75 kg/m hypereutectoid steel rail and eutectoid steel rail air pressure welding method and welding part

A welding method and hypereutectoid technology, applied in the field of 75kg/m hypereutectoid rails and eutectoid rail weldments, can solve problems such as welding difficulties, achieve stable welding quality, improve welding productivity, and uniform temperature field distribution on the left and right sides of the weld Effect

Active Publication Date: 2021-11-09
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

[0004] The invention discloses a gas pressure welding method of 75kg / m hypereutectoid rail and eutectoid rail, which solves the difficult problem of welding the eutectoid rail on the existing heavy-duty railway and the new supereutectoid rail

Method used

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  • 75 kg/m hypereutectoid steel rail and eutectoid steel rail air pressure welding method and welding part
  • 75 kg/m hypereutectoid steel rail and eutectoid steel rail air pressure welding method and welding part
  • 75 kg/m hypereutectoid steel rail and eutectoid steel rail air pressure welding method and welding part

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Experimental program
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Effect test

Embodiment 1

[0046] In this embodiment, in order to ensure the quality of gas pressure welding, a special end milling machine is used to mill the rail before welding, and the rust and oxides near the welding joint are polished to 40 mm until the metallic luster is exposed. After the treatment, the slope deviation of the rail end surface is 0.1mm, and the gap after the joint is 0.15mm. After the end milling is completed, the burrs at the edge of the rail end are processed with a file, and the welded end surface is welded immediately after processing. To avoid secondary pollution such as oil stains after treatment, the rails are hoisted and clamped, and the end sections of the rails are cleaned with carbon tetrachloride before welding. After the end surface treatment is qualified, adopt "detonation ignition", and the ignition position is 40mm away from the weld to avoid contamination of the weld. After supplying gas for 3s, ignite the heater of the pressure welding device with an igniter.

...

Embodiment 2

[0052] In this embodiment, the same steps of welding front end milling and grinding as in embodiment 1 are performed.

[0053] "Detonation ignition" is adopted, and the ignition position is 40mm away from the weld to avoid contamination of the weld. After supplying gas for 4s, ignite the heater of the pressure welding device with an igniter.

[0054] Use an oxy-acetylene flame to heat the part of the rail to be welded, and perform the steps of first-stage heating, second-stage heating, upsetting welding, push-out and pressure-holding in sequence according to the following parameters. The following welding parameters were used for each step:

[0055]

[0056]

[0057] After the blast cooling is completed, the gas pressure welded joint is cooled to 440°C, the blast is stopped, and reheated for normalizing. After the rail is normalized, it is ground. The grinding surface is the rail head tread and the side of the rail. The grinding profile should keep the original rail he...

Embodiment 3

[0059] In this embodiment, the same steps of welding front end milling and grinding as in embodiment 1 are performed.

[0060] "Detonation ignition" is adopted, and the ignition position is 40mm away from the weld to avoid contamination of the weld. After supplying gas for 3s, ignite the heater of the pressure welding device with an igniter.

[0061] Use an oxy-acetylene flame to heat the part of the rail to be welded, and perform the steps of first-stage heating, second-stage heating, upsetting welding, push-out and pressure-holding in sequence according to the following parameters. The following welding parameters were used for each step:

[0062]

[0063] After the blast cooling is completed, the gas pressure welded joint is cooled to 445°C, the blast is stopped, and reheated for normalizing. After the rail is normalized, it is ground. The grinding surface is the rail head tread and the side of the rail. The grinding profile should keep the original rail head profile a...

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Abstract

The invention discloses a 75 kg / m hypereutectoid steel rail and eutectoid steel rail air pressure welding method. The 75 kg / m hypereutectoid steel rail and eutectoid steel rail air pressure welding method comprises the following steps that 1, first-stage heating is conducted, wherein the oxygen flow ranges from 95-105 SLM, the acetylene flow ranges from 105-115 SLM, and the heating time ranges from 250-300 s; 2, second-stage heating is conducted, wherein the oxygen flow is 85-90 SLM, the acetylene flow is 90-95 SLM, the heating time is 80-100 s, and when the surface temperature of to-be-welded parts of steel rails is 1250-1320 DEG C, fuel gas is closed to stop heating; 3, upsetting welding is executed; 4, knot pushing is executed, and pressure maintaining is carried out; 5, air spraying cooling is conducted; and 6, heat treatment is conducted. The method solves the problem that the eutectoid steel rail and the new hypereutectoid steel rail on an existing heavy haul railway are difficult to weld. The invention also discloses a welding part welded by using the method.

Description

technical field [0001] The invention belongs to the field of welding technology, and in particular relates to a gas pressure welding method for 75kg / m hypereutectoid rail and eutectoid rail, and a welded piece of 75kg / m hypereutectoid rail and eutectoid rail welded by the method. Background technique [0002] In response to the development trend of heavy-haul railways with large axle loads and high-density transportation modes, rails with tread hardness above 420HB have broad prospects in the heavy-haul line market. The existing all-pearlite rails can only adopt special production processes such as alloying + controlled rolling + controlled cooling, and the highest tread hardness can only reach about 430HB. Therefore, heavy-duty lines at home and abroad focus on hypereutectoid rails. Due to the increase in carbon content of the hypereutectoid rail, the metallographic structure is pearlite + a small amount of secondary cementite, which improves the wear resistance of the rai...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K5/00B23K5/24
CPCB23K5/00B23K5/24Y02P10/25
Inventor 王若愚李大东陆鑫白威
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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