Hypoeutectoid steel rail post-weld heat processing method

A post-weld heat treatment and hypoeutectoid technology, which is applied in heat treatment furnaces, heat treatment equipment, furnaces, etc., can solve problems not involved in post-weld heat treatment methods of hypoeutectoid rails, and achieve the effect of ensuring service performance and railway operation safety

Inactive Publication Date: 2019-11-12
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

This invention does not relate to the post-weld heat treatment method for hypoeutectoid steel rails with a carbon content of 0.55% to 0.65%

Method used

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  • Hypoeutectoid steel rail post-weld heat processing method
  • Hypoeutectoid steel rail post-weld heat processing method
  • Hypoeutectoid steel rail post-weld heat processing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The hypoeutectoid rail welded joint obtained by flash welding at a temperature of 1200 °C was air-cooled. When the joint was cooled from 1200 °C to 180 °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 tread temperature of the rail reaches 900°C, then immediately air-cool the obtained rail welded joint to 350°C, and finally air-cool the welded joint to room temperature (25°C), thereby obtaining the post-weld heat-treated sub- Eutectoid rail welded joints.

[0038] The hypoeutectoid rail welded joint obtained in this embodiment is machined into a longitudinal hardness sample, and the longitudinal Rockwell hardness test is carried out on the welded joint at a position 5 mm below the tread. The measuring points are arranged symmetrically to the left and right sides with the weld seam as the center. The measuring point spacing is 5mm. The Rockwell hardness test method ...

Embodiment 2

[0043] Air-cool the hypoeutectoid rail welded joint with a temperature of 1300°C obtained by gas pressure welding. When the welded joint is cooled from 1300°C to 200°C, use an oxygen-acetylene flame profiling heater to heat the entire section of the welded joint area of ​​the rail . Stop heating when the tread temperature of the rail reaches 920°C, then air-cool the welded joint of the rail to 380°C, and finally air-cool the welded joint to room temperature (25°C), thereby obtaining the post-weld heat-treated hypoeutectoid rail of the present invention Welded joints.

[0044] Take the longitudinal hardness sample of the hypoeutectoid rail welded joint obtained in this embodiment and carry out the longitudinal Rockwell hardness test at the position 5 mm below the rail head tread. 5mm. The Rockwell hardness test method is carried out according to the provisions of GB / T 230.1-2009, and the HRC scale is used. The longitudinal hardness data at the 5mm position below the rail hea...

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Abstract

The invention discloses a hypoeutectoid steel rail post-weld heat processing method, and belongs to the technical field of railway steel rail manufacturing. The hypoeutectoid steel rail post-weld heatprocessing method can achieve the effects that the tread longitudinal hardness of a hypoeutectoid steel rail welding joint can be controlled within a reasonable range. The heat processing method sequentially comprises the following steps that A, first cooling is carried out on the welding joint with the temperature of 1100-1400 DEG C to be not higher than 200 DEG C, wherein welding joint is obtained by welding hypoeutectoid steel rails, and the first cooling mode is natural cooling in air; B, the welding joint is heated to 840-920 DEG C; and C, second cooling is carried out on the welding joint, the second cooling is stopped when the welding joint is cooled to 320-400 DEG C, then third cooling is carried out until the welding joint reaches 5-40 DEG C, and the welding joint with the longitudinal hardness of the rail head tread being 85%-90% of the average hardness of the steel rail base material is obtained, wherein the second cooling mode is rapid cooling in which a cooling medium isapplied, the cooling temperature of the second cooling is 800 DEG C or above, and the third cooling mode is natural cooling in the air.

Description

technical field [0001] The invention relates to the technical field of railway rail manufacturing, in particular to a post-weld heat treatment method for hypoeutectoid rails. Background technique [0002] At this stage, the global railway system mainly covers three types: heavy-haul railway, high-speed railway and mixed passenger and freight railway. The heavy-duty railway train has a heavy axle (axle load 25t-40t), the carbon content of the rail used is usually greater than 0.75%, the tensile strength is above 1200MPa, has a full pearlite structure or is mainly pearlite, and contains a small amount of secondary carburization Body, with high strength, high hardness while ensuring wear resistance. Since the passenger-freight mixed railway has to undertake both passenger transport and cargo transport, it is required that the rails not only have a certain wear resistance, but also have good fatigue resistance. Therefore, the carbon content of rails used in mixed passenger and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/50
CPCC21D9/50
Inventor 白威李大东陆鑫徐飞翔
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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