Wear-resistant stainless steel tube for pneumatic cylinder and its preparation process

Abstract

The present invention relates to the technical field of stainless steel pneumatic cylinders, and specifically discloses a wear-resistant stainless steel tube for a pneumatic cylinder and a preparation process thereof. First, a powder metallurgy method is adopted to add components such as tungsten carbide, cerium oxide and chromium nitride to stainless steel powder to enhance the performance of the steel tube matrix. Then, a corrosion-resistant alloy layer is deposited on the surface of the steel tube by magnetron sputtering, thereby enhancing the corrosion resistance and wear resistance of the steel tube. Finally, a silicon nitride wear-resistant ceramic layer is sintered on the surface of the corrosion-resistant coating, and two lubricants, graphite and molybdenum sulfide, are synthesized in the pores and cracks of the wear-resistant ceramic layer to seal defects on the ceramic surface and give the ceramic coating a self-lubricating function.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel pneumatic cylinders, in particular to a wear-resistant stainless steel pipe for a pneumatic cylinder and a preparation process thereof. Background Art

[0002] Pneumatic actuators are mechanically driven devices powered by compressed air and are widely used in automation, industrial machinery, instrumentation, and valves. The pneumatic cylinder is a component of its core component—the pneumatic cylinder. Within the cylinder, air moves the piston or vane during a compression-release cycle, generating mechanical energy output.

[0003] Since the pressure in the cylinder is constantly changing during the operation of the actuator, and the gas in the cylinder is generally inhaled from the external environment, under complex and harsh working conditions, the pneumatic cylinder will interact with dust particles in the air to cause wear, or inhale acidic gases in the environment, causing corrosion in the cylinder, which in turn leads to problems such as poor cylinder sealing and cylinder leakage, seriously affecting production progress and production safety. Therefore, it is particularly important to enhance the wear resistance and corrosion resistance of the pneumatic cylinder, increase the life of the pneumatic cylinder during continuous operation, and reduce the replacement frequency of the pneumatic cylinder for the development of pneumatic cylinders. Summary of the Invention

[0004] The purpose of the present invention is to provide a wear-resistant stainless steel tube for a pneumatic cylinder and a preparation process thereof, so as to enhance the wear resistance and corrosion resistance of the pneumatic cylinder and solve the problem that the pneumatic cylinder is prone to wear or corrosion under complex and harsh working conditions, resulting in poor cylinder sealing and cylinder leakage.

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

[0006] A preparation process for a wear-resistant stainless steel tube for a pneumatic cylinder, specifically comprising:

[0007] Step 1: After the stainless steel powder and the reinforcement phase are ball-milled and mixed evenly, they are placed in a cylinder mold and pressed at a pressure of 700-800 MPa to form a shape. Subsequently, under nitrogen protection, the temperature is raised to 1350-1400℃ and fired for 1-3 hours. After the firing is completed, the cylinder steel pipe is obtained through heat treatment and tempering processes;

[0008] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a base layer, a transition layer, and an alloy layer on the surface of the cylinder steel pipe in sequence to obtain a corrosion-resistant steel pipe;

[0009] Step 3: Disperse polysilazane, silicon nitride, and ytterbium oxide in xylene to form a dispersion, which is then sprayed onto a corrosion-resistant steel pipe. After spraying, the temperature is raised to 50-70°C to completely volatilize the xylene. The pipe is then fired at 1250-1300°C for 3-5 hours under nitrogen protection. After firing, the pipe is cooled to room temperature to obtain a ceramic-coated steel pipe.

[0010] Step 4: Dissolve D-glucose, sodium molybdate and thiourea in deionized water to form a lubricating coating solution. Finally, immerse the ceramic-coated steel pipe in the lubricating coating solution and ultrasonicate for 10-20 minutes. After the immersion is completed, the ceramic-coated steel pipe and the lubricating coating solution are reacted together at 270-300°C and 10-15MPa for 24 hours to obtain a wear-resistant stainless steel pipe for pneumatic cylinders.

[0011] As a limitation of the present invention, in step 1, the reinforcing phase is composed of cerium oxide, chromium nitride, copper powder, cobalt powder, ferroboron powder and tungsten carbide; in the cylinder steel pipe, the mass fraction of cerium oxide is 0.05%-0.3%, the mass fraction of chromium nitride is 3.4%-3.8%, the mass fraction of copper powder is 3%-5%, the mass fraction of cobalt powder is 2%-4%, the mass fraction of ferroboron powder is 0.8%-1.2%, the mass fraction of tungsten carbide is 6%-8%, and the balance is stainless steel powder.

[0012] As a limitation of the present invention, in step 1, the heat treatment and tempering process is specifically as follows: alumina and ammonium chloride are mixed in a mass ratio of (93-97): (3-7) and covered on the surface of the fired product with a thickness of 5-10 mm, and kept at 1100-1150°C for 4 hours. After the insulation is completed, it is cooled to room temperature and tempered at 250-300°C for 3-5 hours to obtain a cylinder steel pipe.

[0013] The use of a mixed powder of alumina and ammonium chloride helps in the heat treatment of stainless steel. Alumina powder is inert, and ammonium chloride decomposes when heated to produce a reducing atmosphere. Covering the stainless steel surface can isolate the air and prevent the stainless steel from oxidizing and decarburizing. At the same time, the thermal conductivity of alumina powder is good, which helps the stainless steel pipe to be heated evenly. In addition, the use of mixed powder can also prevent the stainless steel pipe fittings from deforming or sticking to each other during the treatment process.

[0014] As a limitation of the present invention, in step 2, the thickness of the primer layer is 0.1-0.3 μm, the thickness of the transition layer is 0.05-0.1 μm, and the thickness of the alloy layer is 0.18-0.28 μm.

[0015] As a limitation of the present invention, in step 2, the specific process of magnetron sputtering is:

[0016] First, turn on the power and start the vacuum pump to 1.2×10 -3 -1.5×10 -3Pa, then start the heater, heat the cylinder steel pipe to 380-400℃ at a heating rate of 6-10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70-80sccm, set the bias voltage to (-60)-(-80)V, and bias etch for 10-20min. After the etching is completed, turn on the chromium target power supply to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. After the base layer is deposited, introduce nitrogen to deposit a transition layer on the surface of the base layer. After the transition layer is deposited, turn on the titanium aluminum vanadium alloy target power supply to deposit an alloy layer on the surface of the transition layer.

[0017] First, a chromium layer is deposited on the steel pipe as a base layer that is tightly bonded to the steel pipe substrate. Then, nitrogen is introduced to deposit chromium nitride on the base layer as a transition between the base layer and the alloy layer, relieving stress within the coating while reducing defect density. Finally, a corrosion-resistant alloy layer is deposited on the transition layer to enhance the hardness and corrosion resistance of the steel pipe.

[0018] As a limitation of the present invention, during magnetron sputtering, the argon flow rate is 30-40 sccm, the sputtering pressure is 0.4-0.5 Pa, the chromium target power is 180-200 W, and the sputtering deposition time for the base layer is 10-15 min; the nitrogen flow rate is 10-20 sccm, and the sputtering deposition time for the transition layer is 5-10 min; the titanium aluminum vanadium alloy target power is 150-180 W, and the sputtering deposition time for the alloy layer is 2-3 h.

[0019] As a limitation of the present invention, in step 2, the heat treatment after magnetron sputtering is specifically:

[0020] After the deposition is completed, the temperature is heated to 280-300°C at a heating rate of 10-15°C / min, then kept warm for 5-6 hours and cooled. The heating-keeping-cooling process is cyclically repeated 3-5 times to obtain a corrosion-resistant steel pipe.

[0021] Through cyclic heat treatment, atomic rearrangement is promoted, crystallization is induced, coating defects are reduced, residual stress in the coating is released, the formation of brittle compounds (such as titanium-aluminum metal compounds) is inhibited, atomic mutual diffusion at the interface is promoted, coating adhesion is increased, and grain coarsening and interface reactions caused by a single high temperature are avoided.

[0022] As a limitation of the present invention, in step 3, the mass ratio of polysilazane, silicon nitride powder, and ytterbium oxide powder is (8-12):(4-6):(1-2); and the viscosity of the dispersion is 8-12 Pa·s.

[0023] As a limitation of the present invention, in step 4, the mass ratio of D-glucose, sodium molybdate, thiourea and deionized water is (50-60):(8-10):(10-15):(180-220).

[0024] A wear-resistant stainless steel tube for a pneumatic cylinder is manufactured by adopting the above-mentioned preparation process.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention first adopts a powder metallurgy method, and adds a reinforcing phase consisting of cerium oxide, chromium nitride, copper powder, cobalt powder, ferroboron powder and tungsten carbide to the stainless steel powder during the metallurgical process, wherein the addition of cerium oxide can refine the grains, purify impurities such as sulfur and oxygen in the stainless steel, reduce grain boundary brittleness, and improve the strength and toughness of the steel pipe; chromium nitride is dispersed in the stainless steel matrix, promotes the formation of chromium oxide passivation film, improves the hardness, wear resistance and corrosion resistance of the steel pipe, and can also delay the formation of iron-chromium brittle phase at high temperature, and improve the high-temperature stability of the steel pipe; the addition of copper powder can promote sintering densification; cobalt powder acts as a bonding phase to enhance the interface bonding ability of stainless steel powder and other powders, and can also improve the red hardness of stainless steel and maintain hardness at high temperature; ferroboron powder is used to reduce the sintering temperature and improve the hardenability of stainless steel, and tungsten carbide can significantly improve the wear resistance and high-temperature stability of the steel pipe; the performance of the stainless steel pipe is enhanced through appropriate proportions.

[0027] The present invention adopts magnetron sputtering to first deposit a chromium layer with good compatibility with the steel pipe substrate on the surface of the steel pipe as a base layer, then introduce nitrogen to deposit a chromium nitride layer on the surface of the base layer as a transition layer, and then add a titanium aluminum vanadium alloy target to deposit a corrosion-resistant alloy layer on the surface of the transition layer. Titanium aluminum vanadium can form a hard phase on the surface of the substrate during deposition, thereby enhancing the wear resistance and corrosion resistance of the steel pipe.

[0028] The present invention uses polysilazane as a ceramic bonding phase, silicon nitride as a ceramic phase, and ytterbium oxide as a sintering-promoting phase. After being dispersed in xylene, they are sprayed on the surface of a steel pipe. After high-temperature sintering, a ceramic coating with good wear resistance, corrosion resistance, and high-temperature resistance is formed on the surface of the steel pipe. Then, three lubricating phase precursors, D-glucose, sodium molybdate, and thiourea, are introduced. Two lubricating phases, graphite and molybdenum sulfide, are synthesized in situ in the defective holes of the ceramic coating, which assists in lubrication and friction reduction during the friction process of the ceramic coating, fills the ceramic defects, and further enhances the wear resistance of the ceramic. 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] Stainless steel powder (316L stainless steel, particle size: 100 mesh, Cr: 16.8%, Ni: 10.7%, Mo: 2.1%, C: 0.02%, Fe: ≥69.1%), cerium oxide (particle size: 200 mesh), chromium nitride (particle size: 120 mesh), copper powder (particle size: 200 mesh), cobalt powder (particle size: 200 mesh), ferroboron powder (boron content: 18%, particle size: 200 mesh), tungsten carbide (particle size: 120 mesh), chromium target (purity: ≥99.9%), titanium aluminum vanadium alloy target (aluminum: 6.0%, vanadium: 4.0%, others: 0.66%, balance titanium), polysilazane (poly 1,1-dimethylsilazane, Mn: 600-800), silicon nitride powder (particle size: 200 mesh), ytterbium oxide powder (particle size: 200 mesh).

[0031] Example 1: A process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder, specifically comprising:

[0032] Step 1: 80.9% stainless steel powder, 0.1% cerium oxide, 4% chromium nitride, 4% copper powder, 3% cobalt powder, 1% ferroboron powder, and 7% tungsten carbide are mixed by mass fraction, ball milled for 20 minutes in a planetary ball mill to make the mixture uniform, then placed in a cylinder mold, and pressed and shaped at a pressure of 750 MPa. After that, it is placed in a tubular furnace and fired at 1350-1400 ° C for 2 hours under nitrogen as a protective gas. After firing, it is transferred to a vacuum heat treatment furnace and a 10 mm thick covering layer is formed on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. It is kept at 1100 ° C for 4 hours, cooled to room temperature after the heat preservation is completed, and tempered at 250 ° C for 4 hours to obtain a cylinder steel pipe;

[0033] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a 0.2μm thick primer layer, a 0.1μm thick transition layer, and a 0.23μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power and start the vacuum pump to 1.5×10 -3Pa, then start the heater, heat the cylinder steel pipe to 400℃ at a heating rate of 10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70sccm, set the bias voltage to -80V, and bias etch for 15min to remove the oxide layer and pollutants on the cylinder surface. After the etching is completed, set the argon flow rate to 30sccm, the sputtering pressure to 0.42Pa, the chromium target power to 200W, and the magnetron sputtering time to 10min to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. The base layer deposition is completed. Then, keeping other parameters unchanged, nitrogen was introduced with a nitrogen flow rate of 10 sccm, and magnetron sputtering was performed for 10 minutes to deposit a transition layer on the surface of the base layer. After the deposition of the transition layer was completed, the titanium aluminum vanadium alloy target power was turned on and the titanium aluminum vanadium alloy target power was set to 160W. The alloy layer was deposited on the surface of the transition layer. After the deposition was completed, it was placed in a heat treatment furnace, heated to 300°C at a heating rate of 15°C / min, and then kept warm for 6 hours and cooled. The heating-keeping-cooling process was cyclically repeated for three times to obtain a corrosion-resistant steel pipe.

[0034] Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 minutes to form a dispersion with a viscosity of 10 Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 MPa, and the spraying thickness to 100 μm. After spraying, heat to 60°C to completely volatilize the xylene, and finally place it in a heat treatment furnace. Under nitrogen protection, it is fired at a firing temperature of 1300°C for 4 hours. After firing, it is cooled to room temperature with the furnace to obtain a ceramic coated steel pipe;

[0035] Step 4: Add 50 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe in the solution and ultrasonicate for 15 minutes. After the ultrasonic immersion is completed, transfer them together to a high-pressure reactor and react at 280°C and 12 MPa for 24 hours to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder.

[0036] Example 2: A process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder, specifically comprising:

[0037] Step 1: 81.5% stainless steel powder, 0.2% cerium oxide, 3.8% chromium nitride, 4% copper powder, 3% cobalt powder, 1% ferroboron powder, and 6.5% tungsten carbide are mixed by mass fraction, ball milled for 20 minutes in a planetary ball mill to make the mixture uniform, then placed in a cylinder mold, and pressed and shaped at a pressure of 750 MPa. After that, it is placed in a tubular furnace and fired at 1350-1400 ° C for 2 hours under nitrogen as a protective gas. After firing, it is transferred to a vacuum heat treatment furnace and a 10 mm thick covering layer is formed on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. It is kept at 1100 ° C for 4 hours, cooled to room temperature after the heat preservation is completed, and tempered at 250 ° C for 4 hours to obtain a cylinder steel pipe;

[0038] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a 0.2μm thick primer layer, a 0.1μm thick transition layer, and a 0.23μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power and start the vacuum pump to 1.5×10 -3 Pa, then start the heater, heat the cylinder steel pipe to 400℃ at a heating rate of 10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70sccm, set the bias voltage to -80V, and bias etch for 15min to remove the oxide layer and pollutants on the cylinder surface. After the etching is completed, set the argon flow rate to 30sccm, the sputtering pressure to 0.42Pa, the chromium target power to 200W, and the magnetron sputtering time to 10min to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. The base layer deposition is completed. Then, keeping other parameters unchanged, nitrogen was introduced with a nitrogen flow rate of 10 sccm, and magnetron sputtering was performed for 10 minutes to deposit a transition layer on the surface of the base layer. After the deposition of the transition layer was completed, the titanium aluminum vanadium alloy target power was turned on and the titanium aluminum vanadium alloy target power was set to 160W. The alloy layer was deposited on the surface of the transition layer. After the deposition was completed, it was placed in a heat treatment furnace, heated to 300°C at a heating rate of 15°C / min, and then kept warm for 6 hours and cooled. The heating-keeping-cooling process was cyclically repeated for three times to obtain a corrosion-resistant steel pipe.

[0039] Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 minutes to form a dispersion with a viscosity of 11 Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 MPa, and the spraying thickness to 100 μm. After spraying, heat to 60°C to completely volatilize the xylene, and finally place it in a heat treatment furnace. Under nitrogen protection, it is fired at a firing temperature of 1300°C for 4 hours. After firing, it is cooled to room temperature with the furnace to obtain a ceramic coated steel pipe;

[0040] Step 4: Add 55 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe in the solution and ultrasonicate for 15 minutes. After the ultrasonic immersion is completed, transfer them together to a high-pressure reactor and react at 280°C and 12 MPa for 24 hours to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder.

[0041] Example 3: A process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder, specifically comprising:

[0042] Step 1: 81.8% stainless steel powder, 0.25% cerium oxide, 3.6% chromium nitride, 4% copper powder, 3% cobalt powder, 0.85% ferroboron powder, and 6.5% tungsten carbide are mixed by mass fraction, ball milled for 20 minutes in a planetary ball mill to make the mixture uniform, then placed in a cylinder mold, and pressed and shaped at a pressure of 750 MPa. After that, it is placed in a tubular furnace and fired at 1350-1400 ° C for 2 hours under nitrogen as a protective gas. After firing, it is transferred to a vacuum heat treatment furnace and a 10 mm thick covering layer is formed on the surface with a mixed powder consisting of 95% alumina and 5% ammonium chloride. It is kept at 1100 ° C for 4 hours, cooled to room temperature after the heat preservation is completed, and tempered at 250 ° C for 4 hours to obtain a cylinder steel pipe;

[0043] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a 0.2μm thick primer layer, a 0.1μm thick transition layer, and a 0.23μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power and start the vacuum pump to 1.5×10 -3 Pa, then start the heater, heat the cylinder steel pipe to 400℃ at a heating rate of 10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70sccm, set the bias voltage to -80V, and bias etch for 15min to remove the oxide layer and pollutants on the cylinder surface. After the etching is completed, set the argon flow rate to 30sccm, the sputtering pressure to 0.42Pa, the chromium target power to 200W, and the magnetron sputtering time to 10min to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. The base layer deposition is completed. Then, keeping other parameters unchanged, nitrogen was introduced with a nitrogen flow rate of 10 sccm, and magnetron sputtering was performed for 10 minutes to deposit a transition layer on the surface of the base layer. After the deposition of the transition layer was completed, the titanium aluminum vanadium alloy target power was turned on and the titanium aluminum vanadium alloy target power was set to 160W. The alloy layer was deposited on the surface of the transition layer. After the deposition was completed, it was placed in a heat treatment furnace, heated to 300°C at a heating rate of 15°C / min, and then kept warm for 6 hours and cooled. The heating-keeping-cooling process was cyclically repeated for three times to obtain a corrosion-resistant steel pipe.

[0044] Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 minutes to form a dispersion with a viscosity of 12 Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 MPa, and the spraying thickness to 100 μm. After spraying, heat to 60°C to completely volatilize the xylene, and finally place it in a heat treatment furnace. Under nitrogen protection, it is fired at a firing temperature of 1300°C for 4 hours. After firing, it is cooled to room temperature with the furnace to obtain a ceramic coated steel pipe;

[0045] Step 4: Add 60 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe in the solution and ultrasonicate for 15 minutes. After the ultrasonic immersion is completed, transfer them together to a high-pressure reactor and react at 280°C and 12 MPa for 24 hours to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder.

[0046] Based on Example 1, control experiments were conducted, specifically Comparative Example 1, Comparative Example 2, and Comparative Example 3, as described below:

[0047] Comparative Example 1: This comparative example relates to a preparation process for a wear-resistant stainless steel tube for a pneumatic cylinder. The difference from Example 1 is that when the cylinder steel tube is processed by powder metallurgy, the reinforcing phase is only copper powder, cobalt powder, boron iron powder, specifically:

[0048] Step 1: 92% stainless steel powder, 4% copper powder, 3% cobalt powder, and 1% ferroboron powder are mixed by mass fraction, ball-milled for 20 minutes in a planetary ball mill to make the mixture uniform, then placed in a cylinder mold and pressed into shape at a pressure of 750 MPa. After that, the mixture is placed in a tubular furnace and fired at 1350-1400°C for 2 hours under nitrogen as a protective gas. After firing, it is transferred to a vacuum heat treatment furnace and a 10 mm thick covering layer is formed on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. The mixture is kept at 1100°C for 4 hours, cooled to room temperature after the heat preservation is completed, and tempered at 250°C for 4 hours to obtain a cylinder steel pipe.

[0049] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a 0.2μm thick primer layer, a 0.1μm thick transition layer, and a 0.23μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power and start the vacuum pump to 1.5×10 -3Pa, then start the heater, heat the cylinder steel pipe to 400℃ at a heating rate of 10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70sccm, set the bias voltage to -80V, and bias etch for 15min to remove the oxide layer and pollutants on the cylinder surface. After the etching is completed, set the argon flow rate to 30sccm, the sputtering pressure to 0.42Pa, the chromium target power to 200W, and the magnetron sputtering time to 10min to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. The base layer deposition is completed. Then, keeping other parameters unchanged, nitrogen was introduced with a nitrogen flow rate of 10 sccm, and magnetron sputtering was performed for 10 minutes to deposit a transition layer on the surface of the base layer. After the deposition of the transition layer was completed, the titanium aluminum vanadium alloy target power was turned on and the titanium aluminum vanadium alloy target power was set to 160W. The alloy layer was deposited on the surface of the transition layer. After the deposition was completed, it was placed in a heat treatment furnace, heated to 300°C at a heating rate of 15°C / min, and then kept warm for 6 hours and cooled. The heating-keeping-cooling process was cyclically repeated for three times to obtain a corrosion-resistant steel pipe.

[0050] Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 minutes to form a dispersion with a viscosity of 10 Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 MPa, and the spraying thickness to 100 μm. After spraying, heat to 60°C to completely volatilize the xylene, and finally place it in a heat treatment furnace. Under nitrogen protection, it is fired at a firing temperature of 1300°C for 4 hours. After firing, it is cooled to room temperature with the furnace to obtain a ceramic coated steel pipe;

[0051] Step 4: Add 50 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe in the solution and ultrasonicate for 15 minutes. After the ultrasonic immersion is completed, transfer them together to a high-pressure reactor and react at 280°C and 12 MPa for 24 hours to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder.

[0052] Comparative Example 2: This comparative example relates to a preparation process of a wear-resistant stainless steel tube for a pneumatic cylinder. The difference from Example 1 is that during magnetron sputtering deposition, the metal target used is only a chromium target, specifically:

[0053] Step 1: 80.9% stainless steel powder, 0.1% cerium oxide, 4% chromium nitride, 4% copper powder, 3% cobalt powder, 1% ferroboron powder, and 7% tungsten carbide are mixed by mass fraction, ball milled for 20 minutes in a planetary ball mill to make the mixture uniform, then placed in a cylinder mold, and pressed and shaped at a pressure of 750 MPa. After that, it is placed in a tubular furnace and fired at 1350-1400 ° C for 2 hours under nitrogen as a protective gas. After firing, it is transferred to a vacuum heat treatment furnace and a 10 mm thick covering layer is formed on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. It is kept at 1100 ° C for 4 hours, cooled to room temperature after the heat preservation is completed, and tempered at 250 ° C for 4 hours to obtain a cylinder steel pipe;

[0054] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a 0.2μm thick primer layer, a 0.1μm thick transition layer, and a 0.23μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power and start the vacuum pump to 1.5×10 -3 Pa, then start the heater, heat the cylinder steel pipe to 400℃ at a heating rate of 10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70sccm, set the bias voltage to -80V, and bias etch for 15min to remove the oxide layer and pollutants on the cylinder surface. After etching is completed, set the argon flow rate to 30sccm, the sputtering pressure to 0.42Pa, the chromium target power to 200W, and the magnetron sputtering time to 10min. Deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. After the deposition of the base layer is completed, keep other parameters unchanged, introduce nitrogen gas with a nitrogen flow rate of 10sccm, and magnetron sputter for 10min. Deposit a transition layer on the surface of the base layer. After the deposition of the transition layer is completed, set the sputtering time to 2h, and deposit an alloy layer on the surface of the transition layer. After deposition is completed, put it into a heat treatment furnace, heat it to 300℃ at a heating rate of 15℃ / min, then keep it warm for 6h and cool it. Repeat the heating-keeping-cooling process for 3 times to obtain a corrosion-resistant steel pipe.

[0055] Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 minutes to form a dispersion with a viscosity of 10 Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 MPa, and the spraying thickness to 100 μm. After spraying, heat to 60°C to completely volatilize the xylene, and finally place it in a heat treatment furnace. Under nitrogen protection, it is fired at a firing temperature of 1300°C for 4 hours. After firing, it is cooled to room temperature with the furnace to obtain a ceramic coated steel pipe;

[0056] Step 4: Add 50 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe in the solution and ultrasonicate for 15 minutes. After the ultrasonic immersion is completed, transfer them together to a high-pressure reactor and react at 280°C and 12 MPa for 24 hours to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder.

[0057] Comparative Example 3: This comparative example relates to a preparation process for a wear-resistant stainless steel tube for a pneumatic cylinder. The difference from Example 1 is that the tube is not immersed in a mixed solution of D-glucose, sodium molybdate and thiourea. Specifically,

[0058] Step 1: 80.9% stainless steel powder, 0.1% cerium oxide, 4% chromium nitride, 4% copper powder, 3% cobalt powder, 1% ferroboron powder, and 7% tungsten carbide are mixed by mass fraction, ball milled for 20 minutes in a planetary ball mill to make the mixture uniform, then placed in a cylinder mold, and pressed and shaped at a pressure of 750 MPa. After that, it is placed in a tubular furnace and fired at 1350-1400 ° C for 2 hours under nitrogen as a protective gas. After firing, it is transferred to a vacuum heat treatment furnace and a 10 mm thick covering layer is formed on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. It is kept at 1100 ° C for 4 hours, cooled to room temperature after the heat preservation is completed, and tempered at 250 ° C for 4 hours to obtain a cylinder steel pipe;

[0059] Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a 0.2μm thick primer layer, a 0.1μm thick transition layer, and a 0.23μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power and start the vacuum pump to 1.5×10 -3Pa, then start the heater, heat the cylinder steel pipe to 400℃ at a heating rate of 10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70sccm, set the bias voltage to -80V, and bias etch for 15min to remove the oxide layer and pollutants on the cylinder surface. After the etching is completed, set the argon flow rate to 30sccm, the sputtering pressure to 0.42Pa, the chromium target power to 200W, and the magnetron sputtering time to 10min to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. The base layer deposition is completed. Then, keeping other parameters unchanged, nitrogen was introduced with a nitrogen flow rate of 10 sccm, and magnetron sputtering was performed for 10 minutes to deposit a transition layer on the surface of the base layer. After the deposition of the transition layer was completed, the titanium aluminum vanadium alloy target power was turned on and the titanium aluminum vanadium alloy target power was set to 160W. The alloy layer was deposited on the surface of the transition layer. After the deposition was completed, it was placed in a heat treatment furnace, heated to 300°C at a heating rate of 15°C / min, and then kept warm for 6 hours and cooled. The heating-keeping-cooling process was cyclically repeated for three times to obtain a corrosion-resistant steel pipe.

[0060] Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 minutes to form a dispersion with a viscosity of 10Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4Mpa, and the spraying thickness to 100μm. After spraying, heat to 60°C to completely volatilize the xylene, and finally place it in a heat treatment furnace. Under nitrogen protection, fire at a firing temperature of 1300°C for 4 hours. After firing, cool to room temperature with the furnace to obtain a wear-resistant stainless steel tube for pneumatic cylinders.

[0061] Detection experiment:

[0062] According to the preparation processes of wear-resistant stainless steel tubes for pneumatic cylinders in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3, steel plates of the same material were processed to prepare a batch of wear-resistant stainless steel plate samples, and adhesion tests, microhardness tests, friction and wear performance tests, and corrosion resistance tests were carried out.

[0063] Adhesion test: The adhesion test of the coating on the sample surface is based on the "Review of test methods for adhesion strength of metal coatings by electrodeposition and chemical deposition on metal substrates" (GB / T 5270-2024). The test is performed using a UMT-3 comprehensive mechanical properties testing machine. After the sample is fixed with a fixture, a conical diamond indenter with a top radius of 0.2mm is pressed on the coating surface. The initial load is set to 0N, the load acceleration is 10N / min, and the scratch speed is 5mm / min. The test is continued until the coating peels off. The critical load of the sample is recorded. Three different locations of each sample are selected for measurement, and the results are averaged.

[0064] Microhardness test: The microhardness test of the sample is based on the "Metallic Materials, Metals and Other Inorganic Coatings - Vickers Hardness and Knoop Microhardness Test" (GB / T 9790-2020). The test uses an HSV-1000 digital microhardness tester (Sivaka Precision Instruments) and a Knoop indenter. After the sample is fixed with a fixture, the fixture is moved to align the center of the indenter with the test area on the sample. The load is set to 100 gf and the application time is 10 seconds. Five points are selected for testing on each sample, and the results are averaged.

[0065] Friction and wear performance test: The friction and wear performance test was conducted using an HSR-2M reciprocating friction and wear tester (Zhongke Kaihua). The sample size was 10mm×10mm×10mm. After the sample was fixed with a clamp, the coated side of the sample was rubbed against the grinding material. The grinding material was a GCr15 high-carbon chromium bearing steel ball with a diameter of 4mm. The load was 500g, the sliding stroke was 5mm, the friction time was 15min, and the ambient temperature was 25°C. After the friction, the wear morphology of the sample was observed with a scanning electron microscope, and the wear rate of the sample was calculated.

[0066] Corrosion resistance test: The corrosion resistance test is based on the "Artificial Atmosphere Corrosion Test Salt Spray Test" (GB / T10125-2012), and is tested in a neutral salt spray test chamber. The sample is weighed and placed in the test chamber. The sample angle is adjusted to 25° with the vertical direction. The coated side is used as the effective test surface, and the non-test area is covered with tape. The corrosion solution is a 5% by mass sodium chloride solution. The temperature in the salt spray chamber is 35°C. After 48 hours, the sample is removed from the test chamber and soaked in a 20% by mass diamine citric acid solution for 10 minutes. After 10 minutes, the sample is removed and the surface is washed with ethanol and deionized water. After drying at 60°C, the sample is weighed and the mass loss of the sample is calculated.

[0067]

[0068] Conclusion: The test results of each test show that the adhesion, microhardness, wear rate, and corrosion mass loss of the wear-resistant stainless steel plate samples processed according to the preparation process of each embodiment are all superior to those of the comparative example. The preparation process of the wear-resistant stainless steel tube for pneumatic cylinder provided by the present invention can produce stainless steel tubes with excellent hardness, wear resistance, and corrosion resistance. The wear-resistant and corrosion-resistant coating on the steel tube is tightly bonded and not easy to fall off, which can meet complex and harsh working conditions, has a long service life, and reduces the number of cylinder damages and replacement frequency during use.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder, characterized in that: Specifically: Step 1: After the stainless steel powder and the reinforcement phase are ball-milled and mixed evenly, they are placed in a cylinder mold and pressed at a pressure of 700-800 MPa to form a shape. Subsequently, under nitrogen protection, the temperature is raised to 1350-1400℃ and fired for 1-3 hours. After the firing is completed, the cylinder steel pipe is obtained through heat treatment and tempering processes; Step 2: After the cylinder steel pipe is polished and smooth, it is washed with anhydrous ethanol and deionized water, dried at 80°C, and magnetron sputtering technology is used to deposit a base layer, a transition layer, and an alloy layer on the surface of the cylinder steel pipe in sequence to obtain a corrosion-resistant steel pipe; Step 3: Disperse polysilazane, silicon nitride, and ytterbium oxide in xylene to form a dispersion, which is then sprayed onto a corrosion-resistant steel pipe. After spraying, the temperature is raised to 50-70°C to completely volatilize the xylene. The pipe is then fired at 1250-1300°C for 3-5 hours under nitrogen protection. After firing, the pipe is cooled to room temperature to obtain a ceramic-coated steel pipe. Step 4: Dissolve D-glucose, sodium molybdate, and thiourea in deionized water to form a lubricating coating solution. Finally, immerse the ceramic-coated steel pipe in the lubricating coating solution and ultrasonicate for 10-20 minutes. After the immersion is completed, the ceramic-coated steel pipe and the lubricating coating solution are reacted together at 270-300°C and 10-15 MPa for 24 hours to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder. Among them, the reinforcing phase is composed of cerium oxide, chromium nitride, copper powder, cobalt powder, ferroboron powder and tungsten carbide; in the cylinder steel pipe, the mass fraction of cerium oxide is 0.05%-0.3%, the mass fraction of chromium nitride is 3.4%-3.8%, the mass fraction of copper powder is 3%-5%, the mass fraction of cobalt powder is 2%-4%, the mass fraction of ferroboron powder is 0.8%-1.2%, the mass fraction of tungsten carbide is 6%-8%, and the balance is stainless steel powder.

2. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 1, characterized in that: In step 1, the heat treatment and tempering process is specifically as follows: alumina and ammonium chloride are mixed in a mass ratio of (93-97): (3-7) and covered on the surface of the fired product with a thickness of 5-10 mm, and kept at 1100-1150 ° C for 4 hours. After the insulation is completed, it is cooled to room temperature and tempered at 250-300 ° C for 3-5 hours to obtain a cylinder steel pipe.

3. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 1, characterized in that: In step 2, the thickness of the primer layer is 0.1-0.3 μm, the thickness of the transition layer is 0.05-0.1 μm, and the thickness of the alloy layer is 0.18-0.28 μm.

4. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 1, characterized in that: In step 2, the specific process of magnetron sputtering is as follows: First, turn on the power and start the vacuum pump to 1.2×10 -3 -1.5×10 -3 Pa, then start the heater, heat the cylinder steel pipe to 380-400℃ at a heating rate of 6-10℃ / min, introduce argon gas into the magnetron sputtering device with a flow rate of 70-80sccm, set the bias voltage to (-60)-(-80)V, and bias etch for 10-20min. After the etching is completed, turn on the chromium target power supply to deposit a base layer on the surface of the corrosion-resistant cylinder steel pipe. After the base layer is deposited, introduce nitrogen to deposit a transition layer on the surface of the base layer. After the transition layer is deposited, turn on the titanium aluminum vanadium alloy target power supply to deposit an alloy layer on the surface of the transition layer.

5. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 4, characterized in that: During magnetron sputtering, the argon flow rate is 30-40sccm, the sputtering pressure is 0.4-0.5Pa, the chromium target power is 180-200W, and the sputtering deposition time for the base layer is 10-15min; the nitrogen flow rate is 10-20sccm, and the sputtering deposition time for the transition layer is 5-10min; the titanium aluminum vanadium alloy target power is 150-180W, and the sputtering deposition time for the alloy layer is 2-3h.

6. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 1, characterized in that: In step 2, heat treatment is performed after magnetron sputtering, specifically: After the deposition is completed, the temperature is heated to 280-300°C at a heating rate of 10-15°C / min, then kept warm for 5-6 hours and cooled. The heating-keeping-cooling process is cyclically repeated 3-5 times to obtain a corrosion-resistant steel pipe.

7. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 1, characterized in that: In step 3, the mass ratio of polysilazane, silicon nitride powder, and ytterbium oxide powder is (8-12):(4-6):(1-2); and the viscosity of the dispersion is 8-12 Pa·s.

8. The process for preparing a wear-resistant stainless steel tube for a pneumatic cylinder according to claim 1, characterized in that: In step 4, the mass ratio of D-glucose, sodium molybdate, thiourea and deionized water is (50-60):(8-10):(10-15):(180-220).

9. A wear-resistant stainless steel tube for a pneumatic cylinder, manufactured by the preparation process according to any one of claims 1 to 8.

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