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Post-welding heat treatment method for groove-shaped steel rail flash welding joint

A technology for post-weld heat treatment and grooved rails, applied in heat treatment furnaces, heat treatment equipment, furnace types, etc., can solve problems affecting train driving safety, wear at parts with low hardness, low hardness of welded joints, etc., to achieve good shape and Toughness, increased strength and hardness, and low cost effects

Inactive Publication Date: 2019-09-20
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

At present, after the post-welding heat treatment of the channel rail flash welding joint, the hardness of the top surface of the channel rail flash welding joint is less than the hardness of the rail base material, and the hardness of the welded joint is low, which leads to serious wear of the low hardness part after long-term operation of the train, resulting in The running of the train is not stable, which seriously affects the safety of the train. Therefore, in order to cooperate with the rapid development of modern tram line construction in my country, there is an urgent need for a heat treatment method suitable for flash welded joints of channel rails to solve the problem after heat treatment of flash welded joints of channel rails. Low hardness of rail top surface

Method used

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  • Post-welding heat treatment method for groove-shaped steel rail flash welding joint
  • Post-welding heat treatment method for groove-shaped steel rail flash welding joint
  • Post-welding heat treatment method for groove-shaped steel rail flash welding joint

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030]When the channel rail flash welding joint is air-cooled to 40°C, the oxygen-liquefied petroleum gas flame is used to heat the channel rail welding joint. h, the heating time is 340s; when the temperature of the top surface of the welded joint rail reaches 910°C, stop heating, and then use the air blowing device to cool the top surface of the welded joint rail and the working side, and the distance between the air spray port and the top surface of the welded joint rail is 40mm. The wind pressure is 0.20MPa; when the temperature of the top surface of the rail is air-cooled to the final cooling temperature of 500°C, stop the air spray cooling, and then the welded joints are naturally cooled to room temperature; the welded joints of the channel rails that are post-weld heat treated refer to CECS429: According to the 2016 standard, after the sample is taken and processed, it is corroded with 3% nitric acid alcohol after processing, and the test point position is marked on the ...

Embodiment 2

[0033] When the channel rail flash welding joint is air-cooled to 32°C, the oxygen-liquefied petroleum gas flame is used to heat the channel rail welding joint. h, the heating time is 330s; when the temperature of the top surface of the welded joint rail reaches 900°C, stop heating, and then use the air blowing device to spray air on the top surface of the welded joint rail and the working side to cool it. The blowing air pressure is 0.20MPa; when the temperature of the top surface of the rail is air-cooled to the final cooling temperature of 480°C, stop the blowing air cooling, and then the welded joints are naturally cooled to room temperature; the post-weld heat-treated grooved rail welded joints shall refer to CECS429 :2016 standard, after the sample is taken and processed, it is corroded with 3% nitric acid alcohol after the processing is completed, the test point position is marked on the top surface of the welded joint rail and the hardness of the top surface of the rail...

Embodiment 3

[0036] When the channel rail flash welding joint is air-cooled to 30°C, the oxygen-liquefied petroleum gas flame is used to heat the channel rail welding joint. h, the heating time is 352s; when the temperature of the top surface of the welded joint rail reaches 920°C, stop heating, and then use the air blowing device to spray air on the top surface of the welded joint rail and the working side to cool it. The blowing air pressure is 0.18MPa; when the temperature of the top surface of the rail is air-cooled to the final cooling temperature of 460°C, stop the blowing air cooling, and then the rail joints are naturally cooled to room temperature; the welded joints of the grooved rails after post-welding heat treatment refer to CECS429 :2016 standard, after the sample is taken and processed, it is corroded with 3% nitric acid alcohol after the processing is completed, the test point position is marked on the top surface of the welded joint rail and the hardness of the top surface ...

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Abstract

The invention belongs to the technical field of railway steel rail welding, and particularly relates to a post-welding heat treatment method for a groove-shaped steel rail flash welding joint. The method comprise the steps: firstly, cooling the groove-shaped steel rail welding joint obtained by welding to 50 DEG C or less, heating the welding joint to 880-920 DEG C by oxygen-liquefied petroleum gas flame and then stopping heating, immediately performing air injection cooling on rail top surface and traveling side of the welding joint through an air injection device, and stopping air injection after the center temperature of a welding seam on the rail top surface of the welding joint is reduced to 450-520 DEG C; and finally naturally cooling the welding joint to room temperature. According to the flash welding joint treated by the heat treatment method, the hardness of the rail top surface of the welding joint is matched with the hardness of steel rail base material, the joint has no abnormal structures such as Martensite and Bainite, the cost is low, meanwhile, a rail lip, a rail waist and a rail flange of the welding joint are not blown, and the parts have the characteristics of being slow in cooling speed, low in hardness, good in shaping and toughness.

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): C21D9/50C21D1/52C22C38/02C22C38/04C22C38/12
CPCC21D1/52C21D9/50C22C38/02C22C38/04C22C38/12
Inventor 王若愚李大东陆鑫邓健
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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