A corrosion-resistant anchor bolt and its manufacturing process

Abstract

This invention relates to the field of anchor bolt technology, and proposes a corrosion-resistant anchor bolt and its manufacturing process. The corrosion-resistant anchor bolt is obtained by hot-dip galvanizing and passivation treatment of the anchor bolt body. The anchor bolt body is composed of the following components by weight percentage: Mn 0.55%~0.75%, Mo 0.035%~0.055%, C 0.15%~0.25%, Dy 0.015%~0.035%, V 0.05%~0.25%, Gd 0.025%~0.045%, W 0.01%~0.025%, with the remainder being iron and unavoidable impurities. This technical solution solves the problem of poor mechanical properties in corrosion-resistant anchor bolts in related technologies.

Description

Technical Field

[0001] This invention relates to the field of anchor bolt technology, specifically to a corrosion-resistant anchor bolt and its manufacturing process. Background Technology

[0002] Anchor bolts are tension members that penetrate deep into the ground, primarily used to reinforce soil and rock masses and prevent deformation or collapse. Especially in coal mining, anchor bolts serve as a support measure to ensure roadway stability and safe underground operations. Currently, many mining areas in my country have entered the deep mining stage. With increasing mining depth, the reliability of anchoring systems becomes increasingly important. However, as mining depth increases, the underground working environment becomes more complex, constantly affected by environmental factors such as mine water, surrounding clay, and the mine atmosphere. This leads to more severe corrosion of anchor bolts used to fix roadways, increasing the possibility of anchor bolt failure and posing safety hazards to underground operations. Therefore, corrosion-resistant anchor bolts have emerged. However, currently, corrosion-resistant anchor bolts suffer from poor mechanical properties, making them unsuitable for current working conditions. Improving the mechanical properties of corrosion-resistant anchor bolts is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] This invention proposes a corrosion-resistant anchor bolt and its manufacturing process, which solves the problem of poor mechanical properties of corrosion-resistant anchor bolts in related technologies.

[0004] The technical solution of the present invention is as follows:

[0005] This invention proposes a corrosion-resistant anchor bolt, which is obtained by hot-dip galvanizing and passivation treatment of the anchor bolt body. The anchor bolt body is composed of the following components by weight percentage:

[0006] Mn 0.55%~0.75%, Mo 0.035%~0.055%, C 0.15%~0.25%, Dy 0.015%~0.035%, V 0.05%~0.25%, Gd 0.025%~0.045%, W 0.01%~0.025%, with the remainder being iron and unavoidable impurities.

[0007] As a further technical solution, the weight ratio of Dy and W to Mo is 0.8~1:1.

[0008] When the weight ratio of Dy and W to Mo is 0.8 to 1:1, the mechanical properties of the anchor bolt can be further improved.

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

[0010] This invention also proposes a manufacturing process for corrosion-resistant anchor bolts, comprising the following steps:

[0011] S1. Distribute the ingredients according to the weight percentage, smelt, and cast to obtain a billet;

[0012] S2. After heat treatment, the billet is rolled, drawn, and threaded to obtain the anchor bolt body.

[0013] S3. After pickling, washing, and hot-dip galvanizing, the anchor rod body is passivated and cooled to obtain a corrosion-resistant anchor rod.

[0014] As a further technical solution, in step S3, during the hot-dip galvanizing process, the zinc bath is composed of the following components by weight percentage: Pb 0.1%~0.2%, Sn 0.05%~0.1%, Bi 0.05%~0.1%, Sb 0.03%~0.1%, with the remainder being zinc and unavoidable impurities.

[0015] As a further technical solution, in step S3, the thickness of the zinc coating is 15~20μm during the hot-dip galvanizing process.

[0016] As a further technical solution, in step S3, a passivation solution is used during passivation, and the passivation solution comprises the following components in parts by weight:

[0017] Chromium nitrate 25-35 parts, carboxymethyl dextran 3-18 parts, sodium molybdate 10-15 parts, iminodisuccinic acid 4-11 parts, potassium sodium tartrate 6-10 parts, nano silicon nitride 8-22 parts, water 100 parts.

[0018] The passivation solution includes carboxymethyl dextran and iminodisuccinic acid. By combining carboxymethyl dextran and iminodisuccinic acid in a reasonable manner, the interaction between the passivation solution and the metal ions on the surface of the anchor bolt body can be enhanced, thereby forming a denser and more stable protective film on the surface of the anchor bolt body, which further improves the corrosion resistance of the anchor bolt.

[0019] As a further technical solution, the weight ratio of the carboxymethyl dextran to the iminodisuccinic acid is 1~1.5:1.

[0020] When the weight ratio of carboxymethyl dextran to iminodisuccinic acid is 1~1.5:1, the corrosion resistance of anchor bolts can be further improved by reasonably controlling the content of carboxymethyl dextran and iminodisuccinic acid.

[0021] As a further technical solution, the nano-silicon nitride is modified nano-silicon nitride, and the raw materials for the modified nano-silicon nitride include nano-silicon nitride and ternary hydroxychloroester resin.

[0022] The surface of nano-silicon nitride is modified by using ternary hydroxyl chloride resin, which makes the nano-silicon nitride less prone to agglomeration in the passivation solution and enhances its interaction with carboxymethyl dextran and iminodisuccinic acid. This enhances the passivation effect of the passivation solution on the surface of the anchor bolt body, thereby further improving the corrosion resistance of the anchor bolt.

[0023] As a further technical solution, the preparation method of the modified nano silicon nitride includes the following steps: dissolving the ternary hydroxychloroacetic acid resin in ethyl acetate to obtain a ternary hydroxychloroacetic acid resin solution, adding the nano silicon nitride to the ternary hydroxychloroacetic acid resin solution, dispersing it evenly, and concentrating it to obtain modified nano silicon nitride.

[0024] As a further technical solution, the mass fraction of the ternary hydroxychloroacetic acid resin solution is 5%~10%.

[0025] As a further technical solution, the weight ratio of the nano-silicon nitride to the ternary hydroxyl chloride resin is 9~19:1.

[0026] When the weight ratio of nano-silicon nitride to ternary hydroxyl chloride resin is 9~19:1, the corrosion resistance of the anchor bolt can be further improved.

[0027] As a further technical solution, in step S2, the heat treatment temperature is 1000~1200℃ and the holding time is 30~60min.

[0028] As a further technical solution, in step S2, the rolling process includes rough rolling and finish rolling. During rough rolling, the initial rolling temperature is 900~1000℃; during finish rolling, the initial rolling temperature is 850~950℃.

[0029] As a further technical solution, during passivation, the temperature of the passivation solution is 100~120℃, and the passivation time is 2~5min.

[0030] The working principle and beneficial effects of this invention are as follows:

[0031] In this invention, the anchor bolt body is hot-dip galvanized and passivated to give it excellent corrosion resistance. By optimizing the content of each component in the anchor bolt body, the advantages of each component can be complemented, thereby improving the mechanical properties of the anchor bolt. In particular, the reasonable control of the weight percentages of Dy, W, and Mo, and the appropriate use of these three components, can significantly improve the mechanical properties of the anchor bolt. Detailed Implementation

[0032] 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.

[0033] In the following examples and comparative examples, the manganese content in the ferromanganese alloy is 68 wt%; the molybdenum content in the ferromolybdenum alloy is 60 wt%; the dysprosium iron alloy is 80 wt%; the vanadium iron alloy is 50 wt%; the gadolinium iron alloy is 73 wt%; the ferrotungsten alloy is 80 wt%; the iron content in the scrap steel is 97.6 wt%; the ternary hydroxychlorovinyl acetate resin is TP-500A; the particle size of the nano-silicon nitride is 100 nm; and the thickness of the zinc coating on the corrosion-resistant anchor bolt is 18 μm.

[0034] Example 1

[0035] A corrosion-resistant anchor bolt is obtained by hot-dip galvanizing and passivation of the anchor bolt body. The anchor bolt body is composed of the following components by weight percentage:

[0036] Mn 0.55%, Mo 0.035%, C 0.15%, Dy 0.015%, V 0.05%, Gd 0.025%, W 0.01%, with the remainder being iron and unavoidable impurities;

[0037] During hot-dip galvanizing, the zinc bath consists of the following components by weight percentage: Pb 0.15%, Sn 0.08%, Bi 0.08%, Sb 0.05%, with the remainder being zinc and unavoidable impurities;

[0038] The passivation solution comprises the following components in parts by weight:

[0039] 25 parts chromium nitrate, 10 parts sodium molybdate, 6 parts potassium sodium tartrate, 8 parts nano silicon nitride, 100 parts water;

[0040] The manufacturing process of corrosion-resistant anchor bolts includes the following steps:

[0041] S1. The ferromanganese alloy, ferromolybdenum alloy, dysprosium alloy, ferrovanadium alloy, gadolinium alloy, ferrotungsten alloy, and scrap steel are mixed according to the above weight percentages, smelted, and cast to obtain a billet.

[0042] S2. The billet is heat-treated at 1000℃ and held for 60 minutes. It is then rough-rolled at 900℃, fine-rolled at 850℃, drawn, and threaded to obtain the anchor rod body.

[0043] S3. After pickling, washing, and hot-dip galvanizing, the anchor rod body is passivated in a passivation solution at 120℃ for 2 minutes and then cooled to obtain a corrosion-resistant anchor rod.

[0044] Example 2

[0045] A corrosion-resistant anchor bolt is obtained by hot-dip galvanizing and passivation of the anchor bolt body. The anchor bolt body is composed of the following components by weight percentage:

[0046] Mn 0.6%, Mo 0.054%, C 0.2%, Dy 0.018%, V 0.15%, Gd 0.035%, W 0.018%, with the remainder being iron and unavoidable impurities;

[0047] During hot-dip galvanizing, the zinc bath consists of the following components by weight percentage: Pb 0.15%, Sn 0.08%, Bi 0.08%, Sb 0.05%, with the remainder being zinc and unavoidable impurities;

[0048] The passivation solution comprises the following components in parts by weight:

[0049] 25 parts chromium nitrate, 10 parts sodium molybdate, 6 parts potassium sodium tartrate, 8 parts nano silicon nitride, 100 parts water;

[0050] The manufacturing process of corrosion-resistant anchor bolts includes the following steps:

[0051] S1. The ferromanganese alloy, ferromolybdenum alloy, dysprosium alloy, ferrovanadium alloy, gadolinium alloy, ferrotungsten alloy, and scrap steel are mixed according to the above weight percentages, smelted, and cast to obtain a billet.

[0052] S2. The billet is heat-treated at 1100℃ and held for 45 minutes. It is then rough-rolled at 950℃, fine-rolled at 900℃, drawn, and threaded to obtain the anchor rod body.

[0053] S3. After pickling, washing, and hot-dip galvanizing, the anchor rod body is passivated in a passivation solution at 110℃ for 4 minutes and then cooled to obtain a corrosion-resistant anchor rod.

[0054] Example 3

[0055] A corrosion-resistant anchor bolt is obtained by hot-dip galvanizing and passivation of the anchor bolt body. The anchor bolt body is composed of the following components by weight percentage:

[0056] Mn 0.75%, Mo 0.055%, C 0.25%, Dy 0.035%, V 0.25%, Gd 0.045%, W 0.025%, with the remainder being iron and unavoidable impurities;

[0057] During hot-dip galvanizing, the zinc bath consists of the following components by weight percentage: Pb 0.15%, Sn 0.08%, Bi 0.08%, Sb 0.05%, with the remainder being zinc and unavoidable impurities;

[0058] The passivation solution comprises the following components in parts by weight:

[0059] 25 parts chromium nitrate, 10 parts sodium molybdate, 6 parts potassium sodium tartrate, 8 parts nano silicon nitride, 100 parts water;

[0060] The manufacturing process of corrosion-resistant anchor bolts includes the following steps:

[0061] S1. The ferromanganese alloy, ferromolybdenum alloy, dysprosium alloy, ferrovanadium alloy, gadolinium alloy, ferrotungsten alloy, and scrap steel are mixed according to the above weight percentages, smelted, and cast to obtain a billet.

[0062] S2. The billet is heat-treated at 1200℃ and held for 30 minutes. It is then rough-rolled at 1000℃, fine-rolled at 950℃, drawn, and threaded to obtain the anchor rod body.

[0063] S3. After pickling, washing, and hot-dip galvanizing, the anchor rod body is passivated in a passivation solution at 100℃ for 5 minutes and then cooled to obtain a corrosion-resistant anchor rod.

[0064] Example 4

[0065] The only difference between this embodiment and embodiment 2 is that in this embodiment, the anchor body contains 0.024% Dy by weight, 0.024% W by weight, and 0.042% Mo by weight.

[0066] Example 5

[0067] The only difference between this embodiment and embodiment 2 is that in this embodiment, the anchor body contains 0.02% Dy by weight, 0.02% W by weight, and 0.05% Mo by weight.

[0068] Example 6

[0069] The only difference between this embodiment and embodiment 2 is that in this embodiment, the anchor body contains 0.0225% Dy by weight, 0.0225% W by weight, and 0.045% Mo by weight.

[0070] Example 7

[0071] The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the passivation solution comprises the following components in parts by weight:

[0072] 25 parts chromium nitrate, 7 parts carboxymethyl dextran, 10 parts sodium molybdate, 6 parts potassium sodium tartrate, 8 parts nano silicon nitride, 100 parts water.

[0073] Example 8

[0074] The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the passivation solution comprises the following components in parts by weight:

[0075] 25 parts chromium nitrate, 10 parts sodium molybdate, 7 parts iminodisuccinic acid, 6 parts potassium sodium tartrate, 8 parts nano silicon nitride, 100 parts water.

[0076] Example 9

[0077] The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the passivation solution comprises the following components in parts by weight:

[0078] 25 parts chromium nitrate, 3 parts carboxymethyl dextran, 10 parts sodium molybdate, 4 parts iminodisuccinic acid, 6 parts potassium sodium tartrate, 8 parts nano silicon nitride, 100 parts water.

[0079] Example 10

[0080] The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the passivation solution comprises the following components in parts by weight:

[0081] 30 parts chromium nitrate, 9.5 parts carboxymethyl dextran, 13 parts sodium molybdate, 10.5 parts iminodisuccinic acid, 8 parts potassium sodium tartrate, 20 parts nano silicon nitride, and 100 parts water.

[0082] Example 11

[0083] The only difference between this embodiment and Embodiment 6 is that, in this embodiment, the passivation solution comprises the following components in parts by weight:

[0084] 35 parts chromium nitrate, 18 parts carboxymethyl dextran, 15 parts sodium molybdate, 11 parts iminodisuccinic acid, 10 parts potassium sodium tartrate, 22 parts nano silicon nitride, and 100 parts water.

[0085] Example 12

[0086] The only difference between this embodiment and Embodiment 10 is that in this embodiment, 13 parts of carboxymethyl dextran and 7 parts of iminodisuccinic acid are added to the passivation solution.

[0087] Example 13

[0088] The only difference between this embodiment and Embodiment 10 is that, in this embodiment, 10 parts of carboxymethyl dextran and 10 parts of iminodisuccinic acid are added to the passivation solution.

[0089] Example 14

[0090] The only difference between this embodiment and Embodiment 10 is that in this embodiment, 12 parts of carboxymethyl dextran and 8 parts of iminodisuccinic acid are added to the passivation solution.

[0091] Example 15

[0092] The only difference between this embodiment and Embodiment 14 is that in this embodiment, the nano-silicon nitride is modified nano-silicon nitride. The preparation method of modified nano-silicon nitride includes the following steps: dissolving 3 parts of ternary hydroxychloroacetic acid resin in ethyl acetate to obtain a ternary hydroxychloroacetic acid resin solution with a mass fraction of 6%; adding 17 parts of nano-silicon nitride to the ternary hydroxychloroacetic acid resin solution with a mass fraction of 6%; dispersing evenly; and concentrating to obtain modified nano-silicon nitride.

[0093] Example 16

[0094] The only difference between this embodiment and Embodiment 15 is that in this embodiment, 19.5 parts of nano-silicon nitride and 0.5 parts of ternary hydroxyl chloride resin are added.

[0095] Example 17

[0096] The only difference between this embodiment and Embodiment 15 is that in this embodiment, 19 parts of nano-silicon nitride and 1 part of ternary hydroxychloroacetic acid resin are added.

[0097] Example 18

[0098] The only difference between this embodiment and Embodiment 15 is that in this embodiment, 18 parts of nano-silicon nitride and 2 parts of ternary hydroxychloroacetic acid resin are added.

[0099] Comparative Example 1

[0100] The only difference between this comparative example and Example 1 is that the anchor body in this comparative example does not contain Mo, contains 0.036% Dy by weight, and contains 0.024% W by weight.

[0101] Comparative Example 2

[0102] The only difference between this comparative example and Example 1 is that the anchor body in this comparative example does not contain Dy, and the weight percentage of W is 0.025% and the weight percentage of Mo is 0.035%.

[0103] Comparative Example 3

[0104] The only difference between this comparative example and Example 1 is that the anchor body in this comparative example does not contain W, contains 0.025% Dy by weight, and contains 0.035% Mo by weight.

[0105] Comparative Example 4

[0106] The only difference between this comparative example and Example 1 is that the anchor body in this comparative example does not contain Dy and W, and the weight percentage of Mo is 0.06%.

[0107] Comparative Example 5

[0108] The only difference between this comparative example and Example 1 is that the anchor body in this comparative example does not contain Dy, W and Mo.

[0109] Experimental Example 1: Mechanical Property Testing

[0110] The anchor bodies prepared in Examples 1-6 and Comparative Examples 1-5 were tested for tensile strength and yield strength according to the test methods in GB / T 228.1-2021 "Metallic materials, tensile testing—Part 1: Test at room temperature," with a test speed of 0.006 s. -1 The test result is the average value of 5 samples.

[0111] The test results are shown in Table 1 below:

[0112] Table 1 Test Results

[0113]

[0114] In Table 1, compared with Comparative Examples 1-5, the tensile strength and yield strength of the anchor body prepared in Example 1 are significantly improved, indicating that when the anchor body contains Dy, W, and Mo, reasonable control of the weight percentages of Dy, W, and Mo can significantly improve the mechanical properties of the anchor. Furthermore, compared with Examples 2 and 4, the tensile strength and yield strength of the anchor bodies prepared in Examples 5-6 are improved, indicating that when the weight ratio of Dy and W to Mo is 0.8-1:1, the mechanical properties of the anchor can be further improved.

[0115] Experiment Example 2: Corrosion Resistance Test

[0116] ① The corrosion-resistant anchors prepared in Examples 6 to 18 were subjected to corrosion resistance tests according to the copper accelerated acetic acid salt spray test method in GB / T 10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test". The surface of the sample was observed for rust. The test temperature was 50℃ and the test period was 720h.

[0117] ② The corrosion-resistant anchors prepared in Examples 6 to 18 were subjected to a sodium chloride solution immersion test according to the test method in GB / T 19746-2018 "Corrosion Salt Solution Immersion Test of Metals and Alloys". The test period was 4 weeks. The mass loss of the sample before and after the immersion test was recorded, and the corrosion rate was calculated. The concentration of sodium chloride solution was 35 g / L.

[0118] The test results are shown in Table 2 below:

[0119] Table 2 Test Results

[0120]

[0121] In Table 2, compared with Examples 6-8, the anchor bolts prepared in Examples 9-14 showed no rust after the acetic acid salt spray test. However, after a circumferential immersion test, the corrosion resistance rate of the anchor bolts decreased significantly. This indicates that the addition of carboxymethyl dextran and iminodisuccinic acid to the passivation solution has a synergistic effect, further improving the corrosion resistance of the anchor bolts. Compared with Examples 10-12, the anchor bolts prepared in Examples 13-14 showed no rust after the acetic acid salt spray test. However, after a circumferential immersion test, the corrosion resistance rate of the anchor bolts decreased significantly. This indicates that when the weight ratio of carboxymethyl dextran to iminodisuccinic acid is 1-1.5:1, the corrosion resistance of the anchor bolts can be further improved. Furthermore, compared to Example 14, the anchor bolts prepared in Examples 15-18 showed no rust after acetic acid salt spray testing. However, the corrosion rate decreased after circumferential immersion testing, indicating that surface modification of nano-silicon nitride with ternary hydroxyl chloride resin can further improve the corrosion resistance of the anchor bolts. Compared to Examples 15-16, the anchor bolts prepared in Examples 17-18 showed no rust after acetic acid salt spray testing. However, the corrosion rate decreased after circumferential immersion testing, indicating that a weight ratio of nano-silicon nitride to ternary hydroxyl chloride resin of 9-19:1 can further improve the corrosion resistance of the anchor bolts.

[0122] 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 corrosion-resistant anchor bolt, obtained by hot-dip galvanizing and passivation treatment of the anchor bolt body, characterized in that, The anchor body is composed of the following components by weight percentage: Mn 0.55%~0.75%, Mo 0.035%~0.055%, C 0.15%~0.25%, Dy 0.015%~0.035%, V 0.05%~0.25%, Gd 0.025%~0.045%, W 0.01%~0.025%, with the remainder being iron and unavoidable impurities; During passivation, a passivation solution is used, which comprises the following components in parts by weight: Chromium nitrate 25-35 parts, carboxymethyl dextran 3-18 parts, sodium molybdate 10-15 parts, iminodisuccinic acid 4-11 parts, potassium sodium tartrate 6-10 parts, nano silicon nitride 8-22 parts, water 100 parts. The nano-silicon nitride is modified nano-silicon nitride, and the raw materials for the modified nano-silicon nitride include nano-silicon nitride and ternary hydroxyl chloride resin. The method for preparing the modified nano-silicon nitride includes the following steps: dissolving the ternary hydroxychloroacetic acid resin in ethyl acetate to obtain a ternary hydroxychloroacetic acid resin solution, adding the nano-silicon nitride to the ternary hydroxychloroacetic acid resin solution, dispersing it evenly, and concentrating it to obtain the modified nano-silicon nitride.

2. The corrosion-resistant anchor bolt according to claim 1, characterized in that, The weight ratio of Dy and W to Mo is 0.8 to 1:

1.

3. The corrosion-resistant anchor bolt according to claim 1, characterized in that, The weight ratio of Dy to W is 1:

1.

4. The corrosion-resistant anchor bolt according to claim 1, characterized in that, The weight ratio of the carboxymethyl dextran to the iminodisuccinic acid is 1~1.5:

1.

5. A corrosion-resistant anchor bolt according to claim 1, characterized in that, The weight ratio of the nano-silicon nitride to the ternary hydroxyl chloride resin is 9~19:

1.

6. The manufacturing process of a corrosion-resistant anchor bolt according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Distribute the ingredients according to the weight percentage, smelt, and cast to obtain a billet; S2. After heat treatment, the billet is rolled, drawn, and threaded to obtain the anchor bolt body. S3. After pickling, washing, and hot-dip galvanizing, the anchor rod body is passivated and cooled to obtain a corrosion-resistant anchor rod.

7. The manufacturing process of a corrosion-resistant anchor bolt according to claim 6, characterized in that, In step S2, the heat treatment is performed at a temperature of 1000~1200℃ and a holding time of 30~60min.

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