A directional multilayer structure heavy-duty stainless steel thick coating material and a method for manufacturing the same

Abstract

The application discloses a kind of directional multilayer structure heavy load stainless steel thick coating material and preparation method thereof, it is related to stainless steel coating preparation method field, comprising: with aluminum alloy as base material, directional structure is prepared in the surface to be sprayed of base material using laser remelting and auxiliary cooling method, then directional layer is carried out stress relief annealing treatment, obtains the aluminum alloy base material to be sprayed;Stainless steel thick coating is sprayed on the surface of coating layer using plasma spraying method, then surface heat preservation and induction heating method are used to process stainless steel thick coating;Again, coating surface is treated using surface plastic deformation and quenching method, obtains directional multilayer structure stainless steel thick coating material.This method has good controllability, process stability and strong repeatability, can realize the high strength, strong interface bonding and excellent wear resistance of stainless steel thick coating material.

Description

[0001] Method Domain

[0002] This invention relates to the field of stainless steel coating preparation methods, and particularly to a directional multilayer structure heavy-duty stainless steel thick coating material and its preparation method.

[0003] Background Method

[0004] Light metal coating is an important surface treatment method, mainly used to improve the wear resistance, corrosion resistance, and high-temperature resistance of light metals and their alloys. Light metal coating refers to a covering layer formed on the surface of a substrate such as aluminum, magnesium, titanium, or their alloys through various methods including spraying, electroplating, anodizing, and chemical vapor deposition. This coating can effectively improve the performance of light metal substrates and meet specific application requirements.

[0005] Molten metal or alloy is sprayed onto the substrate surface using a spray gun to form a coating. Coatings prepared by this method have good adhesion and wear resistance. A layer of metal or alloy is deposited on the substrate surface through electrolysis to form a coating. Electroplating is suitable for preparing thin and uniform coatings. Using an aluminum alloy as the anode, electrolysis is performed in a specific electrolyte to form an oxide film on the surface. This oxide film has good wear resistance and corrosion resistance. A solid thin film is formed on the substrate surface through a chemical reaction. Coatings prepared by this method have high purity and density.

[0006] Lightweight metal coatings are widely used in aerospace, automotive, rail transportation, electronics, and medical fields. For example, in the aerospace field, lightweight metal coatings can improve the high-temperature resistance and corrosion resistance of aircraft components; in the automotive field, lightweight metal coatings can improve the wear resistance and corrosion resistance of components such as wheel hubs and brake discs, while reducing the overall vehicle weight and improving fuel economy.

[0007] With advancements in technology and the deepening of its applications, lightweight metal coating methods will continue to develop and improve. In the future, lightweight metal coatings will place greater emphasis on environmental protection and sustainable development, while exploring new preparation methods and material systems to meet a wider range of application needs.

[0008] Rapid wear and failure of lightweight metal coatings under impact, heavy loads, and friction is one of the main reasons for their shortened service life, restricting their application in lightweight structural components in fields such as vehicle engineering, aerospace, and aircraft. The failure of lightweight metal coatings mainly stems from three aspects: first, the coarse coating structure results in low hardness and poor wear resistance, making it difficult to withstand high-load friction conditions, leading to rapid wear failure; second, the overall coarse-grained structure, inhomogeneity, and porosity of the coating easily lead to fatigue failure; and third, weak interfacial bonding strength makes the coating prone to peeling under alternating loads. Therefore, the coating / substrate interface, the bonding within the coating, and the microstructure characteristics of the coating are crucial factors determining its service performance, and traditional coating preparation methods are insufficient to further improve mechanical strength, interfacial strength, and wear resistance. Summary of the Invention

[0009] To address the aforementioned problems, a series of methods, including laser remelting, spraying, induction heating directional crystallization, and surface plastic deformation, are employed to obtain directional multilayer heavy-duty stainless steel thick coatings, simultaneously improving the coating's mechanical and wear resistance properties. This invention addresses the engineering problem that traditional coating preparation methods struggle to further improve mechanical properties, interfacial strength, and wear resistance, by providing a directional multilayer heavy-duty stainless steel thick coating material and its preparation method.

[0010] To achieve the above objectives, the present invention adopts the following method:

[0011] In a first aspect, the present invention provides a method for preparing a directional multilayer structure heavy-duty stainless steel thick coating material, comprising:

[0012] Using aluminum alloy as the substrate, an oriented structure is prepared on the surface of the substrate to be sprayed by laser remelting and auxiliary cooling. Then, the oriented layer is subjected to stress-relief annealing to obtain the aluminum alloy substrate to be sprayed.

[0013] A thick stainless steel coating is applied to the surface of the coating using plasma spraying, followed by surface insulation and induction heating. The coating surface is then treated with surface plastic deformation and quenching to obtain a directional multilayer stainless steel thick coating material.

[0014] As a further improvement of the present invention, the aluminum alloy is 6061 or 5052.

[0015] As a further improvement of the present invention, the laser remelting and auxiliary cooling method is based on 1.3 × 10⁻⁶. 5 ~1.6×10 5 The process is carried out in an argon atmosphere. The laser remelting temperature is 680–710°C. First, the molten part is directionally cooled with hot argon gas at 270–320°C at a speed of 7–9 m / s for 22–29 seconds, and then cooled with the device.

[0016] As a further improvement of the present invention, the laser remelting and auxiliary cooling method further includes:

[0017] The cooled substrate is placed in a heat treatment furnace and stress-relieved annealed at 120–150°C for 73–82 minutes.

[0018] As a further improvement to the present invention, the plasma spraying method is as follows:

[0019] The raw material is 70-90 micrometer stainless steel powder. The spraying distance is 56-63 mm, the argon flow rate is 40-46 liters per minute, and the coating thickness is 1.9-2.4 mm.

[0020] As a further improvement of the present invention, the surface insulation and induction heating method includes:

[0021] A 1.3–1.6 cm thick carbon fiber felt is laid on the surface of the sprayed coating. The coating is then treated with induction heating directional crystallization at 1480–1560 °C and an induction coil moving at a speed of 1–3 mm per second, followed by air cooling.

[0022] As a further improvement to the present invention, the surface plastic deformation and quenching method is as follows:

[0023] The surface of the oriented crystallization coating is subjected to plastic deformation treatment using a friction stir welding device. The friction welding head rotates at 170-195 revolutions per minute, and the normal pressure on the coating surface is 32-37 MPa. Finally, the deformed surface is rapidly cooled with air at 20-25°C at a speed of 9-12 meters per second.

[0024] Secondly, the present invention provides a directional multilayer structure heavy-duty stainless steel thick coating material, which is prepared by the method for preparing the directional multilayer structure heavy-duty stainless steel thick coating material.

[0025] As a further improvement of the present invention, the obtained stainless steel thick coating material has a directional multilayer structure, a coating and interface porosity ≤0.2%, a coating / substrate interface bonding strength ≥79MPa, and a coating surface hardness ≥520H. V1 Compressive strength ≥470MPa, sliding friction wear ≤1.3 micrograms per square centimeter per hour.

[0026] Compared with existing methods, the present invention has the following features and advantages:

[0027] This invention first uses aluminum alloy as a substrate, and prepares an oriented structure on the surface of the substrate to be coated using laser remelting and assisted cooling methods. The oriented layer is then subjected to stress-relief annealing. Next, a thick stainless steel coating is sprayed onto the coating surface using plasma spraying. The thick stainless steel coating is then treated using surface insulation and induction heating methods. Finally, the coating surface is treated using surface plastic deformation and quenching methods. The laser remelting and assisted cooling methods ensure controllability of the melting area and depth, while the inert hot airflow cooling refines the dendrite size, improving the surface hardness and strength of the substrate. The surface insulation and induction heating methods control the transverse dendrite structure of the coating while protecting the equiaxed grain structure adjacent to the substrate surface. The surface plastic deformation and quenching methods facilitate the formation of a thin, ultra-fine grain structure on the coating surface, improving the surface hardness and wear resistance of the coating.

[0028] The stainless steel thick coating material obtained by this invention has a directional multilayer structure, with coating and interface porosity ≤0.2%, coating / substrate interface bonding strength ≥79MPa, and coating surface hardness ≥520H. V1 Compressive strength ≥470MPa, sliding friction wear ≤1.3 micrograms per square centimeter per hour. Detailed Implementation

[0029] To make the problems, solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0030] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0031] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0032] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0033] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0034] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0035] The terms "first" and "second" are used only to describe purposes and to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of method features indicated. For example, without departing from the scope of the embodiments of this application, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0036] Terminology Explanation:

[0037] Induction heating directional crystallization is an important materials processing technology that utilizes the principle of electromagnetic induction to generate heat within materials and achieves directional solidification and crystallization through precise control of the heating process. Based on the principle of electromagnetic induction, induction heating directional crystallization uses a radio frequency (RF) generator to produce high-frequency currents. These currents generate an alternating magnetic field in an induction coil. When a material (such as molten metal) is placed in this alternating magnetic field, induced currents (i.e., eddy currents) are generated within the material. These induced currents interact with the magnetic field to generate heat, thereby heating the material.

[0038] Laser remelting is a technique that uses a laser beam to heat the surface of a material, aiming to improve its surface microstructure through a rapid melting and solidification process. Laser remelting uses a high-energy-density laser beam to rapidly heat the material surface to above its melting point and melt it, followed by rapid cooling to resolidify the molten material. During this process, impurities, pores, and compounds on the material surface are released, while the grains are refined, thereby improving the material's surface properties.

[0039] Plasma spraying is an advanced material surface strengthening and modification technology. It uses a plasma arc as a heat source to heat materials such as ceramics, alloys, and metals to a molten or semi-molten state, which is then sprayed at high speed onto the pre-treated workpiece surface to form a firmly adhered surface layer. Plasma spraying technology uses a DC-driven plasma arc as its heat source. During the spraying process, gas is discharged through a high-frequency electric field, ionizing gas molecules into plasma. These plasmas are accelerated under the influence of the high-frequency electric field, forming high-energy electron beams and ion beams. When these charged particles collide with the surface of the object being treated, chemical reactions and physical effects occur, resulting in a uniform, dense, and strongly adherent thin film or coating on the substrate surface.

[0040] Surface plastic deformation is a phenomenon in which a solid material undergoes deformation after being subjected to external force and retains its new shape and structure. Unlike elastic deformation, plastic deformation is permanent, meaning that the material cannot fully recover to its original shape after the external force is removed.

[0041] The first objective of this invention is to provide a method for preparing a directional multilayer structure heavy-duty stainless steel thick coating material, comprising:

[0042] Using aluminum alloy as the substrate, an oriented structure is prepared on the surface of the substrate to be sprayed by laser remelting and auxiliary cooling. Then, the oriented layer is subjected to stress-relief annealing to obtain the aluminum alloy substrate to be sprayed.

[0043] A thick stainless steel coating is applied to the surface of the coating using plasma spraying, followed by surface insulation and induction heating. The coating surface is then treated with surface plastic deformation and quenching to obtain a directional multilayer stainless steel thick coating material.

[0044] This invention uses aluminum alloy as the substrate and prepares an oriented structure on the substrate surface to be coated using laser remelting and assisted cooling technology. Laser remelting utilizes a high-energy laser beam to rapidly heat and cool the substrate surface, forming a microstructure with a specific orientation. Assisted cooling technology ensures rapid cooling after rapid heating, resulting in a stable oriented structure. The oriented structure prepared by laser remelting and assisted cooling significantly improves the mechanical properties and wear resistance of the coating. This structure allows the coating to better resist stress and wear under heavy loads.

[0045] Furthermore, the orientation layer undergoes stress-relief annealing to eliminate residual stress generated during laser remelting, ensuring the stability of the substrate and the quality of the coating.

[0046] Furthermore, plasma spraying technology is used to coat a thick stainless steel coating onto the surface of a treated aluminum alloy substrate. Plasma spraying melts the stainless steel material using a high-temperature plasma jet and sprays it onto the substrate, forming a dense coating. Combining surface insulation and induction heating technologies with plasma spraying ensures a strong bond between the stainless steel coating and the aluminum alloy substrate, preventing coating peeling.

[0047] Furthermore, surface insulation combined with induction heating technology is used to treat the thick stainless steel coating to further improve its density and adhesion. Surface insulation ensures uniform temperature distribution during heating, while induction heating generates heat within the coating through electromagnetic induction, achieving rapid and uniform heating. The coating treated with surface plastic deformation and quenching technology has higher hardness and wear resistance, meeting the requirements for use in heavy-duty environments.

[0048] Finally, the coating surface is treated with surface plastic deformation and quenching techniques. Plastic deformation can improve the microstructure of the coating, increasing its strength and wear resistance; while quenching, through rapid cooling, enables the coating to achieve higher hardness and better wear resistance.

[0049] The entire preparation process utilizes advanced technology and equipment, enabling stable control of coating quality and ensuring product consistency and reliability. This directional multilayer structure heavy-duty stainless steel thick coating material and its preparation method have significant advantages, providing excellent wear resistance and mechanical properties under heavy-duty environments, and have broad application prospects.

[0050] Specifically, each step of the present invention includes the following steps:

[0051] 1) Using 6061 or 5052 aluminum alloy as the base material, at a thickness of 1.3×10 5 ~1.6×10 5Laser remelting and auxiliary cooling are carried out in an argon atmosphere. The laser remelting temperature is 680-710℃. First, the molten part is directionally cooled with hot argon gas at 270-320℃ at a speed of 7-9 meters per second for 22-29 seconds. The cooled part is then placed in a heat treatment furnace and stress-reduced at 120-150℃ for 73-82 minutes to obtain the aluminum alloy substrate to be sprayed.

[0052] 2) A thick stainless steel coating is sprayed onto the surface of the plating layer using plasma spraying. The plasma spraying uses 70-90 micrometer stainless steel powder as the raw material, with a spraying distance of 56-63 mm, an argon flow rate of 40-46 liters per minute, and a coating thickness of 1.9-2.4 mm. Then, a 1.3-1.6 cm thick carbon fiber felt is laid on the sprayed coating surface. The coating is then treated using induction heating directional crystallization at 1480-1560℃ and an induction coil moving speed of 1-3 mm per second. After air cooling, the directional crystallized coating surface is plastically deformed using a friction stir welding device at a speed of 170-195 rpm and a normal pressure of 32-37 MPa on the coating surface. Finally, the deformed surface is rapidly cooled with air at 20-25℃ at a speed of 9-12 m per second, ultimately obtaining a directional multilayer stainless steel thick coating material.

[0053] Furthermore, in the preparation of thick stainless steel coating materials, this invention addresses the engineering problem that traditional coating preparation methods struggle to further improve mechanical strength, interfacial strength, and wear resistance. Through a series of methods including laser remelting, spraying, induction heating directional crystallization, and surface plastic deformation, it investigates the relationship between substrate type, laser remelting process, auxiliary cooling process, induction heating process, surface plastic deformation process, quenching process, and the strength, interfacial bonding, and tribological properties of the stainless steel coating. Specifically, it identifies the optimal substrate type, laser remelting process, auxiliary cooling process, induction heating process, surface plastic deformation process, and quenching process for maintaining high strength, interfacial bonding, and tribological properties in thick stainless steel coating materials. This method offers strong controllability, process stability, and repeatability, enabling the achievement of high strength, strong interfacial bonding, and excellent wear resistance in thick stainless steel coatings.

[0054] Using 6061 or 5052 aluminum alloy as the substrate, the stainless steel thick coating material prepared by this invention has a directional multilayer structure, with coating and interface porosity ≤0.2%, coating / substrate interface bonding strength ≥79MPa, and coating surface hardness ≥520H. V1 Compressive strength ≥470MPa, sliding friction wear ≤1.3 micrograms per square centimeter per hour.

[0055] The strength, interfacial bonding, and tribological properties of the stainless steel thick coating materials prepared in the following examples are shown in Table 1.

[0056] Example 1

[0057] 1) Using 6061 aluminum alloy as the base material, at a thickness of 1.3×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 680℃. First, the molten part was directionally cooled with 270℃ hot argon at a speed of 7 meters per second for 22 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 120℃ for 73 minutes to obtain the aluminum alloy substrate to be sprayed.

[0058] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 70-micron stainless steel powder was used as the raw material for plasma spraying. The spraying distance was 56 mm, the argon flow rate was 40 liters per minute, and the coating thickness was 1.9 mm. Then, a 1.3 cm thick carbon fiber felt was laid on the surface of the sprayed coating. The coating was treated with induction heating directional crystallization at 1480℃ and an induction coil moving at a speed of 1 mm per second. It was then air-cooled. The surface of the directional crystallized coating was then plastically deformed using a friction stir welding device. The friction welding head rotated at 170 rpm and the normal pressure on the coating surface was 32 MPa. Finally, the deformed surface was rapidly cooled with 20℃ air at a speed of 9 m per second to obtain a directional multilayer stainless steel thick coating material.

[0059] Example 2

[0060] 1) Using 5052 aluminum alloy as the base material, at a thickness of 1.6×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 710℃. First, the molten part was directionally cooled with 320℃ hot argon at a speed of 9 meters per second for 29 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 150℃ for 82 minutes to obtain the aluminum alloy substrate to be sprayed.

[0061] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 90-micron stainless steel powder was used as the raw material for plasma spraying. The spraying distance was 63 mm, the argon flow rate was 46 liters per minute, and the coating thickness was 2.4 mm. Then, a 1.6 cm thick carbon fiber felt was laid on the sprayed coating surface. The coating was treated with induction heating directional crystallization at 1560℃ and an induction coil moving speed of 3 mm per second. It was then air-cooled. The directional crystallized coating surface was then plastically deformed using a friction stir welding device. The friction welding head rotated at 195 rpm, and the normal pressure on the coating surface was 37 MPa. Finally, the deformed surface was rapidly cooled with 25℃ air at a speed of 12 m per second to obtain a directional multilayer stainless steel thick coating material.

[0062] Example 3

[0063] 1) Using 6061 aluminum alloy as the base material, at a thickness of 1.4×10 5Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 690℃. First, the molten part was directionally cooled with 280℃ hot argon at a speed of 8 meters per second for 25 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 130℃ for 78 minutes to obtain the aluminum alloy substrate to be sprayed.

[0064] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 80-micron stainless steel powder was used as the raw material for plasma spraying. The spraying distance was 59 mm, the argon flow rate was 43 liters per minute, and the coating thickness was 2.4 mm. Then, a 1.4 cm thick carbon fiber felt was laid on the sprayed coating surface. The coating was treated with induction heating directional crystallization at 1560℃ and an induction coil moving speed of 2 mm per second. It was then air-cooled. The surface of the directional crystallized coating was then plastically deformed using a friction stir welding device. The friction welding head rotated at 185 rpm, and the normal pressure on the coating surface was 34 MPa. Finally, the deformed surface was rapidly cooled with 22℃ air at a speed of 10 m per second to obtain a directional multilayer stainless steel thick coating material.

[0065] Example 4

[0066] 1) Using 5052 aluminum alloy as the base material, at a thickness of 1.5×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 710℃. First, the molten part was directionally cooled with 320℃ hot argon at a speed of 9 meters per second for 28 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 140℃ for 82 minutes to obtain the aluminum alloy substrate to be sprayed.

[0067] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 86-micron stainless steel powder was used as the raw material for plasma spraying. The spraying distance was 63 mm, the argon flow rate was 41 liters per minute, and the coating thickness was 2.4 mm. Then, a 1.4 cm thick carbon fiber felt was laid on the sprayed coating surface. The coating was treated with induction heating directional crystallization at 1520℃ and an induction coil moving speed of 1 mm per second. It was then air-cooled. The directional crystallized coating surface was then plastically deformed using a friction stir welding device. The friction welding head rotated at 195 rpm, and the normal pressure on the coating surface was 32 MPa. Finally, the deformed surface was rapidly cooled with 24℃ air at a speed of 12 m per second to obtain a directional multilayer stainless steel thick coating material.

[0068] The performance parameters of the stainless steel coating materials prepared in Examples 1-4 are shown in Table 1:

[0069] Table 1

[0070]

[0071] As can be seen from the table above, the stainless steel thick coating material prepared by this invention has a directional multilayer structure, a coating and interface porosity ≤0.2%, a coating / substrate interface bonding strength ≥79MPa, and a coating surface hardness ≥520H. V1 Compressive strength ≥470MPa, sliding friction wear ≤1.3 micrograms per square centimeter per hour.

[0072] Example 5

[0073] 1) Using 5052 aluminum alloy as the base material, at a thickness of 1.4×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 690℃. First, the molten part was directionally cooled with 280℃ hot argon at a speed of 7.5 m / s for 23 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 130℃ for 75 minutes to obtain the aluminum alloy substrate to be sprayed.

[0074] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 70-90 micrometer stainless steel powder was used as the raw material, the spraying distance was 58 mm, the argon flow rate was 42 liters per minute, and the coating thickness was 2.0 mm. Then, a 1.4 cm thick carbon fiber felt was laid on the sprayed coating surface. The coating was then treated with induction heating directional crystallization at 1490℃ and an induction coil moving at a speed of 1.2 mm per second, followed by air cooling. Next, the directional crystallized coating surface was plastically deformed using a friction stir welding device at a speed of 175 rpm and a normal pressure of 33 MPa on the coating surface. Finally, the deformed surface was rapidly cooled with 21℃ air at a speed of 10 m per second, ultimately obtaining a directional multilayer stainless steel thick coating material.

[0075] Example 6

[0076] 1) Using 6061 aluminum alloy as the base material, at a thickness of 1.5×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 685℃. First, the molten part was directionally cooled with 300℃ hot argon at a speed of 8.1 m / s for 24 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 141℃ for 76 minutes to obtain the aluminum alloy substrate to be sprayed.

[0077] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 84-micron stainless steel powder was used as the raw material for plasma spraying. The spraying distance was 60 mm, the argon flow rate was 42 liters per minute, and the coating thickness was 2.1 mm. Then, a 1.5 cm thick carbon fiber felt was laid on the surface of the sprayed coating. The coating was treated with induction heating directional crystallization at 1500℃ and an induction coil moving speed of 2.1 mm per second. It was then air-cooled. The surface of the directional crystallized coating was then plastically deformed using a friction stir welding device. The friction welding head rotated at 181 rpm, and the normal pressure on the coating surface was 36 MPa. Finally, the deformed surface was rapidly cooled with 24℃ air at a speed of 11 m per second, and the directional multilayer stainless steel thick coating material was finally obtained.

[0078] Example 7

[0079] 1) Using 6061 aluminum alloy as the base material, at a thickness of 1.5×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 695℃. First, the molten part was directionally cooled with 310℃ hot argon at a speed of 8.2 m / s for 27 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 135℃ for 79 minutes to obtain the aluminum alloy substrate to be sprayed.

[0080] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 70-90 micrometer stainless steel powder was used as the raw material, with a spraying distance of 62 mm, an argon flow rate of 45 liters per minute, and a coating thickness of 2.1 mm. A 1.5 cm thick carbon fiber felt was then laid on the sprayed coating surface. The coating was then treated using induction heating directional crystallization at 1505℃ and an induction coil moving at a speed of 2.8 mm per second. After air cooling, the directional crystallized coating surface was plastically deformed using a friction stir welding device at a speed of 185 rpm and a normal pressure of 36 MPa on the coating surface. Finally, the deformed surface was rapidly cooled with 23℃ air at a speed of 11.5 m per second, ultimately obtaining a directional multilayer stainless steel thick coating material.

[0081] Example 8

[0082] 1) Using 5052 aluminum alloy as the base material, at a thickness of 1.6×10 5 Laser remelting and auxiliary cooling were carried out in an argon atmosphere. The laser remelting temperature was 705℃. First, the molten part was directionally cooled with 270℃ hot argon at a speed of 7 meters per second for 29 seconds. The cooled part was then placed in a heat treatment furnace and stress-reduced at 130℃ for 80 minutes to obtain the aluminum alloy substrate to be sprayed.

[0083] 2) A thick stainless steel coating was sprayed onto the surface of the plating layer using plasma spraying. 88-micron stainless steel powder was used as the raw material for plasma spraying. The spraying distance was 60 mm, the argon flow rate was 40 liters per minute, and the coating thickness was 2.0 mm. Then, a 1.5 cm thick carbon fiber felt was laid on the surface of the sprayed coating. The coating was treated with induction heating directional crystallization at 1560℃ and an induction coil moving speed of 2 mm per second. It was then air-cooled. The surface of the directional crystallized coating was then plastically deformed using a friction stir welding device. The friction welding head rotated at 180 rpm and the normal pressure on the coating surface was 35 MPa. Finally, the deformed surface was rapidly cooled with 25℃ air at a speed of 9 m per second to obtain a directional multilayer stainless steel thick coating material.

[0084] The methods in Examples 5-8 also yielded stainless steel thick coating materials with a directional multilayer structure, coating and interface porosity ≤0.2%, coating / substrate interface bonding strength ≥79MPa, and coating surface hardness ≥520H. V1 The compressive strength is ≥470MPa, and the wear amount in the sliding friction test is ≤1.3 micrograms per square centimeter per hour. This improves the mechanical and wear resistance properties of the coating.

[0085] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a directional multilayer structure heavy-duty stainless steel thick coating material, characterized in that, include: Using aluminum alloy as the base material, at 1.3×10 5 ~1.6×10 5 Laser remelting and auxiliary cooling are carried out in an argon atmosphere. The laser remelting temperature is 680-710℃. First, the molten part is directionally cooled with hot argon gas at 270-320℃ at a speed of 7-9 meters per second for 22-29 seconds. Then, it is cooled with the device. The cooled substrate is then placed in a heat treatment furnace and stress-reduced annealing is performed at 120-150℃ for 73-82 minutes to obtain the aluminum alloy substrate to be sprayed. A thick stainless steel coating is sprayed onto the surface of the aluminum alloy substrate to be coated using a plasma spraying method, and then the thick stainless steel coating is treated using surface insulation and induction heating methods. The coating surface is then treated with surface plastic deformation and quenching methods to obtain a directional multilayer stainless steel thick coating material.

2. The method for preparing the directional multilayer structure heavy-duty stainless steel thick coating material as described in claim 1, characterized in that, The aluminum alloy is 6061 or 5052.

3. The method for preparing the directional multilayer structure heavy-duty stainless steel thick coating material as described in claim 1, characterized in that, The plasma spraying method is as follows: The raw material is 70-90 micrometer stainless steel powder. The spraying distance is 56-63 mm, the argon flow rate is 40-46 liters per minute, and the coating thickness is 1.9-2.4 mm.

4. The method for preparing the directional multilayer structure heavy-duty stainless steel thick coating material as described in claim 1, characterized in that, The surface insulation and induction heating methods include: A 1.3–1.6 cm thick carbon fiber felt is laid on the surface of the sprayed coating. The coating is then treated with induction heating directional crystallization at 1480–1560 °C and an induction coil moving at a speed of 1–3 mm per second, followed by air cooling.

5. The method for preparing the directional multilayer structure heavy-duty stainless steel thick coating material as described in claim 4, characterized in that, The surface plastic deformation and quenching method is as follows: The surface of the directional crystallization coating is subjected to plastic deformation treatment using a friction stir welding device. The friction welding head rotates at 170~195 revolutions per minute, and the normal pressure on the coating surface is 32~37MPa. Finally, the deformed surface is rapidly cooled with air at 20~25℃ at a speed of 9~12 meters per second.

6. A directional multilayer structure heavy-duty stainless steel thick coating material, characterized in that, It is prepared by the method for preparing directional multilayer structure heavy-duty stainless steel thick coating material according to any one of claims 1-5.

7. The directional multilayer structure heavy-duty stainless steel thick coating material according to claim 6, characterized in that, The obtained thick stainless steel coating material has a directional multilayer structure, with coating and interface porosity ≤0.2%, coating / substrate interface bonding strength ≥79MPa, coating surface hardness ≥520HV1, compressive strength ≥470MPa, and sliding friction test wear amount ≤1.3 micrograms per square centimeter per hour.

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