Highly wear-resistant rivet nut and method for producing the same

Abstract

The application relates to the technical field of fastener production, and discloses a high-wear-resistance rivet nut and a production method thereof, the production method comprising the following steps: S1, smelting and casting: smelting and casting after uniformly mixing waste aluminum alloy and silicon nitride, so as to obtain a blank; S2, cold heading: after the blank is subjected to tempering treatment, the blank is cold headed to obtain a semi-finished product; and S3, tapping: after the semi-finished product is tapped, the rivet nut is obtained. Through the technical scheme, the problems of low hardness and poor wear resistance of the rivet nut in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of fastener manufacturing technology, specifically to a high wear-resistant rivet nut and its manufacturing method. Background Technology

[0002] A rivet nut is a fastener primarily used in the connection of non-structural load-bearing materials such as various metal sheets and pipes, including interior parts in rail vehicles, bus cars, and ships. Rivet nuts were specifically developed to address the drawbacks of welded nuts on thin metal sheets and pipes, such as easy melting and stripping of internal threads. Due to their advantages, including not requiring internal thread tapping, providing strong and efficient riveting, and ease of use, rivet nuts are highly favored in the market.

[0003] With advancements in manufacturing, the market demands higher wear resistance from rivet nuts. The wear of rivet nuts is primarily related to their hardness; lower hardness leads to easier wear. There is still significant room for improvement in the hardness and wear resistance of existing rivet nuts. Developing a highly wear-resistant rivet nut is of significant practical and commercial value in order to further expand its application. Summary of the Invention

[0004] This invention proposes a high wear-resistant rivet nut and its manufacturing method, which solves the problems of low hardness and poor wear resistance of rivet nuts in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a method for producing high wear-resistant rivet nuts, comprising the following steps: S1. Melting and casting: After the waste aluminum alloy and silicon nitride are mixed evenly, they are melted and cast to obtain the billet; S2. Cold heading: The billet is cold-headed after tempering to obtain a semi-finished product; S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut.

[0006] As a further technical solution, the waste aluminum alloy is waste 2000 series aluminum alloy, waste 4000 series aluminum alloy or waste 5000 series aluminum alloy.

[0007] As a further technical solution, the waste aluminum alloy is obtained after degreasing and pickling.

[0008] As a further technical solution, the particle size of the silicon nitride is 5~15μm.

[0009] As a further technical solution, in step S1, the mass ratio of the waste aluminum alloy to silicon nitride is 100:1~2.

[0010] As a further technical solution, in step S2, the tempering treatment is carried out at a temperature of 170~200℃ for a time of 60~150min.

[0011] As a further technical solution, in step S1, the silicon nitride is oxidized silicon nitride.

[0012] Oxidation treatment of silicon nitride can improve the wettability of silicon nitride with molten waste aluminum alloy, thereby further improving the hardness and wear resistance of rivet nuts.

[0013] As a further technical solution, the method for preparing the oxidized silicon nitride is as follows: water vapor is introduced into silicon nitride for oxidation treatment to obtain the oxidized silicon nitride.

[0014] As a further technical solution, the water vapor injection rate is 6~7m³. 3 / h.

[0015] As a further technical solution, the oxidation treatment is carried out at a temperature of 250~300℃ for a time of 20~50min.

[0016] As a further technical solution, the time ratio of the tempering treatment to the oxidation treatment is 3~4:1.

[0017] When the time ratio of tempering treatment to silicon nitride oxidation treatment is 3~4:1, it helps to further improve the bonding strength of silicon nitride in the blank, thereby further improving the hardness and wear resistance of the rivet nut.

[0018] As a further technical solution, the time ratio of the tempering treatment to the oxidation treatment is 4:1.

[0019] The present invention also proposes a high wear-resistant rivet nut, which is produced by the aforementioned production method.

[0020] The working principle and beneficial effects of this invention are as follows: 1. In this invention, the addition of silicon nitride serves two purposes: firstly, it strengthens the second phase; secondly, it provides nucleation sites for the molten aluminum alloy, thereby refining the grains and significantly improving the hardness and wear resistance of the rivet nut. Furthermore, tempering the billet increases the grain boundary strength of the silicon nitride, further enhancing the hardness and wear resistance of the rivet nut. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Unless otherwise specified, the particle size of silicon nitride in the following examples and comparative examples is 10 μm.

[0023] Example 1 A method for producing high wear-resistant rivet nuts includes the following steps: S1. Melting and casting: By weight, 100 parts of degreased and pickled waste 2024 aluminum alloy are mixed evenly with 1 part of silicon nitride, then melted and cast to obtain a billet. S2, Cold heading: After the billet is tempered at 170℃ for 150 minutes, it is cold headed to obtain a semi-finished product; S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut.

[0024] Example 2 A method for producing high wear-resistant rivet nuts includes the following steps: S1. Melting and casting: By weight, 100 parts of degreased and pickled waste 4043 aluminum alloy are mixed evenly with 1.5 parts of silicon nitride, then melted and cast to obtain a billet; S2, Cold heading: After the billet is tempered at 200℃ for 60 minutes, it is cold headed to obtain a semi-finished product; S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut.

[0025] Example 3 A method for producing high wear-resistant rivet nuts includes the following steps: S1. Melting and casting: By weight, 100 parts of waste 5052 aluminum alloy after degreasing and pickling are mixed with 2 parts of silicon nitride, and then melted and cast to obtain a billet. S2, Cold heading: After the billet is tempered at 180℃ for 120 minutes, it is cold headed to obtain a semi-finished product; S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut.

[0026] Example 4 The only difference between this embodiment and Embodiment 3 is that, in this embodiment, the silicon nitride is oxidized silicon nitride. The preparation method of oxidized silicon nitride is as follows: oxygen is introduced into 2 parts of silicon nitride (the amount introduced is 9 mg / L). 3 The silicon nitride was oxidized at 1000℃ for 50 min ( / h) to obtain oxidized silicon nitride.

[0027] Example 5 The only difference between this embodiment and Embodiment 4 is that, in this embodiment, the silicon nitride is oxidized silicon nitride. The preparation method of oxidized silicon nitride is as follows: water vapor is introduced into 2 parts of silicon nitride (the amount introduced is 6m). 3 The silicon nitride was oxidized at 250°C for 50 min (h / h) to obtain oxidized silicon nitride.

[0028] Example 6 The only difference between this embodiment and Embodiment 5 is that, in this embodiment, the method for preparing the oxidized silicon nitride is as follows: water vapor is introduced into 2 parts of silicon nitride (the amount introduced is 7m). 3 The silicon nitride was oxidized at 300℃ for 50 min ( / h) to obtain oxidized silicon nitride.

[0029] Example 7 The only difference between this embodiment and Embodiment 6 is that in this embodiment, the oxidation treatment time is 20 minutes.

[0030] Example 8 The only difference between this embodiment and Embodiment 6 is that in this embodiment, the oxidation treatment time is 30 minutes.

[0031] Example 9 The only difference between this embodiment and Embodiment 6 is that the oxidation treatment time in this embodiment is 40 minutes.

[0032] Comparative Example 1 A method for producing high wear-resistant rivet nuts includes the following steps: S1. Melting and casting: 100 parts by weight of waste 2024 aluminum alloy after degreasing and pickling are melted and cast to obtain billet; S2, Cold heading: After the billet is tempered at 170℃ for 150 minutes, it is cold headed to obtain a semi-finished product; S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut.

[0033] Comparative Example 2 A method for producing high wear-resistant rivet nuts includes the following steps: S1. Melting and casting: By weight, 100 parts of degreased and pickled waste 2024 aluminum alloy are mixed evenly with 1 part of silicon nitride, then melted and cast to obtain a billet. S2, Cold heading: After the billet is cold-headed, a semi-finished product is obtained; S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut.

[0034] The following performance tests were performed on the rivet nuts produced in Examples 1-9 and Comparative Examples 1-2: ① Hardness: The hardness was tested according to GB / T 231.1-2018 "Metallic materials - Brinell hardness test - Part 1: Test method", where the ratio of the test force to the square of the indenter ball diameter was 10 N / mm. 2 ; ② Wear loss weight: The wear loss weight was tested according to GB / T 12444-2006 "Metallic Materials Wear Test Method Test Ring-Block Sliding Wear Test", where the rotation speed was 500 r / min and the number of revolutions was 15000 revolutions.

[0035] The test results are shown in Table 1 below.

[0036] Table 1 Performance Test Results

[0037] A comparison between Example 1 and Comparative Example 1 shows that the addition of silicon nitride helps improve the hardness and wear resistance of the rivet nut. A comparison between Example 1 and Comparative Example 2 shows that tempering the blank helps improve the hardness and wear resistance of the rivet nut. A comparison between Examples 3 and Examples 4-9 shows that oxidizing silicon nitride further improves the hardness and wear resistance of the rivet nut. A comparison between Examples 8-9 and Examples 6-7 shows that a tempering to silicon nitride oxidation time ratio of 3-4:1 further improves the hardness and wear resistance of the rivet nut. A comparison between Example 8 and Example 9 shows that the optimal tempering to silicon nitride oxidation time ratio is 4:1.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing a high wear-resistant rivet nut, characterized in that, Includes the following steps: S1. Melting and casting: After the waste aluminum alloy and the oxidized silicon nitride are mixed evenly, they are melted and cast to obtain the billet; S2. Cold heading: After tempering, the billet is cold-headed to obtain a semi-finished product. The tempering process is carried out at a temperature of 170~200℃ for 60~150 minutes. S3. Tapping: After tapping, the semi-finished product is obtained as a rivet nut; The method for preparing the oxidized silicon nitride is as follows: water vapor is introduced into silicon nitride for oxidation treatment to obtain the oxidized silicon nitride. The amount of water vapor introduced is 6-7 mg / L. 3 / h, during the oxidation treatment, the temperature is 250~300℃ and the time is 20~50min; The mass ratio of the waste aluminum alloy to silicon nitride is 100:1~2; The time ratio of the tempering treatment to the oxidation treatment is 3~4:

1.

2. The method for producing a high wear-resistant rivet nut according to claim 1, characterized in that, The time ratio of the tempering treatment to the oxidation treatment is 4:

1.

3. A high wear-resistant rivet nut, characterized in that, It is produced by the production method described in any one of claims 1 to 2.

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