Corrosion-resistant pipe-joint anchor rod and method for manufacturing the same

Abstract

The application discloses a kind of corrosion-resistant pipe joint type anchor rod and preparation method thereof, preparation method includes the following steps: S1.steel band is bent into shape by cold bending forming agent, and cut, form the main body of pipe joint type anchor rod;S2.in the end of main body by automatic welding machine welding steel ring, make pipe joint type anchor rod;S3.pipe joint type anchor rod is carried out shot blasting treatment, and the rust removal grade of pipe joint type anchor rod reaches Sa3 grade;S4.pipe joint type anchor rod is carried out zinc infiltration treatment, and the infiltrant is added to the zinc infiltration furnace with pipe joint type anchor rod, and add infiltrant, so that the temperature in zinc infiltration furnace keeps at 395-405 DEG C, and keeps warm;S5.after pipe joint type anchor rod is infiltrated with zinc, it is passivated, and passivated with alkaline passivation solution, and the surface of pipe joint type anchor rod is passivated to form dense metal film.The pipe joint type anchor rod prepared by the application has very good corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipe slot anchor rod, in particular to a corrosion-resistant pipe slot anchor rod and a preparation method thereof. BACKGROUND

[0002] The pipe slot anchor rod (hereinafter referred to as anchor rod) is a new type of anchor rod with full-length anchoring and active reinforcement of surrounding rock. The three-dimensional part is a longitudinally slotted high-strength steel pipe. When installed in a borehole slightly smaller than the pipe diameter, it can immediately exert radial pressure on the borehole wall and friction force to prevent the surrounding rock from sliding, plus the support force of the anchor rod tray, so that the surrounding rock is in a three-way stress state and the rock stability is achieved. In the case of blasting vibration of surrounding rock and anchor displacement, the post-anchoring force increases significantly, and when the surrounding rock has significant displacement, the anchor rod does not lose its support resistance. It has better properties than the expansion shell anchor rod.

[0003] The service life of the anchor rod depends on its durability, and the biggest threat to the service life of the anchor rod comes from corrosion. According to the results of current technical research, the corrosion of steel anchor rod in the stratum has four types: chemical corrosion, electrochemical corrosion, high stress corrosion and stray current corrosion, among which electrochemical corrosion and stray current corrosion are the main ones, which are mainly caused by the contact of corrosion media such as acidity and alkalinity and conductivity in the stratum with the outer surface of the anchor rod through underground water and air. The corrosion prevention of the anchor rod is to take isolation and insulation measures to make the water and air existing in the stratum or rock fissures as little as possible to contact the anchor rod body. The conventional isolation methods include grouting wrapping protection, anchor rod coating (resin) plating (zinc) method, casing isolation method, etc.

[0004] The applicant's city of Laizhou is rich in gold resources, and the gold mine near Sanshan Island is adjacent to Laizhou Bay. The chemical composition of the groundwater in the sea area and the nearby underground water is similar to that of seawater, which has moderate corrosiveness to steel structures and weak corrosiveness to steel bars in reinforced concrete. The corrosion of ordinary anchor rods in this case is more serious. To solve this technical problem, the applicant has carried out research on corrosion-resistant pipe slot anchor rods and their preparation methods, and thus the present application is obtained.

[0005] Chinese patent document CN115434739A discloses a tunnel combined anchor rod and a surface corrosion prevention treatment method thereof. The content of each element in the multi-element powder co-diffusion agent is as follows: Al accounts for 0.1-6%, Mg accounts for 0-0.3%, Ni accounts for 0-5%, rare earth accounts for 0.05-0.7%, and the balance is zinc. Zn, Ni, Al, and Mg in the co-diffusion agent are obtained from zinc powder, ZnAl 15 , Al Mg5, and NiAl 20The alloy powder is provided, the permeation aid includes 60%-75% of NH4Cl, and the passivation liquid is selected from one or more of a chromium-free environment-friendly water-based passivation liquid, a two-component polyurethane finish, a water-based polyurethane finish and a water-based epoxy finish. The essence is to form a dense and uniform zinc-iron alloy permeation layer containing Zn, Ni, Al, Mg and rare earth elements on the surface layer of the anchor rod body, so as to improve the corrosion resistance of the surface of the anchor rod. The surface corrosion protection treatment method includes multi-element powder furnace material co-permeation, spraying or immersion of the passivation liquid on the surface of the anchor rod, and formation of a co-permeation layer and a passivation layer. After the anchor rod is treated by the surface corrosion protection treatment method, a multi-layer corrosion protection layer (co-permeation layer + passivation layer + mortar layer) is formed, so that the anchor rod has good durability in the surrounding rock and achieves the purpose of long-term support.

[0006] However, there is still room for improvement. SUMMARY

[0007] Therefore, in order to solve the above technical problems, the purpose of the present application is to provide a corrosion-resistant tubular slot anchor rod and a preparation method thereof.

[0008] The technical scheme adopted is as follows:

[0009] The preparation method of the corrosion-resistant tubular slot anchor rod comprises the following steps:

[0010] S1. The steel strip is bent and formed by a cold bending forming agent, and is cut off to form a main body of the tubular slot anchor rod;

[0011] S2. A steel ring is welded on the end of the main body by an automatic welding machine to form the tubular slot anchor rod;

[0012] S3. The tubular slot anchor rod is subjected to shot blasting treatment, so that the rust removal level of the surface of the tubular slot anchor rod reaches Sa3 level;

[0013] S4. The tubular slot anchor rod is subjected to zinc permeation treatment, a permeation aid is added to a zinc permeation furnace provided with the tubular slot anchor rod, a permeation aid is added, the temperature in the zinc permeation furnace is kept at 395-405 DEG C, and the temperature is kept constant;

[0014] S5. The tubular slot anchor rod after zinc permeation is subjected to passivation treatment, and is passivated by an alkaline passivation liquid to form a dense metal film on the surface of the tubular slot anchor rod.

[0015] Further, in S4, the permeation aid consists of the following components and contents by weight parts: zinc powder 40-50 parts, aluminum oxide 20-25 parts, rare earth cerium oxide 4-7 parts, magnesium oxide 1-2 parts, nickel powder 2-4 parts and graphene 6-8 parts; and the permeation aid is ammonium chloride and zinc chloride.

[0016] Further, in S4, the penetrant is added into the zinc infiltration furnace at a ratio of 20 kg / T, and the weight ratio of the penetrant to the penetration aid is 1:0.1-0.3.

[0017] Further, in S4, the furnace is kept for 4-5 hours before the pipe slot anchor is taken out.

[0018] Further, in S4, after being kept for 4-5 hours, the furnace is stopped when the furnace temperature is reduced to 300 DEG C, and the pipe slot anchor after zinc infiltration is taken out when the temperature is reduced to 60-100 DEG C.

[0019] Further, in S5, the pH of the alkaline passivation solution is 10-12, the temperature of the alkaline passivation solution is 5-35 DEG C, and the time is greater than 60 seconds.

[0020] Further, in S5, before the passivation treatment is performed, spraying cleaning is performed, and the spraying cleaning time is greater than 10 minutes.

[0021] Further, S6 is further included, that is, the pipe slot anchor after passivation is painted.

[0022] Further, in S6, the paint used is water-based polyurethane topcoat.

[0023] The corrosion-resistant pipe slot anchor is prepared by the preparation method in any one of the above-mentioned schemes.

[0024] In the above technical scheme,

[0025] Zinc infiltration is a ferrite state chemical heat treatment. It is prepared by taking the penetrant as raw material and adding the penetration aid, the penetrant is composed of zinc powder, aluminum oxide, rare earth cerium oxide, magnesium oxide and nickel powder, the penetration aid is ammonium chloride and zinc chloride, and the pipe slot anchor is the infiltrated piece, in the rotating zinc infiltration furnace, through a very complex physical and chemical reaction process, Zn, Ni, Al, Mg and Ce are uniformly diffused and infiltrated into the surface layer of the pipe slot anchor, and graphene is covered on the surface layer, so that the composition, organization and structure of the surface layer of the pipe slot anchor are changed, a dense and uniform intermetallic compound layer containing Zn, Ni, Al, Mg and Ce, that is, a zinc-iron alloy infiltration layer covered with graphene, is formed on the surface layer of the pipe slot anchor, and a graphene-metal composite layer is formed.

[0026] Graphene is a new material in which carbon atoms connected in a hybrid manner are tightly packed into a single-layer two-dimensional honeycomb lattice structure. 2 In the chemical heat treatment, graphene can form a graphene-metal layer with the metal, and the graphene is partially left on the surface layer of the pipe slot anchor due to the penetration of the metal. Graphene can greatly enhance the corrosion resistance of the pipe slot anchor.

[0027] Nickel can improve the mechanical properties of slotted pipe anchors, giving them higher strength, hardness, and toughness. It can also enhance corrosion resistance, making them more resistant to corrosion in harsh environments.

[0028] The role of cerium is to stabilize the structural phase of the zinc-iron alloy diffusion layer in slotted anchor bolts, thereby improving the service life of slotted anchor bolts.

[0029] Compared with electro-galvanizing and hot-dip galvanizing, the advantages of zinc diffusion process are:

[0030] It has good wear resistance and scratch resistance. The surface hardness of the zinc-plated layer can reach Hv250-400, while the surface of hot-dip galvanized parts is pure zinc, and the coating hardness is only about Hv70. Therefore, zinc-plated parts have much better wear resistance and scratch resistance than hot-dip galvanized parts.

[0031] Production is virtually pollution-free. Under normal circumstances, the pretreatment for zinc diffusion production only involves shot blasting for rust removal and oil cleaning, along with baghouse dust collection, meeting the national Class III standard. Gas is the primary energy source during production, employing a circulating combustion system with smokeless emissions.

[0032] Powder zinc diffusion technology is a solid zinc diffusion process that does not generate zinc vapor. The workpiece (slotted anchor rod) and the diffusion agent and diffusion aid are diffused and separated in a closed apparatus (zinc diffusion furnace), which does not pollute the surrounding environment.

[0033] Zinc consumption is relatively low. It is understood that hot-dip galvanizing consumes approximately 100 kg of zinc per ton of product, while powder zinc infiltration consumes only about 30 kg, accounting for only 30% of hot-dip galvanizing. Furthermore, it avoids the long-standing problem of zinc pot corrosion in hot-dip galvanizing.

[0034] Zinc-dip galvanizing does not affect the mechanical properties of steel components. The zinc-dip galvanizing temperature is 100–280°C lower than hot-dip galvanizing, at which temperature hydrogen atoms absorbed into the steel matrix have diffused and escaped. Therefore, there is no risk of hydrogen embrittlement in application, and it also avoids the drawback of decreased mechanical properties in high-strength components such as springs due to high processing temperatures.

[0035] The beneficial effects of this invention are as follows:

[0036] The prepared slotted anchor bolts have excellent corrosion resistance. After testing, they remained rust-free for more than 1,600 days of corrosion. Attached Figure Description

[0037] Figure 1 This is a process flow diagram of a method for preparing a corrosion-resistant slotted pipe anchor. Detailed Implementation

[0038] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0039] Embodiment 1

[0040] Referring to Figure 1 As shown in the figure, a preparation method of a corrosion-resistant pipe-joint anchor rod comprises the following steps:

[0041] S1. After the steel strip is fed, the steel strip is bent and formed by a cold bending forming agent, and cut off to form a main body of the pipe-joint anchor rod;

[0042] S2. A steel ring is welded at the end of the main body by an automatic welding machine to make the pipe-joint anchor rod;

[0043] S3. The pipe-joint anchor rod is subjected to shot blasting treatment to make the rust removal level of the surface of the pipe-joint anchor rod reach Sa3 level. The surface cleanliness Sa3 level, under the condition of not magnifying, the surface should have uniform metal luster. The shot blasting is carried out in a shot blasting machine. The shot blasting machine is to impact the surface of the pipe-joint anchor rod by high-speed throwing of the steel sand (steel shot) by a shot blasting device to remove the rust on the surface.

[0044] S4. The pipe-joint anchor rod is subjected to zinc infiltration treatment. The infiltrant is added to a zinc infiltration furnace in which the pipe-joint anchor rod is placed, and a permeation aid is added, so that the temperature in the zinc infiltration furnace is kept at 395-405℃. Specifically, when the temperature of the furnace reaches 395℃, the timing and heat preservation are started. The hearth temperature is controlled to keep the temperature of the furnace at 395-405℃, and the heat preservation is kept for 4-5 hours, while the zinc infiltration furnace is rotating, and the rotating speed is 30-40r / min. The infiltrant consists of the following components and contents by weight parts: zinc powder 45 parts, aluminum oxide 22 parts, rare earth cerium oxide 4 parts, magnesium oxide 1 part, nickel powder 2 parts, and graphene 7 parts; the permeation aid is ammonium chloride and zinc chloride. The infiltrant is added to the zinc infiltration furnace in a ratio of 20kg / T relative to the infiltrated piece (pipe-joint anchor rod), and the weight ratio of the infiltrant to the permeation aid is 1:0.2. When the furnace temperature decreases to 300℃, the furnace body stops rotating, and when the temperature decreases to 60-100℃, the pipe-joint anchor rod after zinc infiltration is taken out of the furnace.

[0045] S5. The workpiece (zinc-penetrated tubular anchor rod) is conveyed by a chain to an automatic spray cleaning area, and the spray time is > 10 minutes to remove surface dust and residual penetrant, and then moved to a passivation area. The zinc-penetrated tubular anchor rod is then subjected to passivation treatment with an alkaline passivation liquid to passivate the surface of the tubular anchor rod to form a dense metal film. The pH of the alkaline passivation liquid is 10-12, the temperature of the alkaline passivation liquid is 25℃, and the time is > 60S. After passivation, the tubular anchor rod is conveyed by a chain to an automatic spray cleaning area, and the tubular anchor rod is sprayed to remove residual passivation liquid.

[0046] S6. The passivated tubular anchor rod is subjected to painting. The paint used is water-based polyurethane topcoat. After painting, composite protection is achieved. The zinc-penetrated layer of the zinc-penetrated product is uniform and has a first-class bonding force with the paint, and the corrosion resistance of the composite protective layer is better than that of hot-dip galvanizing, electroplating zinc, and zinc-penetrated layer.

[0047] Example 2

[0048] With reference to Example 1, different from Example 1, the penetrant of the present example is composed of the following components and contents by weight parts: zinc powder 40 parts, aluminum oxide 20 parts, rare earth cerium oxide 4 parts, magnesium oxide 1 part, nickel powder 2 parts, and graphene 6 parts.

[0049] Example 3

[0050] With reference to Example 1, different from Example 1, the penetrant of the present example is composed of the following components and contents by weight parts: zinc powder 50 parts, aluminum oxide 25 parts, rare earth cerium oxide 7 parts, magnesium oxide 2 parts, nickel powder 4 parts, and graphene 8 parts.

[0051] Comparative Example 1

[0052] With reference to Example 1, different from Example 1, the penetrant of the present example is composed of the following components and contents by weight parts: zinc powder 52 parts, aluminum oxide 22 parts, rare earth cerium oxide 4 parts, magnesium oxide 1 part, and nickel powder 2 parts. That is, the comparative example does not add graphene.

[0053] The workpieces (corrosion-resistant tubular anchor rods) obtained in Examples 1-3 and the comparative example were subjected to salt spray tests, and the results are shown in Table 1.

[0054] Table 1

[0055]

[0056] It can be seen that the workpieces obtained in Examples 1-3 can meet the corrosion resistance requirements in a salt spray environment.

[0057] The workpiece of Example 1-3 (corrosion-resistant pipe-joint anchor) was corroded for 1615 days, and the surface was still free of rust.

[0058] The above detailed description is only a specific description of the feasible embodiments of the present application, and is not intended to limit the protection scope of the present application. Any equivalent embodiments or changes made without departing from the spirit of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a corrosion-resistant slotted pipe anchor, characterized in that, Includes the following steps: S1. The steel strip is bent into shape by a cold bending forming machine and then cut to form the main body of the slotted anchor bolt; S2. Steel rings are welded to the ends of the main body using an automatic welding machine to form a slotted anchor bolt; S3. The slotted pipe anchor bolts are shot blasted to achieve a surface rust removal grade of Sa3. S4. The slotted anchor bolts are subjected to zinc diffusion treatment. The diffusion agent is added to the zinc diffusion furnace containing the slotted anchor bolts, and a diffusion aid is added to maintain the temperature inside the zinc diffusion furnace at 395-405℃. The diffusion agent, by weight, consists of the following components and contents: 40-50 parts zinc powder, 20-25 parts alumina, 4-7 parts cerium oxide, 1-2 parts magnesium oxide, 2-4 parts nickel powder, and 6-8 parts graphene. The diffusion aid is ammonium chloride and zinc chloride. The diffusion agent is added to the zinc diffusion furnace at a ratio of 20 kg / t, and the weight ratio of the diffusion agent to the diffusion aid is 1:(0.1-0.3). S5. Passivate the zinc-distilled slotted anchor rods by using an alkaline passivation solution to passivate the surface of the slotted anchor rods and form a dense metal film.

2. The method for preparing corrosion-resistant slotted anchor bolts according to claim 1, characterized in that, In S4, keep warm for 4-5 hours before removing from the oven.

3. The method for preparing corrosion-resistant slotted anchor bolts according to claim 2, characterized in that, In S4, after holding the temperature for 4-5 hours, the furnace is stopped when the furnace temperature drops to 300℃. When the temperature drops to 60-100℃, the zinc-treated slotted anchor rods are taken out of the furnace.

4. The method for preparing corrosion-resistant slotted anchor bolts according to claim 1, characterized in that, In S5, the pH of the alkaline passivation solution is 10-12, the temperature of the alkaline passivation solution is 5-35℃, and the time is greater than 60s.

5. The method for preparing corrosion-resistant slotted anchor bolts according to claim 1, characterized in that, In S5, before passivation, a spray cleaning process is performed for more than 10 minutes.

6. The method for preparing corrosion-resistant slotted anchor bolts according to claim 1, characterized in that, It also includes S6. Painting the passivated slotted anchor bolt.

7. The method for preparing corrosion-resistant slotted anchor bolts according to claim 6, characterized in that, In S6, the paint used is a water-based polyurethane topcoat.

8. A corrosion-resistant slotted pipe anchor, characterized in that, It is prepared by any of the preparation methods described in claims 1-7.

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