A high energy density irradiation process for treating rail reinforcement layer

Abstract

The present invention belongs to the technical field of surface treatment of rail reinforcement layers and provides a high-energy-density irradiation process for treating rail reinforcement layers. The high-energy-density irradiation process for treating rail reinforcement layers includes inspecting the rails, irradiating the reinforcement layer surface with high-density energy, heat preservation, and testing. This process can eliminate or reduce the tensile stress on the surface of the rail reinforcement layer and refine the coarse-grained structure on the surface of the rail reinforcement layer, thereby improving the toughness and fatigue resistance of the reinforcement layer structure, preventing the reinforcement layer from peeling off due to internal cracks during the external compressive stress cycle, and greatly extending the service life of the rails after being treated with high-energy instant quenching technology. This process plays a vital role in ensuring the quality and safety of the entire high-energy beam reinforced rail.

Description

Technical Field

[0001] The invention belongs to the technical field of surface treatment of rail reinforcement layers, and in particular relates to a high-energy-density irradiation process for treating rail reinforcement layers. Background Art

[0002] Compared with traditional surface quenching technology, high-energy instantaneous quenching technology (including but not limited to laser, plasma, and electron beam) has become the most advanced rail surface strengthening treatment technology at home and abroad due to its advantages such as low energy consumption, no change in the metallographic structure of the parent material, small deformation, and controllable strengthening area. It has significant economic and social benefits.

[0003] The main principle of high-energy instantaneous quenching technology is to use high-energy density heat sources such as plasma, laser, electron beam, etc. to quickly heat the rail, so that the surface temperature of the rail reaches above the phase change critical point and below the melting point. When the plasma beam is removed, the rapid cooling effect of the rail itself, coupled with the good thermal conductivity of the rail metal material, forms an ultra-fine and uniform hardened structure in the heated surface area without changing the internal structure and properties of the matrix, thereby achieving the purpose of strengthening the rail surface.

[0004] High-energy instantaneous quenching technology has achieved good results in practical use in various industries. However, since this technology is the latest rail surface treatment technology, there are still many practical problems in the process of use. The most important problem is: due to the high energy density instantaneous irradiation, the metal phase change will occur locally on the surface of the rail metal, and the phase change structure is a microcrystalline martensite morphology. The transition range of the interface between the strengthening layer and the original base material structure is narrow, which will cause the stress of the strengthening layer to be characterized by a large tensile stress of 0-800Mpa, and the surface structure of the strengthening layer has a trace of large-grained lamellar martensite structure, which will lead to The surface of the strengthening layer becomes hard and brittle, and the huge surface tensile stress is superimposed. If the rail surface is not subsequently treated and put into actual working conditions, under the cyclic action of external stress, small crack sources will be generated inside the strengthening layer in a relatively short period of time. The crack sources will quickly develop into through-cracks that penetrate the entire strengthening layer under the interaction of the harsh oily environment and cyclic fatigue stress. The through-cracks develop along the interface between the strengthening layer and the bottom of the substrate, and eventually penetrate the entire strengthening layer, causing the strengthening layer to vibrate and fall off, and the anti-wear performance of the strengthening layer to fail, which greatly affects the life extension effect of the strengthened rail and leads to new safety hazards. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a high-energy-density irradiation process for treating the rail reinforcement layer. This process can eliminate or reduce the tensile stress on the surface of the rail reinforcement layer and refine the coarse-grained structure on the surface of the rail reinforcement layer, thereby improving the toughness and fatigue resistance of the reinforcement layer, preventing the reinforcement layer from peeling off due to internal cracks during the external compressive stress cycle, and greatly extending the service life of the rail after being treated with high-energy instant quenching technology. This process plays a vital role in ensuring the quality and safety of the entire high-energy beam reinforced rail.

[0006] In order to achieve the above object, the solution adopted by the present invention is:

[0007] A high energy density irradiation process for treating a rail reinforcement layer comprises: inspecting the rail after high energy instantaneous quenching, irradiating the reinforcement layer surface with high density energy, heat preservation, and testing.

[0008] Furthermore, in a preferred embodiment of the present invention, the high-density energy includes laser, electron beam and plasma beam.

[0009] Furthermore, in a preferred embodiment of the present invention, the energy density of the high-density energy is 10 3 -10 9 w / cm 2 , the irradiation time is 100-800ms.

[0010] Furthermore, in a preferred embodiment of the present invention, the irradiation mode of high-density energy includes discontinuous discrete mode and continuous scanning mode.

[0011] Furthermore, in a preferred embodiment of the present invention, the surface of the strengthening layer after being irradiated with high-density energy is heated to 100-500° C. and then kept warm.

[0012] Furthermore, in a preferred embodiment of the present invention, the heat preservation method includes heat preservation by heat preservation cotton, heat preservation by infrared irradiation and heat preservation by heat preservation box.

[0013] Furthermore, in a preferred embodiment of the present invention, it also includes a shot blasting process or a grinding process; the shot blasting process includes: sequentially performing shot blasting treatment on the strengthening layer, checking the stress state of the strengthening surface, sand blasting treatment on the strengthening layer, and checking the stress state of the strengthening surface; the grinding process includes: sequentially performing hard grinding wheel grinding on the strengthening layer, checking the stress state of the strengthening surface, soft grinding wheel grinding on the strengthening layer, and checking the stress state of the strengthening surface.

[0014] The beneficial effects of the high energy density irradiation process for treating the rail reinforcement layer provided by the present invention are:

[0015] (1) This application is a subsequent treatment process for the strengthening layer after the surface strengthening treatment of the rail is performed based on high-energy instantaneous quenching technology. The process of the present application is based on the principle of using high-density energy (taking a plasma generator as an example) to irradiate or scan the strengthening layer over a short distance and for a short time. The plasma medium gas is nitrogen, argon, helium, or a combination of these. The gas is ionized by a high-voltage current in the plasma generator and ejected through a confined channel. It has the characteristics of high energy density and easy temperature control. The plasma jet is irradiated on the surface of the strengthening layer, and the temperature of the plasma-strengthened layer can be increased to 1200°C within 0-3 seconds. During this process, the coarse-grained martensite structure on the surface is fully decomposed into a tempered structure, adjusting the hardness of the strengthening layer and increasing the toughness of the strengthening layer. It can eliminate or change the tensile stress state of the strengthening layer and refine the coarse-grained structure on the surface of the strengthening layer, and refine the metallographic structure of the microcrystalline martensite in the strengthening layer, thereby improving the toughness and fatigue resistance of the strengthening layer. It then prevents the strengthening layer from peeling off due to internal cracks during the external compressive stress cycle, and can greatly extend the service life of the high-energy instantaneous treated rail.

[0016] (2) The use of shot blasting or grinding technology in conjunction with high energy density irradiation technology can further eliminate or reduce surface tensile stress and refine the coarse grain structure on the surface of the strengthening layer. DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0018] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0019] Example 1

[0020] This embodiment provides a high energy density irradiation process for treating the rail reinforcement layer, including: the rail is subjected to high energy instant quenching technology, and then the rail is inspected in sequence, using an energy density of 10 3 w / cm 2 The plasma beam irradiates the surface of the strengthening layer for 800ms, and after heating to 100℃, it is kept warm with thermal insulation cotton and tested.

[0021] Example 2

[0022] This embodiment provides a high energy density irradiation process for treating the rail reinforcement layer, including: the rail is subjected to high energy instant quenching technology, and then the rail is inspected in sequence, using an energy density of 10 9 w / cm 2The plasma beam irradiates the surface of the strengthening layer for 100ms, and after heating to 500℃, it is kept warm with thermal insulation cotton and tested.

[0023] Example 3

[0024] This embodiment provides a high energy density irradiation process for treating the rail reinforcement layer, including: the rail is subjected to high energy instant quenching technology, and then the rail is inspected in sequence, using an energy density of 10 6 w / cm 2 The plasma beam irradiates the surface of the strengthening layer for 500ms, and after heating to 400℃, it is kept warm with thermal insulation cotton and tested.

[0025] In summary, the high-energy-density irradiation process for treating the rail reinforcement layer provided by the present invention can eliminate or reduce the tensile stress on the surface of the rail reinforcement layer and refine the coarse-grained structure on the surface of the rail reinforcement layer, thereby improving the toughness and fatigue resistance of the reinforcement layer structure, preventing the reinforcement layer from peeling off due to internal cracks during the external compressive stress cycle, and greatly extending the service life of the rail after being treated with high-energy instant quenching technology; this process plays a vital role in ensuring the quality and safety of the entire high-energy beam reinforced rail.

[0026] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A high energy density irradiation process for treating a rail reinforcement layer, comprising: The rails are inspected in turn after high energy instant quenching technology, using an energy density of 10 3 -10 9 w / cm 2 The plasma beam is intermittently and discretely irradiated on the surface of the strengthening layer for 100-800ms; then the temperature is raised to 100-500℃, and insulation cotton is used for insulation and detection; it is characterized in that: it also includes using a shot blasting process or a grinding process to treat the said strengthening layer; the said shot blasting process includes: shot blasting the strengthening layer in sequence, checking the stress state of the strengthening surface, sand blasting the strengthening layer, and checking the stress state of the strengthening surface; the said grinding process includes: grinding the strengthening layer with a hard grinding wheel in sequence, checking the stress state of the strengthening surface, grinding the strengthening layer with a soft grinding wheel and checking the stress state of the strengthening surface.