Prestressed high-strength steel strand and production process thereof

Abstract

This application relates to the field of prestressed material technology, specifically disclosing a prestressed high-strength steel strand and its production process. The prestressed high-strength steel strand is obtained by twisting multiple steel wires together and then stabilizing them. The chemical composition of the steel wires, by weight percentage, is: C: 0.88-0.92%, Si: 0.60-0.70%, Mn: 0.50-0.60%, Cr: 0.35-0.40%, V: 0.06-0.10%, Ti: 0.04-0.08%, Nb: 0.03-0.07%, Mo: 0.10-0.15%, Sc: 0.01-0.03%, Y: 0.005-0.015%, P≤0.010%, S≤0.005%, with the balance being Fe. This prestressed high-strength steel strand possesses advantages such as high tensile strength, good plasticity, and high toughness, meeting the requirements of large-scale projects for high-performance prestressed materials.

Description

Technical Field

[0001] This application relates to the field of prestressed materials technology, and more specifically, to a prestressed high-strength steel strand and its manufacturing process. Background Technology

[0002] Prestressed steel strands are key load-bearing materials in prestressed concrete structures, widely used in infrastructure such as bridges, high-rise buildings, nuclear power plants, large stadiums, and offshore platforms. With the rapid development of modern engineering towards longer spans, higher loads, and greater durability, the requirements for prestressed steel strands are becoming increasingly stringent. Currently, the tensile strength of traditional prestressed steel strands on the market is generally 1860 MPa. However, with bridge spans exceeding 2000 meters and high-rise buildings exceeding 500 meters, traditional prestressed steel strands are no longer sufficient to meet design requirements. Therefore, developing a high-strength prestressed high-strength steel strand has become one of the urgent technical problems to be solved in this field. Summary of the Invention

[0003] While taking into account the good plasticity and toughness of prestressed high-strength steel strands, this application provides a prestressed high-strength steel strand and its manufacturing process in order to improve the tensile strength of prestressed high-strength steel strands.

[0004] In a first aspect, this application provides a prestressed high-strength steel strand, which adopts the following technical solution: A prestressed high-strength steel strand is obtained by twisting multiple steel wires together and then stabilizing them. The chemical composition of the steel wires, by weight percentage, is as follows: C: 0.88-0.92%, Si: 0.60-0.70%, Mn: 0.50-0.60%, Cr: 0.35-0.40%, V: 0.06-0.10%, Ti: 0.04-0.08%, Nb: 0.03-0.07%, Mo: 0.10-0.15%, Sc: 0.01-0.03%, Y: 0.005-0.015%, P≤0.010%, S≤0.005%, with the balance being Fe.

[0005] The prestressed high-strength steel strand of this application is obtained by twisting multiple steel wires together and then stabilizing them. Twisting multiple steel wires allows the wires to be distributed in a spiral shape and tightly interlocked, increasing load-bearing capacity. The stabilization treatment eliminates residual stress generated during the twisting process, ensuring the long-term stability of the prestressed high-strength steel strand. This application also controls the chemical composition of the steel wires, achieving a tensile strength >2100MPa, a reduction of area >40%, an impact energy at -80℃ >35J, and a sorbite content >95%. This results in prestressed high-strength steel strand exhibiting advantages such as high tensile strength, good plasticity, and high toughness, possessing superior comprehensive performance and meeting higher requirements.

[0006] The steel wire of this application uses C, Si, Mn, and Cr as base elements. C provides sufficient carbon source, Si mainly provides solid solution strength, Mn mainly plays a role in deoxidation and desulfurization, and Cr can improve hardenability and form alloy cementite with C. Based on this, V, Ti, and Nb, which are strong carbide-forming elements, can form fine and dispersed carbonitrides during rolling and cooling. Mo, Sc, and Y are also added. Mo can strengthen through solid solution, refine pearlite lamellae, and inhibit P segregation; Sc not only plays a role in deoxidation and desulfurization but also spheroidizes MnS, reduces stress concentration, hinders austenite grain growth, and refines grains; Y can refine the microstructure, reduce dendrite spacing, alleviate compositional segregation, and accumulate at grain boundaries, purifying grain boundaries and improving grain boundary bonding. Furthermore, by utilizing the synergistic effect between Mo, Sc, and Y, the steel wire simultaneously achieves high strength, high plasticity, and excellent toughness, enabling prestressed high-strength steel strands to meet the requirements of large-scale projects for high-performance prestressed materials.

[0007] Optionally, the chemical composition of the steel wire, by weight percentage, is: C: 0.90%, Si: 0.64%, Mn: 0.55%, Cr: 0.37%, V: 0.08%, Ti: 0.06%, Nb: 0.05%, Mo: 0.12%, Sc: 0.02%, Y: 0.010%, P≤0.010%, S≤0.005%, with the balance being Fe.

[0008] By adopting the above technical solution, the chemical composition of the steel wire is further optimized, the proportion of each chemical component is reasonable, and the steel wire achieves the best balance between strength, plasticity and toughness, which facilitates mass production.

[0009] Optionally, the prestressed high-strength steel strand uses 2-30 steel wires.

[0010] By adopting the above technical solutions, the number of steel wires covers various twisting structures ranging from 2 to 30, including common standard specifications such as 1×3, 1×7, and 1×19, meeting the diameter and load-bearing capacity requirements of prestressed high-strength steel strands for different engineering teams. In several implementation schemes, the number of steel wires used in the prestressed high-strength steel strand is 7, but it can also be set to 2, 3, 5, 19, 25, 30, etc., as needed, but it is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0011] Optionally, the diameter of the steel wire is 3-30 mm.

[0012] By adopting the above technical solutions, the wire diameter covers a range from thin to thick, meeting the stress requirements of different projects. In several implementation schemes, the wire diameter is 7.2mm, but it can also be set to 3mm, 5mm, 8mm, 10mm, 13mm, 15mm, 18mm, 20mm, 23mm, 25mm, 28mm, 30mm, etc., as needed, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0013] Secondly, this application provides a production process for the aforementioned prestressed high-strength steel strand, employing the following technical solution: A manufacturing process for the prestressed high-strength steel strand includes the following steps: S1. Smelt and refine according to the chemical composition to obtain molten steel; S2. The molten steel is continuously cast to obtain a billet; S3. The billet is heated, rolled, cooled under controlled conditions, and drawn to obtain steel wire; S4. Twist multiple steel wires together and stabilize them to obtain prestressed high-strength steel strand.

[0014] By adopting the above technical solution, the production of prestressed high-strength steel strands can be facilitated.

[0015] Optionally, in the continuous casting of step S2, the superheating temperature of the molten steel is 20-30℃, and the casting speed is 1-2m / min.

[0016] By adopting the above technical solutions, the overheating temperature is controlled within the range of 20-30℃, and the casting speed is controlled within the range of 1-2m / min. This enables the molten steel to solidify rapidly in the crystallizer and obtain a fine equiaxed crystal structure, reducing columnar crystal regions, alleviating central segregation and porosity, reducing surface cracks and depressions, increasing surface quality, and ensuring production efficiency and billet quality.

[0017] In several implementation schemes, in the continuous casting of step S2, the superheating temperature of the molten steel is 25°C and the casting speed is 1.2 m / min. The superheating temperature can also be set to 20°C, 23°C, 28°C, 30°C, etc., as needed, and the casting speed can also be set to 1 m / min, 1.5 m / min, 1.8 m / min, 2 m / min, etc., as needed. However, it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0018] Optionally, in the heating treatment of step S3, the billet is heated sequentially through a preheating section, a heating section, and a soaking section. The temperature of the preheating section is 650-700℃, the temperature of the heating section is 1150-1200℃, the temperature of the soaking section is 1180-1220℃, the total heating time is 140-170 min, and the heating time of the soaking section is 50-70 min.

[0019] By adopting the above technical solutions, the preheating section reduces thermal stress in the billet and avoids thermal shock cracking; the heating section promotes the solidification of chemical components and improves efficiency; the soaking section ensures uniform temperature inside and outside the billet, achieves high-temperature diffusion, and promotes uniform diffusion of chemical components, eliminating as-cast segregation and reducing regional performance differences. Controlling the total heating time ensures sufficient homogenization while avoiding excessively long heating times that could lead to oxidation and decarburization.

[0020] In several implementations, in step S3, the billet is heated sequentially through a preheating section, a heating section, and a soaking section. The temperature of the preheating section is 680°C, the temperature of the heating section is 1160°C, and the temperature of the soaking section is 1200°C. The total heating time is 160 minutes, and the heating time in the soaking section is 60 minutes. Alternatively, the temperature of the preheating section can be set to 650°C, 660°C, 670°C, 690°C, 700°C, etc., as needed. Similarly, the temperature of the heating section can be set to 1150°C, 1170°C, etc., as needed. The temperature of the soaking zone can be set to 1180℃, 1190℃, 1200℃, etc., or the temperature of the soaking zone can be set to 1180℃, 1190℃, 1210℃, 1220℃, etc., as needed. The total heating time can also be set to 140min, 150min, 170min, etc., as needed. The heating time of the soaking zone can also be set to 50min, 55min, 65min, 70min, etc., as needed. However, it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Optionally, in the rolling process of step S3, the initial rolling temperature is 1080-1120℃, the finishing rolling inlet temperature is 950-980℃, the sizing inlet temperature is 860-900℃, and the wire drawing temperature is 780-820℃.

[0022] By adopting the above technical solution, the microstructure is refined as follows: By using precise control of multiple passes and multiple temperature ranges, the austenite grains are fully refined, ultimately obtaining a fine sorbite microstructure, which improves strength and toughness.

[0023] In several implementations, during the rolling process in step S3, the initial rolling temperature is 1100℃, the finishing rolling inlet temperature is 960℃, the reduction sizing inlet temperature is 870℃, and the wire drawing temperature is 790℃. The initial rolling temperature can also be set to 1080℃, 1090℃, 1110℃, 1120℃, etc., as needed. Similarly, the finishing rolling inlet temperature can be set to 950℃, 970℃, 980℃, etc., the reduction sizing inlet temperature can be set to 860℃, 880℃, 890℃, 900℃, etc., and the wire drawing temperature can be set to 780℃, 800℃, 810℃, 820℃, etc., as needed. However, these are not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0024] Optionally, in the controlled cooling process of step S3, the temperature is reduced to 580-630℃ at a cooling rate of 15-20℃ / s, held for 1-2 minutes, and then reduced to below 500℃ at a cooling rate of 1-3℃ / s.

[0025] By employing the above technical solution, cooling to 580-630℃ at a cooling rate of 15-20℃ / s effectively suppresses the formation of ferrite and coarse pearlite, promoting the transformation of sorbite. Holding the temperature for 1-2 minutes allows austenite to fully transform into fine lamellar sorbite. Cooling to below 500℃ at a cooling rate of 1-3℃ / s effectively reduces cooling stress, prevents billet cracking, and controls the formation of iron oxide scale, thus improving the overall performance of the steel wire.

[0026] In several implementations, in the controlled cooling process of step S3, the temperature is lowered to 610°C at a cooling rate of 16°C / s, held at that temperature for 1.2 minutes, and then lowered to 450°C at a cooling rate of 2°C / s. The cooling rate to 610°C can also be set to 15°C / s, 17°C / s, 18°C / s, 19°C / s, 20°C / s, etc., as needed. Similarly, the cooling rate to 450°C can be set to 1°C / s, 1.5°C / s, 2.5°C / s, 3°C / s, etc., as needed. The temperature can be set at ℃ / s, etc., and can also be cooled to 580℃, 590℃, 600℃, 620℃, 630℃, etc. at a cooling rate of 16℃ / s as needed. The holding time can also be set to 1min, 1.5min, 1.8min, 2min, etc., as needed. The temperature can also be cooled to 490℃, 400℃, 350℃, 300℃, etc. at a cooling rate of 2℃ / s as needed. However, it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] Optionally, in the drawing process of step S3, the total compression rate of the drawing is 75-85%, the single compression rate is ≤14%, and the linear speed is 3-5m / min.

[0028] By adopting the above technical solutions, the control of the total compression ratio can enable the steel wire to obtain sufficient work hardening, thereby improving strength while maintaining plasticity; the control of the single compression ratio avoids excessive deformation in a single compression, which could lead to microcracks, thus ensuring the stability and yield of the drawing process; and the control of the linear speed allows the deformation heat to dissipate in time, preventing excessive heat from being generated during the drawing process and thus avoiding the deterioration of the microstructure.

[0029] In several implementation schemes, in the drawing process of step S3, the total compression rate is 80%, the single compression rate is 10%, and the linear speed is 4 m / min. The total compression rate can also be set to 75%, 78%, 83%, 85%, etc., as needed. The single compression rate can also be set to 5%, 8%, 10%, 12%, 14%, etc., as needed. The linear speed can also be set to 3 m / min, 3.5 m / min, 4.5 m / min, 5 m / min, etc., as needed. However, it is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0030] Optionally, in the stabilization process of step S4, the stabilization temperature is 380-440℃ and the linear velocity is 30-50m / min.

[0031] By adopting the above technical solution, residual stress generated during the twisting process is eliminated, ensuring the dimensional stability of prestressed high-strength steel strands during long-term use and reducing prestress loss during construction. In several implementation schemes, the stabilization treatment in step S4 is performed at a temperature of 400℃ and a linear speed of 40m / min. However, the temperature can be set to 380℃, 390℃, 410℃, 420℃, 430℃, 440℃, etc., and the linear speed can be set to 30m / min, 35m / min, 45m / min, 50m / min, etc., as needed. These are not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0032] Optionally, in step S4, the twist pitch is 50-200mm and the twist angle is 5-30 degrees.

[0033] By adopting the above technical solutions, the lay length is controlled within the range of 50-200mm, avoiding excessive bending of the steel wire due to an excessively small lay length, and preventing loosening of the prestressed high-strength steel strand due to an excessively large lay length. The lay angle is controlled within the range of 5-30 degrees, enabling the steel wires to be distributed in a spiral shape and tightly bound together. Through the control of lay length and lay angle, the prestressed high-strength steel strand structure is made compact and the stress is uniform, increasing the load-bearing capacity.

[0034] In several implementations, in the twisting process of step S4, the twist pitch is 100mm and the twist angle is 10 degrees. The twist pitch can also be set to 50mm, 80mm, 130mm, 150mm, 180mm, 200mm, etc., as needed, and the twist angle can also be set to 5 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, etc., as needed, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] In summary, this application has at least the following beneficial effects: 1. The prestressed high-strength steel strand of this application is obtained by twisting multiple steel wires together and stabilizing them. By controlling the chemical composition of the steel wires, the tensile strength, plasticity, and toughness of the steel wires are improved, thereby enabling the prestressed high-strength steel strand to exhibit the advantages of high tensile strength, good plasticity, and high toughness, meeting the needs of large-scale projects for high-performance prestressed materials.

[0036] 2. The steel wire of this application is based on C, Si, Mn and Cr as the base elements. On this basis, V, Ti, Nb, Mo, Sc and Y are added. By utilizing the synergistic effect between Mo, Sc and Y, the tensile strength is >2100MPa, the reduction of area is >40%, the impact energy at -80℃ is >35J and the sorbite content is >95%, which improves the tensile strength, plasticity and toughness of the steel wire and increases the sorbite content. Detailed Implementation

[0037] The present application will be further described in detail below with reference to the embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present application. Unless otherwise specified, the raw materials or components used in the present application can be obtained commercially or by conventional methods.

[0038] Example

[0039] Example 1 A prestressed high-strength steel strand is obtained by twisting seven steel wires together and then stabilizing them. Of the seven steel wires, one wire is located in the center, and the other six wires surround the outer periphery of the center wire, forming a 1×7 structure prestressed high-strength steel strand.

[0040] The chemical composition of the steel wire, by weight percentage, is as follows: C: 0.90%, Si: 0.64%, Mn: 0.55%, Cr: 0.37%, V: 0.08%, Ti: 0.06%, Nb: 0.05%, Mo: 0.12%, Sc: 0.02%, Y: 0.010%, P: 0.006%, S: 0.003%, with the balance being Fe.

[0041] A manufacturing process for prestressed high-strength steel strand includes the following steps: S1. Smelt and refine according to the chemical composition to obtain molten steel.

[0042] S2. The molten steel is continuously cast at a superheated temperature of 25℃ and a casting speed of 1.5m / min to obtain a billet.

[0043] S3. The billet is heated sequentially through the preheating section, heating section, and soaking section. The temperature of the preheating section is 680℃, the temperature of the heating section is 1160℃, and the temperature of the soaking section is 1200℃. The total heating time is 160 min, the heating time of the soaking section is 60 min, and the residual oxygen content is 1.3%.

[0044] Then rolling is carried out at an initial rolling temperature of 1100℃, a finishing rolling inlet temperature of 960℃, a sizing inlet temperature of 870℃, and a wire drawing temperature of 790℃.

[0045] Then, controlled cooling was performed, with the temperature reduced to 610℃ at a cooling rate of 16℃ / s, held for 1.2 minutes, and then reduced to 450℃ at a cooling rate of 2℃ / s.

[0046] Then, the wire is drawn with a total compression rate of 80% and a single compression rate of 10% at a linear speed of 4 m / min to obtain a steel wire. The diameter of the steel wire is 7.2 mm.

[0047] S4. Twist the 7 steel wires together with a twist pitch of 100mm and a twist angle of 10 degrees. Then, perform a stabilization treatment at a temperature of 400℃ and a linear speed of 40m / min to obtain prestressed high-strength steel strand.

[0048] Example 2 A prestressed high-strength steel strand differs from Example 1 in that the chemical composition of the steel wire is different.

[0049] The chemical composition of the steel wire, by weight percentage, is as follows: C: 0.88%, Si: 0.70%, Mn: 0.60%, Cr: 0.35%, V: 0.06%, Ti: 0.08%, Nb: 0.03%, Mo: 0.15%, Sc: 0.01%, Y: 0.015%, P: 0.08%, S: 0.005%, with the balance being Fe.

[0050] Example 3 A prestressed high-strength steel strand differs from Example 1 in that the chemical composition of the steel wire is different.

[0051] The chemical composition of the steel wire, by weight percentage, is as follows: C: 0.92%, Si: 0.60%, Mn: 0.50%, Cr: 0.40%, V: 0.10%, Ti: 0.04%, Nb: 0.07%, Mo: 0.10%, Sc: 0.03%, Y: 0.005%, P: 0.05%, S: 0.003%, with the balance being Fe.

[0052] Comparative Example Comparative Example 1 A prestressed high-strength steel strand differs from Example 1 in that the chemical composition of the steel wire does not contain Mo, Sc, or Y.

[0053] Comparative Example 2 A prestressed high-strength steel strand differs from Example 1 in that, in the chemical composition of the steel wire, Sc and Y are replaced with equal amounts of Mo.

[0054] That is, the weight percentages of Mo, Sc, and Y are different, and the weight percentage of Mo is 0.15%, the weight percentage of Sc is 0%, and the weight percentage of Y is 0%.

[0055] Comparative Example 3 A prestressed high-strength steel strand differs from Example 1 in that, in the chemical composition of the steel wire, Mo and Y are replaced by an equal amount of Sc.

[0056] That is, the weight percentages of Mo, Sc, and Y are different, and the weight percentage of Mo is 0%, the weight percentage of Sc is 0.15%, and the weight percentage of Y is 0%.

[0057] Comparative Example 4 A prestressed high-strength steel strand differs from Example 1 in that, in the chemical composition of the steel wire, Mo and Sc are replaced with equal amounts of Y.

[0058] That is, the weight percentages of Mo, Sc, and Y are different, and the weight percentages of Mo, Sc, and Y are 0.15%.

[0059] Comparative Example 5 A prestressed high-strength steel strand differs from Example 1 in that the chemical composition of the steel wire is modified by replacing Y with equal amounts of Mo and Sc.

[0060] That is, the weight percentages of Mo, Sc, and Y are different, with Mo having a weight percentage of 0.13%, Sc having a weight percentage of 0.02%, and Y having a weight percentage of 0%.

[0061] Comparative Example 6 A prestressed high-strength steel strand differs from Example 1 in that the chemical composition of the steel wire is modified by replacing Sc with equal amounts of Mo and Y.

[0062] That is, the weight percentages of Mo, Sc, and Y are different, with Mo accounting for 0.14%, Sc for 0%, and Y for 0.01%.

[0063] Comparative Example 7 A prestressed high-strength steel strand differs from Example 1 in that the chemical composition of the steel wire is modified by replacing Mo with equal amounts of Sc and Y.

[0064] That is, the weight percentages of Mo, Sc, and Y are different, with Mo having a weight percentage of 0%, Sc having a weight percentage of 0.10%, and Y having a weight percentage of 0.05%.

[0065] Performance testing The steel wires obtained in step S3 of Examples 1-3 and Comparative Examples 1-7 were taken as samples, and the following performance tests were performed on the steel wires. The test results are shown in Table 1.

[0066] In accordance with GB / T228.1-2021 "Metallic materials - Tensile testing - Part 1: Test method at room temperature", the tensile strength and reduction of area of ​​the steel wire were tested.

[0067] According to GB / T229-2020 "Metallic Materials Charpy Pendulum Impact Test Method", the impact energy of steel wire at -80℃ was tested.

[0068] According to YB / T169-2014 "Metallographic Test Method for Sorbite Content in High Carbon Steel Wire Rod", the sorbite content of the steel wire was tested.

[0069] Table 1 Test Results

[0070] As shown in Table 1, the steel wire of this application possesses higher tensile strength, reduction of area, and impact energy at -80℃. Its tensile strength > 2100 MPa, reduction of area > 40%, and impact energy at -80℃ > 35 J, demonstrating advantages such as high tensile strength, high reduction of area, and high low-temperature impact resistance. Furthermore, it exhibits a higher sorbite content, > 95%, showcasing the advantages of a high sorbite content. In other words, the prestressed high-strength steel strand of this application possesses good tensile strength, plasticity, and toughness, exhibiting superior comprehensive performance and meeting higher requirements.

[0071] Comparative Examples 1-4 were compared. Comparative Example 2, compared to Comparative Example 1, added Mo to the chemical composition of the steel wire; Comparative Example 3, compared to Comparative Example 1, added Sc to the chemical composition of the steel wire; and Comparative Example 4, compared to Comparative Example 1, added Y to the chemical composition of the steel wire. This shows that adding Mo, Sc, or Y alone to the chemical composition can increase the performance of the steel wire to some extent, but the performance improvement is limited.

[0072] Furthermore, comparing Comparative Examples 5-7 and Example 1, Comparative Example 5, compared to Comparative Example 1, added Mo and Sc to the chemical composition of the steel wire; Comparative Example 6, compared to Comparative Example 1, added Mo and Y to the chemical composition of the steel wire; Comparative Example 7, compared to Comparative Example 1, added Sc and Y to the chemical composition of the steel wire; and Example 1, compared to Comparative Example 1, added Mo, Sc, and Y to the chemical composition of the steel wire. It can be seen that the simultaneous addition of Mo, Sc, and Y significantly increases tensile strength, plasticity, and toughness, and improves the sorbite ratio. This may be because Mo can cause lattice distortion, hindering dislocation movement and refining pearlite lamellae, inhibiting the segregation of harmful chemical components at grain boundaries, and improving toughness; Sc can spheroidize MnS, reduce stress concentration, increase mechanical properties, and can also form carbides or nitrides, pinning grain boundaries, hindering austenite grain growth, and refining grains. Y can refine the microstructure, reduce dendrite spacing, alleviate compositional segregation, increase the uniformity of chemical element distribution, and also enrich at grain boundaries, improving grain boundary conditions and enhancing grain boundary bonding. Furthermore, the synergistic effect among Mo, Sc, and Y is beneficial for improving the overall performance of prestressed high-strength steel strands.

[0073] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A prestressed high-strength steel strand, characterized in that: It is obtained by twisting multiple steel wires together and then stabilizing them. The chemical composition of the steel wires, by weight percentage, is as follows: C: 0.88-0.92%, Si: 0.60-0.70%, Mn: 0.50-0.60%, Cr: 0.35-0.40%, V: 0.06-0.10%, Ti: 0.04-0.08%, Nb: 0.03-0.07%, Mo: 0.10-0.15%, Sc: 0.01-0.03%, Y: 0.005-0.015%, P≤0.010%, S≤0.005%, with the balance being Fe.

2. The prestressed high-strength steel strand according to claim 1, characterized in that: The chemical composition of the steel wire, by weight percentage, is as follows: C: 0.90%, Si: 0.64%, Mn: 0.55%, Cr: 0.37%, V: 0.08%, Ti: 0.06%, Nb: 0.05%, Mo: 0.12%, Sc: 0.02%, Y: 0.010%, P≤0.010%, S≤0.005%, with the balance being Fe.

3. The prestressed high-strength steel strand according to claim 1, characterized in that: The prestressed high-strength steel strand uses 2-30 steel wires.

4. The prestressed high-strength steel strand according to claim 1, characterized in that: The diameter of the steel wire is 3-30mm.

5. A production process for prestressed high-strength steel strand as described in any one of claims 1-4, characterized in that: Includes the following steps: S1. Smelt and refine according to the chemical composition to obtain molten steel; S2. The molten steel is continuously cast to obtain a billet; S3. The billet is heated, rolled, cooled under controlled conditions, and drawn to obtain steel wire; S4. Twist multiple steel wires together and stabilize them to obtain prestressed high-strength steel strand.

6. A prestressed high-strength steel strand according to claim 5, characterized in that: In the heating treatment of step S3, the billet passes through the preheating section, the heating section and the soaking section in sequence for heating. The temperature of the preheating section is 650-700℃, the temperature of the heating section is 1150-1200℃, the temperature of the soaking section is 1180-1220℃, the total heating time is 140-170min, and the heating time of the soaking section is 50-70min.

7. A prestressed high-strength steel strand according to claim 5, characterized in that: In the rolling process of step S3, the initial rolling temperature is 1080-1120℃, the finishing rolling inlet temperature is 950-980℃, the sizing inlet temperature is 860-900℃, and the wire drawing temperature is 780-820℃.

8. A prestressed high-strength steel strand according to claim 5, characterized in that: In step S3, the temperature is reduced to 580-630℃ at a cooling rate of 15-20℃ / s, held for 1-2 minutes, and then reduced to below 500℃ at a cooling rate of 1-3℃ / s.

9. A prestressed high-strength steel strand according to claim 5, characterized in that: In step S3, the total compression rate of the pull is 75-85%, the single compression rate is ≤14%, and the linear speed is 3-5 m / min.

10. A prestressed high-strength steel strand according to claim 5, characterized in that: In step S4, the stabilization treatment is carried out at a temperature of 380-440℃ and a linear velocity of 30-50m / min.

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