920 DEG C, performing second-time cooling, stopping second-time cooling while cooling to a temperature of 430-520 DEG C, and performing third-time cooling to a temperature of 10-30 DEG C. The rail head longitudinal section hardness of the post-welded thermally treated channel type rail welding joint is 90% or more of average hardness of a steel rail base material, a joint softening region width is within 20 mm, and abnormal structures such as martensite and bainite are avoided. The post-welded thermally treated channel type steel rail all-section welding seam impact power Aku is higher than or equal to 15 J.

Description

technical field [0001] The invention belongs to the technical field of railway rail welding, and in particular relates to a post-weld heat treatment method for flash welding joints of grooved rails. Background technique [0002] Modern trams are known for their energy saving, environmental protection, relatively small investment (the cost is only 100 million yuan / km, which is a quarter of the subway), moderate passenger capacity (capacity reaches 7,000 people per hour, more than buses), Better riding comfort and less post-maintenance costs. After more than 20 years of development in foreign countries, there are already mature application performances in more than 150 cities. Tram has played an important role in solving transfers in urban core areas, suburban connections, and sightseeing in scenic spots, and represents the future development direction. It is currently the most common practice in the world to lay seamless grooved rail lines in the middle of the road to form t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/78C21D9/04C21D9/50C21D6/00C22C38/02C22C38/04C22C38/12
Inventor 王若愚李大东陆鑫邓健
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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