Anti-corrosion coating for heavy haul railway steel rail and coating method of anti-corrosion coating

Abstract

The invention relates to an anti-corrosion coating for a heavy haul railway steel rail and a coating method of the anti-corrosion coating. The coating comprises an alloy layer tightly attached to the heavy haul railway steel rail and a passivation layer arranged on the outer side of the alloy layer. By adopting the double-layer structure of the alloy layer and the passivation layer, the obtained coating is high in adhesive force and high in wear resistance. The passivation layer not only plays a role in passivation, but also plays a role in hole sealing.

Description

Technical Field

[0001] The present invention relates to an anti-corrosion coating for heavy-haul railway rails and a coating method thereof. Background Art

[0002] In recent years, with the continuous advancement of heavy-haul railway engineering construction, the problem of rail corrosion failure has also become an issue that cannot be ignored and restricts the safe operation of heavy-haul railways.

[0003] When rails are long-term exposed to complex corrosion environments such as humidity, rainfall, polluted gases, acid-base-salt solutions, etc., serious corrosion phenomena will occur. Corrosion will cause the surface of the rails to become loose, the effective cross-sectional area to decrease, and the mechanical properties to decline. There may even be a sudden rail breakage, leading to transportation safety problems. It is found through research that the rusting of the rail waist and rail bottom in the rail structure is particularly serious. The corrosion pits generated by the rusting of the rail bottom will cause local stress concentration of the rail, triggering corrosion fatigue fracture of the rail. Data literature and research statistics show that the cases of rail failure caused by the rusting of the rail bottom account for the highest proportion in all rail failure cases of the line, reaching more than about 40%. At present, the corrosion fatigue fracture of rails in China mostly occurs in severely corroded sections of heavy-haul coal transportation railways. Especially for the rails of heavy-haul coal transportation railway lines, on the one hand, the use of antifreeze by coal transportation trains accelerates the development of rust pits, and on the other hand, due to the large axle load and large traffic volume of heavy-haul railways, the rust pits at the rail bottom are more likely to develop into crack sources. For example, there have been many incidents of rail fractures caused by rust on the Datong-Qinhuangdao line. Even in some cases of rail breakage caused by rail rust, the service life of some rails does not exceed 2 years. Frequent rail replacement not only increases the working intensity of workers, but also significantly affects the normal railway transportation plan arrangement and increases the overall maintenance cost of the railway. Among them, the cost generated by the rail replacement skylight is much higher than the cost of the rails.

[0004] Due to the high operation density and short maintenance time of heavy-haul railways, in order to reduce on-site operations and extend the service life of rails, the requirements for the anti-corrosion performance of metal parts are getting higher and higher. The measures to enhance the anti-corrosion performance of rails abroad are as follows: one is to add metal elements such as Mo, Cr, Cu, etc. to the rails; the second is to spray anti-rust oil on the surface of the rails; the third is to conduct composite protection on the tunnel railway track surface. The domestic research on rail anti-corrosion mainly includes the following: one is to optimize the alloy composition of rail steel; the second is to add rare earth elements to the rail composition; the third is to automatically spray special anti-rust oil on the side of railway rails. However, these anti-corrosion measures for railway rail metal components all have problems such as high cost and general anti-corrosion effect, and some protection measures also cause environmental pollution, etc.

[0005] At present, the following obvious problems exist in the rail anti-corrosion technology on the market:

[0006] (1) When using a zinc-rich coating to conduct anti-corrosion treatment on rails, the adhesion is low, the durability is poor, and it is not resistant to bumps.

[0007] (2) Anti-corrosion treatment of steel rails with waterborne coatings cannot ensure the thickness of the coating at the rail bottom, and the corrosion resistance of the coating can only meet the anti-rust requirement for half a year.

[0008] (3) Anti-corrosion treatment of steel rails with oil-based high anti-corrosion coatings has great environmental protection pressure and high costs.

[0009] (4) Anti-corrosion treatment of steel rails with heavy anti-corrosion coatings requires heating the steel rails to above 200 °C, and the spraying construction is difficult.

[0010] (5) The cost of high-strength corrosion-resistant steel rails is too high.

[0011] (6) The environment of heavy-haul railways is harsh, facing environments such as pulverized coal falling off and covering the upper surface of the rail bottom, antifreeze dripping on the steel rails, and fretting wear. At present, there is no anti-corrosion technology for steel rails in the corrosion environment of heavy-haul railways. The existing anti-corrosion technologies can no longer meet the needs of the safe operation and maintenance of heavy-haul railways in China. Summary of the Invention

[0012] In order to overcome the defects of the above-mentioned existing technologies, the present invention provides an anti-corrosion coating for heavy-haul railway steel rails and its coating method. The long-term anti-corrosion coating of the present invention has high adhesion and high wear resistance. The anti-corrosion coating for heavy-haul railway steel rails involved in the present invention adopts a unique alloy coating plus passivation and sealing composite formula. After strict testing, its adhesion is twice that of traditional epoxy zinc-rich anti-corrosion coatings, and it can still be tightly attached to the surface of the steel rails under the extreme working conditions of frequent rolling of heavy-haul trains, greatly reducing the risk of steel rail corrosion caused by coating peeling. In terms of wear resistance, the wear resistance of its alloy coating is much greater than that of the organic coating, and it can effectively maintain its own integrity and continuously provide a protective barrier for the steel rails.

[0013] On the one hand, the present invention provides an anti-corrosion coating for heavy-haul railway steel rails, which includes an alloy layer closely attached to the heavy-haul railway steel rails and a passivation layer provided outside the alloy layer.

[0014] Preferably, the alloy layer is composed of zinc, magnesium, and aluminum alloy wires;

[0015] Preferably, the diameter of the alloy wire is 1 mm to 3 mm, preferably 1.2 mm;

[0016] Preferably, in the alloy layer, aluminum is 3 to 25 wt.%, magnesium is 1 to 5 wt.%, and the balance is zinc;

[0017] Preferably, in the alloy layer, aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%.

[0018] Preferably, the thickness of the alloy layer is 80 μm to 100 μm.

[0019] Preferably, by mass parts, the passivation layer is composed of 8-10 parts of silane coupling agent, 37-45 parts of silicate, and 0.01-0.1 parts of silicate.

[0020] Preferably, the thickness of the passivation layer is 1-10 μm.

[0021] Preferably, the anti-corrosion coating is provided at the bottom of the heavy-haul railway rail, as Figure 1 shown.

[0022] The present invention adopts a double-layer structure of an alloy layer and a passivation layer, and the obtained coating has high adhesion and high wear resistance. The passivation layer of the present invention not only plays a passivation role but also plays a sealing role.

[0023] Aiming at the corrosion problem of heavy-haul railway rails, the present invention designs a unique double-layer structure coating system of an alloy layer and a passivation layer. Each layer has its own characteristics and works together to create excellent adhesion and wear resistance.

[0024] First of all, the alloy layer is made by melting and atomizing a variety of metal elements in a specific ratio and then spraying it on the surface of the rail. These metal elements are carefully formulated to form a microscopic structure that tightly interlocks with the rail substrate during the solidification process, resulting in a strong mechanical anchoring effect between the coating and the rail, just like a mortise and tenon connection, greatly improving the initial adhesion of the coating. At the same time, the alloy layer itself has a good balance of toughness and hardness, and can buffer energy through its own deformation without brittle cracking and peeling, providing a stable support for the upper passivation layer and continuously ensuring the attachment state of the overall coating to the rail.

[0025] The passivation layer is another key innovation point of the present invention. The passivation layer is composed of an organic and inorganic hybrid material containing a special passivating agent. On the one hand, the active components in the passivating agent can quickly react with the metal atoms exposed on the alloy layer to form a dense and stable passivation film, effectively blocking the erosion of external corrosive media such as rainwater and salts on the rail, which is its key passivation function. On the other hand, this hybrid material will fill the tiny pores on the surface of the alloy layer during the curing process to form a continuous and smooth closed interface, just like putting on a "seamless armor" for the coating system, which not only avoids the penetration of corrosive media through the pores to the bottom of the coating to cause corrosion, but also reduces the internal stress concentration points during the friction process of the coating, enabling the entire coating to still maintain its structural integrity under repeated friction and significantly enhancing the wear resistance.

[0026] To sum up, the alloy layer and the passivation layer complement each other. With their unique material compositions and structural characteristics, they endow the anti-corrosion coating of the present invention with excellent properties of high adhesion and high wear resistance, providing a reliable guarantee for the long-term protection of heavy-haul railway rails.

[0027] On the other hand, the present invention provides a coating method for the long-term anti-corrosion coating of the above-mentioned heavy-haul railway rail, and the method comprises the following steps:

[0028] (1) Pretreatment

[0029] Before coating, the surface of the heavy-haul railway rail is subjected to sandblasting treatment so that the cleanliness of the surface of the heavy-haul railway rail is Sa3 level and the roughness is 10 μm - 30 μm, and the treated heavy-haul railway rail is obtained;

[0030] (2) Coating the alloy layer

[0031] The surface of the treated heavy-haul railway rail obtained in step (1) is thermally sprayed with an alloy layer by using a wire arc spray gun, and the heavy-haul railway rail coated with the alloy layer is obtained;

[0032] (3) Coating the passivation layer

[0033] The water-based passivation liquid is coated onto the heavy-haul railway rail coated with the alloy layer obtained in step (2) by means of brushing or rolling to obtain the product.

[0034] Preferably, in step (1), the sand is composed of G18 steel sand with a particle size of 1.0 mm - 1.2 mm and G25 steel sand with a particle size of 0.7 mm - 1.0 mm;

[0035] Preferably, in the sand, the mass ratio between the G18 steel sand with a particle size of 1.0 mm - 1.2 mm and the G25 steel sand with a particle size of 0.7 mm - 1.0 mm is 0.5 - 5, preferably 80:20.

[0036] Preferably, in step (2), the alloy layer is composed of zinc, magnesium, and aluminum alloy wires;

[0037] Preferably, in step (2), the diameter of the alloy wire is 1 mm - 3 mm, preferably 1.2 mm;

[0038] Preferably, in step (2), in the alloy layer, aluminum is 3 - 25 wt.%, magnesium is 1 - 5 wt.%, and the balance is zinc;

[0039] Preferably, in step (2), in the alloy layer, aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%.

[0040] Preferably, in step (2), the thickness of the alloy layer is 80 μm - 100 μm.

[0041] Preferably, in step (2), the voltage of the thermal spraying is 25 V - 30 V.

[0042] Preferably, in step (2), the pressure of the air compressor for thermal spraying is above 0.6 MPa, preferably 0.8 MPa.

[0043] Preferably, in step (2), the thermal spraying includes using a spray gun for thermal spraying.

[0044] Preferably, in step (2), a nozzle is provided on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm.

[0045] Preferably, in step (2), a nozzle is provided on the spray gun, and the spraying angle between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is > 60°.

[0046] Preferably, in step (3), by mass, the aqueous passivation solution includes 8 to 10 parts of silane coupling agent, 37 to 45 parts of silicate, 45 to 55 parts of deionized water, and 0.01 to 0.1 part of silicate.

[0047] Preferably, in step (3), the pH value of the aqueous passivation solution is > 10.

[0048] In a specific embodiment, the coating method of the present invention includes the following steps:

[0049] (1) Pretreatment

[0050] Before spraying, Figure 1 The surface of the rail at the red line part shown is sandblasted so that the cleanliness of the rail surface is Sa3 level and the roughness is 10 μm - 30 μm, obtaining a treated heavy-haul railway rail; wherein, the sand is bearing steel sand, and G18 steel sand with a particle size of 1.0 mm to 1.2 mm and G25 steel sand with a particle size of 0.7 mm to 1.0 mm are proportioned according to the ratio of G18:G25 = 80:20.

[0051] (2) Coating the alloy layer

[0052] Using a wire arc spray gun to thermally spray the surface of the treated heavy-haul railway rail obtained in step (1), obtaining a heavy-haul railway rail coated with an alloy layer;

[0053] Wherein, the wire is a zinc-aluminum alloy wire, wherein aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%, and the diameter of the wire is 1.2 mm;

[0054] Wherein, the working voltage of the thermal spraying equipment is 25 V to 30 V, and the compressed air pressure of the thermal spraying air compressor is above 0.6 MPa, preferably 0.8 MPa;

[0055] Among them, the thermal spraying includes a spray gun, and a nozzle is provided on the spray gun. The spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm, and the spraying angle is > 60°;

[0056] Among them, the thickness of the alloy coating obtained in this step is 80 μm to 100 μm, the adhesion force is greater than 20 Mpa, and there is no missed spraying.

[0057] (3) Coating the passivation layer

[0058] Adopt the brushing or rolling method to coat the water-based passivation liquid onto the heavy-haul railway rail coated with the alloy layer obtained in step (2) for passivation and sealing hole treatment;

[0059] Among them, by mass, the water-based passivation liquid includes 8 to 10 parts of silane coupling agent, 37 to 45 parts of silicate, 45 to 55 parts of deionized water, and 0.01 to 0.1 part of silicate, and the pH value of the water-based passivation liquid > 10.

[0060] The present invention protects the rail for the complex and harsh corrosion environment of heavy-haul railways, which not only meets the requirements of corrosion resistance but also meets the requirements of wear resistance.

[0061] Adopting the coating method of the present invention does not require improvement of the metallurgical composition of the rail, nor does it require heating of the rail, with low cost and mild conditions.

[0062] The water-based passivation liquid used in the present invention is environmentally friendly. Using this water-based passivation liquid to seal the alloy layer can improve the durability and anti-corrosion performance of the coating.

[0063] The coating method of the present invention has high spraying efficiency, does not require heat treatment, and the obtained coating has high adhesion, high corrosion resistance, and high weather resistance, and can effectively defend against the corrosion of the rail in the heavy-haul environment with low comprehensive cost.

[0064] Compared with the prior art, the present invention has at least the following technical advantages:

[0065] The present invention does not use an organic coating, but uses an alloy layer and a passivation layer, which have high adhesion and high wear resistance.

[0066] If only the alloy layer is used to protect heavy-haul railway rails, although the alloy layer itself has certain advantages. For example, the microstructure formed by melting and spraying a variety of metal elements in a specific ratio can tightly bite with the rail substrate, improving the initial adhesion. And its good balance of toughness and hardness can buffer the wheel impact to a certain extent, ensuring that the coating does not peel off easily. However, the alloy layer has some limitations that cannot be ignored. Since there are inevitably some tiny pores on its surface, in the long-term complex service environment, external corrosive media such as rainwater and salts are likely to penetrate through these pores to the interface between the coating and the rail, thus triggering corrosion phenomena, gradually weakening the bonding force between the coating and the rail, and resulting in a significant decrease in adhesion over time. Moreover, in the face of the frequent and intense friction between the wheel and the rail, these pores on the surface of the alloy layer are also prone to become stress concentration points, causing the coating to be more easily worn and peeled in local areas, making it difficult to maintain a high level of overall wear resistance and unable to meet the requirements of long-term and efficient protection of heavy-haul railway rails.

[0067] When the structure combining the alloy layer and the passivation layer of the present invention is adopted, the situation is greatly improved. The alloy layer still plays its basic role of tightly bonding with the rail substrate and buffering impact, providing a stable bottom support for the entire coating system. And the addition of the passivation layer plays a key role in making up for and strengthening. The passivation layer is composed of an organic-inorganic hybrid material containing a special passivating agent. The active components in the passivating agent will quickly react with the metal atoms exposed on the rail surface and the alloy layer to generate a dense and stable passivation film, fundamentally preventing the erosion of the corrosive media on the rail and the alloy layer, which is an advantage that the single alloy layer does not have. At the same time, during the curing process of this hybrid material, it can accurately fill the tiny pores on the surface of the alloy layer to form a continuous and smooth closed interface, which is equivalent to putting a "protective coat" on the alloy layer, completely eliminating the hidden danger of the corrosive media penetrating through the pores, and effectively ensuring that the adhesion between the coating and the rail can be stably maintained at a high level for a long time. And during the friction process, this seamless closed interface reduces the internal stress concentration, making the overall structure of the coating more complete, greatly enhancing the wear resistance of the coating. Compared with using only the alloy layer, the wear amount of the coating is reduced, and it can provide long-term and reliable protection for heavy-haul railway rails.

[0068] In summary, the present invention combines the alloy layer and the passivation layer, and through their synergistic effect, effectively overcomes the deficiencies of using only the alloy layer, realizes the excellent performance of high adhesion and high wear resistance, shows obvious advantages over the single alloy layer protection, and has outstanding application value in the field of heavy-haul railway rail anti-corrosion.

[0069] The present invention does not need to improve the metallurgical composition of the rail and has low cost.

[0070] The present invention does not use an oily organic coating. When coating the alloy layer and the passivation layer, only an aqueous passivation solution is used. This aqueous passivation solution is environmentally friendly and has no environmental protection problems.

[0071] The present invention does not require heating the rail, and the conditions are mild and easy to achieve.

[0072] The present invention further improves the coating durability and anti-corrosion performance by using an aqueous passivation solution for sealing holes on the surface of the alloy layer.

[0073] The present invention can meet the anti-corrosion requirements during the long-term storage and service of heavy-haul railway rails, conforms to the development trend of the long-life of railway track infrastructure, can effectively reduce the failure problems caused by the corrosion of metal components, ensure transportation safety, and has remarkable economic and social benefits. Brief Description of the Drawings

[0074] Figure 1 It is a schematic diagram of the cross-sectional structure of the rail. Among them, 1 is the rail head, 2 is the rail web, and 3 is the rail base (the marked red part). Detailed Embodiments

[0075] The following further illustrates the present invention in conjunction with specific embodiments and the drawings. However, the embodiments do not limit the present invention in any form. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0076] Example 1: Coating Method of the Present Invention

[0077] (1) Pretreatment

[0078] Before spraying, Figure 1 The surface of the rail at the red line part shown in the figure is sandblasted so that the cleanliness of the rail surface is Sa3 level and the roughness is 10μm - 30μm, obtaining the treated heavy-haul railway rail; among them, the sand is bearing steel sand, and the G18 steel sand with a particle size of 1.0mm - 1.2mm and the G25 steel sand with a particle size of 0.7mm - 1.0mm are proportioned according to the ratio of G18:G25 = 80:20.

[0079] (2) Coating the alloy layer

[0080] The surface of the treated heavy-haul railway rail obtained in step (1) is thermally sprayed by using a wire arc spray gun, obtaining a heavy-haul railway rail coated with an alloy layer;

[0081] Among them, the wire is a zinc-aluminum alloy wire, in which aluminum is 15wt.%, magnesium is 2wt.%, and zinc is 83wt.%, and the diameter of the wire is 1.2mm;

[0082] Among them, the working voltage of the thermal spraying equipment is 25V - 30V, and the compressed air pressure of the thermal spraying air compressor is 0.8MPa;

[0083] Among them, the thermal spraying includes a spray gun, a nozzle is provided on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in the step (1) is 250mm - 300mm, and the spraying angle is > 60°;

[0084] Among them, the thickness of the alloy coating obtained in this step is 80μm - 100μm.

[0085] (3) Coating the passivation layer

[0086] Adopt the brushing or rolling method to coat the water-based passivation liquid onto the heavy-haul railway rail coated with the alloy layer obtained in the step (2) for passivation and sealing treatment;

[0087] Among them, the water-based passivation liquid includes 10g of silane coupling agent, 37g of silicate, 20g of deionized water and 0.05g of silicate, and the pH value of the water-based passivation liquid is > 10.

[0088] Example 2: The coating method of the present invention

[0089] (1) Pretreatment

[0090] Before spraying, Figure 1 Sandblasting treatment is carried out on the surface of the rail at the position of the red line shown in the figure to make the cleanliness of the rail surface reach Sa3 level and the roughness reach 10μm - 30μm, and the treated heavy-haul railway rail is obtained; among them, the sand is bearing steel sand, and G18 steel sand with a particle size of 1.0mm - 1.2mm and G25 steel sand with a particle size of 0.7mm - 1.0mm are proportioned according to the ratio of G18:G25 = 80:20.

[0091] (2) Coating the alloy layer

[0092] Use a wire arc spray gun to thermally spray the surface of the treated heavy-haul railway rail obtained in the step (1) to obtain a heavy-haul railway rail coated with an alloy layer;

[0093] Among them, the wire is a zinc-aluminum alloy wire, in which aluminum is 5wt.%, magnesium is 2wt.%, and zinc is 93wt.%, and the diameter of the wire is 1.2mm;

[0094] Among them, the working voltage of the thermal spraying equipment is 25V - 30V, and the compressed air pressure of the thermal spraying air compressor is 0.8MPa;

[0095] Among them, the thermal spraying includes a spray gun, and a nozzle is provided on the spray gun. The spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm, and the spraying angle is > 60°;

[0096] Among them, the thickness of the alloy coating obtained in this step is 80 μm to 100 μm.

[0097] (3) Coating the passivation layer

[0098] By means of brushing or rolling, coat the water-based passivation liquid onto the heavy-haul railway rail coated with the alloy layer obtained in step (2) to perform passivation and sealing treatment;

[0099] Among them, the water-based passivation liquid includes 10 g of silane coupling agent, 37 g of silicate, 20 g of deionized water, and 0.05 g of silicate, and the pH value of the water-based passivation liquid is > 10.

[0100] Example 3: The coating method of the present invention

[0101] (1) Pretreatment

[0102] Before spraying, Figure 1 Perform sandblasting on the surface of the rail at the position of the red line shown in the figure to make the cleanliness of the rail surface reach Sa3 level and the roughness reach 10 μm - 30 μm, and obtain the treated heavy-haul railway rail; among them, the sand is bearing steel sand, and the G18 steel sand with a particle size of 1.0 mm to 1.2 mm and the G25 steel sand with a particle size of 0.7 mm to 1.0 mm are proportioned according to the ratio of G18:G25 = 80:20.

[0103] (2) Coating the alloy layer

[0104] Use a wire arc spray gun to perform thermal spraying on the surface of the treated heavy-haul railway rail obtained in step (1) to obtain a heavy-haul railway rail coated with an alloy layer;

[0105] Among them, the wire is a zinc-aluminum alloy wire, in which aluminum is 10 wt.%, magnesium is 2 wt.%, and zinc is 88 wt.%, and the diameter of the wire is 2 mm;

[0106] Among them, the working voltage of the thermal spraying equipment is 25 V to 30 V, and the compressed air pressure of the thermal spraying air compressor is 0.8 MPa;

[0107] Among them, the thermal spraying includes a spray gun, and a nozzle is provided on the spray gun. The spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm, and the spraying angle is > 60°;

[0108] Among them, the thickness of the alloy coating obtained in this step is 80 μm to 100 μm.

[0109] (3) Coating the passivation layer

[0110] Apply the aqueous passivation solution to the heavy-haul railway rail coated with the alloy layer obtained in step (2) by brushing or rolling to perform passivation and sealing treatment;

[0111] Among them, the aqueous passivation solution includes 10 g of silane coupling agent, 37 g of silicate, 20 g of deionized water and 0.05 g of silicate, and the pH value of the aqueous passivation solution > 10.

[0112] Comparative Example 1:

[0113] (1) Pretreatment

[0114] Before spraying, Figure 1 Sandblast the surface of the rail at the position of the red line shown to make the cleanliness of the rail surface reach Sa3 level and the roughness reach 10 μm - 30 μm, and obtain the treated heavy-haul railway rail; among them, the sand is bearing steel sand, and the G18 steel sand with a particle size of 1.0 mm to 1.2 mm and the G25 steel sand with a particle size of 0.7 mm to 1.0 mm are proportioned according to the ratio of G18:G25 = 80:20.

[0115] (2) Coating the alloy layer

[0116] Thermally spray the surface of the treated heavy-haul railway rail obtained in step (1) by using a wire arc spray gun to obtain a heavy-haul railway rail coated with an alloy layer;

[0117] Among them, the wire is a zinc-aluminum alloy wire, in which aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%, and the diameter of the wire is 1.2 mm;

[0118] Among them, the working voltage of the thermal spraying equipment is 25 V to 30 V, and the compressed air pressure of the thermal spraying air compressor is 0.8 MPa;

[0119] Among them, the thermal spraying includes a spray gun, a nozzle is provided on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm, and the spraying angle is > 60°;

[0120] Among them, the thickness of the alloy coating obtained in this step is 80 μm to 100 μm.

[0121] Comparative Example 2:

[0122] (1) Pretreatment

[0123] Before spraying,Figure 1 The surface of the rail at the red line part shown is sandblasted so that the cleanliness of the rail surface is Sa3 level and the roughness is 10μm - 30μm, obtaining a treated heavy - haul railway rail; wherein, the sand is bearing steel sand, and G18 steel sand with a particle size of 1.0mm - 1.2mm and G25 steel sand with a particle size of 0.7mm - 1.0mm are proportioned according to the ratio of G18:G25 = 80:20.

[0124] (2) Coating alloy layer

[0125] The surface of the treated heavy - haul railway rail obtained in step (1) is thermally sprayed by a wire - arc spray gun, obtaining a heavy - haul railway rail coated with an alloy layer;

[0126] wherein, the wire is a zinc - aluminum alloy wire, in which aluminum is 15wt.%, magnesium is 2wt.%, and zinc is 83wt.%, and the diameter of the wire is 1.2mm;

[0127] wherein, the working voltage of the thermal spraying equipment is 25V - 30V, and the compressed air pressure of the thermal spraying air compressor is 0.8MPa;

[0128] wherein, the thermal spraying includes a spray gun, and a nozzle is arranged on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy - haul railway rail obtained in step (1) is 250mm - 300mm, and the spraying angle is > 60°;

[0129] wherein, the thickness of the alloy coating obtained in this step is 10μm - 40μm.

[0130] (3) Coating passivation layer

[0131] The water - based passivation liquid is coated onto the heavy - haul railway rail coated with an alloy layer obtained in step (2) by brushing or rolling to carry out passivation and sealing treatment;

[0132] wherein, the water - based passivation liquid includes 10g of silane coupling agent, 37g of silicate, 20g of deionized water and 0.05g of silicate, and the pH value of the water - based passivation liquid > 10.

[0133] Comparative example 3:

[0134] (1) Pretreatment

[0135] Before spraying Figure 1The surface of the rail at the red line part shown is sandblasted so that the cleanliness of the rail surface is Sa3 level and the roughness is 10μm - 30μm, obtaining a treated heavy - haul railway rail; wherein, the sand is bearing steel sand, and G18 steel sand with a particle size of 1.0mm - 1.2mm and G25 steel sand with a particle size of 0.7mm - 1.0mm are proportioned according to the ratio of G18:G25 = 80:20.

[0136] (2) Coating the alloy layer

[0137] The surface of the treated heavy - haul railway rail obtained in step (1) is thermally sprayed using a wire - arc spray gun, obtaining a heavy - haul railway rail coated with an alloy layer;

[0138] wherein, the wire is a zinc wire, in which zinc is greater than 99wt.%, and the diameter of the wire is 1.2mm;

[0139] wherein, the working voltage of the thermal spraying equipment is 25V - 30V, and the compressed air pressure of the thermal spraying air compressor is 0.8MPa;

[0140] wherein, the thermal spraying includes a spray gun, a nozzle is arranged on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy - haul railway rail obtained in step (1) is 250mm - 300mm, and the spraying angle is > 60°;

[0141] wherein, the thickness of the alloy coating obtained in this step is 80μm - 100μm.

[0142] (3) Coating the passivation layer

[0143] The water - based passivation liquid is coated onto the heavy - haul railway rail coated with an alloy layer obtained in step (2) by brushing or rolling to carry out passivation and sealing - hole treatment;

[0144] wherein, the water - based passivation liquid includes 10g of silane coupling agent, 37g of silicate, 20g of deionized water and 0.05g of silicate, and the pH value of the water - based passivation liquid is > 10.

[0145] Comparative example 4:

[0146] (1) Pretreatment

[0147] Before spraying, Figure 1 The surface of the rail at the red line part shown is sandblasted so that the cleanliness of the rail surface is Sa3 level and the roughness is 10μm - 30μm, obtaining a treated heavy - haul railway rail; wherein, the sand is bearing steel sand, and G18 steel sand with a particle size of 1.0mm - 1.2mm and G25 steel sand with a particle size of 0.7mm - 1.0mm are proportioned according to the ratio of G18:G25 = 80:20.

[0148] (2) Coated alloy layer

[0149] Use a wire arc spray gun to thermally spray the surface of the treated heavy-haul railway rail obtained in step (1) to obtain a heavy-haul railway rail coated with an alloy layer;

[0150] Among them, the wire is a zinc-aluminum alloy wire, in which aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%, and the diameter of the wire is 1.2 mm;

[0151] Among them, the working voltage of the thermal spraying equipment is 25 V - 30 V, and the compressed air pressure of the thermal spraying air compressor is 0.4 MPa;

[0152] Among them, the thermal spraying includes a spray gun, and a nozzle is provided on the spray gun. The spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 100 mm - 200 mm, and the spraying angle is 30 - 45°;

[0153] Among them, the thickness of the alloy coating obtained in this step is 80 μm - 100 μm.

[0154] (3) Coated passivation layer

[0155] Use a brushing or rolling method to coat the water-based passivation liquid onto the heavy-haul railway rail coated with an alloy layer obtained in step (2) for passivation and sealing hole treatment;

[0156] Among them, the water-based passivation liquid includes 10 g of silane coupling agent, 37 g of silicate, 20 parts of deionized water, and 0.05 g of silicate, and the pH value of the water-based passivation liquid > 10.

[0157] Comparative example 5:

[0158] (1) Pretreatment

[0159] Before spraying, sandblast the surface of the rail at the position of the red line shown in Figure 1 to make the surface cleanliness of the rail reach Sa3 level and the roughness reach 10 μm - 30 μm, and obtain a treated heavy-haul railway rail; among them, the sand is bearing steel sand, and G18 steel sand with a particle size of 1.0 mm - 1.2 mm and G25 steel sand with a particle size of 0.7 mm - 1.0 mm are proportioned according to the ratio of G18:G25 = 80:20.

[0160] (2) Coated alloy layer

[0161] Use a wire arc spray gun to thermally spray the surface of the treated heavy-haul railway rail obtained in step (1) to obtain a heavy-haul railway rail coated with an alloy layer;

[0162] Among them, the wire material is a zinc-aluminum alloy wire material, in which aluminum is 15 wt.%, magnesium is 2 wt.%, zinc is 83 wt.%, and the diameter of the wire material is 1.2 mm;

[0163] Among them, the working voltage of the thermal spraying equipment is 25 V to 30 V, and the compressed air pressure of the thermal spraying air compressor is 0.8 MPa;

[0164] Among them, the thermal spraying includes a spray gun, a nozzle is provided on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm, and the spraying angle is > 60°;

[0165] Among them, the thickness of the alloy coating obtained in this step is 80 μm to 100 μm.

[0166] (3) Coating the passivation layer

[0167] Adopt the brushing or rolling method to coat the water-based passivation liquid on the heavy-haul railway rail coated with the alloy layer obtained in step (2) for passivation and sealing hole treatment;

[0168] Among them, the water-based passivation liquid includes 5 g of silane coupling agent, 42 g of silicate, 20 g of deionized water and 0.05 g of silicate, and the pH value of the water-based passivation liquid > 10.

[0169] Experimental example

[0170] In this experimental example, the adhesion and neutral salt spray corrosion resistance of the coatings of Examples 1-3 and Comparative Examples 1-5 were detected. The detection methods are as follows:

[0171] 1. Adhesion experiment: Refer to the standard requirements of GB / T 9793-2012 "Thermal Sprayed Metal and Other Inorganic Coatings Zinc, Aluminum and Their Alloys";

[0172] 2. Neutral salt spray corrosion resistance: The standard requirements of GB / T 10125-2022 "Artificial Atmosphere Corrosion Test Salt Spray Test";

[0173] The detection results are shown in Table 1 below.

[0174] Table 1 Coating performance results of Examples 1-3 and Comparative Examples 1-5

[0175]

[0176]

[0177] It can be seen from the above results that the results of Examples 1-3 are better than those of Comparative Examples 1-5, and Example 1 has the best salt spray resistance.

Claims

1. An anti-corrosion coating for heavy-haul railway rails, the coating comprising an alloy layer closely attached to the heavy-haul railway rails and a passivation layer provided outside the alloy layer.

2. The coating according to claim 1, wherein The alloy layer is composed of zinc, magnesium, and aluminum alloy wires; Preferably, the diameter of the alloy wires is 1 mm to 3 mm, preferably 1.2 mm.

3. The coating according to claim 1 or 2, wherein In the alloy layer, aluminum is 3 to 25 wt.%, magnesium is 1 to 5 wt.%, and the balance is zinc; Preferably, in the alloy layer, aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%.

4. The coating according to any one of claims 1 to 3, wherein The thickness of the alloy layer is 80 μm to 100 μm.

5. The coating according to any one of claims 1 to 4, wherein, By mass, the passivation layer is composed of 8 to 10 parts of silane coupling agent, 37 to 45 parts of silicate, and 0.01 to 0.1 part of silicate; Preferably, the thickness of the passivation layer is 1 to 10 μm; Preferably, the anti-corrosion coating is provided on the bottom of the heavy-haul railway rails.

6. A coating method for the coating according to any one of claims 1 to 5, the method comprising the following steps: (1) Pretreatment Before coating, the surface of the heavy-haul railway rails is subjected to sandblasting treatment so that the cleanliness of the surface of the heavy-haul railway rails is Sa3 level and the roughness is 10 μm - 30 μm, obtaining the treated heavy-haul railway rails; (2) Coating the alloy layer The surface of the treated heavy-haul railway rails obtained in step (1) is thermally sprayed with an alloy layer by a wire arc spray gun, obtaining the heavy-haul railway rails coated with the alloy layer; (3) Coating the passivation layer The water-based passivation liquid is coated onto the heavy-haul railway rails coated with the alloy layer obtained in step (2) by brushing or rolling, and that's it.

7. The painting method according to claim 6, wherein, In step (1), the sand is composed of G18 steel sand with a particle size of 1.0 mm to 1.2 mm and G25 steel sand with a particle size of 0.7 mm to 1.0 mm; Preferably, in the sand, the mass ratio between the G18 steel sand with a particle size of 1.0 mm to 1.2 mm and the G25 steel sand with a particle size of 0.7 mm to 1.0 mm is 0.5 to 5, preferably 80:

20.

8. The painting method according to claim 6 or 7, wherein In step (2), the alloy layer is composed of zinc, magnesium, and aluminum alloy wires; Preferably, in step (2), the diameter of the alloy wires is 1 mm to 3 mm, preferably 1.2 mm; Preferably, in step (2), in the alloy layer, aluminum is 3 to 25 wt.%, magnesium is 1 to 5 wt.%, and the balance is zinc; Preferably, in step (2), in the alloy layer, aluminum is 15 wt.%, magnesium is 2 wt.%, and zinc is 83 wt.%; Preferably, in step (2), the thickness of the alloy layer is 80 μm to 100 μm.

9. The painting method according to any one of claims 6 to 8, wherein, In step (2), the voltage of the thermal spraying is 25 V to 30 V; Preferably, in step (2), the pressure of the air compressor for the thermal spraying is above 0.6 MPa, preferably 0.8 MPa; Preferably, in step (2), the thermal spraying includes using a spray gun for thermal spraying; Preferably, in step (2), a nozzle is provided on the spray gun, and the spraying distance between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is 250 mm to 300 mm; Preferably, in step (2), a nozzle is provided on the spray gun, and the spraying angle between the nozzle and the surface of the treated heavy-haul railway rail obtained in step (1) is > 60°.

10. The painting method according to any one of claims 6 to 9, wherein, In step (3), by mass, the aqueous passivation solution comprises 8 to 10 parts of silane coupling agent, 37 to 45 parts of silicate, 45 to 55 parts of deionized water, and 0.01 to 0.1 part of silicate; Preferably, in step (3), the pH value of the aqueous passivation solution is > 10.

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