Corrosion-resistant hot-dip galvanized bolt and preparation method thereof

Abstract

The invention relates to the technical field of bolts and provides a corrosion-resistant hot-dip galvanized bolt and a preparation method thereof. The corrosion-resistant hot-dip galvanized bolt is obtained by subjecting a bolt body to electroplating and hot-dip galvanizing. The bolt body is composed of the following components in percentage by weight: Mn 0.18%-0.58%, Te 0.02%-0.05%, Bi 0.004%-0.015%, Eu 0.05%-0.25%, Ge 0.015%-0.045%, Ti 0.02%-0.06%, V 0.05%-0.10%, Co 0.20%-0.50%, Nb 0.05%-0.15%, C 0.20%-0.30%, Mo 0.10%-0.30%, B 0.002%-0.005%, S≤0.01%, P≤0.005%, and the remainder is iron and unavoidable impurities. The above technical solution solves the problems of poor tensile strength of the bolt body, uneven zinc coating and poor corrosion resistance in hot-dip galvanized bolts in the related art.

Description

Technical Field

[0001] The present invention relates to the technical field of bolts, and in particular to a corrosion-resistant hot-dip galvanized bolt and a preparation method thereof. Background Art

[0002] Bolts are an indispensable fastener in daily life and industrial production, consisting of a head and a screw. By using them in conjunction with nuts, bolts can be used to connect and fix various mechanical components. They are widely used in various fields, especially when used in outdoor environments, where higher performance requirements are placed on the bolts. Hot-dip galvanized bolts are bolts that have been treated with a hot-dip galvanizing process. Hot-dip galvanizing the bolt body can improve the overall performance of the bolt to a certain extent. However, the tensile strength of the traditional hot-dip galvanized bolt body is poor, and the galvanizing layer is uneven. When the galvanizing layer is uneven, it may cause local areas of the bolt to be too thin, affecting the quality of the galvanizing. When it is exposed to the external environment for a long time, these thin areas are easily corroded, thereby affecting the overall quality of the bolt. Therefore, there is an urgent need to develop a hot-dip galvanized bolt with good tensile strength, uniform galvanizing layer, and good corrosion resistance. This is of great significance for improving the overall performance and service life of the bolt. Summary of the Invention

[0003] The present invention provides a corrosion-resistant hot-dip galvanized bolt and a preparation method thereof, which solves the problems of poor tensile strength of the bolt body, uneven zinc coating and poor corrosion resistance in the hot-dip galvanized bolt in the related art.

[0004] The technical solutions of the present invention are as follows:

[0005] The present invention provides a corrosion-resistant hot-dip galvanized bolt, which is obtained by subjecting a bolt body to assisted plating and hot-dip galvanizing. The bolt body is composed of the following components in percentage by weight:

[0006] Mn 0.18%~0.58%, Te 0.02%~0.05%, Bi 0.004%~0.015%, Eu 0.05%~0.25%, Ge0.015%~0.045%, Ti 0.02%~0.06%, V 0.05%~0.10%, Co 0.20%~0.50%, Nb 0.05%~0.15%, C0.20%~0.30%, Mo 0.10%~0.30%, B 0.002%~0.005%, S≤0.01%, P≤0.005%, the rest are iron and unavoidable impurities.

[0007] As a further technical solution, the weight ratio of the sum of the Eu and Mo to the weight of the Mn is 1-2:1.

[0008] When the weight ratio of Eu and Mo to Mn is 1 to 2:1, the tensile strength of the bolt body in the hot-dip galvanized bolt can be further improved.

[0009] As a further technical solution, the weight ratio of the Eu to the Mo is 1:1.

[0010] As a further technical solution, during the hot-dip galvanizing, the zinc solution is composed of the following components in percentage by weight:

[0011] Pb 0.01%~0.025%, Fe 0.015%~0.025%, Sn 0.15%~0.35%, In 0.015%~0.055%, Al0.10%~0.20%, Ti 0.004%~0.09%, Nb 0.01%~0.06%, and the rest are zinc and unavoidable impurities.

[0012] As a further technical solution, the weight ratio of the sum of the In and Nb to the weight of the Ti is 2-5:1.

[0013] By adding In, Nb, and Ti to the zinc bath, the composition of the bath can be optimized by utilizing their effective complementarity. This helps evenly distribute the components in the zinc coating, thereby improving the uniformity of the coating and the corrosion resistance of hot-dip galvanized bolts. When the weight ratio of the sum of In and Nb to Ti is 2 to 5:1, the uniformity of the coating and the corrosion resistance of the hot-dip galvanized bolts can be further improved.

[0014] As a further technical solution, the weight ratio of the In to the Nb is 1:1.

[0015] As a further technical solution, during the plating assistance, the plating assistance agent includes the following components in parts by weight:

[0016] 30-40 parts of zinc chloride, 10-15 parts of ammonium chloride, 2-18 parts of potassium titanium oxalate, 3-19 parts of polyacrylamide, 10-16 parts of calcium lignin sulfonate, and 100 parts of water.

[0017] When the bolts are galvanized, the plating flux includes potassium titanium oxalate and polyacrylamide. The combined use of potassium titanium oxalate and polyacrylamide can effectively improve the surface activity of the bolts and the plating flux effect, so that during hot-dip galvanizing, the bolts can be better combined with the various components in the zinc liquid, which can further improve the uniformity of the zinc coating, improve the quality of zinc plating, and further improve the corrosion resistance of the hot-dip galvanized bolts.

[0018] As a further technical solution, the weight ratio of the potassium titanium oxalate to the polyacrylamide is 1~3:1.

[0019] When the weight ratio of potassium titanium oxalate to polyacrylamide is 1~3:1, the uniformity of the galvanized layer and the corrosion resistance of the hot-dip galvanized bolts can be further improved.

[0020] The present invention also provides a method for preparing corrosion-resistant hot-dip galvanized bolts, comprising the following steps:

[0021] S1. Melting, casting, cooling and forming the components according to the weight percentage of the bolt body to obtain a bolt blank;

[0022] S2, heat treating the bolt blank and cold heading it to obtain a semi-finished bolt, and threading the semi-finished bolt to obtain a bolt body;

[0023] S3, pickling and washing the bolt body, and then placing the bolt body in a plating flux to obtain a plated bolt;

[0024] S4, placing the bolts after the plating assistance in a zinc solution for hot-dip galvanizing treatment, and then passivating and cooling to obtain hot-dip galvanized bolts.

[0025] As a further technical solution, in step S2, the heat treatment is divided into a first heat treatment and a second heat treatment. During the first heat treatment, the temperature is 850~900℃, and the insulation time is 60~80min. During the second heat treatment, the temperature is 600~650℃, and the insulation time is 80~100min.

[0026] As a further technical solution, in step S3, during the pickling, a hydrochloric acid solution with a mass fraction of 12% to 18% is used.

[0027] As a further technical solution, in step S3, the water washing temperature is 75-85°C.

[0028] As a further technical solution, in step S3, the assist plating time is 2 to 5 minutes.

[0029] As a further technical solution, in step S4, during the hot-dip galvanizing treatment, the temperature of the zinc solution is 430-450° C., and the galvanizing time is 20-30 seconds.

[0030] As a further technical solution, in step S4, during the passivation, the temperature of the passivation solution is 130-170° C., and the passivation time is 8-12 minutes.

[0031] As a further technical solution, in step S4, during the passivation, the passivation solution includes the following components in parts by weight:

[0032] 10-15 parts of potassium sodium tartrate, 3-9 parts of cobalt chloride, 3-6 parts of sodium nitrate, 8-16 parts of hydrogen peroxide, and 60 parts of water.

[0033] The working principle and beneficial effects of the present invention are:

[0034] In the present invention, the bolt body is subjected to a galvanizing and hot-dip galvanizing treatment, resulting in a hot-dip galvanized bolt with excellent corrosion resistance and a uniform zinc coating. By optimizing the components of the bolt body, the internal structural stability of the bolt body is enhanced, resulting in a high tensile strength of the hot-dip galvanized bolt body. The addition of Eu, Mo, and Mn, utilizing their complementary combination, significantly improves the tensile strength of the hot-dip galvanized bolt body. DETAILED DESCRIPTION

[0035] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] In the following examples and comparative examples, the polyacrylamide is nonionic polyacrylamide with a weight-average molecular weight of 6,000,000; the model of calcium lignin sulfonate is Biokeram 210.

[0037] Example 1

[0038] A corrosion-resistant hot-dip galvanized bolt is obtained by subjecting a bolt body to assisted plating and hot-dip galvanizing. The bolt body is composed of the following components in percentage by weight:

[0039] 0.18% Mn, 0.02% Te, 0.004% Bi, 0.05% Eu, 0.015% Ge, 0.02% Ti, 0.05% V, 0.20% Co, 0.05% Nb, 0.20% C, 0.10% Mo, 0.002% B, the rest is iron and unavoidable impurities;

[0040] During hot-dip galvanizing, the zinc solution is composed of the following components in weight percentage:

[0041] 0.01% Pb, 0.015% Fe, 0.15% Sn, 0.015% In, 0.10% Al, 0.004% Ti, 0.01% Nb, the rest is zinc and unavoidable impurities;

[0042] During the plating process, the plating agent includes the following components in parts by weight:

[0043] 30 parts of zinc chloride, 10 parts of ammonium chloride, 2 parts of potassium titanium oxalate, 3 parts of polyacrylamide, 10 parts of calcium lignin sulfonate, 100 parts of water;

[0044] During passivation, the passivation solution includes the following components in parts by weight:

[0045] 10 parts potassium sodium tartrate, 3 parts cobalt chloride, 3 parts sodium nitrate, 8 parts hydrogen peroxide, 60 parts water;

[0046] A method for preparing corrosion-resistant hot-dip galvanized bolts comprises the following steps:

[0047] S1. Melting, casting, cooling and forming the components according to the weight percentage of the bolt body to obtain a bolt blank;

[0048] S2. Performing a first heat treatment on the bolt blank at 850° C. and holding the temperature for 80 min, performing a second heat treatment at 600° C. and holding the temperature for 100 min, and cold heading to obtain a semi-finished bolt. The semi-finished bolt is threaded to obtain a bolt body.

[0049] S3, pickling the bolt body in a 16% by mass hydrochloric acid solution, washing with water at 80°C, and then placing the bolt body in a flux for flux plating for 3 minutes to obtain a flux-plated bolt;

[0050] S4. Place the bolts after galvanizing in a zinc solution at 430°C for hot-dip galvanizing for 30 seconds, then passivate in a passivation solution at 150°C for 10 minutes, and cool to obtain hot-dip galvanized bolts.

[0051] Example 2

[0052] A corrosion-resistant hot-dip galvanized bolt is obtained by subjecting a bolt body to assisted plating and hot-dip galvanizing. The bolt body is composed of the following components in percentage by weight:

[0053] 0.34% Mn, 0.04% Te, 0.01% Bi, 0.13% Eu, 0.025% Ge, 0.04% Ti, 0.08% V, 0.40% Co, 0.10% Nb, 0.35% C, 0.13% Mo, 0.004% B, 0.005% S, 0.003% P, the rest is iron and unavoidable impurities;

[0054] During hot-dip galvanizing, the zinc solution is composed of the following components in weight percentage:

[0055] 0.02% Pb, 0.02% Fe, 0.25% Sn, 0.03% In, 0.15% Al, 0.06% Ti, 0.03% Nb, the remainder is zinc and unavoidable impurities;

[0056] During the plating process, the plating agent includes the following components in parts by weight:

[0057] 35 parts of zinc chloride, 13 parts of ammonium chloride, 8 parts of potassium titanium oxalate, 12 parts of polyacrylamide, 13 parts of calcium lignin sulfonate, 100 parts of water;

[0058] During passivation, the passivation solution includes the following components in parts by weight:

[0059] 13 parts potassium sodium tartrate, 6 parts cobalt chloride, 5 parts sodium nitrate, 12 parts hydrogen peroxide, 60 parts water;

[0060] A method for preparing corrosion-resistant hot-dip galvanized bolts comprises the following steps:

[0061] S1. Melting, casting, cooling and forming the components according to the weight percentage of the bolt body to obtain a bolt blank;

[0062] S2. Performing a first heat treatment on the bolt blank at 870° C. and holding the temperature for 70 minutes, performing a second heat treatment at 630° C. and holding the temperature for 90 minutes, and cold heading to obtain a semi-finished bolt. The semi-finished bolt is threaded to obtain a bolt body.

[0063] S3, pickling the bolt body in a 16% by mass hydrochloric acid solution, washing with water at 80°C, and then placing the bolt body in a flux for flux plating for 3 minutes to obtain a flux-plated bolt;

[0064] S4. Place the bolts after galvanizing in a zinc solution at 440°C for 25 seconds, then passivate in a passivation solution at 150°C for 10 minutes, and cool to obtain hot-dip galvanized bolts.

[0065] Example 3

[0066] A corrosion-resistant hot-dip galvanized bolt is obtained by subjecting a bolt body to assisted plating and hot-dip galvanizing. The bolt body is composed of the following components in percentage by weight:

[0067] 0.58% Mn, 0.05% Te, 0.015% Bi, 0.25% Eu, 0.045% Ge, 0.06% Ti, 0.10% V, 0.50% Co, 0.15% Nb, 0.30% C, 0.30% Mo, 0.005% B, 0.01% S, 0.005% P, the rest is iron and unavoidable impurities;

[0068] During hot-dip galvanizing, the zinc solution is composed of the following components in weight percentage:

[0069] 0.025% Pb, 0.025% Fe, 0.35% Sn, 0.055% In, 0.20% Al, 0.09% Ti, 0.06% Nb, the remainder is zinc and unavoidable impurities;

[0070] During the plating process, the plating agent includes the following components in parts by weight:

[0071] 40 parts of zinc chloride, 15 parts of ammonium chloride, 18 parts of potassium titanium oxalate, 19 parts of polyacrylamide, 16 parts of calcium lignin sulfonate, 100 parts of water;

[0072] During passivation, the passivation solution includes the following components in parts by weight:

[0073] 15 parts potassium sodium tartrate, 9 parts cobalt chloride, 6 parts sodium nitrate, 16 parts hydrogen peroxide, 60 parts water;

[0074] A method for preparing corrosion-resistant hot-dip galvanized bolts comprises the following steps:

[0075] S1. Melting, casting, cooling and forming the components according to the weight percentage of the bolt body to obtain a bolt blank;

[0076] S2. Performing a first heat treatment on the bolt blank at 900° C. and holding the temperature for 60 minutes, performing a second heat treatment at 650° C. and holding the temperature for 80 minutes, and cold heading to obtain a semi-finished bolt. The semi-finished bolt is threaded to obtain a bolt body.

[0077] S3, pickling the bolt body in a 16% by mass hydrochloric acid solution, washing with water at 80°C, and then placing the bolt body in a flux for flux plating for 3 minutes to obtain a flux-plated bolt;

[0078] S4. Place the bolts after galvanizing in a zinc solution at 450°C for 20 seconds, then passivate in a passivation solution at 150°C for 10 minutes, and cool to obtain hot-dip galvanized bolts.

[0079] Example 4

[0080] The only difference between this embodiment and embodiment 2 is that, in this embodiment, the weight percentage of Eu in the bolt body is 0.21%, the weight percentage of Mo is 0.21%, and the weight percentage of Mn is 0.18%.

[0081] Example 5

[0082] The only difference between this embodiment and embodiment 2 is that, in this embodiment, the weight percentage of Eu in the bolt body is 0.15%, the weight percentage of Mo is 0.15%, and the weight percentage of Mn is 0.30%.

[0083] Example 6

[0084] The only difference between this embodiment and embodiment 2 is that, in this embodiment, the weight percentage of Eu in the bolt body is 0.20%, the weight percentage of Mo is 0.20%, and the weight percentage of Mn is 0.20%.

[0085] Example 7

[0086] The only difference between this embodiment and embodiment 6 is that, in this embodiment, the weight percentage of In in the zinc solution is 0.052%, the weight percentage of Nb is 0.052%, and the weight percentage of Ti is 0.016%.

[0087] Example 8

[0088] The only difference between this embodiment and embodiment 6 is that, in this embodiment, the weight percentage of In in the zinc solution is 0.04%, the weight percentage of Nb is 0.04%, and the weight percentage of Ti is 0.04%.

[0089] Example 9

[0090] The only difference between this embodiment and embodiment 6 is that, in this embodiment, the weight percentage of In in the zinc solution is 0.05%, the weight percentage of Nb is 0.05%, and the weight percentage of Ti is 0.02%.

[0091] Example 10

[0092] The only difference between this embodiment and embodiment 9 is that in this embodiment, 16 parts of potassium titanium oxalate and 4 parts of polyacrylamide are added to the plating flux.

[0093] Example 11

[0094] The only difference between this embodiment and embodiment 9 is that in this embodiment, 10 parts of potassium titanium oxalate and 10 parts of polyacrylamide are added to the plating flux.

[0095] Example 12

[0096] The only difference between this embodiment and embodiment 9 is that in this embodiment, 15 parts of potassium titanium oxalate and 5 parts of polyacrylamide are added to the plating flux.

[0097] Example 13

[0098] The only difference between this embodiment and embodiment 9 is that in this embodiment, potassium titanium oxalate is not added, and 20 parts of polyacrylamide are added.

[0099] Example 14

[0100] The only difference between this embodiment and embodiment 9 is that in this embodiment, no polyacrylamide is added, and 20 parts of potassium titanium oxalate are added.

[0101] Example 15

[0102] The only difference between this embodiment and embodiment 9 is that in this embodiment, neither polyacrylamide nor potassium titanium oxalate is added.

[0103] Comparative Example 1

[0104] The only difference between this comparative example and Example 1 is that in this comparative example, the bolt body does not contain Mn, the weight percentage of Eu is 0.11%, and the weight percentage of Mo is 0.22%.

[0105] Comparative Example 2

[0106] The only difference between this comparative example and Example 1 is that in this comparative example, the bolt body does not contain Eu, the weight percentage of Mo is 0.15%, and the weight percentage of Mn is 0.18%.

[0107] Comparative Example 3

[0108] The only difference between this comparative example and Example 1 is that in this comparative example, the bolt body does not contain Mo, the weight percentage of Eu is 0.15%, and the weight percentage of Mn is 0.18%.

[0109] Comparative Example 4

[0110] The only difference between this comparative example and Example 1 is that, in this comparative example, the bolt body does not contain Eu and Mo, and the weight percentage of Mn is 0.33%.

[0111] Comparative Example 5

[0112] The only difference between this comparative example and Example 1 is that in this comparative example, the bolt body does not contain Eu, Mo, and Mn.

[0113] Experimental Example 1 Tensile Strength Test

[0114] The bolt bodies prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were tested for tensile strength according to the test method in GB / T 228.1-2021 "Tensile tests on metallic materials - Part 1: Room temperature test methods", wherein the test speed was 0.006s. -1 , the test results are shown in Table 1 below.

[0115] Table 1 Test results

[0116]

[0117] Table 1 shows that compared to Comparative Examples 1-5, the tensile strength of the bolt body of Example 1 is significantly improved, indicating that the addition of Eu, Mo, and Mn, through their complementary combination, significantly improves the tensile strength of the bolt body in hot-dip galvanized bolts. Compared to Examples 2 and 4, the tensile strength of the bolt body of Examples 5-6 is improved, indicating that a weight ratio of Eu and Mo to Mn of 1 to 2:1 can further improve the tensile strength of the bolt body in hot-dip galvanized bolts.

[0118] Experimental Example 2 Corrosion resistance and zinc coating uniformity test

[0119] ① Corrosion resistance test: The hot-dip galvanized bolts prepared in Examples 6 to 15 were immersed in a 20% by mass hydrochloric acid solution for 120 minutes. The mass loss of the hot-dip galvanized bolt specimens was measured, and the mass loss rate was calculated according to the following formula: mass loss rate (%) = (mass of the hot-dip galvanized bolt before immersion - mass of the hot-dip galvanized bolt after immersion) / mass of the hot-dip galvanized bolt before immersion × 100%. The test results are shown in Table 2 below.

[0120] ② Galvanized layer uniformity test: 314 g of copper sulfate crystals were crushed and dissolved in 1 L of distilled water at 20°C to obtain a test solution. 1 g of copper oxide was added to the 1 L test solution and stirred. The solution was allowed to stand for 24 hours and then filtered to obtain a test solution from which free acid had been removed. The hot-dip galvanized bolt specimens prepared in Examples 6 to 15 were vertically immersed in the center of the static test solution. The solution was not stirred, and the specimen did not contact the wall of the container containing the test solution. After standing for 1 minute, the specimen was steadily removed and immediately rinsed in water. Unfirmly adhered copper and compounds on the surface of the zinc layer were removed with absorbent cotton. The above steps were repeated for the immersion test until firmly adhered metallic copper first appeared on the surface of the specimen. The number of immersions was recorded. The test results are shown in Table 2 below.

[0121] Table 2 Test results

[0122]

[0123] In Table 2, compared with Examples 6-7, the mass loss rate of the hot-dip galvanized bolts in Examples 8-9 was reduced, and the number of immersions in the copper sulfate test solution until the first firmly adhered metallic copper appeared on the surface of the hot-dip galvanized bolts increased. This indicates that when the weight ratio of the sum of In and Nb to Ti is 2-5:1, the corrosion resistance and uniformity of the zinc coating of the hot-dip galvanized bolts can be further improved. Compared with Examples 13-15, the mass loss rate of the hot-dip galvanized bolts in Examples 9-12 was reduced, and the number of immersions in the copper sulfate test solution until the first firmly adhered metallic copper appeared on the surface of the hot-dip galvanized bolts increased. This indicates that when potassium titanium oxalate and polyacrylamide are included in the plating flux, the corrosion resistance and uniformity of the zinc coating of the hot-dip galvanized bolts can be further improved by using potassium titanium oxalate and polyacrylamide together. In addition, compared with Examples 9 and 10, the mass loss rate of the hot-dip galvanized bolts in Examples 11 and 12 is reduced, and the number of immersions when the hot-dip galvanized bolts are immersed in the copper sulfate test solution increases when firmly adhered metallic copper first appears on the surface. This indicates that when the weight ratio of potassium titanium oxalate to polyacrylamide is 1 to 3:1, the corrosion resistance and uniformity of the zinc coating of the hot-dip galvanized bolts can be further improved.

[0124] The above are only 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 should be included in the scope of protection of the present invention.

Claims

1. A corrosion-resistant hot-dip galvanized bolt, obtained by subjecting the bolt body to galvanizing and hot-dip galvanizing, characterized in that: The bolt body is composed of the following components in percentage by weight: Mn 0.18%~0.58%, Te 0.02%~0.05%, Bi 0.004%~0.015%, Eu 0.05%~0.25%, Ge 0.015%~0.045%, Ti 0.02%~0.06%, V 0.05%~0.10%, Co 0.20%~0.50%, Nb 0.05%~0.15%, C 0.20%~0.30%, Mo 0.10%~0.30%, B 0.002%~0.005%, S≤0.01%, P≤0.005%, the rest are iron and unavoidable impurities; The weight ratio of the sum of the weights of Eu and Mo to the weight of Mn is 1-2:1; During hot-dip galvanizing, the zinc solution is composed of the following components in percentage by weight: Pb 0.01%~0.025%, Fe 0.015%~0.025%, Sn 0.15%~0.35%, In 0.015%~0.055%, Al 0.10%~0.20%, Ti 0.004%~0.09%, Nb 0.01%~0.06%, the rest is zinc and unavoidable impurities; The weight ratio of the sum of the In and Nb to the Ti is 2-5:

1.

2. The corrosion-resistant hot-dip galvanized bolt according to claim 1, characterized in that: During the plating assistance, the plating assistance agent includes the following components in parts by weight: 30-40 parts of zinc chloride, 10-15 parts of ammonium chloride, 2-18 parts of potassium titanium oxalate, 3-19 parts of polyacrylamide, 10-16 parts of calcium lignin sulfonate, and 100 parts of water.

3. The corrosion-resistant hot-dip galvanized bolt according to claim 2, characterized in that: The weight ratio of the potassium titanium oxalate to the polyacrylamide is 1-3:

1.

4. The method for preparing a corrosion-resistant hot-dip galvanized bolt according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Melting, casting, cooling and forming the components according to the weight percentage of the bolt body to obtain a bolt blank; S2, heat treating the bolt blank and cold heading it to obtain a semi-finished bolt, and threading the semi-finished bolt to obtain a bolt body; S3, pickling and washing the bolt body, and then placing the bolt body in a plating flux to obtain a plated bolt; S4, placing the bolts after the plating assistance in a zinc solution for hot-dip galvanizing treatment, and then passivating and cooling to obtain hot-dip galvanized bolts.

5. The method for preparing a corrosion-resistant hot-dip galvanized bolt according to claim 4, characterized in that: In step S2, the heat treatment is divided into a first heat treatment and a second heat treatment. During the first heat treatment, the temperature is 850-900°C and the holding time is 60-80 minutes. During the second heat treatment, the temperature is 600-650°C and the holding time is 80-100 minutes.

6. The method for preparing a corrosion-resistant hot-dip galvanized bolt according to claim 4, characterized in that: In step S4, during the hot-dip galvanizing treatment, the temperature of the zinc solution is 430-450° C., and the galvanizing time is 20-30 seconds.

7. The method for preparing a corrosion-resistant hot-dip galvanized bolt according to claim 4, characterized in that: In step S4, during the passivation, the temperature of the passivation solution is 130-170° C., and the passivation time is 8-12 minutes.

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