Rust-proof self-locking galvanized nut and processing technology thereof

Abstract

This invention discloses a rust-proof self-locking galvanized nut and its processing technology. The processing technology includes the following steps: S1, preparing raw materials; S2, pre-treating the self-locking nut blank; S3, hot-dip galvanizing; S4, post-treatment. The self-locking nut produced by this processing technology underwent zinc layer thickness testing by national inspection. The test results showed an average zinc layer thickness of 81.4 μm, exceeding the national standard value of 80 μm for Grade 3 galvanizing. This indicates that the zinc layer quality of the galvanized self-locking nut is qualified, expanding the application range of the self-locking nut and enabling it to maintain its properties for a longer period in harsh environments.

Description

Technical Field

[0001] This invention belongs to the field of nut manufacturing technology, and particularly relates to a rust-proof self-locking galvanized nut and its processing technology. Background Technology

[0002] The use of nuts and bolts is a common locking method in industry. To ensure a tighter connection, self-locking nuts are often used. Self-locking nuts offer the advantages of a more secure connection and are less prone to loosening under external forces. After forming, self-locking nuts require heat treatment to improve their internal structure and increase their mechanical strength. However, conventional heat treatment often results in insufficient zinc plating thickness, leading to poor rust prevention. In humid environments, insufficient zinc plating can reduce the lifespan of galvanized nuts and accelerate the rusting process.

[0003] In the prior art, such as Chinese Patent Publication No. CN111455142B, a heat treatment method for a self-locking nut is disclosed, including the following steps: a) preparing raw materials; b) quenching; c) cooling; d) tempering; e) hot-dip galvanizing; f) passivation treatment; g) cooling. Through the above method, the heat treatment method for the self-locking nut provided by this invention achieves uniform thermal stress treatment within the self-locking nut. This improves the toughness and texture of the self-locking nut, resulting in excellent mechanical properties. Furthermore, it enhances the surface quality of the self-locking nut, thereby effectively improving its corrosion resistance and extending its service life.

[0004] In the aforementioned application, the heat treatment method used to produce the nut causes thermal expansion and contraction of the outermost thread in the threaded hole of the self-locking nut during the cooling process, resulting in deformation of the thread at this position. This affects the subsequent connection and fit between the screw and the nut. Furthermore, the zinc layer thickness of the nut produced by the aforementioned method does not meet the standards for use in humid environments, and the zinc layer will be damaged prematurely, resulting in a significant reduction in the service life of the nut. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a rust-proof self-locking galvanized nut and its processing technology. In the present invention, by increasing the thickness of the zinc layer on the surface of the nut, it can be used normally in a humid environment.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a manufacturing process for rust-proof self-locking galvanized nuts, characterized by comprising the following steps:

[0007] S1. Prepare raw materials: Use 45Cr to make the self-locking nut blank;

[0008] S2. Pre-treat the self-locking nut blank;

[0009] S2.1 Pre-processing: Chamfer the threads of the self-locking nut blank;

[0010] S2.2 Pickling: Pickling removes oil stains, dirt and oxides from the surface of the nut;

[0011] S2.3 Water washing: Clean the residual acid on the surface of the nut after pickling;

[0012] S2.4 Drying: Remove moisture from the surface of the nut;

[0013] S3, hot-dip galvanizing treatment;

[0014] S3.1 Quenching: Place the pretreated self-locking nut blank into a heat treatment furnace. After the temperature rises to 400℃, heat it to the quenching temperature at a heating rate of no more than 200-250℃ / h. The quenching temperature is 850-950℃.

[0015] S3.2 Cooling: Remove the self-locking nut blank from the heat treatment furnace and cool it to room temperature by water cooling;

[0016] S3.3 Tempering: The cooled self-locking nut blank is placed in a tempering device for heating. The temperature in the tempering device gradually rises to 450-650℃ within 30 minutes, is held for 3-4 hours, and then cooled to room temperature.

[0017] S3.4 Hot-dip galvanizing: The tempered self-locking nut blank is placed in a galvanizing pot for hot-dip galvanizing treatment to form a galvanized self-locking nut, wherein the zinc liquid includes an alloy composed of 0.1-0.15% nickel, 0.08-0.11% rhenium, 0.06-0.08% bismuth and 0.05-0.1% aluminum.

[0018] S3.5 Cooling: Cool the galvanized self-locking nut to room temperature with compressed air;

[0019] S4, Post-processing;

[0020] S4.1 Chemical treatment; chemical treatment of galvanized nuts to improve their corrosion resistance and surface finish;

[0021] S4.2 Cleaning; removing residues generated during the chemical and pharmaceutical process;

[0022] S4.3 Apply anti-rust oil. Apply a layer of anti-rust oil to the surface of the nut to further improve its corrosion resistance.

[0023] Optionally, in step S3.4, a zinc plating solution is placed in the zinc plating pot.

[0024] Optionally, in step S3.4, the galvanizing temperature is 465-575℃ and the time is 6-9 minutes.

[0025] Optionally, the zinc plating solution comprises an alloy consisting of 0.1-0.15% nickel, 0.08-0.11% rhenium, 0.06-0.08% bismuth and 0.05-0.1% aluminum.

[0026] Optionally, the pressure of the compressed air in step S3.5 is 0-6 MPa and the wind speed is 3-9 m / min.

[0027] To achieve the above objectives, the present invention also provides the following technical solution: a rust-proof self-locking galvanized nut, comprising an upper nut and a lower nut, wherein an annular groove is provided on the lower surface of the upper nut, and a cylinder is fixedly provided on the upper surface of the lower nut, wherein the cylinder cooperates with the annular groove, the inner wall thread of the cylinder is integral with the inner wall thread of the lower nut, and a chamfer is provided at the position of the upper end thread of the cylinder.

[0028] Optionally, a chamfer is provided at the connection position between the thread teeth on the inner wall of the upper nut and the annular groove.

[0029] In summary, compared with the prior art, the rust-proof self-locking galvanized nut and its processing technology provided by the present invention have the following beneficial effects:

[0030] 1. In this invention, the zinc plating layer of the self-locking nut produced by this processing technology is continuous and complete, with uniform color and strong zinc adhesion. Furthermore, the yield of the self-locking nut is effectively improved, greatly reducing the thread deformation caused by thermal expansion and contraction, and thus reducing the defect rate of nuts and bolts that cannot be matched.

[0031] 2. In this invention, the self-locking nut produced by this processing technology has undergone zinc layer thickness testing by the National Inspection and Testing Center. The test results show that the average zinc layer thickness is 81.4μm, which exceeds the national standard value of 80μm for Grade 3 zinc plating. This indicates that the zinc plating quality of the galvanized self-locking nut is qualified, which expands the application range of the self-locking nut and enables it to maintain its position for a longer period of time in harsh environments.

[0032] 3. In this invention, the self-locking nut produced by this processing technology has undergone a neutral salt spray test by the National Inspection and Testing Center. The test results show that after 240 hours of neutral salt spray testing, no red rust appeared on the surface of the three sample nuts, indicating the corrosion resistance of the galvanized self-locking nut in harsh environments, thus ensuring its reliability and durability in actual use.

[0033] 4. In this invention, the chamfer one and chamfer two on the lower nut and the upper nut can prevent the outer thread teeth of the self-locking nut blank from being mismatched when connected with other screw fasteners due to thermal expansion and contraction caused by subsequent processing after galvanizing heat treatment. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the self-locking nut blank structure of the present invention;

[0035] Figure 2 This is a cross-sectional view of the self-locking nut blank of the present invention;

[0036] In the diagram: 1. Upper nut; 2. Lower nut; 11. Annular groove; 21. Cylinder; 12. Chamfer 2; 22. Chamfer 1. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0038] A processing method for a rust-proof self-locking galvanized nut includes the following steps:

[0039] S1. Prepare raw materials: Use 45Cr to make the self-locking nut blank;

[0040] S2. Pre-treat the self-locking nut blank;

[0041] S2.1 Pre-processing: The outer threads of the self-locking nut blank are chamfered using a chamfering device;

[0042] S2.2 Pickling: Pickling removes oil stains, dirt and oxides from the surface of the nut to ensure good bonding between the zinc layer and the self-locking nut blank;

[0043] S2.3 Water washing: Clean the residual acid on the surface of the nut after pickling;

[0044] S2.4 Drying: Remove moisture from the surface of the nuts to prevent steam or moisture from affecting the galvanizing quality during the hot-dip galvanizing process;

[0045] S3, hot-dip galvanizing treatment;

[0046] S3.1 Quenching: Place the pretreated self-locking nut blank into a heat treatment furnace. After the temperature rises to 400℃, raise the temperature to the quenching temperature at a heating rate of no more than 200-250℃ / h. The quenching temperature is 850-950℃, and the quenching time is 1min / mm and no less than 30min.

[0047] S3.2 Cooling: Remove the self-locking nut blank from the heat treatment furnace and cool it to room temperature by water cooling;

[0048] S3.3 Tempering: The cooled self-locking nut blank is placed in a tempering device for heating. The temperature in the tempering device gradually rises to 450-650℃ within 30 minutes, is held for 3-4 hours, and then cooled to room temperature.

[0049] S3.4 Hot-dip galvanizing: The tempered self-locking nut blank is placed in a galvanizing pot for hot-dip galvanizing treatment to form a galvanized self-locking nut. The galvanizing temperature is 465-575℃ and the time is 6-9 minutes.

[0050] S3.5 Cooling: Cool the galvanized self-locking nut to room temperature with compressed air;

[0051] S4, Post-processing;

[0052] S4.1 Chemical treatment: The galvanized nuts are chemically treated to improve their corrosion resistance and surface finish;

[0053] S4.2 Cleaning: Remove residues generated during the chemical and pharmaceutical process;

[0054] S4.3 Apply anti-rust oil: Apply a layer of anti-rust oil to the surface of the nut to further improve its corrosion resistance.

[0055] The self-locking nut blank in step S2.1 above includes an upper nut 1 and a lower nut 2. The lower surface of the upper nut 1 is provided with an annular groove 11. The upper surface of the lower nut 2 is fixedly provided with a cylinder 21. The cylinder 21 cooperates with the annular groove 11. The inner wall thread of the cylinder 21 is integral with the inner wall thread of the lower nut 2. A chamfer 22 is provided at the position of the upper thread of the cylinder 21.

[0056] The thread on the inner wall of the upper nut 1 is chamfered at the connection point with the annular groove 11.

[0057] Chamfer 1.22 and chamfer 2.12 ensure that after the self-locking nut blank has undergone galvanizing heat treatment, the outer thread of the self-locking nut blank will not be mismatched when connected with other screw fasteners due to thermal expansion and contraction caused by subsequent processing.

[0058] In step S3.4 above, the zinc plating pot contains a zinc plating solution, which is an alloy consisting of 0.1-0.15% nickel, 0.08-0.11% rhenium, 0.06-0.08% bismuth and 0.05-0.1% aluminum.

[0059] The compressed air pressure in step S3.5 above is 0-6 MPa, and the air velocity is 3-9 m / min.

[0060] The zinc plating layer of the self-locking nut obtained through the above steps is continuous, complete, uniform in color, and has strong zinc adhesion. Furthermore, the yield of the self-locking nut is effectively improved, greatly reducing the rate of defective products caused by thread deformation due to thermal expansion and contraction, which results in the nut and bolt not fitting together.

[0061] The self-locking nut produced through the above steps underwent zinc layer thickness testing by the National Inspection and Testing Center. The test results showed that the average zinc layer thickness was 81.4 μm, exceeding the national standard value of 80 μm for Grade 3 zinc plating. This indicates that the zinc plating quality of the galvanized self-locking nut is qualified, expanding the application range of the self-locking nut and enabling it to maintain its quality for a longer period of time in harsh environments.

[0062]

[0063] Furthermore, the self-locking nuts obtained through the above steps underwent a neutral salt spray test conducted by the National Inspection and Testing Center. The test results showed that none of the three sample nuts developed red rust after 240 hours of neutral salt spray testing, indicating the corrosion resistance of the galvanized self-locking nuts in harsh environments, thus ensuring their reliability and durability in actual use.

[0064]

[0065] Example 1:

[0066] A processing method for a rust-proof self-locking galvanized nut includes the following steps:

[0067] S1. Prepare raw materials: Use 45Cr to make the self-locking nut blank;

[0068] S2. Pre-treat the self-locking nut blank;

[0069] S2.1 Pre-processing: The outer threads of the self-locking nut blank are chamfered using a chamfering device. This ensures that the outer threads of the self-locking nut blank will not be mismatched when connected with other screw fasteners due to thermal expansion and contraction caused by processing after galvanizing heat treatment.

[0070] S2.2 Pickling: Pickling removes oil stains, dirt and oxides from the surface of the nut to ensure good bonding between the zinc layer and the self-locking nut blank;

[0071] S2.3 Water washing: Clean the residual acid on the surface of the nut after pickling;

[0072] S2.4 Drying: Remove moisture from the surface of the nuts to prevent steam or moisture from affecting the galvanizing quality during the hot-dip galvanizing process;

[0073] S3, hot-dip galvanizing treatment;

[0074] S3.1 Quenching: Place the pretreated self-locking nut blank into a heat treatment furnace. After the temperature rises to 400℃, raise the temperature to the quenching temperature at a heating rate not exceeding 200℃ / h. The quenching temperature is 900℃, and the quenching time is 1min / mm and not less than 30min.

[0075] S3.2 Cooling: Remove the self-locking nut blank from the heat treatment furnace and cool it to room temperature by water cooling;

[0076] S3.3 Tempering: The cooled self-locking nut blank is placed in a tempering device for heating. The temperature in the tempering device gradually rises to 500℃ within 30 minutes, is held for 3.5 hours, and then cooled to room temperature.

[0077] S3.4 Hot-dip galvanizing: The tempered self-locking nut blank is placed in a galvanizing pot for hot-dip galvanizing treatment to form a galvanized self-locking nut. The galvanizing temperature is 520℃ and the time is 6min.

[0078] S3.5 Cooling: Cool the galvanized self-locking nut to room temperature with compressed air;

[0079] S4, Post-processing;

[0080] S4.1 Chemical treatment: The galvanized nuts are chemically treated to improve their corrosion resistance and surface finish;

[0081] S4.2 Cleaning: Remove residues generated during the chemical and pharmaceutical process;

[0082] S4.3 Apply anti-rust oil: Apply a layer of anti-rust oil to the surface of the nut to further improve its corrosion resistance.

[0083] In step S3.4 above, the zinc plating pot contains a zinc plating solution, which comprises an alloy consisting of 0.12% nickel, 0.09% rhenium, 0.08% bismuth and 0.08% aluminum.

[0084] Example 2:

[0085] A processing method for a rust-proof self-locking galvanized nut includes the following steps:

[0086] S1. Prepare raw materials: Use 45Cr to make the self-locking nut blank;

[0087] S2. Pre-treat the self-locking nut blank;

[0088] S2.1 Pre-processing: The outer threads of the self-locking nut blank are chamfered using a chamfering device. This ensures that the outer threads of the self-locking nut blank will not be mismatched when connected with other screw fasteners due to thermal expansion and contraction caused by processing after galvanizing heat treatment.

[0089] S2.2 Pickling: Pickling removes oil stains, dirt and oxides from the surface of the nut to ensure good bonding between the zinc layer and the self-locking nut blank;

[0090] S2.3 Water washing: Clean the residual acid on the surface of the nut after pickling;

[0091] S2.4 Drying: Remove moisture from the surface of the nuts to prevent steam or moisture from affecting the galvanizing quality during the hot-dip galvanizing process;

[0092] S3, hot-dip galvanizing treatment;

[0093] S3.1 Quenching: Place the pretreated self-locking nut blank into a heat treatment furnace. After the temperature rises to 400℃, raise the temperature to the quenching temperature at a heating rate not exceeding 250℃ / h. The quenching temperature is 910℃, and the quenching time is 2min / mm and not less than 30min.

[0094] S3.2 Cooling: Remove the self-locking nut blank from the heat treatment furnace and cool it to room temperature by water cooling;

[0095] S3.3 Tempering: The cooled self-locking nut blank is placed in a tempering device for heating. The temperature in the tempering device gradually rises to 480℃ within 30 minutes, is held for 3.8 hours, and then cooled to room temperature.

[0096] S3.4 Hot-dip galvanizing: The tempered self-locking nut blank is placed in a galvanizing pot for hot-dip galvanizing treatment to form a galvanized self-locking nut. The galvanizing temperature is 560℃ and the time is 9min.

[0097] S3.5 Cooling: Cool the galvanized self-locking nut to room temperature with compressed air;

[0098] S4, Post-processing;

[0099] S4.1 Chemical treatment: The galvanized nuts are chemically treated to improve their corrosion resistance and surface finish;

[0100] S4.2 Cleaning: Remove residues generated during the chemical and pharmaceutical process;

[0101] S4.3 Apply anti-rust oil: Apply a layer of anti-rust oil to the surface of the nut to further improve its corrosion resistance.

[0102] In step S3.4 above, the zinc plating pot contains a zinc plating solution, which comprises an alloy consisting of 0.15% nickel, 0.11% rhenium, 0.08% bismuth and 0.1% aluminum.

[0103] The specification and claims use certain terms to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0104] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0105] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A manufacturing process for a rust-proof self-locking galvanized nut, characterized in that, Includes the following steps: S1. Prepare raw materials: Use 45Cr to make the self-locking nut blank; S2. Pre-treat the self-locking nut blank; S2.1 Pre-processing: Chamfer the threads of the self-locking nut blank; S2.2 Pickling: Pickling removes oil stains, dirt and oxides from the surface of the nut; S2.3 Water washing: Clean the residual acid on the surface of the nut after pickling; S2.4 Drying: Remove moisture from the surface of the nut; S3, hot-dip galvanizing treatment; S3.1 Quenching: Place the pretreated self-locking nut blank into a heat treatment furnace. After the temperature rises to 400℃, heat it to the quenching temperature at a rate not exceeding 200-250℃ / h. The quenching temperature is 850-950℃. S3.2 Cooling: Remove the self-locking nut blank from the heat treatment furnace and cool it to room temperature by water cooling. S3.3 Tempering: The cooled self-locking nut blank is placed in a tempering device for heating. The temperature in the tempering device gradually rises to 450-650℃ within 30 minutes, is held for 3-4 hours, and then cooled to room temperature. S3.4 Hot-dip galvanizing: The tempered self-locking nut blank is placed in a galvanizing pot for hot-dip galvanizing treatment to form a galvanized self-locking nut, wherein the zinc liquid includes an alloy composed of 0.1-0.15% nickel, 0.08-0.11% rhenium, 0.06-0.08% bismuth and 0.05-0.1% aluminum. S3.5 Cooling: Cool the galvanized self-locking nut to room temperature with compressed air; S4, Post-processing; S4.1 Chemical treatment; chemical treatment of galvanized nuts to improve their corrosion resistance and surface finish; S4.2 Cleaning; removing residues generated during the chemical and pharmaceutical process; S4.3 Apply anti-rust oil: Apply a layer of anti-rust oil to the surface of the nut to further improve its corrosion resistance; In step S3.4, the galvanizing temperature is 465-575℃ and the time is 6-9 minutes; The self-locking nut blank in step S2.1 above includes an upper nut (1) and a lower nut (2). The lower surface of the upper nut (1) is provided with an annular groove (11). The upper surface of the lower nut (2) is fixedly provided with a cylinder (21). The cylinder (21) cooperates with the annular groove (11). The inner wall thread of the cylinder (21) is integrated with the inner wall thread of the lower nut (2). A chamfer (22) is provided at the position of the upper end thread of the cylinder (21). The connection between the thread teeth on the inner wall of the upper nut (1) and the annular groove (11) is provided with a chamfer (12).

2. The rust-proof self-locking galvanized nut and its processing technology according to claim 1, characterized in that, The compressed air pressure in step S3.5 is 0-6 MPa, and the wind speed is 3-9 m / min.

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