Wire rod and steel wire for high-toughness sorbite bridge cable and manufacturing method of wire rod and steel wire

Abstract

The invention discloses a wire rod for a high-strength and high-toughness sorbite bridge cable, which contains Fe and inevitable impurities, and further contains the following chemical elements in percentage by mass: 0.70 to 1.10 percent of C, 0.30 to 2.00 percent of Si, 0.30 to 0.90 percent of Mn, 0.30 to 0.90 percent of Cr, 0.01 to 0.30 percent of Mo, 0.01 to 0.30 percent of Ni, 0.01 to 0.50 percent of Cu and 0.01 to 0.20 percent of Al. Wherein the chemical elements also meet the following condition: 1.56 < = [C] + 0.8 [Mn] + [Cr] + 0.7 [Mo] + 1.1 [Ni] + 0.5 [Cu] < = 2.03, wherein [C], [Mn], [Cr], [Mo], [Ni] and [Cu] are respectively substituted into numerical values before the mass percentage of each chemical element.

Description

Technical Field

[0001] This invention relates to a type of steel and its preparation method, and more particularly to a cable wire rod, steel wire and its preparation method. Background Technology

[0002] As bridges develop towards ultra-long spans, the requirements for bridge construction are also increasing. The research and application of higher-strength hot-dip galvanized steel wire has become a development trend for bridge cable wires. For example, in suspension bridges... Hot-dip galvanized steel wire requires a tensile strength of 2160 MPa for use in cable-stayed bridges. The tensile strength requirement for hot-dip galvanized steel wire is 2100MPa or even higher.

[0003] Therefore, achieving ultra-high strength with limited cold drawing deformation is becoming the future development trend for steel wires used in bridge cables. For example:

[0004] Chinese patent document CN110066963A, published on July 30, 2019, entitled "A 2000MPa Grade Galvanized Steel Wire for Bridge Cables and Its Manufacturing Method," discloses a 2000MPa grade galvanized steel wire for bridge cables and its manufacturing method. The chemical composition of the steel wire is: C = 0.88-0.94%, Si = 1.05-1.35%, Mn = 0.40-0.50%, Cr = 0.25-0.35%, Cu ≤ 0.07%, with the balance being Fe and unavoidable impurities. It also includes any one or more of B = 0.0005-0.0015%, Nb = 0.01-0.03%, and Mo = 0.01-0.03%. The produced galvanized steel wire can achieve a tensile strength of over 2000MPa and a torsion value of not less than 18 turns.

[0005] The publication number is CN112458356A, the publication date is March 9, 2021, and the title is "A galvanized steel wire for 1860MPa grade bridge cables". "Wire Rod and Preparation Method" discloses a galvanized steel wire for bridge cables with a strength of 1860MPa. The wire rod and its preparation method are described. The chemical composition of the steel wire is as follows: C = 0.84-0.88%, Si = 0.15-0.25%, Mn = 0.65-0.80%, Cr = 0.35-0.45%, P ≤ 0.015%, S ≤ 0.010%, Al ≤ 0.005%. After drawing and galvanizing, the finished steel wire has a strength higher than 1860MPa, a torsion value ≥ 17 times, and the core network cementite level can be guaranteed to be ≤ 1.0 grade, the decarburization depth can be guaranteed to be ≤ 0.7%D, the sorbitization rate can reach more than 95%, and the pearlite lamellar spacing can be guaranteed to be 100-150nm. Summary of the Invention

[0006] One of the objectives of this invention is to provide a high-strength and high-toughness sorbitic bridge cable wire rod. This high-strength and high-toughness sorbitic bridge cable wire rod achieves precise control of the material's microstructure and properties through optimized design of chemical composition and thorough study of the content ratio of key elements C, Mn, Cr, Mo, Ni, and Cu on the sorbitic phase transformation temperature, phase transformation time, and microstructure properties. It also has significant advantages in fatigue resistance and relaxation resistance.

[0007] To achieve the above objectives, the present invention provides a high-strength and high-toughness sorbitic bridge cable wire rod, which contains Fe and unavoidable impurities, and also contains the following chemical elements in the following mass percentages:

[0008] C: 0.70~1.10wt.%, Si: 0.30~2.00wt.%, Mn: 0.30~0.90wt.%, Cr: 0.30~0.90wt.%, Mo: 0.01 to 0.30wt.%, Ni: 0.01 to 0.30wt.%, Cu: 0.01 to 0.50wt.%, Al: 0.01 to 0.20wt.%.

[0009] The chemical elements also satisfy the following condition: 1.56≤[C]+0.8[Mn]+[Cr]+0.7[Mo]+1.1[Ni]+0.5[Cu]≤2.03, where [C], [Mn], [Cr], [Mo], [Ni], and [Cu] are respectively substituted with the values ​​before the mass percentage sign of each chemical element.

[0010] Furthermore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the mass percentage content of each chemical element is as follows:

[0011] C: 0.70–1.10 wt.%, Si: 0.30–2.00 wt.%, Mn: 0.30–0.90 wt.%, Cr: 0.30–0.90 wt.%, Mo: 0.01–0.30 wt.%, Ni: 0.01–0.30 wt.%, Cu: 0.01–0.50 wt.%, Al: 0.01–0.20 wt.%; balance Fe and unavoidable impurities.

[0012] In this invention, considering the influence of the composite addition of C, Mn, Cr, Mo, Ni, and Cu on the sorbite phase transformation during the rolling and cooling process of wire rod, by controlling 1.56≤[C]+0.8[Mn]+[Cr]+0.7[Mo]+1.1[Ni]+0.5[Cu]≤2.03, the sorbite phase transformation temperature of the wire rod can be ensured to be between 510 and 560℃, and the phase transformation start time can be between 40 and 60s, thereby achieving precise control of the sorbite structure and improving its strength and plasticity.

[0013] The design principles of each chemical element in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention are as follows:

[0014] C: In the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, carbon (C) is an essential chemical component for ensuring the strength of the steel. Increasing the C content in the steel is beneficial for forming more cementite lamellars and a refined sorbitic lamellar structure, thereby giving the steel better deformation and work hardening properties, which is beneficial for improving the strength of the steel wire during subsequent processing. Under this alloy composition system, when the C content in the wire rod is less than 0.70%, the strength of the material will not meet the design requirements. However, when the carbon content in the steel is too high, it will lead to increased component segregation during alloy solidification and deterioration of the material's toughness. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the mass percentage of C is controlled between 0.70 and 1.10 wt.%.

[0015] Si: In the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, Si is often added to the steel as a deoxidizer during the smelting process. Simultaneously, Si dissolved in the ferrite phase significantly improves the strength of the steel. Furthermore, during the cooling phase transformation process, Si accumulates at the interface between the ferrite and cementite phases. After the steel wire is drawn with a large reduction in surface area, degreasing in a lead bath and hot-dip galvanizing, the accumulation of Si at the phase interface slows down the decomposition of the cementite lamellars under large deformation, thereby effectively reducing the strength loss of the steel. However, when the Si content in the steel is too high, it will significantly reduce the plasticity of the steel, causing the material to become brittle. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the mass percentage of Si is controlled between 0.30 and 2.00 wt.%.

[0016] Mn: In the high-strength and high-toughness sorbitic bridge cable wire rod of the present invention, Mn is added to the steel as a deoxidizer during the steelmaking process. Simultaneously, Mn readily combines with sulfur (S), a harmful element in steel, to form MnS, thereby reducing its harmful effects. Furthermore, Mn is also a commonly used strengthening element in steel, primarily playing a role in solid solution strengthening, resulting in alloy cementite with higher strength. However, the Mn content in the steel should not be too high. Excessive Mn content increases the tendency for grain coarsening during heating, making controlled cooling microstructure control more difficult. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod of the present invention, the mass percentage of Mn is controlled between 0.30 and 0.90 wt.%.

[0017] Cr: In the high-strength and high-toughness sorbitic bridge cable wire rod of the present invention, the addition of Cr element is beneficial to refining the lamellar structure of the sorbitic microstructure of the steel, while improving the strength of cementite, thereby effectively improving the strength and plasticity of the material. To ensure that Cr element can effectively exert its benefits, the Cr element content in the steel needs to be higher than 0.30%. Correspondingly, to prevent the occurrence of abnormal martensitic microstructure and reduce the difficulty of microstructure control, the Cr element content in the steel needs to be controlled below 0.90%. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod of the present invention, the mass percentage content of Cr element is controlled between 0.30 and 0.90 wt.%.

[0018] Mo, Ni, Cu: In the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, Mo, Ni, and Cu elements can stabilize the supercooled austenitic phase, which is beneficial for increasing the content of sorbite and troostite phases in the wire rod and reducing the lamellar spacing, thereby improving strength and plasticity. The effect is even better when Mo, Ni, and Cu are added in combination. However, adding too much Mo, Ni, and Cu elements increases cost and easily leads to abnormal martensitic structures. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the mass percentage of Mo is controlled between 0.01 and 0.30 wt%, the mass percentage of Ni is controlled between 0.01 and 0.30 wt.%, and the mass percentage of Cu is controlled between 0.01 and 0.50 wt.%.

[0019] Al: In the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, Al is a deoxidizer, and its deoxidizing ability is much stronger than that of Si and Mn. Simultaneously, Al is an effective element for adjusting the grain size of steel; during solidification, a large amount of finely dispersed alumina can promote the formation of fine-grained steel. However, when the Mn content in the steel is too high, the coarse alumina will severely reduce the drawing and fatigue properties of the wire rod and galvanized steel wire. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the mass percentage of Al is controlled between 0.01 and 0.20 wt.%.

[0020] Furthermore, the high-strength and high-toughness sorbitic bridge cable wire rod of the present invention also contains at least one of the following chemical elements:

[0021] 0 < Ti ≤ 0.30 wt.%;

[0022] 0 < Nb ≤ 0.10 wt.%;

[0023] 0 < V ≤ 0.30 wt.%.

[0024] In the above technical solution, Nb, V, and Ti elements can further improve the performance of the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention. The design principle of its chemical elements is as follows:

[0025] Ti, Nb, and V: In the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, Ti, Nb, and V elements can refine grains and promote precipitation strengthening, thereby improving the strength of the wire rod. However, when the content of Ti, Nb, and V elements in the steel is too high, large hard inclusions are easily formed, which is detrimental to the fatigue performance of the steel wire. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the mass percentage content of Ti element is controlled to 0 < Ti ≤ 0.30 wt.%, the mass percentage content of Nb element is controlled to 0 < Nb ≤ 0.10 wt.%, and the mass percentage content of V element is controlled to 0 < V ≤ 0.30 wt.%.

[0026] Furthermore, in the unavoidable impurities of the high-strength and high-toughness sorbitic bridge cable wire rods described in this invention: P ≤ 0.015 wt.%, S ≤ 0.015 wt.%.

[0027] It should be noted that in the above technical solution of the present invention, P element and S element are both impurity elements in the high strength and toughness sorbitic bridge cable wire rod of the present invention. When technical conditions permit, in order to obtain steel with better performance and better quality, the content of impurity elements in steel should be reduced as much as possible.

[0028] P and S: In the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, impurity elements P and S are prone to segregation at grain boundaries, reducing the toughness of the steel and significantly affecting its cold working properties. Therefore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, the content of P and S elements in the steel must be strictly controlled, with the mass percentage of P element controlled to P≤0.015wt.% and the mass percentage of S element controlled to S≤0.015wt.%.

[0029] Furthermore, in the high-strength and tough sorbitic bridge cable wire rod described in this invention, the sorbitization rate is ≥85% and the troostitization rate is ≥10%.

[0030] Furthermore, in the high-strength and high-toughness sorbitic bridge cable wire rod described in this invention, its tensile strength is ≥1380MPa and its reduction of area is ≥32%.

[0031] Another objective of this invention is to provide a steel wire that has significant advantages in fatigue resistance and relaxation resistance, and can be effectively applied to long-span suspension bridges and cable-stayed bridges.

[0032] To achieve the above objectives, the present invention provides a steel wire which is made from the above-mentioned high-strength and tough sorbitic bridge cable wire rod through at least drawing and galvanizing processes.

[0033] Furthermore, in the steel wire described in this invention, the tensile strength is ≥2000MPa, the relaxation resistance is ≤2.0%, and the fatigue life is ≥2 million cycles.

[0034] Another objective of this invention is to provide a method for manufacturing high-strength and high-toughness sorbitic bridge cable wire rods. This method involves smelting, casting, and rolling the wire rods into wire rods, and by controlling the online air-cooling process of the wire rods, wire rods with good performance can be obtained.

[0035] To achieve the above objectives, the present invention provides a method for manufacturing high-strength and high-toughness sorbitic bridge cable wire rod, comprising the following steps:

[0036] Smelting and casting;

[0037] Rolled into wire rod;

[0038] Online air cooling of wire rod: control the spinning temperature at 900-920℃, the rapid air cooling time is 40-60s, and the temperature of the wire rod after cooling is 510-560℃, and then keep it warm.

[0039] Furthermore, in the online air-cooling step of the manufacturing method of high-strength and tough sorbitic bridge cable wire rods described in this invention, the wire rods are placed in an insulation cover for insulation for a duration of >30 seconds, and the temperature exiting the insulation cover is 460-500°C.

[0040] Another objective of this invention is to provide a method for manufacturing steel wire, which involves drawing and galvanizing the high-strength and high-toughness sorbitic bridge cable wire prepared by the above method. The resulting steel wire has significant advantages in terms of fatigue resistance and relaxation resistance, and can be effectively applied to long-span suspension bridges and cable-stayed bridges.

[0041] To achieve the above objectives, the present invention provides a method for manufacturing steel wire, comprising the steps of:

[0042] Smelting and casting;

[0043] Rolled into wire rod;

[0044] Online air cooling of wire rod: control the spinning temperature at 900-920℃, the rapid air cooling time is 40-60s, the temperature of the wire rod after cooling is 510-560℃, and then keep it at that temperature;

[0045] Pull;

[0046] Galvanized.

[0047] Furthermore, in the online air-cooling step of the wire rod manufacturing method of the present invention, the wire rod enters the heat insulation cover for heat preservation for a time of >30s, and the temperature of the wire rod exiting the heat insulation cover is 460-500℃.

[0048] Furthermore, in the drawing step of the steel wire manufacturing method of the present invention, the total drawing compression is controlled to be ≤80% and the single-pass compression is controlled to be ≤20%.

[0049] Furthermore, in the galvanizing step of the steel wire described in this invention, the galvanizing temperature is controlled at 430–470°C, and / or the galvanizing time is 40–90 seconds.

[0050] The high-strength and high-toughness sorbitic bridge cable wire rods, steel wires, and their manufacturing method described in this invention have the following advantages and beneficial effects compared to the prior art:

[0051] The high-strength and tough sorbitic bridge cable wire rod of the present invention, through reasonable design of chemical element composition and optimization of online air cooling process, can achieve a sorbitization rate of ≥85%, a troostitization rate of ≥10%, a tensile strength of ≥1380MPa, and a reduction of area of ​​≥32%. The wire rod has good uniformity of structure and excellent strength and plasticity.

[0052] The high-strength and high-toughness sorbitic bridge cable wire rods described in this invention, after being drawn, galvanized, and stabilized into steel wires, have a tensile strength ≥2000MPa, a relaxation resistance ≤2.0% (maintained for 1000h under a loading force of 0.7Fm), and a fatigue life ≥2 million cycles (loaded stress 0.45Fm, amplitude 460MPa).

[0053] The steel wire made from high-strength and high-toughness sorbitic bridge cable wire rods described in this invention has significant advantages in fatigue resistance and relaxation resistance, and can be effectively applied to long-span suspension bridges and cable-stayed bridges. Detailed Implementation

[0054] The following will further explain and illustrate the high-strength and tough sorbitic bridge cable wire rods, steel wires and their manufacturing methods described in this invention with reference to specific embodiments. However, this explanation and illustration do not constitute an undue limitation on the technical solution of this invention.

[0055] Examples 1-11

[0056] The high-strength and high-toughness sorbitic bridge cable wire rods described in Examples 1-11 of this invention are all prepared using the following steps:

[0057] (1) Smelting and casting: Smelting can be carried out in an electric furnace or converter, followed by ladle refining. It should be noted that during ladle refining, an LF furnace with VD or RH degassing treatment can be used, with vacuum degassing time > 20 min and settling time > 20 min. Casting can use a light reduction technique at the end of solidification, and carbon segregation in the billet core can be controlled by adjusting the superheat of the tundish, the billet casting speed, cooling, and reduction.

[0058] (2) Rolled into wire rod;

[0059] (3) Online air cooling of wire rod: control the spinning temperature to 900-920℃, the air cooling time to 40-60s, the temperature of the wire rod after cooling to 510-560℃, and then keep it warm;

[0060] In some implementations, during the online air-cooling step of the wire rod, it enters an insulation hood for insulation for more than 30 seconds, and the temperature exiting the insulation hood is 460-500°C.

[0061] The steel wires of Examples 1-11 of this invention are further manufactured using the following steps based on the high-strength and high-toughness sorbitic bridge cable wires obtained in each example:

[0062] (4) Drawing: During the drawing process, the total compression amount can be controlled to be ≤80%, and the compression amount per pass can be ≤20%;

[0063] (5) Galvanizing: During the galvanizing process, the galvanizing temperature can be controlled between 430 and 470°C, and the galvanizing time can be controlled between 40 and 90 seconds.

[0064] Table 1 lists the mass percentage of each chemical element in the high-strength and high-toughness sorbitic bridge cable wire rods and steel wires of Examples 1-11 of the present invention.

[0065] Table 1. (wt%, balance Fe and other unavoidable impurities besides P and S)

[0066] serial number C Si Mn Cr Mo Ni Cu Al Ti Nb V P S I value Example 1 0.84 0.9 0.5 0.3 0.01 0.01 0.01 0.03 0 0 0 0.011 0.012 1.56 Example 2 0.95 1.2 0.7 0.5 0.01 0.01 0.01 0.01 0.2 0.1 0.2 0.008 0.009 2.03 Example 3 0.8 0.5 0.4 0.4 0.2 0.12 0.4 0.05 0.3 0 0.1 0.012 0.010 1.99 Example 4 0.7 0.3 0.3 0.3 0.3 0.3 0.5 0.2 0.1 0.1 0.3 0.012 0.015 2.03 Example 5 1.1 2.0 0.4 0.3 0.01 0.01 0.01 0.05 0.23 0.05 0.15 0.015 0.014 1.74 Example 6 0.7 0.4 0.9 0.5 0.02 0.02 0.1 0.13 0.15 0.07 0.21 0.007 0.009 2.01 Example 7 0.7 1.8 0.3 0.9 0.02 0.03 0.05 0.18 0.19 0.03 0.08 0.011 0.013 1.91 Example 8 0.8 1.2 0.4 0.4 0.2 0.15 0.4 0.04 0.23 0.04 0 0.010 0.014 2.03 Example 9 0.9 1.6 0.5 0.5 0.04 0.01 0.01 0.02 0.28 0 0.05 0.009 0.012 1.84 Example 10 0.8 1.5 0.4 0.4 0.2 0.02 0.03 0.03 0 0 0 0.011 0.013 1.70 Example 11 0.7 0.5 0.3 0.4 0.1 0.2 0.3 0.07 0.09 0 0.26 0.009 0.011 1.78

[0067] Note: I value = [C] + 0.8[Mn] + [Cr] + 0.7[Mo] + 1.1[Ni] + 0.5[Cu], where [C], [Mn], [Cr], [Mo], [Ni], and [Cu] are respectively replaced by the values ​​before the mass percentage sign of the corresponding chemical element.

[0068] Table 2 lists the specific process parameters of the high-strength and high-toughness sorbitic bridge cable wire rods and steel wires in the above process steps of Embodiments 1-11 of the present invention.

[0069] Table 2.

[0070]

[0071]

[0072] Samples were taken from the high-strength and high-toughness sorbitic bridge cable wire rods of Examples 1-11 prepared through steps 1-3 above, and microstructure and mechanical property tests were performed on the wire rod samples of each example. The results of the microstructure and mechanical property tests are listed in Table 3. The relevant microstructure and mechanical property testing methods are described below:

[0073] Microstructure testing: GB / T 13298—2015 "Metallic Microstructure Testing Methods" is used to test the metallographic structure of wire rods.

[0074] Mechanical property testing: GB / T 228.1—2010 "Metallic materials, tensile testing - Part 1: Test method at room temperature" is used to test the mechanical properties of wire rod.

[0075] Table 3 lists the performance test results of the high-strength and tough sorbitic bridge cable wire rods of Examples 1-11 of the present invention.

[0076] Table 3.

[0077]

[0078]

[0079] As can be seen from Table 3 above, the sorbitization rate of the high-strength and high-toughness sorbitic bridge cable wire rods in Examples 1-11 of the present invention is all greater than or equal to 85%, and the troostitization rate is all greater than or equal to 10%. Furthermore, the high-strength and high-toughness sorbitic bridge cable wire rods in Examples 1-11 of the present invention possess excellent mechanical properties, with tensile strength all greater than or equal to 1380 MPa and reduction of area all greater than or equal to 32%.

[0080] Furthermore, to verify the mechanical properties of the steel wires in Examples 1-11 of this invention, the inventors sampled the steel wires obtained through the above-described process steps and conducted relevant performance tests on the steel wires of each example. The results of the performance tests are listed in Table 4. The specific testing methods are as follows:

[0081] Mechanical property testing: The mechanical properties of the steel wire were tested in accordance with GB / T 228.1—2010 "Metallic materials, tensile testing - Part 1: Test method at room temperature".

[0082] Relaxation and fatigue performance tests: The relaxation and fatigue performance of the steel wires were tested in accordance with GB / T 21839—2019 "Test Methods for Steel for Prestressed Concrete".

[0083] Table 4 lists the performance test results of the steel wires in Examples 1-11 of the present invention.

[0084] Table 4.

[0085] serial number Tensile strength (MPa) Relaxation performance (%) Fatigue life (10,000 cycles) Example 1 2000 2 200 Example 2 2043 1.7 210 Example 3 2031 1.8 234 Example 4 2034 1.9 328 Example 5 2021 2 267 Example 6 2011 1.7 251 Example 7 2041 1.8 283 Example 8 2035 1.7 340 Example 9 2037 1.6 331 Example 10 2021 1.8 289 Example 11 2048 1.9 267

[0086] As can be seen from Table 4 above, the steel wires of Examples 1-11 of the present invention have significant advantages in terms of fatigue resistance and relaxation resistance. Their tensile strength is greater than or equal to 2000MPa, their relaxation performance is less than or equal to 2%, and their fatigue life is greater than or equal to 2 million cycles.

[0087] Furthermore, 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.

[0088] 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 high-strength and high-toughness sorbitic bridge cable wire rod, containing Fe and unavoidable impurities, characterized in that, It also contains the following chemical elements in the following mass percentages: C: 0.70~1.10wt.%, Si: 0.30~2.00wt.%, Mn: 0.30~0.90wt.%, Cr: 0.30~0.90wt.%, Mo: 0.01~0.30wt.%, Ni: 0.01~0.30wt.%, Cu: 0.01~0.50wt.%, Al: 0.01~0.20wt.%; The chemical elements also satisfy the following condition: 1.56≤[C]+0.8[Mn]+[Cr]+0.7[Mo]+1.1[Ni]+0. 5[Cu]≤2.03, where [C], [Mn], [Cr], [Mo], [Ni], and [Cu] are respectively replaced with the values ​​before the mass percentage sign of each chemical element.

2. The high-strength and high-toughness sorbitic bridge cable wire rod as described in claim 1, characterized in that, Its mass percentage content of each chemical element is as follows: C: 0.70–1.10 wt.%, Si: 0.30–2.00 wt.%, Mn: 0.30–0.90 wt.%, Cr: 0.30–0.90 wt.%, Mo: 0.01–0.30 wt.%, Ni: 0.01–0.30 wt.%, Cu: 0.01–0.50 wt.%, Al: 0.01–0.20 wt.%; balance Fe and unavoidable impurities.

3. The high-strength and high-toughness sorbitic bridge cable wire rod as described in claim 1 or 2, characterized in that, It also contains at least one of the following chemical elements: 0 < Ti ≤ 0.30 wt.%; 0 < Nb ≤ 0.10 wt.%; 0 < V ≤ 0.30 wt.%.

4. The high-strength and high-toughness sorbitic bridge cable wire rod as described in claim 1 or 2, characterized in that, In unavoidable impurities: P ≤ 0.015 wt.%, S ≤ 0.015 wt.%.

5. The high-strength and high-toughness sorbitic bridge cable wire rod as described in claim 1 or 2, characterized in that, Its sorbitization rate is ≥85%, and its troostitization rate is ≥10%.

6. The high-strength and high-toughness sorbitic bridge cable wire rod as described in claim 1 or 2, characterized in that, Its tensile strength is ≥1380MPa and its reduction of area is ≥32%.

7. A steel wire, characterized in that, It is made from high-strength and tough sorbitic bridge cable wire rod as described in any one of claims 1-6, through at least drawing and galvanizing processes.

8. The steel wire as described in claim 7, characterized in that, Its tensile strength is ≥2000MPa, its relaxation resistance is ≤2.0%, and its fatigue life is ≥2 million cycles.

9. The method for manufacturing high-strength and high-toughness sorbitic bridge cable wire rod as described in any one of claims 1-6, characterized in that, It includes the following steps: Smelting and casting; Rolled into wire rod; Online air cooling of wire rod: control the spinning temperature at 900-920℃, the rapid air cooling time is 40-60s, and the temperature of the wire rod after cooling is 510-560℃, and then keep it warm.

10. The method for manufacturing high-strength and high-toughness sorbitic bridge cable wire rod as described in claim 9, characterized in that, In the online air-cooling process of wire rod, the wire rod enters the insulation cover for insulation for more than 30 seconds, and the temperature of the wire rod exiting the insulation cover is 460-500℃.

11. The method for manufacturing steel wire as described in claim 7 or 8, characterized in that, Including the following steps: Smelting and casting; Rolled into wire rod; Online air cooling of wire rod: control the spinning temperature at 900-920℃, the rapid air cooling time is 40-60s, the temperature of the wire rod after cooling is 510-560℃, and then keep it at that temperature; Pull; Galvanized.

12. The method for manufacturing steel wire as described in claim 11, characterized in that, In the online air-cooling process of wire rod, the wire rod enters the insulation cover for insulation for more than 30 seconds, and the temperature of the wire rod exiting the insulation cover is 460-500℃.

13. The method for manufacturing steel wire as described in claim 11, characterized in that, During the drawing process, the total compression amount should be controlled to be ≤80%, and the compression amount per pass should be ≤20%.

14. The method for manufacturing steel wire as described in claim 11, characterized in that, In the galvanizing process, the galvanizing temperature is controlled at 430–470°C, and / or the galvanizing time is 40–90 seconds.

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