High-strength high-weather-resistance bolt wire rod, bolt and manufacturing method thereof

Abstract

This invention discloses a high-strength, high-weather-resistant bolt wire rod, which contains Fe and unavoidable impurity elements, and also contains the following chemical elements in the following mass percentages: C: 0.15-0.25%, Si: 0.01-2.0%, Mn: 0.3-2.2%, Cr: 2.5-4.5%, Ni: 0.1-0.4%, Cu: 0.2-0.6%, Al: 0.001-0.1%, Ti: 0.01-0.5%, V: 0.01-0.5%, Re: 0.010-0.045%; and the mass percentages of Cr, C, Ni, and Cu satisfy: Cr / C > 10, Ni / Cu > 0.5. Accordingly, the present invention also discloses a method for manufacturing the above-mentioned high-strength, high-weather-resistant bolt wire rod, comprising the steps of: (1) smelting and casting; (2) heating; (3) wire rolling: high-strength wire rod rolling is performed, with a final rolling temperature of 920–980°C and a high-strength wire drawing temperature of 880–920°C; (4) cooling with a Steyrmore fan. Furthermore, the present invention also discloses a bolt obtained by quenching and tempering the above-mentioned high-strength, high-weather-resistant bolt wire rod.

Description

Technical Field

[0001] This invention relates to a wire rod, a bolt, and a method for manufacturing the same, and more particularly to a high-strength, high-weather-resistant wire rod, a bolt, and a method for manufacturing the same. Background Technology

[0002] As is well known, weathering steel is a low-alloy high-strength steel that exhibits excellent corrosion resistance in the atmosphere by adding small amounts of alloying elements. It has been widely used in bridge structures, transmission towers, photovoltaic supports, and other fields. When trace elements such as phosphorus, copper, chromium, and nickel are added to the steel, an amorphous spinel oxide layer of approximately 50μm to 100μm thick is formed between the rust layer and the substrate. This oxide layer is dense and has good adhesion to the base metal, preventing oxygen and water from penetrating into the steel substrate, slowing down the progression of rust into the steel material, and improving the steel's resistance to atmospheric corrosion.

[0003] Currently, weathering steel typically exhibits atmospheric corrosion resistance 2 to 8 times that of ordinary carbon steel, and its corrosion resistance becomes more pronounced the longer it is used. In addition to its excellent weather resistance, weathering steel also possesses superior mechanical and weldability properties.

[0004] Weathering steel costs about 5% more to manufacture than ordinary steel, but the cost of painting and protecting ordinary steel is three times the difference in manufacturing cost. Considering that the cost of repainting during use is higher than the initial painting cost, it is generally believed that the cost of a weathering steel bridge is far lower than that of an ordinary steel bridge when measured by the total cost over its service life.

[0005] In practical applications, weathering steel is often used to manufacture bolts to extend their service life. Bolt corrosion is a very common phenomenon, causing significant resource waste, and as crucial connecting components, bolt corrosion can seriously compromise structural safety.

[0006] To slow down and control bolt corrosion, prevent bolt material degradation and deterioration, and ensure bolt reliability, safety, and service life, bolts are typically subjected to surface anti-corrosion treatment to improve their corrosion resistance. Surface anti-corrosion treatment refers to applying a protective layer to the metal surface to isolate the metal from the corrosive environment, thereby preventing or inhibiting the corrosion process.

[0007] In current steel structures such as buildings, bridges, and transmission towers, high-strength bolts are primarily used for connection. These bolts generally employ coating methods, such as hot-dip galvanizing, electroplating, and mechanical plating, to achieve corrosion protection. However, high-strength bolts have a large preload torque and significant friction between the threads. The coating itself cannot withstand this high friction, and it is often damaged during bolt preload. This results in a thinner coating, and in severe cases, even exposes the bolt's base material to the service environment, reducing its corrosion resistance.

[0008] Furthermore, surface coating methods require maintenance every 3-5 years and recoating every 10-15 years. This maintenance not only increases costs but also poses health hazards and environmental pollution. Moreover, some coating processes introduce hydrogen sources into the bolts, increasing their hydrogen embrittlement sensitivity, especially for high-strength bolts, and potentially leading to delayed fracture and other safety risks. Therefore, there is an urgent need to develop a high-strength, weather-resistant steel for bolts that can be used without coating.

[0009] Therefore, in order to meet current market demands, this invention aims to develop a new type of high-strength, high-weather-resistant wire rod for bolts, with a strength level of 8.8-10.9 and strong weather resistance. Bolts made from this wire rod can be made without painting, which is of great significance to the development of the bolt industry. Summary of the Invention

[0010] One of the objectives of this invention is to provide a new type of high-strength, high-weather-resistant bolt wire rod. This high-strength, high-weather-resistant bolt wire rod has high strength and high corrosion resistance. Its strength level reaches the requirements of 8.8-10.9, and its atmospheric corrosion resistance meets the requirements for no coating or plating.

[0011] To achieve the above objectives, the present invention provides a high-strength, high-weather-resistant bolt wire rod, which contains Fe and unavoidable impurity elements, and also contains the following chemical elements in the following mass percentages:

[0012] C: 0.15-0.25%, Si: 0.01-2.0%, Mn: 0.3-2.2%, Cr: 2.5-4.5%, Ni: 0.1-0.4%, Cu :0.2-0.6%, Al: 0.001-0.1%, Ti: 0.01-0.5%, V: 0.01-0.5%, Re: 0.010-0.045%;

[0013] Furthermore, the mass percentages of Cr, C, Ni, and Cu satisfy the following conditions: Cr / C > 10, Ni / Cu > 0.5.

[0014] Furthermore, in the high-strength, high-weather-resistant bolt wire rod described in this invention, the mass percentage content of each chemical element is as follows:

[0015] C: 0.15-0.25%, Si: 0.01-2.0%, Mn: 0.3-2.2%, Cr: 2.5-4.5%, Ni: 0.1-0.4%, Cu: 0.2-0.6%, Al: 0.001-0.1%, Ti: 0.01-0.5%, V: 0.01-0.5%, Re: 0.010-0.045%, with the balance being Fe and other unavoidable impurities;

[0016] Furthermore, the mass percentages of Cr, C, Ni, and Cu satisfy the following conditions: Cr / C > 10, Ni / Cu > 0.5.

[0017] The design principles of each chemical element in the high-strength, high-weather-resistant bolt wire rod of the present invention are as follows:

[0018] C: In the high-strength, high-weather-resistant bolt wire rod described in this invention, C is an important element for forming fine, dispersed carbides after quenching and tempering, playing a crucial role in improving the strength of the steel. However, it should be noted that the C content in the steel should not be too high, as excessive C content will affect the material's atmospheric corrosion resistance. Therefore, to ensure that the material of this invention achieves good strength and atmospheric corrosion resistance, the C content in the steel needs to be controlled within a reasonable range. In this invention, the mass percentage of C is specifically controlled between 0.15% and 0.25%.

[0019] Si: In the high-strength, high-weather-resistant bolt wire rod of the present invention, Si has a high solid solubility in steel. Adding an appropriate amount of Si to steel can effectively increase the volume fraction of ferrite and refine the grains, thereby improving the toughness of the steel. Therefore, in order to maximize the beneficial effects of Si, the mass percentage of Si in the high-strength, high-weather-resistant bolt wire rod of the present invention is controlled between 0.01% and 2.0%.

[0020] Mn: In the high-strength, high-weather-resistant bolt wire rod described in this invention, Mn has a strong solid solution strengthening effect and is also an important toughening element. Adding an appropriate amount of Mn to steel can significantly reduce the phase transformation temperature of the steel and refine the microstructure. Based on this, and considering the beneficial effects of Mn, the mass percentage of Mn in the high-strength, high-weather-resistant bolt wire rod described in this invention is controlled between 0.3% and 2.2%.

[0021] Cr: In the high-strength, high-weather-resistant bolt wire rod described in this invention, the presence of Cr significantly accelerates the development of electrochemical corrosion products towards a thermodynamically stable state. In rust layer analysis, Cr can significantly accelerate (Fe... X H Y O ZThe transformation process from α-FeOOH to γ-FeOOH promotes the formation of spinel compounds. Simultaneously, during actual service, Cr in the steel can partially replace Fe to form ferrochromium hydroxide (Cr). X Fe 1-X OOH, thus giving the α-FeOOH rust layer cation selectivity and preventing Cl... - SO4 2- The rust layer penetrates into the substrate surface, thus providing a protective effect. Therefore, in order to maximize the beneficial effects of Cr and ensure a significant improvement in the atmospheric corrosion resistance of steel, the Cr content in the high-strength, high-weather-resistant bolt wire rod described in this invention is controlled between 2.5% and 4.5%.

[0022] Of course, it should be noted that Cr will inevitably combine with C to form precipitated Cr phase. 23 C6, precipitated phase Cr 23 C6 cannot improve the weather resistance of steel. Therefore, in this invention, while controlling the mass percentage of a single chemical element, it is also necessary to further control the Cr and C content in the steel to meet the following condition: Cr / C > 10, so as to ensure that there is enough Cr in the steel to improve weather resistance.

[0023] Ni: In the high-strength, high-weather-resistant bolt wire rod described in this invention, Ni significantly improves the corrosion resistance of the steel and effectively inhibits the formation of copper-rich phases, thereby preventing Cu hot brittleness. However, it should be noted that the Ni content in the steel should not be too high. Excessive Ni content increases the adhesion of oxide scale during the billet heating process and increases the difficulty of pickling and descaling, which can lead to wire rod defects on the surface when pressed into the steel. In addition, excessive Ni content in the steel also increases the cost of the material. Therefore, in the high-strength, high-weather-resistant bolt wire rod described in this invention, the mass percentage of Ni is controlled between 0.1% and 0.4%.

[0024] Cu: In the high-strength, high-weather-resistant bolt wire rod described in this invention, among all alloying elements, Cu has the most significant impact on the material's weather resistance. Adding an appropriate amount of Cu to steel can effectively delay the anodic dissolution of Fe, reduce the electronic conductivity of the rust layer, and decrease the rate at which electrons flow to the cathode region. Simultaneously, Cu in steel can also form small amounts of insoluble copper oxyhydroxide, such as Cu₄(SO₄)(OH)₄ and Cu₄(SO₄)(OH)₄. These compounds can precipitate within the pores of the rust layer and enhance the barrier effect of the corrosion product film. However, it is important to note that the Cu content in the steel should not be too high, as excessive Cu can lead to hot brittleness and increase production difficulty. Therefore, to maximize the beneficial effects of Cu and avoid hot brittleness in the steel, the mass percentage of Cu in the high-strength, high-weather-resistant bolt wire rod described in this invention is controlled between 0.2% and 0.6%.

[0025] Meanwhile, while controlling the mass percentage content of a single chemical element, this invention also controls the Ni and Cu content in the steel to satisfy: Ni / Cu > 0.5, thereby effectively improving the corrosion resistance of the steel and inhibiting the formation of copper-rich phases.

[0026] Al: In the high-strength, high-weather-resistant bolt wire rod described in this invention, Al is a deoxidizer added to the steel, which can play a deoxidizing role. In this invention, the mass percentage content of Al element is controlled between 0.001-0.1%, which is beneficial to refine the grains and improve the strength and toughness of the steel.

[0027] Ti: In the high-strength, high-weather-resistant bolt wire rod described in this invention, Ti can inhibit the growth of austenite grains in the slab during the thermal process, thereby improving the toughness of the steel. Therefore, to maximize the beneficial effects of Ti, the mass percentage of Ti is controlled between 0.01% and 0.5% in this invention.

[0028] V: In the high-strength, high-weather-resistant bolt wire rod described in this invention, vitamin V can effectively refine the grains, reduce the steel's overheat sensitivity and temper brittleness, and improve the steel's strength. However, the vitamin V content in the steel should not be too high, as excessive vitamin V content will increase the material cost. Therefore, in this invention, the mass percentage of vitamin V is controlled between 0.01% and 0.5%.

[0029] Re: In the high-strength, high-weather-resistant bolt wire rod described in this invention, the addition of rare earth elements to the steel can change the composition, morphology, distribution, and properties of inclusions in the steel, thereby improving various properties of the steel. Re is a relatively expensive element, and excessive Re in steel will significantly increase the cost of the material. Considering production costs, in this invention, the mass percentage content of Re is controlled between 0.010-0.045%.

[0030] Furthermore, in the high-strength, high-weather-resistant bolt wire rod described in this invention, among unavoidable impurities, P ≤ 0.012% and S ≤ 0.005%.

[0031] In the high-strength, high-weather-resistant bolt wire rod described in this invention, both P and S elements are impurity elements in steel. When technical conditions permit, in order to obtain steel with better performance and higher quality, the content of impurity elements in steel should be reduced as much as possible.

[0032] S and P: In this invention, the presence of impurity element S will worsen the atmospheric corrosion resistance of steel and lead to hot brittleness. While P can effectively improve the atmospheric corrosion resistance of steel, excessively high P content will significantly reduce the toughness and plasticity of the steel and lead to cold brittleness. Therefore, unless otherwise specified, the content of P and S elements in the steel should be reduced as much as possible, specifically controlling the mass percentage of P to P≤0.012% and the mass percentage of S to S≤0.005%.

[0033] Furthermore, in the high-strength, high-weather-resistant bolt wire rod described in this invention, its microstructure is ferrite + pearlite + bainite.

[0034] Furthermore, in the high-strength, high-weather-resistant bolt wire rod described in this invention, its weather resistance index I > 10, where I = 26.01 × Cu + 3.88 × Ni + 1.20 × Cr + 1.49 × Si + 17.28 × P - 7.29 × Cu × Ni - 9.10 × Ni × P - 33.39 × Cu 2 Substitute the values ​​of each chemical element in the formula into the values ​​preceding the percentage sign.

[0035] In the above technical solution of the present invention, while controlling the mass percentage content of a single chemical element, the present invention can further control the element ratio in the steel. Based on the chemical composition of the above-mentioned high-strength and high-weather-resistant bolt wire rod, the Legault-Leckie empirical formula is used to predict its weather resistance index I > 10.

[0036] It should be noted that for steel, the higher the I value, the higher the atmospheric corrosion resistance of the steel. Generally speaking, materials with a weather resistance index I > 6 have very good atmospheric corrosion resistance.

[0037] Furthermore, in the high-strength, high-weather-resistant bolt wire rod described in this invention, its yield strength is ≥1000MPa, tensile strength is ≥1100MPa, elongation is ≥5%, and reduction of area is ≥12%.

[0038] In addition, another objective of the present invention is to disclose a bolt made from the above-mentioned high-strength and high-weather-resistant bolt wire rod. The bolt made from the high-strength and high-weather-resistant bolt wire rod not only has high strength, but also excellent atmospheric corrosion resistance. It can be applied to bridge structures, transmission towers, photovoltaic supports and other fields without painting, and has good application prospects.

[0039] To achieve the above objectives, the present invention proposes a bolt made from the high-strength, high-weather-resistant bolt wire rod of the present invention after at least tempering treatment. The bolt has a yield strength ≥730MPa, tensile strength ≥880MPa, elongation ≥15%, and reduction of area ≥55%.

[0040] In the above technical solution of the present invention, the finished high-strength and high-weather-resistant bolt wire rod prepared by the present invention can be further processed by downstream users in the specific bolt manufacturing process by pickling, phosphating, drawing, cold heading, heat treatment, thread rolling and other processes to produce high-strength and high-weather-resistant bolts.

[0041] Furthermore, in the bolts described in this invention, insoluble copper hydroxide and ferrochromium hydroxide Cr are generated during service. X Fe 1-X OOH.

[0042] Accordingly, another object of the present invention is to provide a method for manufacturing the above-mentioned high-strength and high-weather-resistant bolt wire rod, which is convenient and simple to implement, and can effectively prepare the high-strength and high-weather-resistant bolt wire rod described in the present invention.

[0043] To achieve the above objectives, the present invention provides a method for manufacturing high-strength, high-weather-resistant bolt wire rod, comprising the following steps:

[0044] (1) Smelting and casting;

[0045] (2) Heating;

[0046] (3) Wire rolling: High wire rolling is carried out, with a final rolling temperature of 920-980℃ and a high wire drawing temperature of 880-920℃;

[0047] (4)Stelmore fan cooling.

[0048] Furthermore, in the manufacturing method described in this invention, in step (2), the steel billet is heated to 1000-1080°C.

[0049] Compared with the prior art, the high-strength, high-weather-resistant bolt wire rod, bolt, and manufacturing method thereof described in this invention have the following advantages and beneficial effects:

[0050] This invention develops a novel high-strength, high-weather-resistant bolt wire rod. Through reasonable component matching and process design, it achieves high strength and excellent weather resistance, meeting the strength requirements of grade 8.8-10.9. Its atmospheric corrosion resistance (weather resistance index I > 10) is sufficient to meet the requirements for coating-free applications. This high-strength, high-weather-resistant bolt wire rod has a yield strength ≥ 1000 MPa, tensile strength ≥ 1100 MPa, elongation ≥ 5%, and reduction of area ≥ 12%.

[0051] Based on the high-strength, high-weather-resistant bolt wire rod of the present invention, downstream users can process this high-strength, high-weather-resistant bolt wire rod into high-performance bolts after processes such as pickling, phosphating, drawing, cold heading, quenching and tempering, and thread rolling. The prepared bolts have a yield strength ≥730MPa, tensile strength ≥880MPa, elongation ≥15%, and reduction of area ≥55%, which can effectively meet the application requirements.

[0052] Bolts made from this high-strength, high-weather-resistant wire rod not only have high strength but also excellent atmospheric corrosion resistance. They can be used in bridge structures, transmission towers, photovoltaic supports, and other fields without painting, which is of great significance to the development of the bolt industry and has good application prospects. Detailed Implementation

[0053] The high-strength, high-weather-resistant bolt wire rod, bolt, and manufacturing method thereof described in this invention will be further explained and described below with reference to specific embodiments. However, this explanation and description do not constitute an improper limitation on the technical solution of this invention.

[0054] Examples 1-6

[0055] Table 1-1 lists the mass percentage of each chemical element in the high-strength, high-weather-resistant bolt wire rods designed in Examples 1-6.

[0056] Table 1-1. (wt%, balance Fe and other unavoidable impurities besides P and S)

[0057]

[0058] Table 1-2 lists the content relationships of some chemical elements in the high-strength, high-weather-resistant bolt wire rods of Examples 1-6.

[0059] Table 1-2.

[0060] serial number Cr / C Ni / Cu I Example 1 23.6 0.52 11.6 Example 2 17.7 0.77 11.4 Example 3 13.1 0.53 10.3 Example 4 20.5 0.73 10.9 Example 5 17.3 0.57 11.1 Example 6 21.4 0.73 10.9

[0061] Note: In Table 1-2 above, the Cr, C, Ni, and Cu in the formulas "Cr / C" and "Ni / Cu" are all substituted with the mass percentage of the corresponding chemical elements; and I = 26.01×Cu + 3.88×Ni + 1.20×Cr + 1.49×Si + 17.28×P - 7.29×Cu×Ni - 9.10×Ni×P - 33.39×Cu 2 Furthermore, each chemical element in the formula is replaced with the value preceding the percentage sign of its corresponding mass percentage content.

[0062] The high-strength, high-weather-resistant bolt wire rods described in Examples 1-6 of this invention are all prepared using the following steps:

[0063] (1) Smelting and casting according to the chemical composition shown in Tables 1-1 and 1-2: Smelting according to the design composition, and casting into 142mm×142mm square billets under protective conditions after the molten steel is calmed.

[0064] (2) Heating: The 142mm×142mm square billet is fed into a heating furnace for heating to 1000~1080℃.

[0065] (3) Wire rolling: The heated billet is output from the heating furnace and rolled into high wire. At the same time, the final rolling temperature is controlled at 920-980℃ and the high wire output temperature is controlled at 880-920℃.

[0066] (4) Steyrmo fan cooling: The Steyrmo line is processed by conventional process and air-cooled by Steyrmo fan to obtain the corresponding φ10~26mm high strength and high weather resistance bolt wire rod.

[0067] The chemical element composition and related process design of the high-strength, high-weather-resistant bolt wire rods in Examples 1-6 of this invention all meet the design specifications of this invention.

[0068] Table 2 lists the specific process parameters for the high-strength, high-weather-resistant bolt wire rods in Examples 1-6 during the above-mentioned process steps.

[0069] Table 2

[0070]

[0071] Samples of the high-strength, high-weather-resistant bolt wire rods of Examples 1-6, obtained after cooling with a Stellmore fan, were taken and observed. The inventors observed that the microstructure of the high-strength, high-weather-resistant bolt wire rods of Examples 1-6 was ferrite + pearlite + bainite.

[0072] Accordingly, after completing the above observations and analyses, the high-strength, high-weather-resistant bolt wire rods of the finished products 1-6 can be sampled again, and relevant mechanical property tests can be performed on the wire rod samples of each embodiment. The mechanical property test results are listed in Table 3.

[0073] The relevant mechanical property testing methods are as follows:

[0074] Tensile test: Under room temperature conditions, according to GBT228-2002 Metallic Materials Room Temperature Tensile Test Method, the yield strength, tensile strength, elongation and reduction of area of ​​the high strength and high weather resistance bolt wire rods of Examples 1-6 were tested.

[0075] Table 3 lists the mechanical property test results of the finished high-strength, high-weather-resistant bolt wire rods of Examples 1-6 obtained after cooling by the Steyrmore fan.

[0076] Table 3.

[0077]

[0078] As shown in Table 3, and in conjunction with Tables 1-2, it can be seen that the high-strength, high-weather-resistant bolt wire rods of Examples 1-6 of the present invention possess excellent corrosion resistance (weather resistance index I between 10.3 and 11.6) while also exhibiting high strength. The atmospheric corrosion resistance of the high-strength, high-weather-resistant bolt wire rods of Examples 1-6 meets the requirements for coating-free operation.

[0079] In this invention, the mechanical properties of the high-strength, high-weather-resistant bolt wire rods of Examples 1-6 are as follows: their yield strength R p0.2 Between 1020-1100 MPa, the tensile strength R m Between 1110-1200 MPa, the elongation A is between 7-9%, and the reduction of area is between 12-15%.

[0080] Accordingly, to further illustrate that the high-strength, high-weather-resistant bolt wire rod prepared by this invention can be further used to produce bolts with excellent performance, downstream users can further process the high-strength, high-weather-resistant bolt wire rods of Examples 1-6 prepared by this invention into high-strength, high-weather-resistant bolts through processes such as pickling, phosphating, drawing, cold heading, tempering, and thread rolling, thereby further processing them into high-strength, high-weather-resistant bolts with excellent performance.

[0081] It should be noted that, in this invention, the inventor designed the following heat treatment process for downstream users: quenching temperature 850℃-930℃, holding temperature for 80 minutes followed by oil quenching; tempering temperature 420-600℃, holding temperature for 1 hour followed by air cooling.

[0082] Accordingly, for the high-strength weather-resistant bolts prepared in Examples 1-6, the inventors conducted mechanical property tests on each bolt, and the test results are listed in Table 4 below. When conducting mechanical property tests on the high-strength weather-resistant bolts prepared in Examples 1-6, the inventors used the same tensile testing method as described in Table 3 above, and will not repeat it here.

[0083] Table 4 lists the mechanical properties of the high-strength weather-resistant bolts prepared in Examples 1-6.

[0084] Table 4.

[0085]

[0086] As shown in Table 4 above, the bolts prepared in Examples 1-6 also have excellent mechanical properties, namely, high strength. Their weather resistance can be inherited from the high-strength, high-weather-resistant bolt wire rods of Examples 1-6, which will not be elaborated here.

[0087] In this invention, the bolts prepared according to Examples 1-6 have a yield strength Rp0.2 between 881-1151 MPa, a tensile strength Rm between 731-1076 MPa, an elongation A between 15-19%, and a reduction of area Z between 60-69%. They have excellent mechanical properties and can be applied to bridge structures, transmission towers, photovoltaic supports, and other fields without painting, showing good application prospects.

[0088] It should be noted that the combination of the technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0089] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A bolt made of a high-strength high-weather-resistance wire rod for a bolt subjected to at least a quenching and tempering treatment, the high-strength high-weather-resistance wire rod for a bolt being characterized by, The mass percentage of each chemical element is: C: 0.15-0.25%, Si: 0.01-2.0%, Mn: 0.3-2.2%, Cr: 2.5-4.5%, Ni: 0.1-0.4%, Cu: 0.2-0.6%, Al: 0.001-0.1%, Ti: 0.01-0.5%, V: 0.01-0.5%, Re: 0.010-0.045%; the balance is Fe and other inevitable impurities; The mass percentage of Cr, C, Ni and Cu satisfies: Cr / C>10, Ni / Cu>0.5; The bolts generate during service insoluble copper hydroxysulfate and chromium iron hydroxyl oxide Cr X Fe 1-X OOH; The yield strength of the bolt is ≥730MPa, the tensile strength is ≥880MPa, the elongation is ≥15%, and the reduction of area is ≥55%.

2. The bolt of claim 1, wherein In the inevitable impurities, P≤0.012%, S≤0.005%.

3. The bolt of claim 1, wherein The high-strength high-weather-resistance bolt wire rod has a microstructure of ferrite+pearlite+beihite.

4. The bolt of claim 1 wherein, The high-strength, high-weather-resistant bolt wire rod has a weathering resistance index I > 10, where I = 26.01 × Cu + 3.88 × Ni + 1.20 × Cr + 1.49 × Si + 17.28 × P - 7.29 × Cu × Ni - 9.10 × Ni × P - 33.39 × Cu 2 Substitute the values ​​of each chemical element in the formula into the values ​​preceding the percentage sign.

5. The bolt of claim 1 wherein, The high-strength high-weather-resistance bolt wire rod has a yield strength of ≥1000MPa, a tensile strength of ≥1100MPa, an elongation of ≥5%, and a reduction of area of ≥12%.

6. The method of manufacturing a bolt according to any one of claims 1 to 5, wherein It comprises the steps of: (1) smelting and casting; (2) heating; (3) wire rod rolling: high wire rolling is carried out, and the finish rolling temperature is 920-980℃, and the high wire wire-drawing temperature is 880-920℃; (4) Stelmor fan cooling to obtain the high-strength high-weather-resistance bolt wire rod; (5) quenching and tempering treatment.

7. The production method according to claim 6, wherein In step (2), the steel billet is heated to 1000-1080℃.

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