A cylindrical stud and its preparation method

Abstract

The present invention relates to the technical field of fasteners, and provides a cylindrical stud and a preparation method thereof. The cylindrical stud is obtained by phosphating treatment of a stud body. The stud body is composed of the following components by weight percentage: C 0.13% - 0.18%, Mn 0.3% - 0.6%, Zr 0.3% - 3%, V 0.3% - 1%, Al 0.4% - 0.8%, S ≤ 0.035%, P ≤ 0.035%, and the balance is Fe and other inevitable impurities. Through the above technical solution, the problems of low tensile strength and poor corrosion resistance of the cylindrical stud in the related art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of fasteners, and specifically, to a cylindrical stud and a preparation method thereof. Background Art

[0002] A cylindrical stud is a special fastener mainly used for welding two or more metal components together, playing an important role in fields such as construction, machinery manufacturing, and automobiles. During the use of a cylindrical stud, the tensile strength and corrosion resistance are crucial. If the tensile strength of the cylindrical stud is insufficient, it may break when subjected to a tensile force, resulting in connection failure and seriously affecting the stability and safety of the structure; if the corrosion resistance of the cylindrical stud is poor, it is prone to corrosion, leading to dimensional changes and even cracking.

[0003] With the continuous development of industry, the market has put forward more stringent requirements for the tensile strength and corrosion resistance of cylindrical studs. However, the existing cylindrical studs' tensile strength and corrosion resistance are difficult to meet the market demand. Therefore, it is of great significance to develop a cylindrical stud with high tensile strength and good corrosion resistance. Summary of the Invention

[0004] The present invention provides a cylindrical stud and a preparation method thereof, which solve the problems of low tensile strength and poor corrosion resistance of cylindrical studs in the related art.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a cylindrical stud obtained by phosphating a stud body, and the stud body is composed of the following components by weight percentage: C 0.13% - 0.18%, Mn 0.3% - 0.6%, Zr 0.3% - 3%, V 0.3% - 1%, Al 0.4% - 0.8%, S ≤ 0.035%, P ≤ 0.035%, and the rest is Fe and other inevitable impurities.

[0007] As a further technical solution, during the phosphating treatment, the phosphating solution includes the following components by weight: 90 - 120 parts of phosphoric acid, 30 - 50 parts of zinc nitrate, 20 - 30 parts of sodium phosphate, and 1000 parts of water.

[0008] As a further technical solution, the weight ratio of the sum of the weights of Zr and V to the weight of Al is 3 - 4:1.

[0009] In the present invention, when the weight ratio of the sum of the weights of Zr and V to the weight of Al is 3 - 4:1, the tensile strength of the stud body can be further improved.

[0010] As a further technical solution, the weight ratio of Zr to V is 2-3:1.

[0011] In the present invention, when the weight ratio of the sum of Zr and V to Al is 3-4:1 and the weight ratio of Zr to V is 2-3:1, it helps to further improve the tensile strength of the stud body.

[0012] As a further technical solution, during the phosphating treatment, the phosphating solution comprises the following components in parts by weight: 90-120 parts of phosphoric acid, 30-50 parts of zinc nitrate, 20-30 parts of sodium phosphate, 15-25 parts of nano chromium carbide, and 1000 parts of water.

[0013] In the present invention, the phosphating solution contains nano chromium carbide, and nano chromium carbide can fill the pores in the phosphating film, making the phosphating film denser, thereby further improving the corrosion resistance of the cylindrical stud.

[0014] As a further technical solution, the nano chromium carbide is carboxyl acrylic resin modified nano chromium carbide.

[0015] In the present invention, the inventors found that modifying nano chromium carbide with carboxyl acrylic resin can further improve the corrosion resistance of the cylindrical stud. It is speculated that: modifying nano chromium carbide with carboxyl acrylic resin can reduce the agglomeration of nano chromium carbide in the phosphating solution, thereby improving the uniformity of nano chromium carbide in the phosphating film.

[0016] As a further technical solution, in the carboxyl acrylic resin modified nano chromium carbide, the weight ratio of carboxyl acrylic resin to nano chromium carbide is 1:19-24.

[0017] In the present invention, when the weight ratio of carboxyl acrylic resin to nano chromium carbide is 1:19-24, it helps to further improve the corrosion resistance of the cylindrical stud.

[0018] As a further technical solution, the preparation method of the carboxyl acrylic resin modified nano chromium carbide comprises the following steps: dissolving the carboxyl acrylic resin in xylene, adding nano chromium carbide, dispersing evenly, and drying to obtain the carboxyl acrylic resin modified nano chromium carbide.

[0019] As a further technical solution, the acid value of the carboxyl acrylic resin is ≤210 mgKOH / g.

[0020] In the present invention, when the acid value of the carboxyl acrylic resin is ≤210 mgKOH / g, it can further improve the corrosion resistance of the cylindrical stud.

[0021] The present invention also provides a preparation method of the above-mentioned cylindrical stud, comprising the following steps:

[0022] S1. Weigh scrap iron, ferromanganese, ferrozirconium, ferrovandium and pure aluminum according to the target composition of the stud body. After melting and casting, a blank is obtained.

[0023] S2. The blank is cold upset and machined to obtain the stud body.

[0024] S3. The stud body is phosphated to obtain a cylindrical stud.

[0025] As a further technical solution, in step S3, during the phosphating treatment, the temperature is 40 - 60 °C and the time is 30 - 40 min.

[0026] The working principle and beneficial effects of the present invention are as follows:

[0027] In the present invention, the cylindrical stud has good tensile strength and corrosion resistance, and can meet the actual use requirements. Among them, by carrying out phosphating treatment, the corrosion resistance of the cylindrical stud can be improved. In addition, by optimizing the component composition of the stud body, especially the contents of Zr, V and Al elements, the tensile strength of the stud body is significantly improved. Specific Embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are only a 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 those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0029] In the following examples and comparative examples, unless otherwise specified, the Fe content in scrap iron is 91.5 wt%; the Mn content in ferromanganese is 81.2 wt%; the Zr content in ferrozirconium is 82 wt%; the V content in ferrovandium is 84.6 wt%.

[0030] Example 1

[0031] A method for preparing a cylindrical stud includes the following steps:

[0032] S1. Weigh scrap iron, ferromanganese, ferrozirconium, ferrovandium and pure aluminum according to the target composition of the stud body. After melting and casting, a blank is obtained.

[0033] Among them, the stud body is composed of the following components by weight percentage: C 0.13%, Mn 0.3%, Zr 0.3%, V 0.3%, Al 0.4%, S 0.035%, P 0.035%, and the rest is Fe and other inevitable impurities.

[0034] S2. The blank is cold upset and turned to obtain the stud body.

[0035] After the stud body is phosphated at 50 °C for 35 min, a cylindrical stud is obtained;

[0036] Among them, the phosphating solution includes the following components in parts by weight: 90 parts of phosphoric acid, 30 parts of zinc nitrate, 20 parts of sodium phosphate, and 1000 parts of water.

[0037] Example 2

[0038] A method for preparing a cylindrical stud includes the following steps:

[0039] S1. Weigh scrap iron, ferromanganese, ferrozirconium, ferrovanadium, and pure aluminum according to the target composition of the stud body, and after melting and casting, a blank is obtained;

[0040] Among them, the stud body is composed of the following components in weight percentage: C 0.18%, Mn 0.6%, Zr 3%, V 1%, Al 0.8%, S 0.03%, P 0.03%, and the rest is Fe and other inevitable impurities;

[0041] S2. After the blank is cold-heading and turned, the stud body is obtained;

[0042] S3. After the stud body is phosphated at 50 °C for 35 min, a cylindrical stud is obtained;

[0043] Among them, the phosphating solution includes the following components in parts by weight: 120 parts of phosphoric acid, 50 parts of zinc nitrate, 30 parts of sodium phosphate, and 1000 parts of water.

[0044] Example 3

[0045] A method for preparing a cylindrical stud includes the following steps:

[0046] S1. Weigh scrap iron, ferromanganese, ferrozirconium, ferrovanadium, and pure aluminum according to the target composition of the stud body, and after melting and casting, a blank is obtained;

[0047] Among them, the stud body is composed of the following components in weight percentage: C 0.14%, Mn 0.5%, Zr 1.76%, V 0.44%, Al 0.8%, S 0.03%, P 0.03%, and the rest is Fe and other inevitable impurities;

[0048] S2. After the blank is cold-heading and turned, the stud body is obtained;

[0049] S3. After the stud body is phosphated at 50 °C for 35 min, a cylindrical stud is obtained;

[0050] Among them, the phosphating solution includes the following components in parts by weight: 120 parts of phosphoric acid, 50 parts of zinc nitrate, 30 parts of sodium phosphate, and 1000 parts of water.

[0051] Example 4

[0052] The difference between this example and Example 3 is only that in this example, the stud body is composed of the following components by weight percentage: C 0.14%, Mn 0.5%, Zr 2%, V 0.5%, Al 0.5%, S 0.03%, P 0.03%, and the balance is Fe and other inevitable impurities.

[0053] Example 5

[0054] The difference between this example and Example 3 is only that in this example, the stud body is composed of the following components by weight percentage: C 0.14%, Mn 0.5%, Zr 1.8%, V 0.45%, Al 0.75%, S 0.03%, P 0.03%, and the balance is Fe and other inevitable impurities.

[0055] Example 6

[0056] The difference between this example and Example 3 is only that in this example, the stud body is composed of the following components by weight percentage: C 0.14%, Mn 0.5%, Zr 1.92%, V 0.48%, Al 0.6%, S 0.03%, P 0.03%, and the balance is Fe and other inevitable impurities.

[0057] Example 7

[0058] The difference between this example and Example 6 is only that in this example, the stud body is composed of the following components by weight percentage: C 0.14%, Mn 0.5%, Zr 1.5%, V 0.9%, Al 0.6%, S 0.03%, P 0.03%, and the balance is Fe and other inevitable impurities.

[0059] Example 8

[0060] The difference between this example and Example 6 is only that in this example, the stud body is composed of the following components by weight percentage: C 0.14%, Mn 0.5%, Zr 1.8%, V 0.6%, Al 0.6%, S 0.03%, P 0.03%, and the balance is Fe and other inevitable impurities.

[0061] Example 9

[0062] The difference between this example and Example 6 is only that in this example, the stud body is composed of the following components by weight percentage: C 0.14%, Mn 0.5%, Zr 1.6%, V 0.8%, Al 0.6%, S 0.03%, P 0.03%, and the balance is Fe and other inevitable impurities.

[0063] Example 10

[0064] The difference between this example and Example 9 is only that in this example, during phosphating treatment, the phosphating solution comprises the following components in parts by weight: 90 parts of phosphoric acid, 30 parts of zinc nitrate, 20 parts of sodium phosphate, 15 parts of nano chromium carbide, and 1000 parts of water.

[0065] Example 11

[0066] The difference between this example and Example 9 is only that in this example, the phosphating solution comprises the following components in parts by weight: 120 parts of phosphoric acid, 50 parts of zinc nitrate, 30 parts of sodium phosphate, 25 parts of nano chromium carbide, and 1000 parts of water.

[0067] Example 12

[0068] The difference between this example and Example 11 is only that in this example, the nano chromium carbide in the phosphating solution is carboxyl acrylic resin modified nano chromium carbide, and the preparation method of the carboxyl acrylic resin modified nano chromium carbide comprises the following steps: Dissolve 0.5 part of carboxyl acrylic resin (model SC8020, acid value 220 - 260 mgKOH / g, purchased from Zhejiang Shuangcai New Materials Co., Ltd.) in 40 parts of xylene, add 24.5 parts of nano chromium carbide, disperse evenly, and dry to obtain carboxyl acrylic resin modified nano chromium carbide.

[0069] Example 13

[0070] The difference between this example and Example 12 is only that in this example, the model of the carboxyl acrylic resin is SC8008, the acid value is 190 - 210 mgKOH / g, and it is purchased from Zhejiang Shuangcai New Materials Co., Ltd.

[0071] Example 14

[0072] The difference between this example and Example 13 is only that in this example, the weight part of the carboxyl acrylic resin is 1.5 parts, and the weight part of the nano chromium carbide is 23.5 parts.

[0073] Example 15

[0074] The difference between this example and Example 13 is only that in this example, the weight part of the carboxyl acrylic resin is 1 part, and the weight part of the nano chromium carbide is 24 parts.

[0075] Example 16

[0076] The difference between this example and Example 13 is only that in this example, the weight part of the carboxyl acrylic resin is 1.25 parts, and the weight part of the nano chromium carbide is 23.75 parts.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 1 is only that in this comparative example, the stud body is composed of the following components by weight percentage: C 0.13%, Mn 0.3%, Zr 0.5%, V 0.5%, S 0.035%, P 0.035%, and the balance is Fe and other inevitable impurities.

[0079] Comparative Example 2

[0080] The difference between this comparative example and Example 1 is only that in this comparative example, the stud body is composed of the following components by weight percentage: C 0.13%, Mn 0.3%, Zr 0.6%, Al 0.4%, S 0.035%, P 0.035%, and the balance is Fe and other inevitable impurities.

[0081] Comparative Example 3

[0082] The difference between this comparative example and Example 1 is only that in this comparative example, the stud body is composed of the following components by weight percentage: C 0.13%, Mn 0.3%, V 0.6%, Al 0.4%, S 0.035%, P 0.035%, and the balance is Fe and other inevitable impurities.

[0083] Comparative Example 4

[0084] The difference between this comparative example and Example 1 is only that in this comparative example, the stud body is composed of the following components by weight percentage: C 0.13%, Mn 0.3%, Al 1%, S 0.035%, P 0.035%, and the balance is Fe and other inevitable impurities.

[0085] Comparative Example 5

[0086] The difference between this comparative example and Example 1 is only that in this comparative example, the stud body is composed of the following components by weight percentage: C 0.13%, Mn 0.3%, S 0.035%, P 0.035%, and the balance is Fe and other inevitable impurities.

[0087] Experimental Example 1 Tensile Strength Test

[0088] The tensile strength of the stud bodies in Examples 1-9 and Comparative Examples 1-5 was tested using a GL8105 microcomputer-controlled electronic tensile testing machine, where the test rate was 0.008 s -1 , and the average value of the results of 3 specimens in each group was taken as the final result. The test results are shown in Table 1 below.

[0089] Table 1 Tensile Strength Test Results

[0090]

[0091] Comparisons between Example 1 and Comparative Examples 1-5 show that by optimizing the component composition of the stud body, especially Zr, V, and Al, the tensile strength of the stud body is significantly improved. Comparisons between Examples 3-4 and Examples 5-6 show that when the weight ratio of the sum of Zr and V to Al is 3-4:1, the tensile strength of the stud body can be further improved. Comparisons between Examples 6-7 and Examples 8-9 show that when the weight ratio of the sum of Zr and V to Al is 3-4:1 and the weight ratio of Zr to V is 2-3:1, it helps to further improve the tensile strength of the stud body.

[0092] Experimental Example 2 Corrosion Resistance Test

[0093] The cylindrical studs prepared in Examples 9-16 were subjected to corrosion resistance tests according to the neutral salt spray test method in GB / T 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test", and the time when corrosion began to appear was recorded. Among them, the test temperature was 35°C, the concentration of the sodium chloride solution was 50 g / L, and the pH value of the collected solution was 7. The test results are shown in Table 2 below.

[0094] Table 2 Corrosion Resistance Test Results

[0095]

[0096] Comparisons between Example 9 and Example 11 show that when the phosphating solution contains nano chromium carbide, it helps to further improve the corrosion resistance of the cylindrical stud. Comparisons between Example 11 and Examples 12-16 show that by modifying nano chromium carbide with carboxyl acrylic resin, the corrosion resistance of the cylindrical stud can be further improved. Comparisons between Example 12 and Example 13 show that when the acid value of the carboxyl acrylic resin is ≤210 mgKOH / g, the corrosion resistance of the cylindrical stud can be further improved. Comparisons between Examples 13-14 and Examples 15-16 show that when the weight ratio of carboxyl acrylic resin to nano chromium carbide is 1:19-24, it helps to further improve the corrosion resistance of the cylindrical stud.

[0097] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cylindrical stud, obtained by phosphating treatment of the stud body, characterized in that, The welding stud body is composed of the following components in weight percentage: C 0.13%~0.18%, Mn 0.3%~0.6%, Zr 0.3%~3%, V 0.3%~1%, Al0.4%~0.8%, S≤0.035%, P≤0.035%, and the rest is Fe and other inevitable impurities; During the phosphating treatment, the phosphating solution includes the following components in parts by weight: 90-120 parts of phosphoric acid, 30-50 parts of zinc nitrate, 20-30 parts of sodium phosphate, 15-25 parts of nano-chromium carbide, and 1000 parts of water.

2. The cylindrical stud according to claim 1, wherein The weight ratio of the Zr and V to the Al is 3-4:

1.

3. The cylindrical stud according to claim 2, characterized in that, The weight ratio of Zr to V is 2-3:

1.

4. A cylindrical stud according to claim 1, characterized in that, The nano-chromium carbide is carboxyl acrylic resin modified nano-chromium carbide.

5. A cylindrical stud according to claim 4, characterized in that, In the carboxyl acrylic resin modified nano-chromium carbide, the weight ratio of the carboxyl acrylic resin to the nano-chromium carbide is 1:19-24.

6. A cylindrical stud according to claim 4, wherein, The preparation method of the carboxyl acrylic resin modified nano-chromium carbide comprises the following steps: dissolving the carboxyl acrylic resin in xylene, adding nano-chromium carbide, dispersing evenly, and drying to obtain the carboxyl acrylic resin modified nano-chromium carbide.

7. A cylindrical stud according to claim 5, characterized in that, The acid value of the carboxyl acrylic resin is ≤210 mgKOH / g.

8. A method for preparing a cylindrical stud as described in any one of claims 1 to 7, characterized in that, The following steps are involved: S1. According to the components of the welding nail body, the ingredients are prepared, and after smelting and casting, a blank is obtained; S2, the blank is subjected to cold heading and machining to obtain a welding nail body; S3. After the welding nail body is phosphating treated, a cylindrical welding nail is obtained.

9. The preparation method of a cylindrical stud according to claim 8, wherein In step S3, during the phosphating treatment, the temperature is 40-60° C. and the time is 30-40 min.

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