Preparation method of high-same-circle-degree SWRH82B wire rod

Abstract

The invention provides a preparation method of a high-same-circle-degree SWRH82B wire rod, and belongs to the technical field of wire rod manufacturing. The preparation method comprises the following steps that S1, cleaning is conducted; s2, heating; s3, rolling; s4, air cooling; and S5, aging treatment. Through multi-stage heating treatment, the uniformity of the material is improved; an advanced controlled rolling and controlled cooling technology is used for rolling, so that a more uniform microstructure and higher strength are obtained; a Stelmor air cooling line is adopted for multi-stage cooling, so that the phase change of the material is effectively controlled, the internal stress is reduced, and the formation of a poor microstructure is avoided; through fine aging treatment, the aging time is shortened, and the reliability and the performance consistency of the material are improved; according to the method, through comprehensive process optimization, the same-circle strength of the SWRH82B wire rod is improved, and the mechanical property wire rod meeting the requirement is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of wire rod manufacturing and relates to a method for preparing a high-convolution SWRH82B wire rod. Background Art

[0002] In the production process of high carbon steel SWRH82B wire rod, it is crucial to ensure the uniformity of the strength of the same circle, because it not only affects the reliability of the material, but is also directly related to the processing efficiency and the performance of the final product. However, in the traditional production technology, there are several major problems that limit product quality and production efficiency: Tension control problems during rolling: In traditional rolling technology, especially during high-speed rolling, improper tension control may lead to uneven stress distribution inside the material, which in turn causes inconsistent material strength and may even cause steel fracture in extreme cases.

[0003] Limitations of rolling accuracy: Conventional rolling mills generally have difficulty achieving high precision in dimensional control, especially in large-scale production. Fluctuations in dimensional accuracy not only reduce the efficiency of subsequent processing, but may also cause the performance of the finished product to fail to meet strict engineering standards.

[0004] Defects in the frame design: Traditional open or semi-open frames used in the rough rolling stage are prone to deformation under high-load working conditions, which directly affects the rolling accuracy and quality.

[0005] Insufficient cooling system: For the cooling operation after spinning, the traditional cooling system usually adopts a one-stage cooling zone, which makes it difficult to achieve optimized control for the cooling needs at different stages. This one-size-fits-all cooling method is not conducive to optimizing material properties.

[0006] Inefficiency and instability of aging treatment: For the aging treatment of SWRH82B wire rod, traditional natural aging usually requires the material to be placed at room temperature for several weeks in the hope that the internal microstructure of the material will naturally adjust and stabilize; this long-term treatment is not only inefficient, but also takes up a lot of production time, increasing manufacturing costs; the results of natural aging are affected by many factors, including ambient temperature, humidity and the characteristics of the material itself. The uncontrollability of these factors makes the aging effect often fluctuate, making it difficult to ensure the consistency and reliability of the product.

[0007] Therefore, an improved preparation method is needed to achieve uniform heating and precise cooling, as well as reasonable rolling and cooling technology to ensure high same-circle strength and excellent mechanical properties of the product. Summary of the invention

[0008] The purpose of the present invention is to solve the above problems in the prior art and to propose a method for preparing a high-convolution SWRH82B wire rod.

[0009] The object of the present invention can be achieved by the following technical scheme: A method for preparing a high-convolution SWRH82B wire rod comprises the following steps: S1 Cleaning: Check whether the chemical composition of the steel billet meets the production requirements, and clean the steel billet that meets the production requirements to remove surface impurities; the parameter requirements for the chemical composition of the steel billet are as follows: carbon content is 0.81%-0.83%wt; silicon content is 0.25%-0.35%wt; manganese content is 0.75%-0.85%wt; nickel content is 0.2-0.3%wt; molybdenum content is 0.15%-0.25%wt; vanadium content is 0.07%-0.009%wt; chromium content is 0.2-0.25%wt; boron content is 0.0015%-0.003%wt; aluminum content is not higher than 0.007%wt; phosphorus content is not higher than 0.02%wt; sulfur content is not higher than 0.015%wt; copper content is not higher than 0.02%wt; the rest is iron and unavoidable impurities; The carbon content of 0.81%-0.83%wt is required for the following reasons: Carbon is a strengthening element in steel, which increases its strength and hardness by forming an iron-carbon alloy microstructure. In the range of 0.81%-0.83%, the carbon content is sufficient to ensure that the steel has high strength and can withstand heavy loads and wear; although increasing the carbon content can improve strength and hardness, too high a carbon content will make the steel too brittle and easy to break. By controlling the carbon content to a relatively high but not extreme level (0.81%-0.83%wt), it is possible to maintain sufficient strength while ensuring that the material does not lose its necessary toughness due to excessive embrittlement; during the subsequent heat treatment process, the carbon content has a significant effect on the transformation of the steel microstructure. The appropriate carbon content helps to form an ideal microstructure that can maintain a certain degree of ductility and toughness while improving hardness and strength. In particular, it is important to pay attention to the carbon content not exceeding 0.83%; controlling the carbon content not to exceed 0.83% helps to maintain the processability and formability of the steel during the rolling process. Too high carbon content will reduce the plasticity of the material, making it more likely to crack and break during processing, which will seriously affect product quality and production efficiency; The reasons for the silicon content of 0.25%-0.35%wt are as follows: Silicon is an effective solid solution strengthening element that can improve the strength and hardness of steel by enhancing the crystal structure of the ferrite matrix. Within the specified content range, silicon can enhance material properties without significantly increasing brittleness, which is essential for preventing the generation and expansion of cracks during rolling; For high carbon steels such as SWRH82B, elasticity is an important property, especially in applications that need to withstand repeated stress. The addition of silicon can increase the elastic modulus of the steel, so that the finished product exhibits better elastic recovery performance when subjected to stress.

[0010] The reasons for the manganese content of 0.75%-0.85%wt are as follows: manganese is an important alloying element that can improve the hardenability of steel; manganese can enhance the hardness, wear resistance and tensile strength of steel, which are achieved by refining the grains and forming a certain proportion of carbides; manganese can effectively improve the impact resistance of the material by improving the microstructure of steel, especially at low temperatures; the cost of manganese is relatively low, but increasing its content can significantly improve the overall performance of the material. In the range of 0.75% to 0.85%, a good balance is achieved between the effect and cost of manganese; The nickel content is 0.2-0.3%wt for the following reasons: Improve strength and toughness: Nickel is an effective alloying element that can significantly improve the strength and toughness of the wire rod, especially in low temperature environments. Adding nickel helps to improve the material's resistance to fracture, which is particularly important for applications that are subject to dynamic or impact loads; Improve corrosion resistance: Nickel can enhance the corrosion resistance of steel, especially corrosion in atmospheric environments. This gives SWRH82B wire rods the advantages of longer service life and lower maintenance costs when used outdoors or in harsh environments; Increase hardenability: Nickel can improve the hardenability of steel and ensure uniform hardness even in steel with larger cross-sections. This is critical to ensuring consistent mechanical properties throughout the material; Balance performance and economy: Although nickel can significantly improve steel performance, its price is relatively high. Within the content range of 0.2% to 0.3%, the strengthening effect of nickel can be fully utilized without excessively increasing costs; Controlling the nickel content within a certain range helps maintain the processability of steel. High nickel content will increase the hardness of steel during processing, resulting in processing difficulties; The molybdenum content is 0.15%-0.25%wt. The reasons are as follows: adding molybdenum in the range of 0.15% to 0.25%wt can ensure that the steel has sufficient strength and hardness. This proportion is sufficient to trigger the required microalloying effect. This content range also takes into account the balance of cost-effectiveness. Although molybdenum is a more expensive alloying element, at this proportion, the performance improvement it provides is reasonable compared with the increased cost; Vanadium plays a key role in the preparation of SWRH82B wire rod, mainly through microalloying technology to improve the mechanical properties of steel. The addition ratio of vanadium is between 0.07%-0.09%wt. This range is selected to maximize its impact on the properties of steel while avoiding exceeding the cost-effective range for the following reasons: Improve strength and toughness: Vanadium can significantly increase the yield strength and tensile strength of steel without causing much impact on its plasticity. This is achieved by forming fine, dispersed vanadium carbide particles, which can effectively hinder the movement of dislocations, thereby increasing the strength of the material. Refining the grain structure: Vanadium contributes to grain refinement, and refined grains can increase the toughness and strength of steel. This is particularly important in high-strength applications because it can provide better impact resistance. Enhance wear resistance and fatigue life: The addition of vanadium can also improve the wear resistance of the material and extend its fatigue life, which is especially important for applications that need to withstand heavy loads for a long time; the reason for choosing this content ratio; Optimize performance and cost: In the content range of 0.07% to 0.09%wt, vanadium can provide its strengthening effect while the cost is still within an acceptable range. This ratio is sufficient to achieve the microalloying effect mentioned above without causing over-alloying, thereby avoiding unnecessary cost increases; Avoid increased brittleness: Excessive vanadium may cause increased brittleness of steel, especially in low temperature environments. Keeping the vanadium content at a relatively low level can optimize its positive effects while reducing negative effects; Adapt to manufacturing processes: During manufacturing processes, such as rolling and heat treatment, this range of vanadium content can ensure that material properties remain consistent and controllable throughout the manufacturing process, especially in controlling grain size and improving hardenability; The reasons for the chromium content of 0.2-0.25%wt are as follows: Improve hardness and strength: As an alloying element, chromium can form strong carbides in steel, which help to improve the hardness and wear resistance of the material; Enhance corrosion resistance: Chromium forms a passive film in steel, which can effectively isolate oxygen and moisture, thereby significantly improving the material's oxidation and corrosion resistance. This feature is especially important for wire rods used outdoors or in humid environments; Improve heat treatment performance: The addition of chromium improves the hardenability of steel, so that even thicker parts can achieve good hardening effects through heat treatment, which can maintain the consistency of the mechanical properties of the entire component. Balance between performance and cost: The cost of adding chromium is relatively high, so keeping its content between 0.2% and 0.25%wt can give full play to the alloying effect of chromium without significantly increasing the cost; although too high chromium content can further improve the hardness, it may also cause excessive hardening of the material, thereby increasing brittleness and reducing the toughness and impact strength of the material. The chromium content in this range helps to achieve a good balance between hardness and toughness; in the preparation process of SWRH82B, the heat treatment, rolling and other process steps used need to consider the presence of chromium to ensure the consistency and controllability of material properties during processing. This range of chromium content adapts to the needs of these processes, especially in controlling the characteristics of iron oxide scale and heat treatment response.

[0011] Boron plays a vital role in the preparation of SWRH82B wire rod. Although it is present in a very small percentage, the addition of boron can significantly improve the hardenability of steel and improve its overall mechanical properties, especially in terms of high strength and wear resistance. The specific reasons are as follows: Improve hardenability: Boron is a very effective alloying element, and even a very small amount can significantly increase the hardenability of steel; Reduce alloy costs: By adding a small amount of boron, the amount of other more expensive alloying elements (such as chromium, nickel, and molybdenum) can be reduced, thereby reducing material costs without sacrificing performance. This is because the effect of boron is very significant, even in small amounts; Balance of efficiency and effect: While maintaining low costs, a boron content of 0.0015% to 0.003% is sufficient to significantly improve the hardenability of steel without causing other adverse changes in material properties; Excessive boron content will lead to a decrease in the toughness of the steel, especially in subsequent air cooling operations. Keeping the boron content at a lower level can avoid such problems while still effectively improving hardenability.

[0012] The reasons for the aluminum content being no higher than 0.007%wt; the phosphorus content being no higher than 0.02%wt; the sulfur content being no higher than 0.015%wt; and the copper content being no higher than 0.02%wt are as follows: Although aluminum is an excellent deoxidizer, excessive aluminum can lead to the formation of aluminum inclusions, which can form hard spots in the steel and increase the likelihood of fracture, especially in high stress environments such as during rolling; phosphorus is a harmful impurity and it is desirable to have as little as possible in the steel. A high phosphorus content can lead to increased brittleness of the steel, especially at low temperatures, a phenomenon known as cold brittleness. A high phosphorus content can also lead to poor weldability and decreased cold deformation performance; a high sulfur content can lead to increased hot brittleness of the steel, especially during hot working, where hot cracks are easily generated. In addition, sulfide inclusions can reduce the ductility and toughness of the steel and increase the risk of fracture; although copper can improve corrosion resistance, its excessive content in steel needs to be controlled. A high copper content can lead to decreased hot working performance of the steel, especially during hot rolling, which can lead to the development of surface cracks and internal defects.

[0013] In summary, the comprehensive performance of SWRH82B wire rod is ensured by strict control of the chemical composition of the steel billet; S2 Heating: In an inert atmosphere, the cleaned steel billet is heat treated to obtain a pre-rolled steel billet. The heat treatment includes four stages, namely, an initial heating stage, a heating stage, a heat-saturation stage, and a short heating heat treatment stage. Compared with the traditional two-stage heat treatment, the two-stage heat treatment includes a heating stage and a temperature rise stage. The reasons for adding the initial temperature rise stage and optimizing the plastic heat treatment stage are as follows: The purposes of the initial heating stage are as follows: Uniform heating: One of the main purposes of gentle heating is to ensure that the inside and outside of the billet are heated evenly. This uniform heating helps to avoid temperature gradients that may occur during the heating process. Reduce internal stress: By controlling the heating rate, gentle heating helps to reduce the internal stress caused by rapid temperature changes. If these internal stresses are not controlled, they will cause stress concentration inside the billet, which will cause cracks or fractures in the material during subsequent processing; Prevent premature precipitation of carbides: During the heating process of steel, the precipitation of carbides is usually associated with increased hardness and brittleness of the material. Gentle heating helps to control the precipitation rate and distribution of carbides, thereby avoiding the formation of hard and brittle areas inside the steel, which is crucial to maintaining the uniformity and processability of the entire billet; Silicon can change its thermal expansion coefficient. Gentle heating helps to maintain the dimensional stability and qualitative properties of the material during the heating process, which is very important to ensure the dimensional accuracy of the finished product; The reasons for the short-term heat treatment stage are as follows: 1. Optimize deformation performance: If the temperature exceeds the set value of the soaking stage for a long time, the steel will become overheated, which will cause the grain growth of the material and affect the mechanical properties and strength of the final product; however, the temperature increase increases the amplitude of atomic thermal vibration, reduces the resistance to slip movement, and continuously generates and activates new slip systems, which reduces the bonding force between metal atoms; it is beneficial to the elastic-plastic deformation of the metal and is more conducive to the subsequent rolling steps; therefore, without affecting the overall performance of the material, the heat treatment temperature is briefly increased on the basis of exceeding the upper limit of the soaking stage, which can better reduce the yield strength of the steel and improve its ductility, so that it is easier to deform during the rolling process. 2. Optimize alloy distribution: Promote the diffusion of alloy elements: Steel contains a variety of alloy elements (such as manganese, nickel, molybdenum, vanadium, chromium, etc.), and the uniform distribution of these elements is crucial to the final performance of the steel. After the billet has passed the soaking stage, although the overall temperature is uniform, the local chemical composition distribution may still be uneven. Short-term high temperature can increase the atomic thermal vibration and diffusion rate of alloying elements, so that these elements are more evenly distributed inside the billet; reduce element separation and segregation: During the heating process, especially when heated for a long time, alloying elements may separate or segregate, resulting in excessive or low element concentrations in certain areas. Short-term heating can effectively reduce these uneven phenomena by accelerating the diffusion of alloying elements to achieve a more even distribution inside the billet, avoiding uneven performance problems in rolled products.

[0014] S3 rolling: After the heated billet is descaled, it is rolled through a controlled rolling and controlled cooling process to obtain a SWRH82B wire coil; the diameter of the SWRH82B wire is 12.5 mm; The rolling process is as follows: the descaled steel billet is sent to the rough rolling section for rough rolling. After the rough rolling, it enters the conveyor roller with a heat preservation cover. The conveyor roller with the heat preservation cover is equipped with a shearing device 1. The shearing device 1 is used to perform head cutting. Then the billet enters the intermediate rolling section for intermediate rolling. After the intermediate rolling, the shearing device 2 is used to perform head cutting. After the head cutting, the billet enters the pre-finishing section for pre-finishing. The pre-finishing adopts a looper rolling mechanism. After the pre-finishing, the billet passes through the No. 1 water cooling box unit. Water cooling: after the No. 1 water cooling box unit, there is a shearing device No. 3. After the head and tail cutting process of the shearing device No. 3, the rolled piece enters the finishing section for finishing rolling. After the finishing rolling, the rolled piece passes through the No. 2 water cooling box unit for water cooling to control the wire temperature and surface iron oxide scale characteristics; after passing through the No. 2 water cooling box unit, the rolled piece enters the sizing reduction section for high-precision rolling; after the high-precision rolling operation, the rolled piece passes through the No. 3 water cooling box unit for water cooling. After cooling, it enters the wire laying section for wire laying to obtain SWRH82B wire; S4 cooling: The SWRH82B wire coil is passed through the Stelmore air cooling line for air cooling, and then collected to obtain the initial SWRH82B wire rod.

[0015] like Figure 1 As shown in the figure: supercooled austenite will decompose into pearlite-type structure in the temperature range of A1-550℃. It relies on the diffusion of carbon atoms and iron atoms to complete the redistribution of carbon in the reaction and the reconstruction of iron lattice. It is a typical diffusion phase transformation. Relatively coarse pearlite is formed in the temperature range of A1-650℃. The disadvantages of coarse pearlite are as follows: Reduced strength and hardness: The thickness of pearlite directly affects the strength and hardness of the material. Relatively coarse pearlite has fewer interfaces and has a poor effect in hindering dislocation movement, resulting in lower hardness and strength of the material than fine pearlite; coarse pearlite structure leads to decreased performance of the material under impact load, and the interface between large grains becomes a favorable path for crack propagation, reducing the impact resistance of the material; poor fatigue performance: coarse pearlite grains may lead to reduced fatigue life of the material. Coarse grains reduce the number of grain boundaries, which can hinder the propagation of cracks, so coarse grains will make crack propagation easier; uneven performance: the presence of coarse pearlite usually means that the microstructure of the material has certain macroscopic unevenness. This structural inhomogeneity may cause the overall properties of the material to show direction dependence or local performance differences, and processing difficulties: coarser pearlite structure may make the material more difficult to process, such as cutting and forming, because larger organizational units require greater processing forces and more complex processing techniques; because during the cooling process, it is necessary to quickly pass through this area, but a certain cooling rate must be maintained to consider the overall performance. The cooling rate will be explained below; In the temperature range of 650-550, at the medium cooling speed, troostite is formed by alternating finer ferrite and cementite layers. Troostite is finer and more uniform than ordinary pearlite, thus having better strength and toughness. This form is the organizational state required before high carbon steel processing. Temperature range: 550℃ to Ms point: This is a semi-diffusive phase transformation. The formation of bainite depends on the shear of iron atoms and the partial diffusion of carbon atoms. Upper bainite: Formed at 550 to 350℃, the structure is feather-like, characterized by discontinuous short rod-shaped Fe-Fe2C distributed between parallel ferrite strips. Due to its wider ferrite strip grains, it has low resistance to plastic deformation and is prone to brittle fracture, so its strength and toughness are poor. Lower bainite: Formed at 350℃ to below the Ms point, characterized by a combination of needle-shaped supersaturated ferrite and carbides. With high-density dislocations and fine carbide precipitation, the lower bainite exhibits better comprehensive mechanical properties than the upper bainite, including higher strength, toughness and plasticity. Therefore, during the cooling process, it is necessary to quickly pass through the cooling area where the upper bainite is formed; Therefore, according to the above TTT curve, the air cooling operation is set to 5 stages, and the specific cooling process is as follows: Cooling stage 1: Cool the SWRH82B wire to 742±5℃ to reduce the formation of primary cementite and ensure rapid passage through the potential unstable area; Cooling stage 2: Cool the SWRH82B wire to 650±5℃ to prevent the formation of undesirable microstructures; Cooling stage 3: Cool the SWRH82B wire to 550±5℃; Cooling stage 4: Cool the SWRH82B wire to 350±5℃; to quickly pass through the temperature area where upper bainite is formed; Cooling stage 5: Cool the SWRH82B wire to room temperature; For cooling stage 1 and cooling stage 4, increase the cooling air volume as much as possible; S5 aging treatment: After the initial SWRH82B wire rod is preheated in an inert atmosphere, it is placed in a preset temperature environment for aging treatment to obtain the SWRH82B wire rod.

[0016] Compared with the traditional aging treatment in natural environment for more than 15 days, the reasons for using preheat treatment and constant temperature aging are as follows: Temperature equalization: Preheat treatment can ensure that the temperature of the wire rod is uniform over the entire volume, avoiding inconsistencies caused by uneven temperature. This is very important, especially in large-scale production. When the temperature of the wire rod is uniform before aging treatment, it can reduce the internal stress caused by temperature gradients. If these stresses are not controlled, they may cause microstructural damage or cracks inside the material; Improve aging effect: Through preheat treatment, the microstructure of the material can be adjusted to a more suitable state, providing a good foundation for precipitation hardening or solid solution strengthening during the aging process; preheat treatment promotes the uniform distribution of the internal chemical composition (such as carbon and other alloy elements) and the optimization of the microstructure of the material through gentle heating, which is beneficial to the efficiency and effect of subsequent aging treatment.

[0017] Shorten the aging treatment time: Compared with the long aging treatment in the natural environment, the total treatment time can be greatly shortened through controlled preheating and constant temperature aging, because the preset temperature and environmental conditions can guide the material to reach the required performance indicators more quickly. Immediately placing it in a controlled constant temperature environment after preheating can accelerate precipitation or strengthen the reaction, thereby reducing the total production cycle and improving production efficiency. Figure 2 As shown, it can be clearly seen that the method is effective not only for the wire rod A of the present invention, but also for other SWRH82B wire rods.

[0018] Preferably, in step S1, the specific steps of the cleaning operation are as follows: A1 pretreatment: use an alkaline cleaning solution to clean the surface of the steel billet to remove grease, slight oxides and other impurities; the alkaline cleaning solution contains a polyoxyethylene fatty alcohol ether non-ionic surfactant; the temperature of the alkaline cleaning solution is 50-60°C; A2 high-pressure water spraying: use a high-pressure water flow to thoroughly rinse the pretreated steel billet, and the water pressure is 150-200bar; A3 hot air drying: use a hot air drying system to thoroughly dry the steel billet that has been sprayed with high-pressure water to ensure that there is no residual moisture.

[0019] The above cleaning steps are explained as follows: Effective removal of grease and impurities: Alkaline cleaning liquid has a strong degreasing ability and can effectively dissolve and remove grease and other organic contaminants on the surface of the steel billet. This is because the alkaline solution can undergo a saponification reaction with grease, converting the grease into soluble soap, which is easy to be cleaned and removed. Removal of slight oxides and impurities: The alkaline environment can also slightly etch the metal surface, helping to remove attached oxides and other inorganic impurities. The role of non-ionic surfactants: The addition of polyoxyethylene fatty alcohol ether non-ionic surfactants further improves the cleaning effect. This type of surfactant can reduce the surface tension of water, increase the contact area between the cleaning liquid and the steel surface, and make the cleaning more thorough. At the same time, non-ionic surfactants are not easy to react with ions in water, avoiding possible chemical precipitation or side reactions. Choice of temperature (50-60°C): At this temperature, the chemical activity of the alkaline cleaning liquid is moderate, which can effectively carry out the cleaning operation without causing excessive chemical attack or thermal stress to the steel. At the same time, warmer liquids are easier to dissolve and remove grease. Overall, these selections ensure that the billet surface reaches the required cleanliness standard, creating an excellent basis for subsequent heating and rolling operations.

[0020] Preferably, in step S2, the parameters of the initial heating stage are as follows: the heating rate is 6-8°C / min; the target temperature is 530-550°C, and the holding time is 15-20 minutes; the parameters of the heating stage are as follows: the target temperature is 1010±10°C°C, and the holding time is 75-85 minutes; the parameters of the equalization stage are as follows: the target temperature is 1080-1120°C; the holding time is 80-90 minutes; the parameters of the short-term heating heat treatment stage are as follows: the target temperature is 1170-1210°C, and the holding time is 5-10 minutes.

[0021] The heat treatment parameters selected reflect the specific chemical composition and desired material properties of the steel billet SWRH82B. These chemical components, such as carbon, silicon, manganese, molybdenum, vanadium, chromium, etc., have a significant impact on the heat treatment response of the steel. The following are the reasons why these specific parameters were selected for heat treatment: Initial heating stage: The presence of carbon and manganese gives the steel good hardenability, but it also means that uneven heating may lead to uneven microstructure such as carbide segregation; gentle heating helps to slowly and evenly resolve the distribution of carbon and manganese in the microstructure. Silicon enhances the strength and hardness of the steel and also affects thermal expansion. Controlling the heating rate helps to reduce internal stresses and deformations caused by thermal expansion. Gentle heating also helps prevent premature carbide precipitation promoted by vanadium and molybdenum, which if precipitated at an early stage, will affect the plasticity and toughness of the material. Heating stage: This temperature range is reached for full austenitization, which is a key process for the uniform distribution of carbon and alloying elements (especially molybdenum and chromium) in the steel. This temperature is high enough to dissolve most of the carbides and make the alloying elements uniformly distributed in the austenite. The choice of temperature and time also takes into account the effects of chromium and nickel, which improve the thermal stability and oxidation resistance of the alloy and are suitable for processing at higher temperatures. Soaking stage: In this stage, the high temperature helps to further homogenize the alloying elements in the steel, especially manganese and silicon. Manganese and silicon contribute to the strength and toughness of the material, but their uniform distribution is essential to achieve these properties. This temperature range is also conducive to optimizing the effect of boron, which, although in very small amounts, greatly affects the hardenability and hardness of the steel. Short-term high-temperature heat treatment stage: A short high-temperature treatment is used to optimize the deformability of the steel billet and reduce any alloying element concentration gradients that may have formed during the soaking stage; the short high-temperature treatment at this stage helps to control the premature re-precipitation of carbides promoted by molybdenum and vanadium, thereby preventing these carbides from causing adverse microstructural changes. In this way, it is ensured that the steel maintains good mechanical properties and structural homogeneity during subsequent processing.

[0022] Preferably, in step S3, the No. 1 water-cooling box unit is provided with 3 water-cooling boxes, the No. 2 water-cooling box unit is provided with 2 water-cooling boxes, and the No. 3 water-cooling box unit is provided with 3 water-cooling boxes, each water-cooling box is arranged with a plurality of water cooling nozzles and a plurality of cleaning nozzles, and the water pressure and water volume are adjustable; the cooling medium of the No. 2 water-cooling box unit is a mixture of cooling water and antioxidant coolant.

[0023] Preferably, in step S3, in the rough rolling operation, the frame structure of the rolling mill is designed as a closed frame; a single-line torsion-free micro-tension controlled rolling technology is adopted; In the intermediate rolling operation, double-line rolling is adopted; micro-tension controlled rolling technology is adopted; In the pre-finishing rolling operation, the loop rolling mechanism is realized based on the loop device, and the loop device has the following components: a rolled piece inlet, which is arranged at one end of the loop device and is used to receive the rolled piece from the intermediate rolling section; a transmission unit, which is arranged between the rolled piece inlet and the outlet, and is used to adjust the speed and position of the rolled piece in the device; a speed regulating mechanism, which is connected to the transmission unit and is used to adjust the speed of the rolled piece according to the requirements of the pre-finishing rolling stage, and the speed regulating mechanism is provided with a positioning controller for real-time monitoring of the position and speed of the rolled piece; a rolled piece outlet, which is arranged at the other end of the loop device and is used to send out the rolled piece after rolling; In the finishing rolling operation, several cantilever rolling mills are used to roll with a collective transmission mechanism, and all cantilever rolling mills are synchronized through a shared transmission system; In the high-precision rolling operation in the sizing stage, a high-precision Morgan sizing precision rolling machine is used, and high-speed diameter measurement technology is used to monitor and adjust the size in real time to ensure the finished product size accuracy of ±0.1mm.

[0024] The design of the closed frame structure for rough rolling operation is very important, mainly due to the following advantages: Rigidity and stability: The closed frame provides higher rigidity and stability than the open frame. This structure can withstand higher rolling loads and reduce the bending and deformation of the frame, which is critical for maintaining accurate rolling size and shape. Vibration control: The closed structure can effectively reduce vibration during operation, improve rolling accuracy and surface quality. Durability: Due to its stable structural design, the closed frame has high durability and is suitable for long-term heavy-load operation, reducing maintenance costs.

[0025] Adoption of single-line torsion-free micro-tension controlled rolling technology: Single-line torsion-free micro-tension controlled rolling technology is an advanced rolling technology, which is mainly used to control the tension during the rolling process to optimize the rolling results: Tension control: This technology can effectively reduce the twisting and bending of the rolled piece during the rolling process by controlling the tension of the rolled piece between the rolling mills. This is very important for maintaining the straightness of the product and reducing internal stress. Reduce defects: Torsion-free micro-tension rolling helps to reduce surface and internal defects and improve the uniformity and overall quality of the material. Suitable for high-speed rolling: This technology is particularly suitable for high-speed rolling operations, which can improve production efficiency while maintaining product quality. The choice of these technologies reflects the high requirements for precision, efficiency and material properties in the production of high-performance steel. The combination of closed stands and torsion-free micro-tension controlled rolling technology not only optimizes the rolling process, but also ensures the high quality standards of the finished product, meeting the strict needs of SWRH82B wire rod for strength, durability and reliability in applications.

[0026] Double-wire rolling and micro-tension controlled rolling technologies are used in intermediate rolling operations. These technologies are mainly selected to improve the efficiency, accuracy and final quality of the rolling process. The role and importance of these technologies are explained in detail below: Adoption of twin-line rolling: Twin-line rolling refers to the use of two production lines to perform rolling operations simultaneously. The main advantages of this method include: Improved production efficiency: By rolling on two lines at the same time, the production volume can be significantly increased, the production time can be reduced, and the entire production process can be more efficient. Uniform load distribution: Twin-line operation can balance the load of mechanical equipment, thereby reducing machine wear and maintenance frequency and extending the service life of the equipment. Flexibility and redundancy: During the production process, if one line fails, the other line can continue production, thereby ensuring the continuity of the production process and reducing downtime.

[0027] Adoption of micro-tension controlled rolling technology: Micro-tension controlled rolling technology is a method of carefully controlling the tension of materials during the rolling process, which is mainly used to improve the dimensional accuracy and physical properties of products: Reduce material deformation: By controlling the micro-tension of the rolled piece, the internal stress and deformation of the material during the rolling process can be effectively reduced, which is especially important for the production of products with high dimensional accuracy.

[0028] Improved surface quality: Reducing tension can reduce scratches and indentations on the material surface, thereby improving the surface finish of the finished product.

[0029] Optimizing material properties: By precisely controlling the tension, the material’s microstructure can be influenced, thereby improving its mechanical properties, such as strength and toughness.

[0030] The application of these technologies in the intermediate rolling stage is crucial because this stage has a direct impact on the dimensional accuracy, physical properties and surface quality of the finished product. The combination of double-line rolling and micro-tension control technology not only improves production efficiency, but also ensures high quality standards of products, meeting the strict requirements of material performance and quality in industrial applications.

[0031] The reason for using a looper rolling mechanism in pre-finishing rolling operations is to improve the continuity and accuracy of the rolling process while reducing the internal stress and surface defects of the material. The looper rolling mechanism has several key advantages: Improved rolling speed and flexibility: The looper rolling mechanism allows the material to move continuously between different rolling mills without stopping through a looper device. This means that the rolled piece can be smoothly transferred between the various rolling mills at a higher speed, thereby improving production efficiency. Control of material tension: The speed adjustment mechanism in the looper rolling mechanism allows precise control of the tensile force of the rolled piece. This control helps maintain uniform tension in the rolled piece during the rolling process, reduces the risk of material breakage, and maintains good surface quality. Reduced internal stress and improved dimensional accuracy: By adjusting the speed and tension at each rolling stage, the looper rolling mechanism helps reduce the accumulation of internal stress in the rolled piece, which is essential for maintaining the mechanical properties and dimensional accuracy of the finished product. In addition, the total accumulated stress to which the rolled piece is subjected during the rolling process is low, which helps to improve the overall quality of the finished product. Adaptability and adjustment capabilities: The design of the looper rolling mechanism allows the production line to be quickly adjusted to meet the needs of different sizes and specifications. The flexible configuration of the speed adjustment mechanism and the transmission unit can quickly adjust the speed and position of the rolled piece according to production needs. This flexibility is the key to maintaining high production efficiency in a high-variable production environment. Improve the quality of finished products: The use of the looper device helps to maintain a uniform thermal state of the rolled piece throughout the rolling process, thereby optimizing the microstructure and mechanical properties and preventing the formation of material defects such as cracks and pores. In short, the application of the looper rolling mechanism in pre-finishing rolling operations ensures a high-efficiency and high-quality production process by improving the continuity, precision and adjustment capabilities of the operation.

[0032] The components of the looper device are as follows: a rolled piece inlet, which is arranged at one end of the looper device and is used to receive the rolled piece from the intermediate rolling section; a transmission unit, which is arranged between the rolled piece inlet and the outlet, and is used to adjust the speed and position of the rolled piece in the device; a speed regulating mechanism, which is connected to the transmission unit and is used to adjust the speed of the rolled piece according to the requirements of the pre-finishing rolling stage, and the speed regulating mechanism is provided with a positioning controller for real-time monitoring of the position and speed of the rolled piece; a rolled piece outlet, which is arranged at the other end of the looper device and is used to send out the rolled piece after rolling; The specific steps of the pre-finishing rolling operation using the looper rolling mechanism are as follows: A1 Workpiece entry: After the workpiece comes out of the middle rolling section, it first enters the looper device; the looper device is used to adjust the speed and position of the workpiece to prepare for entering the pre-finishing rolling; A2 Speed ​​adjustment: In the looper device, the speed and position of the workpiece are adjusted as needed; A3 cantilever mill rolling: after adjusting the speed and position, the workpiece is sent to the cantilever mill for rolling; The decision to use several cantilever mills and adopt a collective drive mechanism for rolling in the finishing operation is mainly based on improving rolling efficiency, ensuring product quality and optimizing the overall performance of the production line. Here are a few key reasons for choosing this mechanism: Synchronous operation improves rolling accuracy: The use of a collective drive mechanism allows all cantilever mills to operate synchronously. This synchronization is very important because it ensures that the rolled product is subjected to uniform forces when passing through each mill, which can effectively control the shape and size of the rolled product. Synchronous operation helps to reduce dimensional deviations and shape irregularities in the product and improve the quality of the finished wire. High efficiency and energy optimization of collective drive: The collective drive mechanism is generally more energy-efficient than the configuration of driving each mill separately because the shared drive system reduces energy losses. This configuration can more effectively use power, reduce maintenance costs, and improve overall production efficiency. Reduced mechanical failures and maintenance requirements: The collective drive system is more stable and reliable than multiple independent drive systems due to its simple design and small number of moving parts. This design reduces downtime caused by component failure and improves the continuous operation ability of the production line. Enhance the flexibility and adaptability of the rolling line: The cantilever mill design using a collective drive mechanism allows for easier adjustment of rolling parameters and adaptation to product requirements of different specifications. Because the drive system is shared, adjustments to the settings of one mill (such as speed or pressure) can be quickly transmitted to the entire production line, allowing more flexible production adjustments to respond to market changes. Maintain the temperature and microstructure consistency of the rolled piece: During the finishing stage, it is critical to maintain the consistency of the temperature and microstructure of the rolled piece, which affects the mechanical properties of the final product. The collective drive mechanism helps maintain uniform temperature and stress distribution of the rolled piece throughout the rolling process through precise control and synchronized operation. In summary, the purpose of choosing to utilize cantilever mills and collective drive mechanisms in finishing operations is to improve production efficiency, ensure product quality, reduce production costs, and enhance the overall operational stability and flexibility of the production line.

[0033] Preferably, in step S3, the inlet temperature of the steel billet in the rough rolling section is required to be 995±15°C; the inlet temperature of the rolled material in the finishing rolling section is required to be 910±10°C, and the inlet temperature of the rolled material in the sizing reduction section is required to be 920±15°C; in the wire laying operation, the wire laying temperature is 840±10°C; In the preparation process of SWRH82B wire rod, strict control of the inlet temperature at different rolling sections is crucial, because these temperature parameters directly affect the microstructure, mechanical properties and dimensional accuracy of the finished product. Here are several key reasons why these specific temperature parameters are selected: 1. The inlet temperature of the steel billet in the rough rolling section is required to be 995±15℃: Maintain the plasticity of the material: This temperature range ensures that the steel billet maintains sufficient plasticity so that it can be smoothly formed in the rolling mill and avoids cracks or other damage to the material during the rolling process. Control the transformation of the microstructure: High temperature during the rolling process can promote the formation of austenite, which is a key factor in controlling the final microstructure and improving product performance.

[0034] 2. The inlet temperature of the rolled material in the finishing rolling section is required to be 910±10℃: Refining the grain structure: Lowering the inlet temperature in the finishing rolling stage helps to refine the grains through dynamic recrystallization, thereby improving the strength and toughness of the material.

[0035] 3. The inlet temperature of the rolled material in the sizing stage is required to be 920±15℃: Ensure smooth rolling and dimensional accuracy: This temperature range optimizes the plasticity of the material, making the flow of the material more uniform during the rolling process, and helps to maintain the size and shape accuracy of the rolled piece. Adjustment of the final physical properties: By controlling the temperature of this section, the final physical properties of the material, such as hardness and toughness, can be adjusted.

[0036] During the entire rolling process, special attention should be paid to the inlet temperature and the spinning temperature of the finishing rolling. In conventional finishing rolling operations, the inlet temperature of the finishing rolling is controlled at 920±30°C. The present invention selects a lower inlet temperature for the following reasons: Promote dynamic recrystallization and grain refinement: The lower inlet temperature of the finishing rolling helps to promote dynamic recrystallization of the material during deformation. Dynamic recrystallization can effectively refine the grains, because deformation at a lower temperature increases the migration rate of the grain boundaries, thereby forming smaller grains. This refined grain structure can significantly improve the yield strength and tensile strength of the material, while also enhancing the toughness of the material. Improve the mechanical properties of the material: By rolling at a lower temperature, the yield point and tensile strength of the material can be improved. Lower temperatures make it more difficult for the material to flow during plastic deformation, thereby producing a higher strain hardening effect during the rolling process, and ultimately improving the hardness and strength of the material. Control the transformation of the microstructure: Rolling at a lower temperature can more finely control the phase transformation of the steel, especially the transformation from austenite to martensite. This control not only affects the hardness and toughness of the material, but also has an important impact on the fatigue life and impact resistance of the material. Reduce oxidation and decarburization: Reduce surface defects: Lower rolling temperature can reduce the risk of surface oxidation of materials at high temperatures, thereby reducing the formation of oxide scale and decarburization, and maintaining good surface quality. The above temperature and rolling process cooperate to achieve the purpose of finishing rolling.

[0037] During the production of SWRH82B wire rod in different seasons, there is a problem that the tensile strength of the wire rod in winter is higher than that in summer. In order to improve the stability of mechanical properties, improve the internal tissue stress of the wire rod, optimize the control range of the wire laying temperature, and distinguish the production processes in winter and summer, in order to avoid the excessive tensile strength of the wire rod resulting in reduced plasticity, the wire laying temperature target is controlled at 830℃ in winter, and in summer, in order to prevent the temperature from being too high and the cooling speed of the controlled cooling roller from decreasing, resulting in insufficient tensile strength of the wire rod, the wire laying temperature target value is controlled at 850℃; therefore, in the case of accelerated cooling speed in winter, the wire laying temperature should be appropriately reduced to reduce the tensile strength of the wire rod and improve the plasticity of the wire rod. At the same time, the wire laying temperature fluctuation range is controlled within the range of ±10℃, otherwise the uniformity of the wire rod will be reduced. In addition, the wire needs a period of cooling on the Stelmore line before phase change occurs. In actual production, the wire laying temperature is controlled at 830-850℃. In this temperature range, most of the iron oxide scale formed on the surface of the wire is easy-to-remove iron oxide, rather than the difficult-to-remove iron oxide scale.

[0038] Preferably, in step S4, the Stelmore air cooling line is composed of: a number of high-power cooling fans with adjustable wind speed, a number of medium-power cooling fans with adjustable speed, a number of air ducts, a number of temperature sensors, a control system, a thermal insulation cover and a transportation device, and the transportation device is composed of a number of rollers with adjustable speed; the high-power cooling fans are used for cooling stage 1, cooling stage 2 and cooling stage 4, and the medium-power cooling fans are used for cooling stage 3 and cooling stage 5; the thermal insulation cover is used for cooling stage 3; in cooling stage 2, the cooling rate is controlled to be 10-12°C / s.

[0039] like Figure 3 and Figure 4As shown in the figure, the cooling rate is controlled to be 10-12℃ / s as follows: When the cooling rate is in the range of 1℃ / s to 12℃ / s, the microhardness increases slowly. This change is mainly because as the cooling rate increases, the interlamellar spacing in the pearlite structure decreases, the grain size decreases, and the grain boundary area increases accordingly, which leads to an increase in dislocation density, thereby increasing the deformation resistance of the material. When the cooling rate exceeds 12℃ / s and enters the range of 12℃ / s to 30℃ / s, the rate of increase of microhardness is significantly accelerated and shows a linear growth trend. This is because at a higher cooling rate, more martensite structures begin to form inside the material, and martensite significantly improves the overall microhardness due to its higher hardness; when the cooling rate gradually increases in the range of 1℃ / s to 12℃ / s, the tensile strength and section reduction rate usually show an upward trend, but there is a slight decrease at a specific point of 12℃ / s. However, when the cooling rate continues to increase, reaching 12℃ / s to 30℃ / s, the tensile strength increases significantly with the increase in cooling rate, while the section shrinkage shows the opposite trend, that is, it gradually decreases. This reflects the changes in the internal structure of the material at different cooling rates. At lower cooling rates (1℃ / s to 10℃ / s), the tensile strength and plasticity of the steel are improved due to the uniform refinement of the pearlite structure. However, as the cooling rate further increases to more than 15℃ / s, the tensile strength is enhanced, while the plasticity is reduced, resulting in a significant decrease in the section shrinkage; in summary, in order to maintain excellent comprehensive mechanical properties, the cooling rate is maintained at around 10℃ / s, and the maximum should not exceed 12℃ / s to avoid affecting the overall performance of the material.

[0040] Preferably, the preheating process is as follows: the initial SWRH82B wire rod is heated to 350±5°C, kept warm for 1-2 hours, cooled to 40-50°C, and then placed in a constant temperature environment of 20-25°C for 240-260 hours.

[0041] The temperature range of 350±5℃ is to achieve the release of residual stress and adjustment of microstructure in the wire rod. 350°C is a relatively low temperature at which the material can be effectively tempered while avoiding the formation of upper bainite. The cooling process from 40-50°C to room temperature provides a gradual temperature transition for the material, which helps to further release residual stress, thereby obtaining more uniform and stable properties in the simulated natural aging process.

[0042] Compared with the prior art, the present invention has the following beneficial effects: 1. Multi-stage precise heating and temperature control: The present invention effectively controls the microstructure of the steel and improves the uniformity of the material through multi-stage heating treatment, including gentle heating, homogenization and short heating heat treatment stages. This fine temperature control helps to optimize the microstructure, reduce defects and improve the mechanical properties of the final product.

[0043] 2. Application of controlled rolling and controlled cooling technology: Use advanced controlled rolling and controlled cooling technology for rolling to obtain a more uniform microstructure and higher strength.

[0044] 3. Optimized cooling method: After the spinning operation, multi-stage cooling ensures the gradual cooling of the material from high temperature to room temperature, effectively controls the phase change of the material, reduces internal stress, avoids the formation of undesirable microstructures, and significantly improves the comprehensive performance of the wire rod.

[0045] 4. Fine aging treatment: The precisely controlled aging process, including preheating and long-term heat preservation under an inert atmosphere, effectively stabilizes the microstructure of the material and improves the reliability and performance consistency of the material. This method also shows advantages in reducing production cycles because it reduces the time and variables required for natural aging.

[0046] 5. Application of high-precision rolling technology: The application of high-precision rolling technology ensures strict precision control of product dimensions. Real-time dimension monitoring and adjustment during the rolling process helps to achieve the accuracy requirement of ±0.1mm.

[0047] In conclusion, the method of the present invention improves the same-circle strength of the SWRH82B wire rod through comprehensive process optimization and achieves the required mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is the TTT diagram in the present invention.

[0049] Figure 2 This is a graph showing the relationship between tensile strength and aging days in the present invention.

[0050] Figure 3 Graph showing the relationship between the tensile strength and the cooling rate in cooling stage 2 in the present invention.

[0051] Figure 4 This is a relationship diagram between the cross-sectional shrinkage rate and the cooling rate in cooling stage 2 in the present invention.

[0052] Figure 5 This is the core segregation diagram of the SWRH82B wire rod prepared in a specific example.

[0053] Figure 6 This is the core structure diagram of the SWRH82B wire rod prepared in a specific example. DETAILED DESCRIPTION

[0054] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0055] A method for preparing a high-convolution SWRH82B wire rod comprises the following steps: S1 Cleaning: Check whether the chemical composition of the steel billet meets the production requirements, and clean the steel billet that meets the production requirements to remove surface impurities; the parameter requirements for the chemical composition of the steel billet are as follows: carbon content is 0.81%-0.83%wt; silicon content is 0.25%-0.35%wt; manganese content is 0.75%-0.85%wt; nickel content is 0.2-0.3%wt; molybdenum content is 0.15%-0.25%wt; vanadium content is 0.07%-0.009%wt; chromium content is 0.2-0.25%wt; boron content is 0.0015%-0.003%wt; aluminum content is not higher than 0.007%wt; phosphorus content is not higher than 0.02%wt; sulfur content is not higher than 0.015%wt; copper content is not higher than 0.02%wt; the rest is iron and unavoidable impurities; The specific steps of the cleaning operation are as follows: A1 pretreatment: Use alkaline cleaning liquid to clean the surface of the steel billet to remove grease, slight oxides and other impurities; the alkaline cleaning liquid contains polyoxyethylene fatty alcohol ether non-ionic surfactants; the temperature of the alkaline cleaning liquid is 60°C; A2 high-pressure water spraying: Use high-pressure water flow to thoroughly rinse the pretreated steel billet with a water pressure of 200 bar; A3 hot air drying: Use a hot air drying system to thoroughly dry the steel billet that has been sprayed with high-pressure water to ensure that there is no residual moisture.

[0056] S2 Heating: In an inert atmosphere, the cleaned steel billet is heated to obtain a pre-rolled steel billet. The heating treatment includes four stages, namely, an initial heating stage, a heating stage, a heat-saturation stage, and a short-term heating heat treatment stage. The parameters of the initial heating stage are as follows: the heating rate is 6-8°C / min; the target temperature is 550°C, and the holding time is 20 minutes; the parameters of the heating stage are as follows: the target temperature is 1010℃°, and the holding time is 85 minutes; the parameters of the equalization stage are as follows: the target temperature is 1120°C; the holding time is 90 minutes; the parameters of the short heating heat treatment stage are as follows: the target temperature is 1210°C, and the holding time is 10 minutes.

[0057] S3 rolling: After the heated billet is descaled, it is rolled by controlled rolling and controlled cooling process to obtain SWRH82B wire rod; the diameter of SWRH82B wire rod is 12.5mm; The specific rolling process is as follows: The specific process is as follows: Rough rolling section: Rolling technology: single-line torsion-free micro-tension controlled rolling technology; Rolling mill design: a rolling mill with a closed frame structure design; Inlet temperature: 995°C. Rolling speed: 3m / s, Reduction rate: multiple rolling, 25% reduction per pass, Output: After the rough rolling is completed, the rolled piece enters the conveyor roller with a heat preservation cover, and the head is cut using a shearing device; Intermediate rolling section: rolling technology: double-wire rolling and micro-tension control technology; rolling speed: increased to 4m / s, diameter reduction rate: multiple rolling, 20% diameter reduction per pass; output: after completing the intermediate rolling, use shearing equipment 2 to cut the rolled piece; Pre-finishing rolling section: Rolling technology: loop rolling mechanism; Rolling speed: maintained at 4-5m / s, diameter reduction rate: 15% per pass, close to the final size, Cooling: the rolled piece after pre-finishing rolling is cooled by water through the No. 1 water cooling box unit; Output: Use shearing equipment No. 3 for head and tail cutting.

[0058] Finishing rolling section: Rolling technology: using a number of cantilever rolling mills with a collective transmission mechanism for rolling; inlet temperature: 910°C; rolling speed: 6m / s, quickly approaching the final shape; diameter reduction rate: 10%, fine-tuning the size, after finishing rolling, the rolled piece is cooled by water through the No. 2 water cooling box unit; Sizing stage: Rolling technology: Use high-precision Morgan sizing precision rolling mill, with high-speed diameter measurement technology to monitor and adjust the size in real time; Inlet temperature: 920°C; Rolling speed: 7m / s, the maximum speed to ensure high precision; Dimensional accuracy: ±0.1mm, controlled by high-speed diameter measurement technology, Cooling: After completion, it is cooled by water through the No. 3 water cooling box unit.

[0059] Silk-spinning section: Silk-spinning temperature: 830°C; Speed: The speed is generally 8m / s.

[0060] S4 air cooling: The SWRH82B wire rod is air-cooled through the Stelmore air-cooling line and then collected to obtain the initial SWRH82B wire rod; The specific cooling process is as follows: Fan configuration: Total number of fans: 16; High-power cooling fans: 10; Medium-power cooling fans: 6; The maximum wind pressure of the high-power fan is 2.94MPa, and the maximum air supply volume is 154700m³ / h. The maximum wind pressure of the medium-power cooling fan is 1.2MPa, and the maximum air supply volume is 70000m³ / h; Cooling stage 1: target temperature, (742±5℃); fans: 3 high-power fans; purpose: rapid cooling to reduce the formation of primary cementite; start at maximum power; Cooling stage 2: Target temperature: (650±5℃); Fans: 3 high-power ones; Purpose: Control the cooling rate to 10℃ / s to prevent the formation of undesirable microstructures; Cooling stage 3: Target temperature: (550±5℃); Fans: 3 medium-sized fans; Insulation cover: Use; The insulation cover is made of ceramic fiber insulation material; Purpose: Slow cooling to balance the internal structure, the cooling rate is 2.5-3℃ / s; Cooling stage 4: Target temperature: (350±5℃); Fans: 4 high-power; Purpose: Quickly pass through the temperature zone where upper bainite is formed; Start at maximum power; Cooling stage 5: Target temperature: (room temperature): Fans: 3 medium-sized units; Purpose: Stable cooling to room temperature; Control and monitoring system: 3-4 temperature sensors will be installed in each cooling stage; advanced PLC (Programmable Logic Controller) control and touch screen human-machine interface are used to ensure that the fan speed and roller speed are adjusted according to real-time data; process parameters and operating status can be displayed in real time; This configuration can reduce costs compared to traditional production lines that use all the same high-power fans.

[0061] S5 aging treatment: After the initial SWRH82B wire rod is preheated in an inert atmosphere, it is placed in a preset temperature environment for aging treatment to obtain the SWRH82B wire rod. The specific process is as follows: the initial SWRH82B wire rod is heated to 350°C, kept warm for 2 hours, cooled to 40°C, and placed in a constant temperature environment of 25°C for 240 hours.

[0062] SWRH82B wire rod performance test: Three SWRH82B wire rods from the same batch were selected for verification, numbered 1, 2 and 3. Figure 5 and 6 is the graph numbered 2; the results are shown in Table 1: Table 1

[0063] Tensile strength analysis: The tensile strength of all wire rods meets the standard requirements of CB / T24238-2009, that is, they are all within the specified range of 1130 to 1280 MPa.

[0064] From the data, it can be seen that the tensile strength of the three wire rods is not much different, indicating that the wire rod has high consistency and reliability in tensile strength.

[0065] Sectional reduction analysis: The section reduction of all wire rods exceeded the minimum requirement of 30%, which indicates that the material has good plastic deformation ability when subjected to tension.

[0066] The slight differences in reduction of area (minimum 34% and maximum 35.2%) show small variations in plastic deformation properties between batches, but this variation is within an acceptable range and indicates a high level of production and material consistency.

[0067] Conclusion: In summary, the two key performance indicators of SWRH82B wire rods No. 1, 2, and 3 all meet the requirements of CB / T24238-2009 standard in terms of tensile strength and cross-sectional shrinkage. This shows the stability of the production process and the reliability of the materials. For practical applications, this batch of materials is qualified and has consistent performance, with a high degree of congruence.

[0068] The data provided by downstream customers show the following results: SWRH82B rolled wire rod is used to produce steel strands. The raw material steel of 12.5mm is rinsed with oxidized iron scale → clean water tank (cleaning residual oxidized iron scale) → activation tank (preparing for phosphating) → electrolytic phosphating tank → saponification → drawing (12.5mm → 11.55mm → 10.35mm → 9.27mm → 8.23mm → 7.52mm → 6.73mm → ф6.19mm → ф5.50mm → 5.05mm / 5.25mm) → winding → stranding → stabilization → coiling → coiling → packaging → storage to obtain steel strands. The mechanical properties of SWRH82B steel strand tested according to GB / T228.1-2010 "Tensile test of metallic materials Part 1 Room temperature test method Room temperature tensile test method" and GB / T21839-2008 "Test methods for steel for prestressed concrete" are shown in Table 2. Table 2

[0069] The mechanical indicators of the steel strands produced using the prepared SWRH82B wire rod all meet the requirements, and the surplus is large enough to ensure subsequent use.

[0070] The specific embodiments described herein are merely examples of the spirit of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described or replace them in a similar manner, but will not deviate from the spirit of the present invention or exceed the defined scope. Although the present invention is described and described in detail in the drawings and the foregoing description, such descriptions and descriptions are considered to be illustrative or exemplary rather than restrictive. It should be understood that within the scope of the following claims, changes and modifications may be made by a person of ordinary skill. Specifically, the present invention encompasses additional embodiments having any combination of features from the above-mentioned different embodiments. With respect to the use of the expression "generally" or "substantially", this patent application should be understood to disclose that these features and values ​​are also fully satisfied, i.e., there is no aforementioned characterization as "generally" or "substantially".

Claims

1. A method for preparing a high-convolution SWRH82B wire rod, characterized in that: The preparation method of high-convolution SWRH82B wire rod comprises the following steps: S1 Cleaning: Check whether the chemical composition of the steel billet meets the production requirements, and clean the steel billet that meets the production requirements to remove surface impurities; the parameter requirements for the chemical composition of the steel billet are as follows: carbon content is 0.81%-0.83%wt; silicon content is 0.25%-0.35%wt; manganese content is 0.75%-0.85%wt; nickel content is 0.2-0.3%wt; molybdenum content is 0.15%-0.25%wt; vanadium content is 0.07%-0.009%wt; chromium content is 0.2-0.25%wt; boron content is 0.0015%-0.003%wt; aluminum content is not higher than 0.007%wt; phosphorus content is not higher than 0.02%wt; sulfur content is not higher than 0.015%wt; copper content is not higher than 0.02%wt; the rest is iron and unavoidable impurities; S2 Heating: In an inert atmosphere, the cleaned steel billet is heated to obtain a pre-rolled steel billet. The heating treatment includes four stages, namely, an initial heating stage, a heating stage, a heat-saturation stage, and a short-term heating heat treatment stage. S3 rolling: After the heated billet is descaled, it is rolled by controlled rolling and controlled cooling process to obtain SWRH82B wire rod; the diameter of SWRH82B wire rod is 12.5mm; The rolling process is as follows: the descaled steel billet is sent to the rough rolling section for rough rolling. After the rough rolling is completed, it enters the conveyor roller with a heat preservation cover. A shearing device is installed behind the conveyor roller with a heat preservation cover. The shearing device is used to perform head cutting. Then the billet enters the intermediate rolling section for intermediate rolling. After the intermediate rolling is completed, the shearing device is used to perform head cutting on the rolled piece. After the head cutting, the rolled piece enters the pre-finishing rolling section for pre-finishing rolling. The pre-finishing rolling adopts a looper rolling mechanism. After the pre-finishing rolling is completed, The rolled piece is cooled by water through the No. 1 water cooling box unit. After the No. 1 water cooling box unit, there is a shearing device No.

3. After the head and tail cutting by the shearing device No. 3, the rolled piece enters the finishing section for finishing rolling. After the finishing rolling, the rolled piece passes through the No. 2 water cooling box unit for water cooling. Then the rolled piece enters the sizing reduction section for high-precision rolling. After the high-precision rolling, the rolled piece passes through the No. 3 water cooling box unit for water cooling. After the cooling, the rolled piece enters the wire laying section for wire laying to obtain SWRH82B wire. S4 air cooling: The SWRH82B wire rod is air-cooled through the Stelmore air-cooling line and then collected to obtain the initial SWRH82B wire rod; The specific cooling process is as follows: Cooling stage 1: Cooling the SWRH82B wire to 742±5℃ to reduce the formation of primary cementite and quickly pass through the potential unstable area; Cooling stage 2: Cooling the SWRH82B wire to 650±5℃ to prevent the formation of undesirable microstructures; Cooling stage 3: Cooling the SWRH82B wire to 550±5℃; Cooling stage 4: Cooling the SWRH82B wire to 350±5℃; to quickly pass through the temperature area where upper bainite is formed; Cooling stage 5: Cooling the SWRH82B wire to room temperature; S5 aging treatment: After the initial SWRH82B wire rod is preheated in an inert atmosphere, it is placed in a preset temperature environment for aging treatment to obtain the SWRH82B wire rod.

2. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S1, the specific steps of the cleaning operation are as follows: A1 pretreatment: use an alkaline cleaning solution to clean the surface of the steel billet to remove grease, slight oxides and other impurities; the alkaline cleaning solution contains a polyoxyethylene fatty alcohol ether non-ionic surfactant; the temperature of the alkaline cleaning solution is 50-60°C; A2 high-pressure water spraying: use a high-pressure water flow to thoroughly rinse the pretreated steel billet, and the water pressure is 150-200bar; A3 hot air drying: use a hot air drying system to thoroughly dry the steel billet that has been sprayed with high-pressure water to ensure that there is no residual moisture.

3. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S2, the parameters of the initial heating stage are as follows: the heating rate is 6-8°C / min; the target temperature is 530-550°C, and the holding time is 15-20 minutes; the parameters of the heating stage are as follows: the target temperature is 1010±10℃°C, and the holding time is 75-85 minutes; the parameters of the equalization stage are as follows: the target temperature is 1080-1120°C; the holding time is 80-90 minutes; the parameters of the short heating heat treatment stage are as follows: the target temperature is 1170-1210°C, and the holding time is 5-10 minutes.

4. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S3, the No. 1 water-cooling box unit is provided with 3 water-cooling boxes, the No. 2 water-cooling box unit is provided with 2 water-cooling boxes, and the No. 3 water-cooling box unit is provided with 3 water-cooling boxes. Each water-cooling box is arranged with a plurality of water cooling nozzles and a plurality of cleaning nozzles, and the water pressure and water volume are adjustable; the cooling medium of the No. 2 water-cooling box unit is a mixture of cooling water and antioxidant coolant.

5. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S3, in the rough rolling operation, the frame structure of the rolling mill is designed as a closed frame; a single-line torsion-free micro-tension controlled rolling technology is adopted; In the intermediate rolling operation, double-line rolling is adopted; micro-tension controlled rolling technology is adopted; In the pre-finishing rolling operation, the looper rolling mechanism is realized based on the looper device; In the finishing rolling operation, several cantilever rolling mills are used to roll with a collective transmission mechanism, and all cantilever rolling mills are synchronized through a shared transmission system; In the high-precision rolling operation in the sizing stage, a high-precision Morgan sizing precision rolling machine is used, and high-speed diameter measurement technology is used to monitor and adjust the size in real time to ensure the finished product size accuracy of ±0.1mm.

6. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S3, the inlet temperature of the steel billet in the rough rolling section is required to be 995±15°C; the inlet temperature of the rolled material in the finishing rolling section is required to be 910±10°C, and the inlet temperature of the rolled material in the sizing reduction stage is required to be 920±15°C; in the wire-spinning operation, the wire-spinning temperature is 840±10°C.

7. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S4, the Stelmore air cooling line is composed of: a number of high-power cooling fans with adjustable wind speed, a number of medium-power cooling fans with adjustable wind speed, a number of air ducts, a number of temperature sensors, a control system, a thermal insulation cover and a transportation device, and the transportation device is composed of a number of rollers with adjustable speed; the high-power cooling fans are used for cooling stage 1, cooling stage 2 and cooling stage 4, and the medium-power cooling fans are used for cooling stage 3 and cooling stage 5; the thermal insulation cover is used for cooling stage 3; in cooling stage 2, the cooling rate is controlled to be 10-12℃ / s.

8. The method for preparing the high-convolution SWRH82B wire rod according to claim 1, characterized in that: In step S5, the aging treatment process is as follows: the initial SWRH82B wire rod is heated to 350±5°C, kept warm for 1-2 hours, cooled to 40-50°C, and then placed in a constant temperature environment of 20-25°C for 240-260 hours.

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