Anti-rust coating spraying device and spraying method in steel production process

Abstract

The invention discloses an anti-rust coating spraying device and method in the steel production process, and belongs to the technical field of metal smelting, the anti-rust coating spraying device comprises an anode nozzle, a cathode bar, a molten particle jet flow nozzle, a solid-phase particle jet flow nozzle and a working gas channel. A plasma arc formed between the anode nozzle and the cathode bar ionizes the working gas into a high-temperature jet flow. The coating powder in the molten particle jet nozzle is heated to a molten state by high-temperature jet, and forms a cladding layer on the surface of the steel after being sprayed out, and the cladding layer enhances the adhesive force of the antirust coating on the steel. Particles in the solid-phase particle jet flow nozzle receive part of heat of high-temperature jet flow, and the temperature of the particles is increased under the condition that the particles are kept in a solid phase, so that the particle grinding effect is enhanced. And the solid-phase particle jet flow nozzle is used for carrying out oil removal, rust removal and phosphating treatment on the surface of the steel in advance at the moving front end of the molten particle jet flow nozzle, so that the combination effect of molten particles and the surface of the steel is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of metal smelting technology, specifically a rust-preventive coating spraying device and spraying method in the steel production process. Background Technology

[0002] As a fundamental material of modern industry, steel is highly susceptible to electrochemical corrosion in natural environments, leading to material loss, reduced strength, structural failure, and deterioration of appearance. Applying an effective anti-rust protective layer to the surface of steel products is a crucial process for extending their service life, ensuring structural safety, and maintaining their appearance and function.

[0003] Applying organic or ceramic coatings to steel surfaces is the most widely used and flexible method of rust prevention. By coating the steel surface with one or more layers of a continuous film formed by organic polymers or ceramics, the steel substrate is physically isolated from the corrosive environment, and chemical corrosion inhibition or cathodic protection is provided by rust-inhibiting pigments added to the formulation. However, many problems still exist in the practical application of rust-preventive coating spraying processes.

[0004] The adhesion between the coating and the steel substrate is crucial to the protective effect and service life. In existing technologies, if the pretreatment (such as degreasing, derusting, and phosphating) is not thorough, or if the coating formulation is not properly designed (such as poor wettability between the resin and the substrate or high internal stress), the adhesion may decrease, and the coating may easily blister, peel off, and lose its protective function.

[0005] Patent CN102146563A discloses a manufacturing process for intelligent temperature-regulating rails with a laser cladding layer and a heat-insulating coating. The process involves using laser cladding technology to clad a mixed powder layer onto the rail surface, followed by slow cooling of the rail surface, and finally coating the rail surface with a functional coating. This technology uses the cladding layer as a bonding transition layer, which can improve the bonding effect between the coating and the steel. However, the small area of ​​action per unit time in laser cladding technology leads to a long overall coating processing time and low efficiency. Furthermore, if the degreasing, rust removal, and phosphating treatment of the steel surface is incomplete, these defects will also affect the bonding effect between the cladding layer and the steel. Summary of the Invention

[0006] The purpose of this invention is to provide a rust-preventive coating spraying device and spraying method in the steel production process, so as to solve the problems mentioned in the prior art.

[0007] A rust-preventive coating spraying device is provided for the steel production process, comprising: An anode nozzle, which has an internal cavity structure; Cathode rod, which is used to generate an electric arc between itself and the anode nozzle; A molten particle jet nozzle is connected to the anode nozzle and located on the path of the central axis extension of the cathode rod; The solid-phase particle jet nozzle is connected to the anode nozzle and avoids the central axis extension path of the cathode rod; The working gas passage is connected to the anode nozzle.

[0008] As a further embodiment of the present invention: the sidewall of the solid particle jet nozzle is connected to a temperature-controlled gas channel.

[0009] The temperature-controlled gas channel injects cold gas into the solid-phase particle stream, actively absorbing the heat from the particles to prevent them from overheating and melting, ensuring that the solid-phase particles remain solid to perform their grinding function. The temperature-controlled gas channel provides an active jet temperature control mechanism to the solid-phase particle jet nozzle, compensating for temperature fluctuations caused by the high-temperature jet generated by plasma arc ionization during operation.

[0010] As a further embodiment of the present invention: a labyrinth path is provided inside the solid particle jet nozzle, and the temperature-controlled gas channel is connected upstream of the solid particle jet nozzle relative to the labyrinth path.

[0011] The maze path extends the combination time between the high-temperature jet and the cold gas, allowing them to mix thoroughly and cool evenly within the maze path. This prevents internal stress from forming on the steel surface after contact with the steel plate due to uneven airflow temperature, which could lead to steel deformation or even cracks.

[0012] As a further embodiment of the present invention: the maze path is a spiral-shaped extended channel formed within the solid-phase particle jet nozzle.

[0013] The spiral-shaped extension channel increases the time for the high-temperature jet to combine with the cold air, while the spiral structure maintains the turbulence of the airflow and reduces the energy dissipation of the airflow caused by the vortices generated by unnecessary forced obstruction structures.

[0014] As a further embodiment of the present invention, it also includes a first powder interface and a second powder interface, wherein the first powder interface is connected to the molten particle jet nozzle, and the second powder interface is connected downstream of the solid particle jet nozzle relative to the labyrinth path.

[0015] The first powder inlet supplies molten particles to the molten particle jet nozzle, while the second powder inlet supplies abrasive particles to the solid particle jet nozzle. The second powder inlet is located downstream of the labyrinth path. After the cold air and high-temperature jet fully combine, it carries the abrasive particles out, preventing the abrasive particles from eroding the inner wall during forced turning within the labyrinth path.

[0016] As a further embodiment of the present invention: a plurality of the solid-phase particle jet nozzles are arranged circumferentially around the molten particle jet nozzle.

[0017] The solid-phase particle jet is circumferentially distributed around the molten particle jet, ensuring that regardless of the direction the spraying device moves, the solid-phase particle jet always acts as a preceding step to treat the steel surface, eliminating the need for the spraying device to change direction and reducing the redundancy of the equipment mechanism. Furthermore, after the molten particle jet forms the cladding layer, the subsequent solid-phase particles pass over the surface of the cladding layer again to form a covering layer, providing initial cooling to the cladding layer.

[0018] As a further embodiment of the present invention: the portion of the solid particle jet nozzle near the output port has an extension section that is inclined radially outward.

[0019] The extension section drives the solid-phase particle jet to be ejected at a certain angle relative to the steel surface, forming a horizontal force component on the steel surface. This optimizes the action angle of the solid-phase particles, thereby enhancing their grinding effect. The conical angle of the solid-phase particles cutting into the steel surface forms a cleaning barrier, sweeping away the grinding waste and preventing it from being covered by the cladding layer.

[0020] As a further embodiment of the present invention: the solid particle jet nozzle forms a cavity that gradually narrows along the radial path of the anode nozzle and gradually expands after reaching the minimum narrowing point.

[0021] The integrated constriction and expansion structure within the cavity provides airflow compression, enhances the ejection velocity of the solid particle jet, and thus enhances the grinding effect.

[0022] As a further embodiment of the present invention: a heat insulation body is provided between the molten particle jet nozzle and the solid particle jet nozzle.

[0023] The heat insulation body forcibly blocks the heat conduction from the molten particle jet nozzle to the solid particle jet nozzle, preventing the solid particles from overheating and causing a phase transition, which would affect the particle grinding effect.

[0024] Another aspect of the present invention provides a method for spraying rust-preventive coatings during steel production, comprising the following steps: S1. The molten particle jet nozzle outputs a molten particle jet to the steel, and the solid particle jet nozzle outputs a solid particle jet to the steel, with the solid particle jet located at the moving front end of the molten particle jet. S2. After the molten particle jet forms a cladding layer on the steel surface, the steel is subjected to slow cooling treatment. S3. Spray an anti-rust coating onto the surface of the cladding layer.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The plasma arc formed between the anode nozzle and the cathode rod ionizes the working gas into a high-temperature jet. The paint powder in the molten particle jet nozzle is heated to a molten state by the high-temperature jet, and after being sprayed out, it forms a structurally transitional cladding layer on the steel surface. The cladding layer formed by the molten particles enhances the adhesion of the anti-rust coating to the steel.

[0026] 2. The particles in the solid-phase particle jet nozzle receive part of the heat from the high-temperature jet, increasing the particle temperature while maintaining the particle solid phase, thereby enhancing the particle grinding effect. The solid-phase particle jet nozzle pre-treats the steel surface with degreasing, derusting, and phosphating at the moving front end of the molten particle jet nozzle to enhance the bonding effect between the molten particles and the steel surface.

[0027] 3. The high-temperature jet formed by plasma arc ionization has a larger working surface than laser cladding, and the cladding layer covers a larger area per unit time, thus improving the efficiency of steel coating treatment. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this drawing or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of the anti-rust coating spraying device provided by the present invention.

[0030] In the figure: 1. Anode nozzle; 2. Cathode rod; 3. Molten particle jet nozzle; 4. Solid particle jet nozzle; 41. Labyrinth path; 42. Extension section; 5. Working gas channel; 6. Temperature-controlled gas channel; 71. First powder interface; 72. Second powder interface; 8. Heat insulation. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0032] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0033] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0034] Please see Figure 1 As shown, the anti-rust coating spraying device in the steel production process of this invention includes an anode nozzle 1, a cathode rod 2, a molten particle jet nozzle 3, a solid particle jet nozzle 4, and a working gas channel 5. The anode nozzle 1 has an internal cavity structure. The cathode rod 2 is used to generate an electric arc between itself and the anode nozzle 1. The molten particle jet nozzle 3 is connected to the anode nozzle 1 and located on the central axis extension path of the cathode rod 2. The solid particle jet nozzle 4 is connected to the anode nozzle 1 but avoids the central axis extension path of the cathode rod 2. The working gas channel 5 is connected to the anode nozzle 1.

[0035] The working gas channel 5 is used to supply ionized gas (such as argon or nitrogen) to the anode nozzle 1. An electric arc is generated between the cathode rod 2 and the anode nozzle 1. The internal structure of the anode nozzle 1 provides space for plasma arc generation, and the ionized working gas forms a high-temperature plasma jet. The molten particle jet nozzle 3 is located along the extension path of the cathode central axis and is directly heated by the plasma arc, causing the coating powder to melt. The solid particle jet nozzle 4 avoids the central axis, heating the particles while preventing the high-temperature arc from melting them. The molten particle jet nozzle 3 and the solid particle jet nozzle 4 move synchronously on the steel surface, with the solid particle jet nozzle 4 located at the leading edge of the movement. The solid particle jet nozzle 4 degreases, removes rust, and phosphates the steel surface through the ejected particle jet. Because the abrasive is at a high temperature, the impact of the abrasive on the steel surface causes localized heating, reducing the strength of the defective parts of the steel surface, increasing the crushing efficiency at that location, and improving the surface roughness of the steel. After the pretreatment by the solid particle jet nozzle 4, the molten particle jet nozzle 3 sprays molten particles into the treated area and forms a metallurgical bonding cladding layer.

[0036] Variations in arc discharge power, working gas flow rate, uneven energy distribution due to nozzle carbon buildup, and heat conduction from the molten particle jet nozzle 3 to the solid particle jet nozzle 4 all contribute to temperature fluctuations within the solid particle jet nozzle 4, leading to thermal instability of the solid particles. A real-time compensation system for plasma jet temperature fluctuations was established through a cold gas injection mechanism introduced via the temperature-controlled gas channel 6. This design addresses the inherent thermal instability of plasma processes by reducing the temperature fluctuation range of solid particles through forced convection heat transfer and flow field reconstruction. The cold gas ensures that the solid particle temperature remains below the material's softening point, guaranteeing that the particles impact the steel surface with intact solids and sharp edges, forcing the steel surface to heat up and achieving micro-coarsening to a depth greater than 20 μm, providing an anchoring foundation for the cladding layer.

[0037] A labyrinth path 41 is provided inside the solid-phase particle jet nozzle 4, and the temperature-controlled gas channel 6 is connected upstream of the solid-phase particle jet nozzle 4 relative to the labyrinth path 41. The labyrinth path 41, on the one hand, prolongs the gas mixing time, ensuring that the cold gas fully absorbs the heat from the high-temperature jet; on the other hand, it forces the airflow to change direction multiple times, breaking down temperature stratification, allowing the gas system to reach a thermal equilibrium state, avoiding localized sudden cooling and heating, and achieving temperature uniformity. This design reduces the temperature non-uniformity when the jet contacts the steel, eliminates non-uniform thermal stress sources, and prevents steel deformation and cracking.

[0038] Furthermore, the solid-phase particle jet nozzle 4 is provided with a spirally extending inner wall, and the labyrinth path 41 is a spirally extending channel formed within the solid-phase particle jet nozzle 4 by isolation through the spiral inner wall. The secondary flow effect induced by the spiral curvature replaces the traditional baffle, maintaining the turbulence intensity without physical obstruction. At the same time, the secondary flow effect forces the cold airflow and the high-temperature jet to be squeezed and mixed on the outside of the spiral channel.

[0039] Furthermore, the spraying device also includes a first powder interface 71 and a second powder interface 72. The powder particles used to form the cladding layer can be the same material or different material from the powder particles used for surface treatment. The first powder interface 71 is connected to the molten particle jet nozzle 3, and the second powder interface 72 is connected downstream of the solid particle jet nozzle 4 relative to the labyrinth path 41. The first powder interface 71 and the second powder interface 72 are respectively conveyed to their respective functional areas through independent conveying systems to precisely adjust the amount of molten particle jet and solid particle jet, thereby precisely controlling the thickness of the final cladding layer formed on the steel. In addition, by placing the second powder interface 72 downstream of the labyrinth path 41, the particle injection point is moved backward, and the abrasive particles output by the second powder interface 72 avoid the labyrinth path 41, avoiding impact on the inner wall of the channel and causing channel wear, as well as avoiding blunting of the edges caused by particle collisions within the channel.

[0040] Specifically, multiple solid particle jet nozzles 4 are arranged circumferentially around the molten particle jet nozzle 3. This arrangement eliminates steering dependence, ensuring that regardless of the equipment's direction of travel, a set of solid nozzles is always located at the front of the movement, eliminating the need for rotational positioning and improving equipment response speed. Furthermore, the solid particles impact the steel before the molten jet, and during their journey, the rear-end solid particles cover the newly formed cladding layer. The low-temperature particle cluster forms a porous covering layer, providing initial cooling.

[0041] The solid particle jet nozzle 4 has a radially outward inclined extension section 42 near the output port, creating an angle of 40°-70° between the solid particle jet and the steel surface. The radially outward inclined design of the extension section 42 achieves kinematic decomposition of the solid particles: the normal impact component ensures sufficient grinding depth; the tangential shear component generates horizontal shear force, simultaneously driving the waste material forward. The solid particle stream cuts into the leading edge of the cladding layer at a conical angle, forming a physical isolation zone that sweeps away oxide scale and oil stains from the treatment area, eliminating inclusion defects in the cladding layer. This breaks the single-degree-of-freedom limitation of traditional vertical jetting, integrating grinding and cleaning functions.

[0042] The solid-phase particle jet nozzle 4 forms a cavity that gradually narrows along the radial path of the anode nozzle 1 and gradually expands at the minimum narrowing point. This structure relies on the Venturi effect to generate negative pressure adsorption, which forces the gas to accelerate. The magnitude increase in particle kinetic energy is directly converted into deep grinding force, which is beneficial for removing thick rust layers. The flow field focusing causes the particle cluster to act on the target area, eliminating the edge attenuation effect.

[0043] In one embodiment, after a constriction-expansion integrated Venturi tube structure is formed inside the solid particle jet nozzle 4, an extension section 42 that is radially outward is formed at the flared end, which forces the jet to accelerate and change the injection angle under the guidance of the inner wall of the extension section 42, forming an action surface with a cone angle between it and the steel.

[0044] In one embodiment, the solid particle jet nozzle 4 is provided with a temperature-controlled gas channel 6, a labyrinth path 41, a second powder interface 72, and a constriction-expansion integrated cavity along its length. The cold air input into the temperature-controlled gas channel 6 is fully mixed with the high-temperature jet in the labyrinth path 41 and then flows through the second powder interface 72, carrying solid particles. After being accelerated through the venturi cavity, it forms a solid particle jet that is ejected.

[0045] A heat insulation body 8 is provided between the molten particle jet nozzle 3 and the solid particle jet nozzle 4. The heat insulation body 8 can be composed of multiple layers of composite insulation materials, such as a composite layer of ceramic fiber and aerogel, which is inserted between the molten particle jet nozzle 3 and the solid particle jet nozzle 4 to form a physical isolation layer, which constitutes a thermal resistance barrier and forcibly maintains the respective temperature state of the molten particle jet nozzle 3 and the solid particle jet nozzle 4.

[0046] Another aspect of the present invention provides a method for spraying rust-preventive coatings during steel production, comprising the following steps: Step 1: Molten particle jet nozzle 3 outputs molten particle jet to the steel, and solid particle jet nozzle 4 outputs solid particle jet to the steel, with the solid particle jet located at the moving front end of the molten particle jet.

[0047] Step 2: After the molten particle jet forms a cladding layer on the steel surface, the steel is subjected to slow cooling treatment.

[0048] Step 3: Spray an anti-rust coating onto the surface of the cladding layer.

[0049] Example 1 The steel with grade Q355B was treated with anti-rust coating. The surface of the steel was in the state of having an oil film and slight rust spots. The molten particles were ZnAl15 alloy with a size of 45μm-75μm, and the solid particles were Al2O3 ceramic microspheres with a size of 20μm-50μm.

[0050] Step 1: The molten particle jet nozzle 3 outputs a ZnAl15 alloy molten particle jet to the steel, and the solid particle jet nozzle 4 outputs an Al2O3 ceramic microsphere solid particle jet to the steel. The solid particle jet performs degreasing, derusting and phosphating treatment on the steel surface at the front end of the molten particle jet.

[0051] Step 2: The ZnAl15 alloy molten particles form a 0.5mm-1mm cladding layer on the steel surface, and the material is slowly cooled for 100 minutes; Step 3: After the final temperature of the steel surface is ≤80℃, spray a 60μm epoxy zinc-rich primer and a 40μm polyurethane topcoat onto the cladding layer surface in sequence.

[0052] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A rust-preventive coating spraying device for steel production, characterized in that, include: Anode nozzle (1) has an internal cavity structure; A cathode rod (2) is used to generate an electric arc between itself and the anode nozzle (1); The molten particle jet nozzle (3) is connected to the anode nozzle (1) and is located on the central axis extension path of the cathode rod (2); The solid-phase particle jet nozzle (4) is connected to the anode nozzle (1) and avoids the central axis extension path of the cathode rod (2); The working gas channel (5) is connected to the anode nozzle (1).

2. The anti-rust coating spraying device in the steel production process according to claim 1, characterized in that, The sidewall of the solid particle jet nozzle (4) is connected to a temperature-controlled gas channel (6).

3. The anti-rust coating spraying device in the steel production process according to claim 2, characterized in that, The solid particle jet nozzle (4) is provided with a maze path (41), and the temperature-controlled gas channel (6) is connected upstream of the solid particle jet nozzle (4) relative to the maze path (41).

4. A rust-preventive coating spraying device in the steel production process according to claim 3, characterized in that, The maze path (41) is a spiral-shaped extended channel formed within the solid particle jet nozzle (4).

5. A rust-preventive coating spraying device in the steel production process according to claim 3, characterized in that, It also includes a first powder interface (71) and a second powder interface (72), the first powder interface (71) being connected to the molten particle jet nozzle (3), and the second powder interface (72) being connected downstream of the solid particle jet nozzle (4) relative to the maze path (41).

6. A rust-preventive coating spraying device in the steel production process according to claim 1, characterized in that, Multiple solid particle jet nozzles (4) are arranged circumferentially around the molten particle jet nozzle (3).

7. A rust-preventive coating spraying device in the steel production process according to claim 6, characterized in that, The solid particle jet nozzle (4) has a radially outwardly inclined extension (42) near the outlet.

8. A rust-preventive coating spraying device in the steel production process according to claim 6, characterized in that, The solid particle jet nozzle (4) forms a cavity that gradually narrows along the radial path of the anode nozzle (1) and gradually expands after reaching the minimum narrowing point.

9. A rust-preventive coating spraying device in the steel production process according to claim 1, characterized in that, A heat insulation body (8) is provided between the molten particle jet nozzle (3) and the solid particle jet nozzle (4).

10. A method for spraying rust-preventive coating in a steel production process, implemented using the spraying device as described in claim 1, characterized in that, Includes the following steps: S1. Molten particle jet nozzle (3) outputs molten particle jet to steel, and solid particle jet nozzle (4) outputs solid particle jet to steel, and the solid particle jet is located at the moving front end of the molten particle jet. S2. After the molten particle jet forms a cladding layer on the steel surface, the steel is subjected to slow cooling treatment. S3. Spray an anti-rust coating onto the surface of the cladding layer.

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