Method for optimizing microscopic structure of steel rail welding joint

A technology for welded joints and microstructures, which is applied in the field of rail welding, can solve problems such as abnormal microstructures, and achieve remarkable results, simple process flow, and convenient operation

Inactive Publication Date: 2021-02-12
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

[0008] The purpose of the present invention is to provide a method for optimizing the microstructure of rail joints in order to overcome the problem of abnormal microstructure caused by the precipitation of intergranular cementite in rail welded joints in the prior art

Method used

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  • Method for optimizing microscopic structure of steel rail welding joint
  • Method for optimizing microscopic structure of steel rail welding joint
  • Method for optimizing microscopic structure of steel rail welding joint

Examples

Experimental program
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Effect test

Embodiment 1

[0064] The experimental material of this embodiment is the 68kg rail profile and rail head hardened (heat-treated) pearlitic rail specified in the AS 1085.1: Railway track materials, Part 1: Steelrails standard, and the measured carbon content of the physical chemical composition of the rail is 0.8% by weight. Carry out 5 parallel experiments, the specific experimental process includes the following steps: use GAAS80 / 580 rail fixed flash welding welding machine to carry out welding experiments, use accelerated cooling device 2 (cooling surface 4 is 15mm away from the rail waist surface, and the spray angle is 110 °), using Compressed air (with a pressure of 0.4MPa) is used as the cooling medium to accelerate the cooling of the rail waist of the welded joint to be cooled by flash welding. At the same time, an infrared thermometer is used to measure the temperature of the center of the weld seam of the welded joint rail waist and continuously monitor it. Temperature, the cooling ...

Embodiment 2

[0066] The experimental material of this embodiment is the 68kg rail profile and rail head hardened (heat-treated) pearlitic rail specified in the AS 1085.1: Railway track materials, Part 1: Steelrails standard, and the measured carbon content of the physical chemical composition of the rail is 0.8% by weight. Carry out 5 parallel experiments, the specific experimental process includes the following steps: adopt rail mobile flash welding machine to carry out welding experiment, use accelerated cooling device 2 (cooling surface 4 is apart from rail waist surface 15mm, spray angle is 110 °), adopt compressed air ( The pressure is 0.4MPa) as the cooling medium to accelerate the cooling of the welded joint rail waist part to be cooled by flash welding. The cooling rate at the center of the waist weld is 19-35°C / s. When the temperature drops to 1000°C, the control system automatically shuts off the cooling medium, immediately stops the accelerated cooling, and then places the joint ...

Embodiment 3

[0074]The experimental materials in this example are the 60E1 rail profile specified in the BS EN 13674-1: Railway applications–Track–Rail, Part 1: Vignole railway rails 46kg / m and above standard, the R260 hot-rolled pearlitic rail, and the rail solid chemistry Composition The measured carbon content was 0.6% by weight. Carry out 5 parallel experiments, the specific experimental process includes the following steps: adopt rail mobile flash welding machine to carry out welding experiment, use accelerated cooling device 2 (cooling surface 4 is apart from rail waist surface 30mm, spray angle is 115 °), adopt compressed air ( The pressure is 0.6MPa) as the cooling medium to accelerate the cooling of the rail waist of the welded joint to be cooled by flash welding. The cooling rate at the center of the waist weld is 19-35°C / s. When the temperature drops to 900°C, the control system automatically shuts off the cooling medium, immediately stops the accelerated cooling, and then place...

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Abstract

The invention relates to the field of steel rail welding, in particular to a method for optimizing a microscopic structure of a steel rail welding joint. The method comprises the following steps that1, an accelerated cooling device is used, compressed air is adopted as a cooling medium, accelerated cooling is carried out on a rail waist part of the to-be-cooled welding joint obtained by flash welding, and the temperature of the center position of a welding seam of the rail waist of the welding joint is measured and monitored while cooling is carried out; and 2, when the temperature of the center position of the welding seam of the rail waist is reduced to a preset temperature, accelerated cooling is stopped, and then the welding joint is placed in air to be naturally cooled to the room temperature, wherein a steel rail is a pearlite steel rail with the carbon content being 0.6-0.9 wt%. According to the method, waste heat of the steel rail welding joint is utilized, the joint does notneed to be reheated, it can be effectively ensured that abnormal structures such as intergranular cementite in the pearlite steel rail flash welding joint are normal, and meanwhile it is ensured thatthe hardness, static bending and other performance of the joint meet the use requirements.

Description

technical field [0001] The invention relates to the field of rail welding, in particular to a method for optimizing the microstructure of rail joints. Background technique [0002] With the rapid development of seamless track technology in passenger transport, freight transport, high-speed and heavy-duty railway construction worldwide, the quality of rail joints has attracted more and more attention from relevant departments. As the direct carrier of train operation, the quality and reliability of railway lines is the key to the safe operation of trains. The rail flash welded joint is the weak link of the whole line, its quality can directly affect the safety of the railway, and the microstructure of the rail joint directly determines the performance of the joint. [0003] At present, the mainstream steel rails at home and abroad are pearlitic steel rails. All the current standards applicable to pearlitic rail flash welding and enterprise technical conditions have specific...

Claims

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Application Information

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IPC IPC(8): C21D9/04C21D9/50
CPCC21D9/04C21D9/505C21D2211/009C21D2211/003C21D8/005
Inventor 陆鑫李大东白威徐飞翔
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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