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Aluminothermic welding method of seamless steel rail

A seamless rail and thermite welding technology, applied in the direction of thermite welding equipment, rails, tracks, etc., can solve the problems of difficulty in construction, cracks in the transition zone of welds, and difficulty in application, so as to avoid excessive cooling and solve air holes and The effect of crack defects

Pending Publication Date: 2020-08-28
BEIJING TEYE IND & TRADE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the aluminothermic welding of seamless lines is carried out at the railway laying site. With the development of the railway industry, the railway has to cross different regions. The climate, especially the change of temperature and humidity in different regions, has a great impact on the welding quality , showing welding defects such as cracks and bubbles in the transition zone of the weld
In addition, due to the difference in the composition of different flux alloys, each flux needs to develop a corresponding welding process, and it is difficult to apply the existing process, which also causes a certain degree of difficulty to the construction

Method used

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  • Aluminothermic welding method of seamless steel rail
  • Aluminothermic welding method of seamless steel rail
  • Aluminothermic welding method of seamless steel rail

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Rails, U20Mn bainite rails and U75V rails.

[0033] Thermite flux, CN105921881A thermite flux.

[0034] Time, December 2018, location, Jing County, Hebei Province, temperature minus 5°C.

[0035] The welding process is:

[0036] (1) Grinding and derusting the rail, removing the rust on the welding part of the rail end, and then heating the rail end with a propane and oxygen preheating gun at a temperature of 300-350°C, but do not heat the weld joint to avoid oxidation and carbon deposition;

[0037] (2) Align the rails so that the ends of the rails are aligned, the rail gap is 28mm, assemble, and wipe the welds again after assembly to ensure cleanliness;

[0038] (3) Install the sand mold, use the preheating gun to heat the range of 1000mm on both sides of the rail to 37°C, and then use the preheating gun to preheat the rail for more than 5 minutes until the color of the rail head turns red; in order to reduce the distance between the rail surface to be welded and Th...

Embodiment 2

[0048] Rails, U20Mn bainite rails and U75V rails.

[0049] Thermite flux, CN105921881A thermite flux.

[0050] Time, July 2019, location, Jing County, Hebei Province.

[0051] The welding process is:

[0052] (1) Grinding and derusting the rail, removing the rust on the welding part of the rail end, and then heating the rail end with a propane and oxygen preheating gun at a temperature of 300-350°C;

[0053] (2) Align the rails so that the ends of the rails are aligned, the rail gap is 28mm, assemble, and wipe the welds again after assembly to ensure cleanliness;

[0054] (3) Install the sand mold, and then preheat the rail with a preheating gun for more than 5 minutes until the color of the rail head turns red; in order to reduce the temperature difference between the surface of the rail to be welded and the molten pool of the aluminothermic steel, which is conducive to the fusion of the joint surface Fine grains, improve the stress distribution of welded joints, improve t...

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Abstract

The invention relates to an aluminothermic welding method of a seamless steel rail. A welding flux comprises C, Si, Mn, Cr, Ni, Mo, V, aluminum powder and oxide and iron powder, the process comprisesthe following steps of polishing, derusting and dehumidifying a steel rail; preheating the steel rail until the rail head turns red; igniting and preheating the aluminothermic welding flux, and reacting and pouring; after pouring, heating the steel rail at 250-300 DEG C within the position, 500 mm away from the outside of a sand mold frame, of the two sides of the sand mold frame; knob removing,meanwhile, keeping the temperature of the steel rail at 250-300 DEG C within the position, 500 m away from the outside of the sand mold frame, of the two sides of the sand mold; cooling the welded junction to 500 DEG C, performing hot grinding, cooling weld metal part after the hot grinding, keeping the temperature of the steel rail at 250-300 DEG C within the position, 500 m away from the outsideof the sand mold frame, on the two sides of the sand mold frame in the process till the weld metal part reaches 250-300 DEG C, and performing cover heat preservation on the welded junction for 20 min; and removing the cover, and naturally cooling to room temperature. The method ensures the welding quality.

Description

technical field [0001] The invention relates to a thermite welding method for seamless steel rails. Background technique [0002] The seamless line is a long rail line formed by welding standard length rails, also known as welded long rail line. Since the rail gap is eliminated, the impact of the wheel on the rail head is eliminated, not only the train runs stably, but also the service life of the line equipment and the locomotive is extended. [0003] Thermite welding is a rail welding technology used in seamless lines. It uses the heat generated by the oxidation-reduction reaction between metal oxides and aluminum to melt the metal base material and fill the joints to complete the welding. The welding difficulty is the welding between heterogeneous steel rails, such as the welding between bainitic steel rails and pearlitic steel rails, which is mainly manifested in the heat-affected zone that is prone to produce white spots and stress micro-crack sources. [0004] Beijin...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K23/00B23K101/26
CPCB23K23/00B23K2101/26
Inventor 张绵胜张绵栋陈良旗张志强
Owner BEIJING TEYE IND & TRADE
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