Hexagon nut with high wear resistance and corrosion resistance and preparation method thereof

Abstract

The invention relates to the technical field of nuts, and discloses a high-wear-resistance and corrosion-resistance hexagon nut and a preparation method thereof.The high-wear-resistance and corrosion-resistance hexagon nut comprises a hexagon nut base body, an electroplated layer and an anti-corrosion coating, the electroplated layer and the anti-corrosion coating are attached to the outer surface of the hexagon nut base body, and the hexagon nut base body is prepared from, by mass, 0.2%-0.3% of Ni, 0.5%-0.8% of Mo, 0.03%-0.08% of Cu, the balance Fe and inevitable impurities. The nut material is prepared from the following components in percentage by weight: 0.1%-0.3% of N, 1.1%-1.3% of C, 0.25%-0.45% of Si, 0.6%-0.9% of Mn, 0.45%-0.65% of Cr, 0.01%-0.02% of S, 10%-15% of Cr, 0.01%-0.02% of P, 0.02%-0.045% of AL, 0.01%-0.025% of S, 0.02%-0.04% of Nb, 0.01%-0.015% of Al, 0.1%-0.5% of Ti, 0.1%-1.0% of V and 0.05%-0.1% of Re. According to the scheme, the nut material is prepared by matching multiple metal elements with low carbon content, and has excellent mechanical properties, wear resistance and corrosion resistance; the nut is matched with high hardness, high wear resistance, high temperature resistance, corrosion resistance and the like after being subjected to heat treatment, and meanwhile the nut has good toughness, impact resistance and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nuts, and in particular relates to a highly wear-resistant and corrosion-resistant hexagonal nut and a preparation method thereof. Background Art

[0002] A nut, also known as a nut, is a fixing tool with a hole in the center and threads on the inside of the hole. It is often used with screws of matching size to fix the relevant joints. The nut is a part that is screwed together with a bolt or screw to act as a fastener. It is a component that all manufacturing machinery must use. It is divided into several major types according to the material, such as carbon steel, stainless steel, and non-ferrous metals.

[0003] Most of the existing nut substrates are coated with wear-resistant and corrosion-resistant coatings on the surface. However, the adhesion between the organic coating and the alloy substrate is insufficient. In a long-term torsional shear environment, it is easy to fall off the nut substrate, affecting the use effect and life of the nut. For this reason, we propose a highly wear-resistant and corrosion-resistant hexagonal nut and a preparation method thereof. Summary of the invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a highly wear-resistant and corrosion-resistant hexagonal nut and a preparation method thereof, which effectively solves the above problems.

[0005] To achieve the above object, the present invention provides the following technical solution: a highly wear-resistant and corrosion-resistant hexagonal nut, comprising a hexagonal nut substrate, an electroplating layer and an anti-corrosion coating applied to the outer surface of the hexagonal nut substrate;

[0006] The hexagonal nut matrix is ​​composed of the following raw materials: in mass percentage, Ni: 0.2-0.3%, Mo: 0.5-0.8%, Cu: 0.03-0.08%, N: 0.1-0.3%, C: 1.1-1.3%, Si: 0.25-0.45%, Mn: 0.6-0.9%, Cr: 0.45-0.65%, S: 0.01-0.02%, Cr: 10-15%, P: 0.01-0.02%, AL: 0.02-0.045%, S: 0.01-0.025%, Nb: 0.02%-0.04%, Al: 0.01-0.015%, Ti: 0.1-0.5%, V: 0.1-1.0%, Re: 0.05-0.1%, and the rest is Fe and unavoidable impurities.

[0007] Preferably, the anti-corrosion coating is a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating is 30 to 100 μm.

[0008] A method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut:

[0009] S1: Select raw materials, prepare Ni: 0.2-0.3%, Mo: 0.5-0.8%, Cu: 0.03-0.08%, N: 0.1-0.3%, C: 1.1-1.3%, Si: 0.25-0.45%, Mn: 0.6-0.9%, Cr: 0.45-0.65%, S: 0.01-0.02%, Cr: 10-15%, P: 0.01-0.02%, AL: 0.02-0.045%, S: 0.01-0.025%, Nb: 0.020%-0.040%, Al: 0.01-0.015%, Ti: 0.1-0.5%, V: 0.1-1.0%, Re: 0.05-0.1%, the rest is Fe and unavoidable impurities;

[0010] S2: Ingot forging: The above raw materials are passed through a high-temperature pressure furnace to generate molten iron, which is then cast through a crystallizer. After the molten steel is injected into the steel mold, it is gradually solidified into an ingot by natural cooling or forced cooling. During the cooling process, the structure and composition inside the ingot gradually become uniform. During the casting process, argon gas is passed through the steel mold and all molten steel flow channels to evacuate the existing air and maintain it for 5-10 minutes to prevent oxidation between the molten steel and oxygen, thereby reducing the oxide scale thickness on the surface of the ingot and improving the surface quality and yield rate;

[0011] S3: bar production, the steel ingot obtained by electroslag remelting continuous directional solidification technology is subjected to high temperature solution treatment; the high temperature solution treatment includes heating the steel ingot to 720-750℃ at 10-20℃ / min, keeping it warm for 0.5-2 hours, then continuing to heat it to 1050-1120℃ and keeping it warm for 1-2h, then finishing rolling it into bars through a continuous rolling unit and keeping it warm for 17-25h, cooling it to 700-750℃ at a cooling rate of 80-100℃ / h, and then cooling it to 400-450℃ with the furnace and air cooling it out of the furnace;

[0012] S4: bar processing: the bar is cut into nut blanks, the nut blanks are placed in a cold heading machine for processing and forming, so that the corners of the formed nut blanks are full and consistent, and the center of the nut blank is further punched by the cold heading machine to obtain a through hole;

[0013] S5: pickling treatment, pickling the hexagonal nut embryo obtained in S4, preparing a pickling solution, the pickling solution is prepared by weight: 4-9 parts of hydrofluoric acid, 150-250 parts of deionized water, 40-60 parts of phosphoric acid, 20-40 parts of hydrochloric acid, 8-12 parts of nitric acid, 4-6 parts of sulfuric acid, 15-23 parts of potassium chloride, 4-6 parts of potassium carbonate, 15-20 parts of silver chloride, and then the hexagonal nut embryo obtained in S3 is placed in a pickling tank for immersion, and the pickled hexagonal nut embryo is placed in a water tank to rinse the surface of the hexagonal nut embryo with acid;

[0014] S6: heat treatment, putting the processed hexagonal nut blank into the heat treatment furnace, the heat treatment furnace heats the hexagonal nut blank to 850-900℃, the heating rate is 10-15℃ / min, and then keeps warm for 30-50min, the hexagonal nut blank after being taken out of the furnace is air-cooled, cooled naturally, and then heated again at a temperature of 950-1050℃, the heating rate is 13-18℃ / min, and kept warm for 1-2h, the semi-finished cast iron nut after being taken out of the furnace is air-cooled, cooled naturally, and then the metal rod is heated to 900-950℃ again, the heating rate is 13-18℃ / min, the furnace is cooled to 600-650℃, and then quickly put into the quenching device for quenching, and the surface temperature is reduced to 300-350℃ and taken out, and then the hexagonal nut blank is tempered in the quenching device, the tempering temperature is 380-450℃, the tempering time is 60-95min, and the heat preservation is 1-2h;

[0015] S7: tapping, tapping the heat-treated hexagonal nut blank to form an internal thread to obtain a hexagonal nut base;

[0016] S8: electroplating, electroplating the hexagonal nut substrate three times, and drying after each electroplating;

[0017] S9: Apply coating, apply anti-corrosion coating to the hexagonal nut base.

[0018] Preferably, three electroplating solutions are used in the three electroplating processes in S8, and the three electroplating solutions are respectively prepared with the following raw materials:

[0019] The first electroplating solution: 18-22 parts of main salt, 12-25 parts of aminosulfonic acid, 0.15-0.25 parts of conductive salt, 45-55 parts of distilled water;

[0020] The second electroplating solution: 1 part sodium chloride, 2 parts zinc sulfate, 4-6 parts nickel sulfate, 2-3 parts thiocyanate, 0.2-0.4 parts complexing agent, 50-70 parts pure water;

[0021] The third electroplating solution: 2-6 parts of copper sulfate, 0.5-1 parts of sodium sulfate, 1-3 parts of pure water, 1-2 parts of sulfuric acid, 0.5-2 parts of hydrochloric acid, 0.5-2 parts of sodium chloride, 1-2 parts of complexing agent, 1-2 parts of brightener, 1-2 parts of leveling agent, 0.5-1.5 parts of wetting agent, 70-85 parts of deionized water;

[0022] The complexing agent is one or a mixture of citric acid, ethylene glycol, aminoacetic acid, NTA, EDTA and TEA.

[0023] Preferably, after the pickling in S5 is completed, the hexagonal nut embryos are rinsed one by one with high-pressure and low-pressure flowing water.

[0024] Preferably, during the electroplating process in S8:

[0025] The water flow rate of the first electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 30-40℃, and the current density is 2-4A / m 2 , the electroplating time is 1-3min;

[0026] The water flow rate of the second electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 60-80℃, and the current density is 3-6A / m 2 , the electroplating time is 4-7min;

[0027] The water flow rate of the third electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 40-70℃, and the current density is 2-5A / m 2 , the electroplating time is 2-5min.

[0028] Preferably, after the electroplating in S8 is completed, the surface is cleaned with hot water, and the temperature of the hot water is 40-80°C.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The nut material of the present invention is made of a variety of metal elements with low carbon content, which have excellent mechanical properties, wear resistance, and corrosion resistance. After heat treatment, the nut can achieve high hardness, high wear resistance, high temperature resistance, corrosion resistance and other performance matching, and at the same time has good toughness, impact resistance and other properties;

[0031] 2. The present invention adopts multiple electroplating methods to improve the wear resistance and corrosion resistance of the nut. The plating solution provided by the present invention has a simple formula, is environmentally friendly, has good stability, and the electroplating process is easy to control. The electroplated coating is uniform, dense, and has good bonding strength;

[0032] 3. Compared with the prior art, the mechanical properties of the nut after heat treatment of the present invention are significantly reduced in attenuation, while the elongation and cross-sectional shrinkage are significantly improved. The comprehensive performance of the cast iron nut after heat treatment of the present invention is improved compared with the prior art, ensuring the performance of the nut material;

[0033] 4. The present invention adopts a heat treatment process such as appropriate heating temperature, holding time and cooling method to make the cast iron nut have more excellent comprehensive mechanical properties. While ensuring the elimination of the internal stress of the cast iron nut, the present invention also ensures that the various performance indicators of the cast iron nut meet the design requirements, thereby ensuring the performance of the nut. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0035] In the attached picture:

[0036] Figure 1 The system block diagram of the present invention is DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] A highly wear-resistant and corrosion-resistant hexagonal nut, characterized in that it comprises a hexagonal nut base, an electroplating layer and an anti-corrosion coating applied to the outer surface of the hexagonal nut base;

[0039] The hexagonal nut matrix is ​​composed of the following raw materials: in mass percentage, Ni: 0.2-0.3%, Mo: 0.5-0.8%, Cu: 0.03-0.08%, N: 0.1-0.3%, C: 1.1-1.3%, Si: 0.25-0.45%, Mn: 0.6-0.9%, Cr: 0.45-0.65%, S: 0.01-0.02%, Cr: 10-15%, P: 0.01-0.02%, AL: 0.02-0.045%, S: 0.01-0.025%, Nb: 0.02%-0.04%, Al: 0.01-0.015%, Ti: 0.1-0.5%, V: 0.1-1.0%, Re: 0.05-0.1%, and the rest is Fe and unavoidable impurities.

[0040] The anti-corrosion coating is a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating is 30-100 μm.

[0041] Embodiment 1:

[0042] See also Figure 1 , a method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut, comprising the following steps:

[0043] S1: Select raw materials and prepare Ni: 0.3%, Mo: 0.5%, Cu: 0.04%, N: 0.2%, C: 1.2%, Si: 0.35%, Mn: 0.7%, Cr: 0.45%, S: 0.02%, Cr: 13%, P: 0.02%, AL: 0.025%, S: 0.015%, Nb: 0.02%, Al: 0.01%, Ti: 0.3%, V: 1.0%, Re: 0.1%, and the rest is Fe and unavoidable impurities;

[0044] S2: Ingot forging: The above raw materials are passed through a high-temperature pressure furnace to generate molten iron, which is then cast through a crystallizer. After the molten steel is injected into the steel mold, it is gradually solidified into an ingot by natural cooling or forced cooling. During the cooling process, the structure and composition inside the ingot gradually become uniform. During the casting process, the steel mold and all molten steel flow channels are purged of the existing air with argon gas for 8 minutes to prevent oxidation between the molten steel and oxygen, thereby reducing the oxide scale thickness on the surface of the ingot and improving the surface quality and yield rate;

[0045] S3: bar production, the steel ingot obtained by electroslag remelting continuous directional solidification technology is subjected to high temperature solution treatment; the high temperature solution treatment includes heating the steel ingot to 740℃ at 14℃ / min, keeping it at this temperature for 1 hour, then heating it to 1050℃ and keeping it at this temperature for 1.5h, then finishing rolling it into bars through a continuous rolling unit and keeping it at this temperature for 22h, cooling it to 700℃ at a cooling rate of 90℃ / h, and then cooling it to 450℃ with the furnace and air cooling it out of the furnace;

[0046] S4: bar processing: the bar is cut into nut blanks, the nut blanks are placed in a cold heading machine for processing and forming, so that the corners of the formed nut blanks are full and consistent, and the center of the nut blank is further punched by the cold heading machine to obtain a through hole;

[0047] S5: pickling treatment, pickling the hexagonal nut embryo obtained in S4, preparing a pickling solution, the pickling solution is prepared by weight: 7 parts of hydrofluoric acid, 200 parts of deionized water, 50 parts of phosphoric acid, 20 parts of hydrochloric acid, 8 parts of nitric acid, 4 parts of sulfuric acid, 15 parts of potassium chloride, 4 parts of potassium carbonate, 20 parts of silver chloride, and then the hexagonal nut embryo obtained in S3 is placed in a pickling tank for immersion, and the pickled hexagonal nut embryo is placed in a water tank to rinse the surface of the hexagonal nut embryo with acid. After the pickling is completed, the hexagonal nut embryo is rinsed one by one with clean water high-pressure and low-pressure flow;

[0048] S6: heat treatment, putting the processed hexagonal nut blank into the heat treatment furnace, the heat treatment furnace heats the hexagonal nut blank to 880℃, the heating rate is 13℃ / min, and then keeps it warm for 40min, the hexagonal nut blank after being taken out of the furnace is air-cooled, cooled naturally, and then heated again at 950℃, the heating rate is 16℃ / min, and kept warm for 1h, the semi-finished cast iron nut after being taken out of the furnace is air-cooled, cooled naturally, and then the metal rod is heated to 940℃ again, the heating rate is 17℃ / min, and the furnace is cooled to 620℃ and then quickly put into the quenching device for quenching, and the surface temperature is reduced to 320℃ and taken out, and then the hexagonal nut blank is tempered in the quenching device, the tempering temperature is 420℃, the tempering time is 85min, and the heat is kept for 1.5h;

[0049] S7: tapping, tapping the heat-treated hexagonal nut blank to form an internal thread to obtain a hexagonal nut base;

[0050] S8: electroplating, electroplating the hexagonal nut substrate three times, drying after each electroplating, and washing with hot water after the three electroplatings, the hot water temperature is 60°C;

[0051] Three electroplating solutions are used in the three electroplating processes, and the three electroplating solutions are respectively prepared with the following raw materials:

[0052] The first electroplating solution: 20 parts of main salt, 22 parts of aminosulfonic acid, 0.18 parts of conductive salt, 55 parts of distilled water. The water flow rate of the first electroplating solution is 0.4m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 36℃, and the current density is 3A / m 2 , the electroplating time is 2min;

[0053] The second electroplating solution: 1 part sodium chloride, 2 parts zinc sulfate, 5 parts nickel sulfate, 2 parts thiocyanate, 0.3 parts complexing agent, 60 parts pure water, the water flow rate of the second electroplating solution is 0.4m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 70℃, and the current density is 5A / m 2 , the electroplating time is 5min;

[0054] The third electroplating solution: 5 parts of copper sulfate, 1 part of sodium sulfate, 2 parts of pure water, 2 parts of sulfuric acid, 2 parts of hydrochloric acid, 1 part of sodium chloride, 2 parts of complexing agent, 2 parts of brightener, 1 part of leveling agent, 1 part of wetting agent, 75 parts of deionized water. The water flow rate of the third electroplating solution is 0.4m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 60℃, and the current density is 3A / m 2 , the electroplating time is 3min;

[0055] The complexing agent is one or a mixture of citric acid, ethylene glycol, aminoacetic acid, NTA, EDTA, and TEA;

[0056] S9: Applying a coating, applying an anti-corrosion coating to the hexagonal nut substrate, the anti-corrosion coating being a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating being 30 to 100 μm.

[0057] Embodiment 2:

[0058] See also Figure 1 A method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut comprises the following steps:

[0059] S1: Select raw materials and prepare Ni: 0.3%, Mo: 0.7%, Cu: 0.06%, N: 0.2%, C: 1.2%, Si: 0.35%, Mn: 0.7%, Cr: 0.55%, S: 0.015%, Cr: 12%, P: 0.015%, AL: 0.02%, S: 0.015%, Nb: 0.035%, Al: 0.01%, Ti: 0.4%, V: 0.8%, Re: 0.1%, and the rest is Fe and unavoidable impurities;

[0060] S2: Ingot forging: The above raw materials are passed through a high-temperature pressure furnace to generate molten iron, which is then cast through a crystallizer. After the molten steel is injected into the steel mold, it is gradually solidified into an ingot by natural cooling or forced cooling. During the cooling process, the structure and composition inside the ingot gradually become uniform. During the casting process, the steel mold and all molten steel flow channels are purged of the existing air with argon gas for 7 minutes to prevent oxidation of the molten steel with oxygen, thereby reducing the oxide scale thickness on the surface of the ingot and improving the surface quality and yield rate;

[0061] S3: bar production, the steel ingot obtained by electroslag remelting continuous directional solidification technology is subjected to high temperature solution treatment; the high temperature solution treatment includes heating the steel ingot to 740℃ at 15℃ / min, keeping it warm for 1 hour, then continuing to heat it to 1080℃ and keeping it warm for 1-2h, then finishing rolling it into bars through a continuous rolling unit and keeping it warm for 22h, cooling it to 750℃ at a cooling rate of 90℃ / h, and then cooling it to 450℃ with the furnace and air cooling it out of the furnace;

[0062] S4: bar processing: the bar is cut into nut blanks, the nut blanks are placed in a cold heading machine for processing and forming, so that the corners of the formed nut blanks are full and consistent, and the center of the nut blank is further punched by the cold heading machine to obtain a through hole;

[0063] S5: pickling treatment, pickling the hexagonal nut embryo obtained in S4, preparing a pickling solution, the pickling solution is prepared by weight: 6 parts of hydrofluoric acid, 250 parts of deionized water, 40 parts of phosphoric acid, 20 parts of hydrochloric acid, 8 parts of nitric acid, 6 parts of sulfuric acid, 15 parts of potassium chloride, 6 parts of potassium carbonate, 20 parts of silver chloride, and then the hexagonal nut embryo obtained in S3 is placed in a pickling tank for immersion, and the pickled hexagonal nut embryo is placed in a water tank to rinse the surface of the hexagonal nut embryo with acid. After the pickling is completed, the hexagonal nut embryo is rinsed one by one with clean water high-pressure and low-pressure flow;

[0064] S6: heat treatment, putting the processed hexagonal nut blank into the heat treatment furnace, the heat treatment furnace heats the hexagonal nut blank to 900℃, the heating rate is 15℃ / min, and then keeps it warm for 30min, the hexagonal nut blank after being taken out of the furnace is air-cooled, cooled naturally, and then heated again at a temperature of 1050℃, a heating rate of 18℃ / min, and kept warm for 1h, the semi-finished cast iron nut after being taken out of the furnace is air-cooled, cooled naturally, and then the metal rod is heated to 950℃ again at a heating rate of 13℃ / min, cooled to 600℃ by furnace, and then quickly put into the quenching device for quenching, and taken out when the surface temperature drops to 350℃, and then the hexagonal nut blank is tempered in the quenching device, the tempering temperature is 450℃, the tempering time is 95min, and kept warm for 1h;

[0065] S7: tapping, tapping the heat-treated hexagonal nut blank to form an internal thread to obtain a hexagonal nut base;

[0066] S8: electroplating, electroplating the hexagonal nut substrate three times, drying after each electroplating, and washing with hot water after the three electroplatings, the hot water temperature is 70°C;

[0067] Three electroplating solutions are used in the three electroplating processes, and the three electroplating solutions are respectively prepared with the following raw materials:

[0068] The first electroplating solution: 22 parts of main salt, 18.5 parts of aminosulfonic acid, 0.15 parts of conductive salt, 55 parts of distilled water, the water flow rate of the first electroplating solution is 0.25m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 37.5℃, and the current density is 3A / m 2 , the electroplating time is 2min;

[0069] The second electroplating solution: 1 part sodium chloride, 2 parts zinc sulfate, 4-6 parts nickel sulfate, 2-3 parts thiocyanate, 0.25 parts complexing agent, 65 parts pure water, the water flow rate of the second electroplating solution is 0.25m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 70℃, and the current density is 5A / m 2 , the electroplating time is 5min;

[0070] The third electroplating solution: 5 parts of copper sulfate, 1 part of sodium sulfate, 2 parts of pure water, 2 parts of sulfuric acid, 1 part of hydrochloric acid, 1 part of sodium chloride, 1 part of complexing agent, 2 parts of brightener, 2 parts of leveling agent, 1 part of wetting agent, 75 parts of deionized water. The water flow rate of the third electroplating solution is 0.25m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 50℃, and the current density is 3A / m 2 , the electroplating time is 4min;

[0071] The complexing agent is one or a mixture of citric acid, ethylene glycol, aminoacetic acid, NTA, EDTA, and TEA;

[0072] S9: Apply a coating, apply an anti-corrosion coating to the hexagonal nut substrate, the anti-corrosion coating is a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating is 70 μm.

[0073] Embodiment 3:

[0074] See also Figure 1 A method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut comprises the following steps:

[0075] S1: Select raw materials and prepare Ni: 0.25%, Mo: 0.8%, Cu: 0.08%, N: 0.1%, C: 1.1%, Si: 0.25%, Mn: 0.6%, Cr: 0.65%, S: 0.01%, Cr: 15%, P: 0.01%, AL: 0.045%, S: 0.015%, Nb: 0.03%, Al: 0.015%, Ti: 0.4%, V: 0.7%, Re: 0.08%, and the rest is Fe and unavoidable impurities;

[0076] S2: Ingot forging: The above raw materials are passed through a high-temperature pressure furnace to generate molten iron, which is then cast through a crystallizer. After the molten steel is injected into the steel mold, it is gradually solidified into an ingot by natural cooling or forced cooling. During the cooling process, the structure and composition inside the ingot gradually become uniform. During the casting process, argon gas is passed through the steel mold and all molten steel flow channels to evacuate the existing air and maintain it for 5-10 minutes to prevent oxidation between the molten steel and oxygen, thereby reducing the oxide scale thickness on the surface of the ingot and improving the surface quality and yield rate;

[0077] S3: bar production, the steel ingot obtained by electroslag remelting continuous directional solidification technology is subjected to high temperature solution treatment; the high temperature solution treatment includes heating the steel ingot to 740℃ at 18℃ / min, keeping it at this temperature for 1.3 hours, then heating it to 1100℃ and keeping it at this temperature for 1-2 hours, then finishing rolling it into bars through a continuous rolling unit and keeping it at this temperature for 22 hours, cooling it to 700℃ at a cooling rate of 100℃ / h, and then cooling it to 450℃ with the furnace and air cooling it out of the furnace;

[0078] S4: bar processing: the bar is cut into nut blanks, the nut blanks are placed in a cold heading machine for processing and forming, so that the corners of the formed nut blanks are full and consistent, and the center of the nut blank is further punched by the cold heading machine to obtain a through hole;

[0079] S5: pickling treatment, pickling the hexagonal nut embryo obtained in S4, preparing a pickling solution, the pickling solution is prepared by weight: 6 parts of hydrofluoric acid, 220 parts of deionized water, 55 parts of phosphoric acid, 33 parts of hydrochloric acid, 9 parts of nitric acid, 5 parts of sulfuric acid, 23 parts of potassium chloride, 6 parts of potassium carbonate, and 15 parts of silver chloride, and then the hexagonal nut embryo obtained in S3 is placed in a pickling tank for immersion, and the pickled hexagonal nut embryo is placed in a water tank to rinse the surface of the hexagonal nut embryo with acid, and after the pickling is completed, the hexagonal nut embryo is rinsed one by one with clean water high-pressure and low-pressure flow;

[0080] S6: heat treatment, the processed hexagonal nut blank is put into the heat treatment furnace, the heat treatment furnace heats the hexagonal nut blank to 880℃, the heating rate is 14℃ / min, and then the blank is kept warm for 40min, the hexagonal nut blank is air-cooled after being taken out of the furnace, and then naturally cooled, and then secondary heating is performed at a temperature of 950℃, a heating rate of 14℃ / min, and the blank is kept warm for 1h, the semi-finished cast iron nut is air-cooled after being taken out of the furnace, and then naturally cooled, and then the metal rod is heated to 950℃ again, the heating rate is 13℃ / min, and the furnace is cooled to 650℃ and then quickly placed in a quenching device for quenching, and the surface temperature is reduced to 300℃ and taken out, and then the hexagonal nut blank is tempered in the quenching device, the tempering temperature is 450℃, the tempering time is 60min, and the blank is kept warm for 1.5h;

[0081] S7: tapping, tapping the heat-treated hexagonal nut blank to form an internal thread to obtain a hexagonal nut base;

[0082] S8: electroplating, electroplating the hexagonal nut substrate three times, drying after each electroplating, and washing with hot water after three electroplating, the hot water temperature is 80°C;

[0083] Three electroplating solutions are used in the three electroplating processes, and the three electroplating solutions are respectively prepared with the following raw materials:

[0084] The first electroplating solution: 20 parts of main salt, 18 parts of aminosulfonic acid, 0.25 parts of conductive salt, 45 parts of distilled water. The water flow rate of the first electroplating solution is 0.3m / min, the electroplating voltage is 7V, the temperature of the electroplating solution is 30℃, and the current density is 2A / m 2 , the electroplating time is 3min;

[0085] The second electroplating solution: 1 part sodium chloride, 2 parts zinc sulfate, 6 parts nickel sulfate, 2 parts thiocyanate, 0.3 parts complexing agent, 60 parts pure water, the water flow rate of the second electroplating solution is 0.4m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 70℃, and the current density is 5A / m 2 , the electroplating time is 5min;

[0086] The third electroplating solution: 3 parts of copper sulfate, 1 part of sodium sulfate, 2 parts of pure water, 2 parts of sulfuric acid, 2 parts of hydrochloric acid, 2 parts of sodium chloride, 1 part of complexing agent, 1 part of brightener, 1 part of leveling agent, 0.5 parts of wetting agent, 70 parts of deionized water. The water flow rate of the third electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 70℃, and the current density is 3A / m 2 , the electroplating time is 4min;

[0087] The complexing agent is one or a mixture of citric acid, ethylene glycol, aminoacetic acid, NTA, EDTA, and TEA;

[0088] S9: Apply a coating, apply an anti-corrosion coating to the hexagonal nut substrate, the anti-corrosion coating is a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating is 70 μm.

[0089] Embodiment 4:

[0090] See also Figure 1 A method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut comprises the following steps:

[0091] S1: Select raw materials and prepare Ni: 0.25%, Mo: 0.55%, Cu: 0.035%, N: 0.15%, C: 1.15%, Si: 0.35%, Mn: 0.65%, Cr: 0.55%, S: 0.015%, Cr: 14%, P: 0.015%, AL: 0.035%, S: 0.015%, Nb: 0.03%, Al: 0.015%, Ti: 0.45%, V: 0.55%, Re: 0.075%, and the rest is Fe and unavoidable impurities;

[0092] S2: Ingot forging: The above raw materials are passed through a high-temperature pressure furnace to generate molten iron, which is then cast through a crystallizer. After the molten steel is injected into the steel mold, it is gradually solidified into an ingot by natural cooling or forced cooling. During the cooling process, the structure and composition inside the ingot gradually become uniform. During the casting process, argon gas is passed through the steel mold and all molten steel flow channels to evacuate the existing air and maintain it for 5-10 minutes to prevent oxidation between the molten steel and oxygen, thereby reducing the oxide scale thickness on the surface of the ingot and improving the surface quality and yield rate;

[0093] S3: bar production, the steel ingot obtained by electroslag remelting continuous directional solidification technology is subjected to high temperature solution treatment; the high temperature solution treatment includes heating the steel ingot to 750℃ at 10℃ / min, keeping it warm for 1 hour, then continuing to heat it to 1050℃ and keeping it warm for 1-2h, then finishing rolling it into bars through a continuous rolling unit and keeping it warm for 25h, cooling it to 700℃ at a cooling rate of 80℃ / h, and then cooling it to 450℃ with the furnace and air cooling it out of the furnace;

[0094] S4: bar processing: the bar is cut into nut blanks, the nut blanks are placed in a cold heading machine for processing and forming, so that the corners of the formed nut blanks are full and consistent, and the center of the nut blank is further punched by the cold heading machine to obtain a through hole;

[0095] S5: pickling treatment, pickling the hexagonal nut embryo obtained in S4, preparing a pickling solution, the pickling solution is prepared by weight: 6 parts of hydrofluoric acid, 250 parts of deionized water, 40 parts of phosphoric acid, 20 parts of hydrochloric acid, 8 parts of nitric acid, 6 parts of sulfuric acid, 15 parts of potassium chloride, 6 parts of potassium carbonate, 20 parts of silver chloride, and then the hexagonal nut embryo obtained in S3 is placed in a pickling tank for immersion, and the pickled hexagonal nut embryo is placed in a water tank to rinse the surface of the hexagonal nut embryo with acid. After the pickling is completed, the hexagonal nut embryo is rinsed one by one with clean water high-pressure and low-pressure flow;

[0096] S6: heat treatment, putting the processed hexagonal nut blank into the heat treatment furnace, the heat treatment furnace heats the hexagonal nut blank to 850℃, the heating rate is 15℃ / min, and then the heat is kept for 50min, the hexagonal nut blank after being taken out of the furnace is air-cooled, naturally cooled, and then reheated at a temperature of 950℃, the heating rate is 18℃ / min, and the heat is kept for 2h, the semi-finished cast iron nut after being taken out of the furnace is air-cooled, naturally cooled, and then the metal rod is heated to 900℃ again, the heating rate is 18℃ / min, the furnace is cooled to 600℃, and then it is quickly put into the quenching device for quenching, and the surface temperature is reduced to 350℃ and taken out, and then the hexagonal nut blank is tempered in the quenching device, the tempering temperature is 380℃, the tempering time is 95min, and the heat is kept for 2h;

[0097] S7: tapping, tapping the heat-treated hexagonal nut blank to form an internal thread to obtain a hexagonal nut base;

[0098] S8: electroplating, electroplating the hexagonal nut substrate three times, drying after each electroplating, and washing with hot water after the three electroplatings, the hot water temperature is 70°C;

[0099] Three electroplating solutions are used in the three electroplating processes, and the three electroplating solutions are respectively prepared with the following raw materials:

[0100] The first electroplating solution: 22 parts of main salt, 12 parts of aminosulfonic acid, 0.25 parts of conductive salt, 45 parts of distilled water. The water flow rate of the first electroplating solution is 0.5m / min, the electroplating voltage is 4V, the temperature of the electroplating solution is 35℃, and the current density is 4A / m 2 , the electroplating time is 2min;

[0101] The second electroplating solution: 1 part sodium chloride, 2 parts zinc sulfate, 4 parts nickel sulfate, 3 parts thiocyanate, 0.4 parts complexing agent, 60 parts pure water, the water flow rate of the second electroplating solution is 0.4m / min, the electroplating voltage is 5V, the temperature of the electroplating solution is 70℃, and the current density is 4A / m 2 , the electroplating time is 5min;

[0102] The third electroplating solution: 4 parts of copper sulfate, 1 part of sodium sulfate, 2 parts of pure water, 2 parts of sulfuric acid, 1.5 parts of hydrochloric acid, 1.5 parts of sodium chloride, 1 part of complexing agent, 2 parts of brightener, 1 part of leveling agent, 1.5 parts of wetting agent, 77 parts of deionized water. The water flow rate of the third electroplating solution is 0.4m / min, the electroplating voltage is 4V, the temperature of the electroplating solution is 50℃, and the current density is 4A / m 2 , the electroplating time is 4min;

[0103] The complexing agent is one or a mixture of citric acid, ethylene glycol, aminoacetic acid, NTA, EDTA, and TEA;

[0104] S9: Apply a coating, apply an anti-corrosion coating to the hexagonal nut substrate, the anti-corrosion coating is a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating is 70 μm.

Claims

1. A highly wear-resistant and corrosion-resistant hexagonal nut, characterized in that: It comprises a hexagonal nut base, an electroplating layer and an anti-corrosion coating applied to the outer surface of the hexagonal nut base; The hexagonal nut matrix is ​​composed of the following raw materials: in mass percentage, Ni: 0.2-0.3%, Mo: 0.5-0.8%, Cu: 0.03-0.08%, N: 0.1-0.3%, C: 1.1-1.3%, Si: 0.25-0.45%, Mn: 0.6-0.9%, Cr: 0.45-0.65%, S: 0.01-0.02%, Cr: 10-15%, P: 0.01-0.02%, AL: 0.02-0.045%, S: 0.01-0.025%, Nb: 0.02%-0.04%, Al: 0.01-0.015%, Ti: 0.1-0.5%, V: 0.1-1.0%, Re: 0.05-0.1%, and the rest is Fe and unavoidable impurities.

2. A highly wear-resistant and corrosion-resistant hexagonal nut according to claim 1, characterized in that: The anti-corrosion coating is a nano-modified fluorine-containing polyurethane coating or a fluorine-containing polysiloxane coating or a siloxane-modified acrylic polyurethane coating, and the thickness of the anti-corrosion coating is 30-100 μm.

3. A method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut according to claims 1-2, characterized in that: S1: Select raw materials, prepare Ni: 0.2-0.3%, Mo: 0.5-0.8%, Cu: 0.03-0.08%, N: 0.1-0.3%, C: 1.1-1.3%, Si: 0.25-0.45%, Mn: 0.6-0.9%, Cr: 0.45-0.65%, S: 0.01-0.02%, Cr: 10-15%, P: 0.01-0.02%, AL: 0.02-0.045%, S: 0.01-0.025%, Nb: 0.020%-0.040%, Al: 0.01-0.015%, Ti: 0.1-0.5%, V: 0.1-1.0%, Re: 0.05-0.1%, the rest is Fe and unavoidable impurities; S2: Ingot forging: The above raw materials are passed through a high-temperature pressure furnace to generate molten iron, which is then cast through a crystallizer. After the molten steel is injected into the steel mold, it is gradually solidified into an ingot by natural cooling or forced cooling. During the cooling process, the structure and composition inside the ingot gradually become uniform. During the casting process, argon gas is passed through the steel mold and all molten steel flow channels to evacuate the existing air and maintain it for 5-10 minutes to prevent oxidation between the molten steel and oxygen, thereby reducing the oxide scale thickness on the surface of the ingot and improving the surface quality and yield rate; S3: bar production, the steel ingot obtained by electroslag remelting continuous directional solidification technology is subjected to high temperature solution treatment; the high temperature solution treatment includes heating the steel ingot to 720-750℃ at 10-20℃ / min, keeping it warm for 0.5-2 hours, then continuing to heat it to 1050-1120℃ and keeping it warm for 1-2h, then finishing rolling it into bars through a continuous rolling unit and keeping it warm for 17-25h, cooling it to 700-750℃ at a cooling rate of 80-100℃ / h, and then cooling it to 400-450℃ with the furnace and air cooling it out of the furnace; S4: bar processing: the bar is cut into nut blanks, the nut blanks are placed in a cold heading machine for processing and forming, so that the corners of the formed nut blanks are full and consistent, and the center of the nut blank is further punched by the cold heading machine to obtain a through hole; S5: pickling treatment, pickling the hexagonal nut embryo obtained in S4, preparing a pickling solution, the pickling solution is prepared by weight: 4-9 parts of hydrofluoric acid, 150-250 parts of deionized water, 40-60 parts of phosphoric acid, 20-40 parts of hydrochloric acid, 8-12 parts of nitric acid, 4-6 parts of sulfuric acid, 15-23 parts of potassium chloride, 4-6 parts of potassium carbonate, 15-20 parts of silver chloride, and then the hexagonal nut embryo obtained in S3 is placed in a pickling tank for immersion, and the pickled hexagonal nut embryo is placed in a water tank to rinse the surface of the hexagonal nut embryo with acid; S6: heat treatment, putting the processed hexagonal nut blank into the heat treatment furnace, the heat treatment furnace heats the hexagonal nut blank to 850-900℃, the heating rate is 10-15℃ / min, and then keeps warm for 30-50min, the hexagonal nut blank after being taken out of the furnace is air-cooled, cooled naturally, and then heated again at a temperature of 950-1050℃, the heating rate is 13-18℃ / min, and kept warm for 1-2h, the semi-finished cast iron nut after being taken out of the furnace is air-cooled, cooled naturally, and then the metal rod is heated to 900-950℃ again, the heating rate is 13-18℃ / min, the furnace is cooled to 600-650℃, and then quickly put into the quenching device for quenching, and the surface temperature is reduced to 300-350℃ and taken out, and then the hexagonal nut blank is tempered in the quenching device, the tempering temperature is 380-450℃, the tempering time is 60-95min, and the heat preservation is 1-2h; S7: tapping, tapping the heat-treated hexagonal nut blank to form an internal thread to obtain a hexagonal nut base; S8: electroplating, electroplating the hexagonal nut substrate three times, and drying after each electroplating; S9: Apply coating, apply anti-corrosion coating to the hexagonal nut base.

4. The method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut according to claim 3, characterized in that: In S8, three electroplating processes are performed using three different electroplating solutions, each of which is prepared using the following raw materials: The first electroplating solution: 18-22 parts of main salt, 12-25 parts of aminosulfonic acid, 0.15-0.25 parts of conductive salt, 45-55 parts of distilled water; The second electroplating solution: 1 part sodium chloride, 2 parts zinc sulfate, 4-6 parts nickel sulfate, 2-3 parts thiocyanate, 0.2-0.4 parts complexing agent, 50-70 parts pure water; The third electroplating solution: 2-6 parts of copper sulfate, 0.5-1 parts of sodium sulfate, 1-3 parts of pure water, 1-2 parts of sulfuric acid, 0.5-2 parts of hydrochloric acid, 0.5-2 parts of sodium chloride, 1-2 parts of complexing agent, 1-2 parts of brightener, 1-2 parts of leveling agent, 0.5-1.5 parts of wetting agent, 70-85 parts of deionized water; The complexing agent is one or a mixture of citric acid, ethylene glycol, aminoacetic acid, NTA, EDTA and TEA.

5. The method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut according to claim 3, characterized in that: After S5 pickling is completed, the hexagonal nut blanks are rinsed one by one with high-pressure and low-pressure water.

6. The method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut according to claim 3, characterized in that: During the electroplating process in S8: The water flow rate of the first electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 30-40℃, and the current density is 2-4A / m 2 , the electroplating time is 1-3min; The water flow rate of the second electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 60-80℃, and the current density is 3-6A / m 2 , the electroplating time is 4-7min; The water flow rate of the third electroplating solution is 0.1-0.5m / min, the electroplating voltage is 4-7V, the temperature of the electroplating solution is 40-70℃, and the current density is 2-5A / m 2 , the electroplating time is 2-5min.

7. The method for preparing a highly wear-resistant and corrosion-resistant hexagonal nut according to claim 3, characterized in that: After the electroplating is completed as described in S8, the hot water is used for cleaning, and the hot water temperature is 40-80°C.

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