A corrosion-resistant wheel hub cover stainless steel alloy and preparation method thereof

Abstract

The present invention discloses a corrosion-resistant wheel hub cap stainless steel alloy and a preparation method thereof, relating to the technical field of stainless steel. The preparation method of the corrosion-resistant wheel hub cap stainless steel alloy comprises the following steps: S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy; S2: subjecting the pretreated stainless steel alloy to a primary laser cladding and nitriding treatment to obtain stainless steel alloy A; S3: subjecting stainless steel alloy A to a secondary laser cladding and heat treatment to obtain stainless steel alloy B; S4: subjecting stainless steel alloy B to electroplating to obtain the corrosion-resistant wheel hub cap stainless steel alloy. This method significantly improves the wear resistance and surface hardness of the stainless steel alloy, reduces the occurrence of plating cracks, and improves corrosion resistance.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel, in particular to a corrosion-resistant wheel hub cover stainless steel alloy and a preparation method thereof. Background Art

[0002] Among automobile parts, wheel hub caps, as key components of automobile wheels, not only affect the aesthetics of the automobile, but are also directly related to the driving safety of the vehicle. Traditional automobile wheel hub cap materials include carbon steel and aluminum alloy. Carbon steel has a certain hardness and wear resistance, but poor corrosion resistance and requires frequent maintenance. Aluminum alloy is light and beautiful, but has poor wear resistance and hardness. In the prior art, wheel hub caps made of stainless steel alloys have certain corrosion resistance, wear resistance and hardness, but there are still some shortcomings. Therefore, alloy surface coating methods such as laser cladding and electroplating are adopted. However, laser cladding metal layers are prone to cracks, resulting in poor corrosion resistance and low hardness of the prepared coating. Electroplated coatings, such as conventional nickel plating, have poor wear resistance and are easy to wear.

[0003] In summary, it is of great significance to solve the above problems and prepare a corrosion-resistant wheel hub cover stainless steel alloy. Summary of the Invention

[0004] The object of the present invention is to provide a corrosion-resistant wheel hub cap stainless steel alloy and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for preparing a corrosion-resistant wheel hub cap stainless steel alloy comprises the following steps:

[0007] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0008] S2: laser cladding and nitriding the pretreated stainless steel alloy to obtain stainless steel alloy A;

[0009] S3: Stainless steel alloy A is subjected to secondary laser cladding and heat treatment to obtain stainless steel alloy B;

[0010] S4: electroplating the stainless steel alloy B to obtain a corrosion-resistant wheel hub cover stainless steel alloy.

[0011] Preferably, the metal powder used in the single laser cladding process includes the following raw materials, calculated by mass percentage: 10-15% tungsten carbide, 3-5% aluminum, 0.5-2% cerium, and the rest is nickel-based self-fluxing alloy powder;

[0012] During the secondary laser cladding process, the metal powder used includes the following raw materials, calculated by mass percentage: 25-30% tungsten carbide, 3-5% aluminum, 0.5-2% cerium, and the rest is nickel-based self-fluxing alloy powder.

[0013] Preferably, the processes of the primary laser cladding and the secondary laser cladding are the same, and the specific process is: in a helium atmosphere, the substrate is preheated to 300~350℃; the laser power is 5~6kW, the scanning speed is 400~600mm / min, the spot diameter is 3mm, and the powder feeding rate is 15~20g / min.

[0014] Preferably, the nitriding treatment is ion nitriding, and the specific process is: nitriding treatment at a temperature of 450-470° C. for 4-8 hours under a working gas ammonia pressure of 800-1200 Pa, and then cooling to room temperature with the furnace.

[0015] Preferably, during the heat treatment, the gas atmosphere is nitrogen, the temperature is 600-650° C., and the time is 1-2 hours.

[0016] Preferably, during the electroplating process, the electroplating solution includes the following substances: 250~270g / L nickel sulfate hexahydrate, 40~50g / L nickel chloride hexahydrate, 10~15g / L cerium sulfate, 25~30g / L modified tungsten carbide, 30~40g / L phytic acid, 25~30g / L sodium citrate, 0.1~0.2g / L sodium lauryl sulfate, 0.005~0.01g / L thiourea, and the rest is water; the pH is 5.5~6.5.

[0017] Preferably, the preparation method of the modified tungsten carbide comprises the following steps: (1) adding sodium alginate to deionized water and stirring evenly, adjusting the pH to 3.5±0.1, adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and stirring evenly; adding 3-aminophenylboronic acid, stirring at 35-40°C for 20-24h, using ethanol precipitation, washing, and drying to obtain boric acid-modified sodium alginate;

[0018] (2) Add boric acid-modified sodium alginate to anhydrous tetrahydrofuran and stir evenly, slowly add 3-mercapto-1,2-propanediol dropwise, stir at 25-30°C for 10-12 hours, evaporate the solvent, wash, and dry to obtain thiolated sodium alginate;

[0019] (3) Add nano-tungsten carbide to 30wr% ethanol solution and disperse it evenly by ultrasonication, add 3-(isobutyleneoxy)propyltrimethoxysilane, stir at 40-50°C for 5-6 hours, filter, wash and dry to obtain olefinated tungsten carbide;

[0020] (4) Add thiolated sodium alginate to 100 parts of deionized water and stir evenly, add olefinated tungsten carbide and azobisisobutyronitrile, stir at 50-60°C for 4-5 hours, filter, wash, and dry to obtain modified tungsten carbide.

[0021] Preferably, the boric acid-modified sodium alginate comprises the following raw materials in parts by mass: 2-3 parts of sodium alginate, 100 parts of deionized water, 1.6-1.7 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 2.3-2.4 parts of 3-aminophenylboronic acid;

[0022] The thiolated sodium alginate comprises the following raw materials in parts by weight: 2 to 3 parts of boric acid-modified sodium alginate, 100 parts of anhydrous tetrahydrofuran, and 1.8 to 2 parts of 3-mercapto-1,2-propylene glycol;

[0023] The olefinized tungsten carbide comprises the following raw materials by weight: 1-1.5 parts of nano-tungsten carbide, 100 parts of 30wr% ethanol solution, and 0.5-0.8 parts of 3-(isomethylacryloyloxy)propyltrimethoxysilane;

[0024] The modified tungsten carbide comprises the following raw materials in parts by mass: 4 to 6 parts of thiolated sodium alginate, 100 parts of deionized water, 1 to 1.5 parts of olefinated tungsten carbide, and 0.01 to 0.02 parts of azobisisobutyronitrile.

[0025] Preferably, during the electroplating process, the specific process is: the current density is 3~5A / dm 2 , temperature is 45~55℃, ultrasonic power is 300~400W, and time is 20~30min.

[0026] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: after pre-treating the surface of the stainless steel substrate, the present invention successively performs a laser cladding, a nitriding treatment, a secondary laser cladding, and an electroplating treatment to obtain a stainless steel alloy containing a composite coating, which significantly improves the wear resistance and surface hardness of the stainless steel alloy, reduces the occurrence of coating cracks, and improves corrosion resistance.

[0027] Among them, the metal powder used in the first laser cladding and the second laser cladding respectively uses tungsten carbide content of 10~15% and 25~30%. The first laser cladding forms a bottom layer with a lower tungsten carbide content, which can provide good bonding strength and toughness, helping to prevent the detachment of the coating. The second laser cladding forms a surface layer with a higher tungsten carbide content. The increase in tungsten carbide content improves the wear resistance and hardness of the coating. Such a gradient design helps to reduce stress concentration, thereby reducing the occurrence of cracks. Aluminum and cerium are additionally added to the alloy powder to help refine the grains, improve hardness and wear resistance; at the same time, the nitriding process is introduced between the two laser claddings, which can serve as a buffer layer to reduce fatigue cracks caused by differences in thermal expansion coefficients and stress concentration, and can prevent cracks from extending from the surface layer to the substrate, thereby improving corrosion resistance.

[0028] The coating formed by electroplating, as the outermost layer, provides final protection for the laser cladding layer and enhances its overall performance. During the electroplating process, modified tungsten carbide is added to the plating solution, which helps improve the corrosion and wear resistance of the coating. The preparation method of modified tungsten carbide is as follows: the carboxyl group in sodium alginate reacts with the amino group in 3-aminophenylboronic acid under the activation of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and the formed boric acid group is esterified with 3-mercapto-1,2-propylene glycol to form thiolated sodium alginate containing a borate group, and the tungsten carbide is modified by 3-(isobutyleneoxy)propyltrimethoxysilane alkenylation and then clicked with the thiolated sodium alginate containing a borate group to obtain modified tungsten carbide; on the one hand, after modification, the dispersibility of tungsten carbide in the electroplating solution is improved, and on the other hand, the borate group and the thiol group can coordinate with the metal ions, thereby improving the coordination effect of sodium alginate, helping to adsorb on the surface of the coating and coordinate with the metal ions, improving the electroplating efficiency and the quality of the coating, thereby improving the wear resistance and corrosion resistance of the coating. DETAILED DESCRIPTION

[0029] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0030] It should be noted that the following parts are calculated by weight, and the purchase manufacturers of all raw materials involved in the present invention are not particularly limited. Examples include: nickel sulfate hexahydrate CAS number: 15244-37-8; nickel chloride hexahydrate CAS number: 7791-20-0; cerium sulfate CAS number: 13590-82-4; nano-tungsten carbide, particle size of 200~400nm; phytic acid CAS number: 83-86-3; sodium citrate CAS number: 68-04-2; sodium lauryl sulfate CAS number: 151-21-3; thiourea CAS number: 62-56-6; sodium alginate, model A434495, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; CAS number: 25952-53-8 for 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride; CAS number: 30418-59-8 for 3-aminophenylboronic acid; CAS number: 96-27-5 for 3-mercapto-1,2-propanediol; CAS number: 2530-85-0 for 3-(methacryloyloxy)propyltrimethoxysilane; nickel-based self-fluxing alloy powder, model Deloro 60, provided by Kennametal Metal (Shanghai) Co., Ltd.

[0031] In the following examples, parts are by mass, and the above-mentioned and other raw materials used but not mentioned are commercially available; wherein, the stainless steel alloy in each example and comparative example is 304 stainless steel.

[0032] Example 1: A method for preparing a corrosion-resistant wheel hub cap stainless steel alloy comprises the following steps:

[0033] Step 1: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0034] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0035] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under an ammonia working gas pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0036] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain a corrosion-resistant wheel hub cover stainless steel alloy. The metal powder used in the primary laser cladding process included the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0037] Example 2: A method for preparing a corrosion-resistant wheel hub cap stainless steel alloy comprises the following steps:

[0038] Step 1: Preparation of modified tungsten carbide: (1) Add 2.5 parts of sodium alginate to 100 parts of deionized water and stir evenly, adjust the pH to 3.5±0.1, add 1.65 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and stir evenly; add 2.35 parts of 3-aminophenylboronic acid, stir at 35°C for 24 hours, precipitate with ethanol, wash, and dry to obtain boric acid-modified sodium alginate;

[0039] (2) Add 2.5 parts of boric acid-modified sodium alginate to 100 parts of anhydrous tetrahydrofuran and stir evenly, slowly add 1.9 parts of 3-mercapto-1,2-propylene glycol, stir at 25°C for 12 hours, evaporate the solvent, wash, and dry to obtain thiolated sodium alginate;

[0040] (3) Add 1 part of nano-tungsten carbide to 100 parts of 30wr% ethanol solution and disperse it evenly by ultrasonication, add 0.6 parts of 3-(isobutyleneoxy)propyltrimethoxysilane, stir at 45°C for 5 hours, filter, wash and dry to obtain olefinated tungsten carbide;

[0041] (4) Add 5 parts of thiolated sodium alginate to 100 parts of deionized water and stir evenly, add 1 part of olefinated tungsten carbide and 0.01 parts of azobisisobutyronitrile, stir at 55 ° C for 4 hours, filter, wash, and dry to obtain modified tungsten carbide.

[0042] Step 2: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0043] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0044] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under an ammonia working gas pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0045] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain stainless steel alloy B. The metal powder used in the primary laser cladding comprised the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder nickel-based self-fluxing alloy powder.

[0046] S4: Stainless steel alloy B is heated at a current density of 4A / dm 2 , temperature is 50°C, under ultrasonic power of 300W, electroplating treatment is carried out for 25 minutes, washing, and drying to obtain a corrosion-resistant wheel hub cover stainless steel alloy; wherein, during the electroplating process, the electroplating solution includes the following substances: 260g / L nickel sulfate hexahydrate, 45g / L nickel chloride hexahydrate, 12g / L cerium sulfate, 27g / L modified tungsten carbide, 35g / L phytic acid, 27g / L sodium citrate, 0.1g / L sodium dodecyl sulfate, 0.005g / L thiourea, and the rest is water; the pH value is 6.0.

[0047] Example 3: A method for preparing a corrosion-resistant wheel hub cap stainless steel alloy comprises the following steps:

[0048] Step 1: Preparation of modified tungsten carbide: (1) Add 2.5 parts of sodium alginate to 100 parts of deionized water and stir evenly, adjust the pH to 3.5±0.1, add 1.65 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and stir evenly; add 2.35 parts of 3-aminophenylboronic acid, stir at 35°C for 24 hours, precipitate with ethanol, wash, and dry to obtain boric acid-modified sodium alginate;

[0049] (2) Add 2.5 parts of boric acid-modified sodium alginate to 100 parts of anhydrous tetrahydrofuran and stir evenly, slowly add 1.9 parts of 3-mercapto-1,2-propylene glycol, stir at 25°C for 12 hours, evaporate the solvent, wash, and dry to obtain thiolated sodium alginate;

[0050] (3) Add 1 part of nano-tungsten carbide to 100 parts of 30wr% ethanol solution and disperse it evenly by ultrasonication, add 0.6 parts of 3-(isobutyleneoxy)propyltrimethoxysilane, stir at 45°C for 5 hours, filter, wash and dry to obtain olefinated tungsten carbide;

[0051] (4) Add 5 parts of thiolated sodium alginate to 100 parts of deionized water and stir evenly, add 1 part of olefinated tungsten carbide and 0.01 parts of azobisisobutyronitrile, stir at 55 ° C for 4 hours, filter, wash, and dry to obtain modified tungsten carbide.

[0052] Step 2: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0053] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0054] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under an ammonia working gas pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0055] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain stainless steel alloy B. The metal powder used in the primary laser cladding comprised the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder nickel-based self-fluxing alloy powder.

[0056] S4: Stainless steel alloy B is heated at a current density of 4A / dm 2 , temperature is 50℃, under ultrasonic power of 300W, electroplating treatment is carried out for 25 minutes, washing, and drying to obtain a corrosion-resistant wheel hub cover stainless steel alloy; wherein, during the electroplating process, the electroplating solution includes the following substances: 250g / L nickel sulfate hexahydrate, 40g / L nickel chloride hexahydrate, 10g / L cerium sulfate, 25g / L modified tungsten carbide, 30g / L phytic acid, 25g / L sodium citrate, 0.1g / L sodium lauryl sulfate, 0.005g / L thiourea, and the rest is water; the pH value is 6.2.

[0057] Example 4: A method for preparing a corrosion-resistant wheel hub cap stainless steel alloy comprises the following steps:

[0058] Step 1: Preparation of modified tungsten carbide: (1) Add 2.5 parts of sodium alginate to 100 parts of deionized water and stir evenly, adjust the pH to 3.5±0.1, add 1.65 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and stir evenly; add 2.35 parts of 3-aminophenylboronic acid, stir at 35°C for 24 hours, precipitate with ethanol, wash, and dry to obtain boric acid-modified sodium alginate;

[0059] (2) Add 2.5 parts of boric acid-modified sodium alginate to 100 parts of anhydrous tetrahydrofuran and stir evenly, slowly add 1.9 parts of 3-mercapto-1,2-propylene glycol, stir at 25°C for 12 hours, evaporate the solvent, wash, and dry to obtain thiolated sodium alginate;

[0060] (3) Add 1 part of nano-tungsten carbide to 100 parts of 30wr% ethanol solution and disperse it evenly by ultrasonication, add 0.6 parts of 3-(isobutyleneoxy)propyltrimethoxysilane, stir at 45°C for 5 hours, filter, wash and dry to obtain olefinated tungsten carbide;

[0061] (4) Add 5 parts of thiolated sodium alginate to 100 parts of deionized water and stir evenly, add 1 part of olefinated tungsten carbide and 0.01 parts of azobisisobutyronitrile, stir at 55 ° C for 4 hours, filter, wash, and dry to obtain modified tungsten carbide.

[0062] Step 2: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0063] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0064] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under an ammonia working gas pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0065] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain stainless steel alloy B. The metal powder used in the primary laser cladding comprised the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder nickel-based self-fluxing alloy powder.

[0066] S4: Stainless steel alloy B is heated at a current density of 4A / dm 2 , temperature is 50℃, under ultrasonic power of 300W, electroplating treatment is carried out for 25 minutes, washing, and drying to obtain a corrosion-resistant wheel hub cover stainless steel alloy; wherein, during the electroplating process, the electroplating solution includes the following substances: 270g / L nickel sulfate hexahydrate, 50g / L nickel chloride hexahydrate, 15g / L cerium sulfate, 30g / L modified tungsten carbide, 40g / L phytic acid, 30g / L sodium citrate, 0.2g / L sodium lauryl sulfate, 0.01g / L thiourea, and the rest is water; the pH value is 6.1.

[0067] Comparative Example 1: Based on Example 1, the metal powder for the first laser cladding was adjusted to be consistent with that for the second laser cladding, and the other processes remained unchanged, as follows:

[0068] Step 1: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0069] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0070] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under a working gas ammonia pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0071] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain a corrosion-resistant wheel hub cover stainless steel alloy. The metal powder used in the primary laser cladding process included the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0072] Comparative Example 2: Based on Example 1, nitriding treatment was not performed, and the other processes remained unchanged, as follows:

[0073] Step 1: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0074] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0075] S2: Preheat the pretreated stainless steel alloy to 350°C and perform a laser cladding operation at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy is then cooled to obtain stainless steel alloy A. The metal powder used in the laser cladding operation comprises the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder nickel-based self-fluxing alloy powder.

[0076] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain a corrosion-resistant wheel hub cover stainless steel alloy. The metal powder used in the primary laser cladding process included the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0077] Comparative Example 3: Based on Example 2, the tungsten carbide was not modified, and the other processes remained unchanged, as follows:

[0078] Step 1: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0079] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0080] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under an ammonia working gas pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0081] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain stainless steel alloy B. The metal powder used in the primary laser cladding comprised the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder nickel-based self-fluxing alloy powder.

[0082] S4: Stainless steel alloy B is heated at a current density of 4A / dm 2 , temperature is 50℃, under ultrasonic power of 300W, electroplating treatment is carried out for 25 minutes, washing, and drying to obtain a corrosion-resistant wheel hub cover stainless steel alloy; wherein, during the electroplating process, the electroplating solution includes the following substances: 260g / L nickel sulfate hexahydrate, 45g / L nickel chloride hexahydrate, 12g / L cerium sulfate, 27g / L tungsten carbide, 35g / L phytic acid, 27g / L sodium citrate, 0.1g / L sodium dodecyl sulfate, 0.005g / L thiourea, and the rest is water; the pH value is 6.0.

[0083] Comparative Example 4: Based on Example 2, tungsten carbide is modified using only sodium alginate, and the rest of the process remains unchanged, as follows:

[0084] Step 1: Preparation of modified tungsten carbide: (1) Add 1 part of nano-tungsten carbide to 100 parts of 30wr% ethanol solution and disperse it evenly by ultrasonication, add 0.6 parts of 3-aminopropyltriethoxysilane, stir at 45°C for 5 hours, filter, wash and dry to obtain amino tungsten carbide;

[0085] (2) Add 2.5 parts of sodium alginate to 100 parts of deionized water and stir evenly, adjust the pH to 3.5±0.1, add 1.65 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and stir evenly, add 2.5 parts of amino tungsten carbide and ultrasonically disperse it evenly, stir at 35°C for 24 hours, use ethanol to precipitate, wash, and dry to obtain modified tungsten carbide;

[0086] Step 2: Preparation of corrosion-resistant wheel hub cap stainless steel alloy:

[0087] S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy;

[0088] S2: The pretreated stainless steel alloy was preheated to 350°C, and laser cladding was performed once at a power of 6kW, a scanning speed of 500mm / min, a spot diameter of 3mm, and a powder feeding rate of 15g / min. The alloy was cooled, transferred to an ion nitriding device, and nitrided at 460°C for 6 hours under an ammonia working gas pressure of 1000Pa. The alloy was then cooled to room temperature to obtain stainless steel alloy A. The metal powder used in the laser cladding once included the following raw materials, calculated by mass percentage: 15% tungsten carbide, 4% aluminum, 1% cerium, and the remainder was nickel-based self-fluxing alloy powder.

[0089] S3: Stainless steel alloy A was preheated to 350°C and subjected to secondary laser cladding at a power of 6 kW, a scanning speed of 500 mm / min, a spot diameter of 3 mm, and a powder feeding rate of 15 g / min. The alloy was then heat treated at 625°C for 1.5 h in a nitrogen atmosphere and cooled to obtain stainless steel alloy B. The metal powder used in the primary laser cladding comprised the following raw materials, calculated by mass percentage: 30% tungsten carbide, 4% aluminum, 1% cerium, and the remainder nickel-based self-fluxing alloy powder.

[0090] S4: Stainless steel alloy B is heated at a current density of 4A / dm 2 , temperature is 50°C, under ultrasonic power of 300W, electroplating treatment is carried out for 25 minutes, washing, and drying to obtain a corrosion-resistant wheel hub cover stainless steel alloy; wherein, during the electroplating process, the electroplating solution includes the following substances: 260g / L nickel sulfate hexahydrate, 45g / L nickel chloride hexahydrate, 12g / L cerium sulfate, 27g / L modified tungsten carbide, 35g / L phytic acid, 27g / L sodium citrate, 0.1g / L sodium dodecyl sulfate, 0.005g / L thiourea, and the rest is water; the pH value is 6.0.

[0091] Performance test (1): The samples prepared in Example 1 and Comparative Examples 1-2 were respectively measured for Vickers microhardness and corrosion current; wherein, the test parameters of the corrosion current were: potential scanning range of -1.5-0.5V, scanning rate of 2mv / s, and response time of 3s; the experimental data are shown in Table 1:

[0092]

[0093] It can be seen from Table 1 that the hardness and corrosion resistance of the coating are improved by the design of primary laser cladding, nitriding treatment and secondary laser cladding; in Comparative Example 1, the tungsten carbide content is not gradient designed, the stress distribution inside the cladding layer is uneven, cracks are generated, and the corrosion resistance and hardness are reduced; in Comparative Example 2, no nitriding treatment is performed, and the buffer layer is lacking. The cracks generated are easy to penetrate into the substrate, resulting in a decrease in corrosion resistance, and since the tungsten carbide particles are easy to sink to the bottom during the cladding process, the hardness is further reduced.

[0094] Performance test (2): The samples prepared in Examples 2 to 4 and Comparative Examples 3 to 4 were subjected to wear resistance test and corrosion current measurement respectively; wherein the wear resistance test was conducted in accordance with GB / T 12444-2006, with the following parameters: pressure of 300 N, friction ring speed of 120 r / min, and time of 3 hours; the corrosion current test parameters were: potential scanning range of -1.5 to 0.5 V, scanning rate of 2 mV / s, and response time of 3 s; the experimental data are shown in Table 2:

[0095]

[0096] It can be seen from Table 2 that by introducing modified tungsten carbide into the electroplating solution, the corrosion resistance and wear resistance of the coating are further improved; in Comparative Example 3, the tungsten carbide is not modified, the dispersibility is poor, the tungsten carbide content in the coating is small and unevenly distributed, and the wear resistance and corrosion resistance are reduced; in Comparative Example 4, although the dispersion of tungsten carbide is improved to a certain extent after modification with sodium alginate, and the wear resistance and corrosion resistance of the coating are improved, sodium alginate itself is easy to agglomerate, so the dispersibility and stability are relatively poor, so the wear resistance and corrosion resistance are not as good as Example 2.

[0097] In summary, the present invention performs a laser cladding, a nitriding treatment, a secondary laser cladding, and an electroplating treatment on the surface of the stainless steel substrate after pretreatment, thereby obtaining a stainless steel alloy containing a composite coating, which significantly improves the wear resistance and surface hardness of the stainless steel alloy, reduces the occurrence of coating cracks, and improves corrosion resistance.

[0098] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a corrosion-resistant wheel hub cap stainless steel alloy, characterized in that: The following steps are involved: S1: grinding, alkali washing, pickling, water washing, and drying the stainless steel alloy in sequence to obtain a pretreated stainless steel alloy; S2: laser cladding and nitriding the pretreated stainless steel alloy to obtain stainless steel alloy A; S3: Stainless steel alloy A is subjected to secondary laser cladding and heat treatment to obtain stainless steel alloy B; S4: electroplating the stainless steel alloy B to obtain a corrosion-resistant wheel hub cover stainless steel alloy; Wherein, in the process of the single laser cladding, the metal powder used includes the following raw materials, calculated by mass percentage: 10-15% tungsten carbide, 3-5% aluminum, 0.5-2% cerium, and the rest is nickel-based self-fluxing alloy powder; During the secondary laser cladding process, the metal powder used includes the following raw materials, calculated by mass percentage: 25-30% tungsten carbide, 3-5% aluminum, 0.5-2% cerium, and the rest is nickel-based self-fluxing alloy powder; Wherein, during the electroplating process, the electroplating solution includes the following substances: 250-270 g / L nickel sulfate hexahydrate, 40-50 g / L nickel chloride hexahydrate, 10-15 g / L cerium sulfate, 25-30 g / L modified tungsten carbide, 30-40 g / L phytic acid, 25-30 g / L sodium citrate, 0.1-0.2 g / L sodium lauryl sulfate, 0.005-0.01 g / L thiourea, and the rest is water; the pH is 5.5-6.5; The preparation method of the modified tungsten carbide comprises the following steps: (1) adding sodium alginate to deionized water and stirring evenly, adjusting the pH to 3.5±0.1, adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and stirring evenly; adding 3-aminophenylboronic acid, stirring at 35-40°C for 20-24h, using ethanol precipitation, washing, and drying to obtain boric acid-modified sodium alginate; (2) Add boric acid-modified sodium alginate to anhydrous tetrahydrofuran and stir evenly, slowly add 3-mercapto-1,2-propanediol dropwise, stir at 25-30°C for 10-12 hours, evaporate the solvent, wash, and dry to obtain thiolated sodium alginate; (3) Add nano-tungsten carbide to 30wr% ethanol solution and disperse it evenly by ultrasonication, add 3-(isobutyleneoxy)propyltrimethoxysilane, stir at 40-50°C for 5-6 hours, filter, wash and dry to obtain olefinated tungsten carbide; (4) Add thiolated sodium alginate to 100 parts of deionized water and stir evenly, add olefinated tungsten carbide and azobisisobutyronitrile, stir at 50-60°C for 4-5 hours, filter, wash, and dry to obtain modified tungsten carbide.

2. The method for preparing a corrosion-resistant wheel hub cap stainless steel alloy according to claim 1, characterized in that: The processes of the primary laser cladding and the secondary laser cladding are the same. The specific processes are: in a helium atmosphere, the substrate is preheated to 300~350℃; the laser power is 5~6kW, the scanning speed is 400~600mm / min, the spot diameter is 3mm, and the powder feeding rate is 15~20g / min.

3. The method for preparing a corrosion-resistant wheel hub cap stainless steel alloy according to claim 1, characterized in that: The nitriding treatment is ion nitriding, and the specific process is: nitriding treatment at a temperature of 450-470° C. for 4-8 hours under a working gas ammonia pressure of 800-1200 Pa, and then cooling to room temperature with the furnace.

4. The method for preparing a corrosion-resistant wheel hub cap stainless steel alloy according to claim 1, characterized in that: During the heat treatment, the gas atmosphere is nitrogen, the temperature is 600-650° C., and the time is 1-2 hours.

5. The method for preparing a corrosion-resistant wheel hub cap stainless steel alloy according to claim 1, characterized in that: The boric acid-modified sodium alginate comprises the following raw materials in parts by weight: 2-3 parts of sodium alginate, 100 parts of deionized water, 1.6-1.7 parts of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, and 2.3-2.4 parts of 3-aminophenylboronic acid; The thiolated sodium alginate comprises the following raw materials in parts by weight: 2 to 3 parts of boric acid-modified sodium alginate, 100 parts of anhydrous tetrahydrofuran, and 1.8 to 2 parts of 3-mercapto-1,2-propylene glycol; The olefinized tungsten carbide comprises the following raw materials by weight: 1-1.5 parts of nano-tungsten carbide, 100 parts of 30wr% ethanol solution, and 0.5-0.8 parts of 3-(isomethylacryloyloxy)propyltrimethoxysilane; The modified tungsten carbide comprises the following raw materials in parts by mass: 4 to 6 parts of thiolated sodium alginate, 100 parts of deionized water, 1 to 1.5 parts of olefinated tungsten carbide, and 0.01 to 0.02 parts of azobisisobutyronitrile.

6. The method for preparing a corrosion-resistant wheel hub cap stainless steel alloy according to claim 1, characterized in that: During the electroplating process, the specific process is: the current density is 3~5A / dm 2 , temperature is 45~55℃, ultrasonic power is 300~400W, and time is 20~30min.

7. The stainless steel alloy prepared according to the method for preparing a corrosion-resistant wheel hub cap stainless steel alloy according to any one of claims 1 to 6.

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