Industrial atmosphere corrosion resistant and earthquake resistant steel bar and preparation method thereof

Abstract

The application relates to an anti-industrial atmosphere corrosion and anti-seismic steel bar and a preparation method thereof. The anti-industrial atmosphere corrosion and anti-seismic steel bar comprises the following components in percentage by weight: C: 0.17wt%-0.21wt%, Mn: 0.95wt%-1.25wt%, Si: 0.35wt%-0.65wt%, Cr: 0.20wt%-0.40wt%, V: 0.025wt%-0.035wt%, Cu: 0.30wt%-0.50wt%, P: 0.08wt%-0.10wt%, S<=0.010wt%, and the balance is Fe and inevitable impurities.

Description

Technical Field

[0001] This application relates to the field of steel technology, specifically to a shock-resistant steel bar resistant to industrial atmospheric corrosion and its preparation method. Background Technology

[0002] Corrosion-resistant steel bars refer to steel bars with anti-corrosion properties. In addition to the tensile stress-bearing function of ordinary steel bars, they also possess corrosion-resistant characteristics, with a relative corrosion rate of less than 70%, effectively extending the service life of the steel bars and saving costs. With changes in market demand and economic conditions, product upgrading and transformation, and high-quality production are the primary tasks for enterprise survival and development. The development, production, and application of corrosion-resistant steel bars align with the national requirements of "green, low-carbon, and sustainable development," offering broad market prospects and significant economic and social benefits. Depending on the application environment, such as industrial atmospheric corrosion environments and chloride ion corrosion environments, corrosion-resistant steel bars can be divided into industrial atmospheric corrosion-resistant steel bars and chloride ion corrosion-resistant steel bars. Industrial atmospheric corrosion-resistant steel bars, due to their excellent corrosion resistance, are widely used in steel structures such as buildings, vehicles, bridges, and towers. How to further improve the corrosion resistance and strength of industrial atmospheric corrosion-resistant steel bars is one of the urgent problems to be solved. Summary of the Invention

[0003] To address the problems existing in the prior art, this application provides an example of an industrial atmospheric corrosion-resistant and earthquake-resistant steel bar and its preparation method.

[0004] In a first aspect, this application provides a seismic-resistant steel bar resistant to industrial atmospheric corrosion, comprising the following components by weight percentage: C: 0.17wt%~0.21wt%, Mn: 0.95wt%~1.25wt%, Si: 0.35wt%~0.65wt%, Cr: 0.20wt%~0.40wt%, V: 0.025wt%~0.035wt%, Cu: 0.30wt%~0.50wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the balance being Fe and unavoidable impurities.

[0005] According to embodiments of this application, industrial atmospheric corrosion-resistant and earthquake-resistant steel bars achieve synergistic optimization of corrosion resistance and mechanical properties through a reasonable proportion of alloying elements. The carbon content is controlled within the range of 0.17wt%~0.21wt% to ensure appropriate strength. The manganese content is 0.95wt%~1.25wt% to improve the strength and toughness of the steel bars. The silicon content is 0.35wt%~0.65wt% to increase the oxidation resistance of the steel bars. The chromium content is 0.20wt%~0.40wt% to form a dense passivation film and improve corrosion resistance. The vanadium content is 0.025wt%~0.035wt% to refine the grains and improve strength and toughness. The copper content is 0.30wt%~0.50wt% to improve the bonding force of the corrosion product layer. The phosphorus content is 0.08wt%~0.10wt% to improve the strength and corrosion resistance of the steel bars. The sulfur content is controlled below 0.010wt% to reduce grain boundary segregation and improve toughness. The elements work together to form a stable passivation film that resists industrial atmospheric corrosion, while ensuring that the steel bars have good mechanical properties.

[0006] Through the above-described scheme, this application improves the corrosion resistance of reinforcing steel in industrial atmospheric environments and extends its service life. A stable and dense passivation film forms on the surface of the reinforcing steel, effectively blocking the penetration of corrosive media. The bonding force between the corrosion product layer and the matrix is ​​enhanced, reducing the risk of delamination. The internal grains of the reinforcing steel are refined, improving its resistance to stress corrosion cracking. Simultaneously, it ensures that the reinforcing steel possesses good mechanical properties, meeting seismic requirements. The rate of mechanical property degradation of the reinforcing steel during service is reduced, extending the service life of the building structure and reducing maintenance costs.

[0007] In some embodiments, the industrial atmospheric corrosion-resistant seismic steel reinforcement comprises the following components by weight percentage: C: 0.17wt%~0.21wt%, Mn: 1.08wt%~1.18wt%, Si: 0.46wt%~0.52wt%, Cr: 0.25wt%~0.32wt%, V: 0.025wt%~0.035wt%, Cu: 0.35wt%~0.38wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the balance being Fe and unavoidable impurities. This can further improve the corrosion resistance and mechanical properties of the industrial atmospheric corrosion-resistant seismic steel reinforcement.

[0008] In some embodiments, the yield strength of the industrial atmospheric corrosion resistant and earthquake-resistant steel bar is 430MPa-470MPa.

[0009] In some embodiments, the tensile strength of the industrial atmospheric corrosion resistant and earthquake-resistant steel bar is 615MPa-655MPa.

[0010] In some embodiments, the strength-to-yield ratio of the industrial atmospheric corrosion-resistant and earthquake-resistant steel reinforcement is 1.35-1.46.

[0011] In some embodiments, the elongation of the industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement is 18%-26%.

[0012] In some embodiments, the maximum total elongation of the industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement is 12.5%-14.9%.

[0013] According to the embodiments of this application, in the preparation of industrial atmospheric corrosion-resistant and earthquake-resistant reinforcing bars, the control of the chemical composition of the molten steel and the synergistic effect of subsequent processing technology directly affect the corrosion resistance and mechanical properties of the final product. Precise control of the molten steel composition needs to be combined with parameter adjustments in steps such as smelting, continuous casting, and rolling to ensure the uniformity and stability of the microstructure of the reinforcing bars, thereby meeting the dual requirements of high strength and corrosion resistance. Secondly, this application provides a method for preparing industrial atmospheric corrosion-resistant and earthquake-resistant reinforcing bars, comprising the following steps: Molten steel is provided, the chemical composition of which, by mass percentage, comprises: C: 0.17wt%~0.21wt%, Mn: 0.95wt%~1.25wt%, Si: 0.35wt%~0.65wt%, Cr: 0.20wt%~0.40wt%, V: 0.025wt%~0.035wt%, Cu: 0.30wt%~0.50wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the remainder being Fe and unavoidable impurities; The molten steel is sequentially smelted in a converter, refined in an LF furnace, and continuously cast to obtain a continuously cast billet. The continuously cast billet is heated and then rolled and cooled sequentially to obtain the reinforcing steel.

[0014] According to the embodiments of this application, by employing the above-described preparation method, the industrial atmospheric corrosion-resistant seismic steel bars prepared in this application possess excellent mechanical properties and corrosion resistance. The yield strength of the steel bars reaches 450 MPa, the tensile strength reaches 635 MPa, the strength-to-yield ratio is 1.41, the elongation is 22%, and the total elongation at maximum force is 13.7%. Simultaneously, the corrosion rate of the steel bars in the industrial atmospheric environment is significantly reduced, effectively extending their service life. Furthermore, due to the adoption of a reasonable chemical composition design and preparation process, the seismic performance of the steel bars is also improved, meeting the requirements for use in high-intensity earthquake zones.

[0015] In some embodiments, the continuous casting speed of the billet is 3.2 m / min to 3.8 m / min. The casting speed setting must match the solidification rate of the molten steel to ensure that the billet forms a uniform and dense microstructure during solidification. The lower limit of the casting speed range of 3.2 m / min can avoid the risk of steel leakage caused by an excessively thin solidified shell, while the upper limit of 3.8 m / min can prevent internal cracks caused by an excessively long liquidus cavity at the end of solidification. The casting speed parameter is related to the carbon and manganese content in the molten steel. When the carbon equivalent is high, the casting speed needs to be appropriately reduced to ensure solidification uniformity.

[0016] In some embodiments, the heating temperature of the continuously cast billet is 950℃-1210℃, and the heating time is 40min-80min. The final rolling temperature is 960℃-1020℃, and the final rolling speed is 8m / s-12.5m / s.

[0017] The heating temperature range controls austenite grain size to prevent coarsening, while the heating time range ensures sufficient diffusion of alloying elements. The final rolling temperature range maintains dynamic recrystallization conditions, and the final rolling speed range balances rolling deformation resistance and grain refinement. The synergistic control of heating temperature and time prevents excessively thick surface oxide layers; the combination of final rolling temperature and speed enables strain-induced precipitation, promoting uniform distribution of nanoscale carbides.

[0018] This application achieves full austenitization and uniform grain size in the internal structure of the continuously cast billet by precisely controlling the heating temperature and time, while avoiding oxidation loss caused by overheating. The coordinated adjustment of the final rolling temperature and rolling speed can effectively suppress abnormal grain growth after rolling, reduce banded structure and component segregation, thereby improving the density and uniformity of the internal structure while ensuring the surface quality of the steel bar, laying the foundation for obtaining stable corrosion resistance and mechanical properties in the future. Detailed Implementation

[0019] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples. In the following description, at least some well-known structures and techniques are not shown to avoid unnecessarily obscuring the application; and, for clarity, the dimensions of some structures may be exaggerated. Furthermore, the features, structures, or characteristics described below can be combined in any suitable manner in one or more embodiments.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0021] In traditional industrial atmospheric corrosion-resistant steel reinforcement systems, the alloy element ratio and microstructure control have not yet achieved synergistic optimization of corrosion resistance and mechanical properties. The combined corrosive effects of sulfur oxides, nitrogen oxides, and particulate matter in industrial atmospheres lead to insufficient stability of the passivation film on the steel reinforcement surface, making the corrosion product layer prone to localized peeling and accelerating the uniform corrosion and pitting process of the base metal. Simultaneously, stress concentration at grain boundaries under dynamic loads triggers microcrack propagation, further reducing the material's resistance to stress corrosion cracking. These problems directly affect the durability and structural safety redundancy of steel reinforcement in complex service environments, making it difficult to achieve the expected design life of critical load-bearing components in building and bridge engineering.

[0022] For example, in industrial atmospheric environments with high concentrations of sulfur dioxide, the non-dense corrosion product layer formed on the surface of steel reinforcement cannot effectively block the penetration of corrosive media. Cyclic changes in temperature and humidity cause the corrosion product layer to expand and contract in volume, leading to a decrease in interfacial bonding strength. Under dynamic wind loads, the increased dislocation density inside the steel reinforcement promotes an increase in corrosion current density, and the electrochemical difference between the precipitated phase at the grain boundary and the matrix exacerbates the local micro-cell effect. These coupling effects cause the effective bearing area of ​​the steel reinforcement cross-section to continuously decrease, the yield strength and tensile strength to exhibit nonlinear decay, and the strength-to-yield ratio and elongation to deviate from the design thresholds, directly affecting the plastic deformation capacity and energy dissipation mechanism of the building structure under seismic loads.

[0023] If these problems are not addressed, reinforced steel will face a positive feedback effect of declining mechanical properties and increasing corrosion depth throughout its service life. Stress redistribution at critical structural nodes may lead to localized overloads, triggering a cascading failure risk. Simultaneously, frequent maintenance and repairs will significantly increase total life-cycle costs and reduce the reliability of building structures during extreme weather or seismic events. These systemic risks will severely hinder the development of green buildings and sustainable infrastructure.

[0024] [Industrial Atmosphere Corrosion Resistant and Earthquake-Resistant Steel Bars] An embodiment of the first aspect of this application provides an industrial atmospheric corrosion resistant and earthquake-resistant steel bar, the chemical composition of which, by weight percentage, includes: C: 0.17wt%~0.21wt%, Mn: 0.95wt%~1.25wt%, Si: 0.35wt%~0.65wt%, Cr: 0.20wt%~0.40wt%, V: 0.025wt%~0.035wt%, Cu: 0.30wt%~0.50wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the balance being Fe and unavoidable impurities.

[0025] In this embodiment, by optimizing the chemical composition of the reinforcing steel and controlling the proportion of each component, the corrosion resistance of the reinforcing steel can be effectively improved, while maintaining high strength. This allows for its successful application in various high-atmospheric-corrosion environments. The chemical composition of the industrial atmospheric corrosion-resistant and earthquake-resistant reinforcing steel in this embodiment is described in detail below.

[0026] C (carbon) element: Specifically, the carbon content during smelting can be controlled within the range of 0.17wt% to 0.21wt%, balancing the strength and toughness of the steel reinforcement. Mn (manganese): Specifically, the content can be adjusted by adding ferromanganese alloy to achieve a content of 0.95wt% to 1.25wt%, used to improve the strength and hardenability of the steel reinforcement. Si (silicon): Specifically, the content can be controlled within the range of 0.35wt% to 0.65wt% by adding ferrosilicon alloy, used for deoxidation and improving tensile strength. Cr (chromium): Specifically, the content can be adjusted within the range of 0.20wt% to 0.40wt% by using ferrochrome alloy, used to form a dense oxide film on the surface of the steel reinforcement to improve corrosion resistance. V (vanadium): Specifically, the content can be maintained within the range of 0.025wt% to 0.035wt% by adding ferrovanadium alloy, used to refine grains and improve the strength-to-yield ratio. Cu (copper): Specifically, the copper content can be controlled within the range of 0.30wt% to 0.50wt%, enhancing resistance to industrial atmospheric corrosion through the passivation effect of copper. P (phosphorus) element: Specifically, the phosphorus content is limited to 0.08wt% to 0.10wt%, utilizing the solid solution strengthening effect of phosphorus to improve corrosion resistance while avoiding cold brittleness. S (sulfur) element: Specifically, the sulfur content is reduced to below 0.010wt% through refining processes to reduce the negative impact of sulfide inclusions on toughness.

[0027] This application embodiment achieves a comprehensive improvement in corrosion resistance and seismic performance by precisely controlling the synergistic ratio of carbon, manganese, silicon, chromium, vanadium, copper, phosphorus and sulfur, while ensuring the mechanical properties of steel bars. It also enhances the resistance to industrial atmospheric corrosion by utilizing the chromium-copper-phosphorus composite corrosion resistance mechanism, and optimizes the strength-to-yield ratio and elongation by vanadium microalloying.

[0028] Through the above-described scheme, this application improves the corrosion resistance of reinforcing steel in industrial atmospheric environments and extends its service life. A stable and dense passivation film forms on the surface of the reinforcing steel, effectively blocking the penetration of corrosive media. The bonding force between the corrosion product layer and the matrix is ​​enhanced, reducing the risk of delamination. The internal grains of the reinforcing steel are refined, improving its resistance to stress corrosion cracking. Simultaneously, it ensures that the reinforcing steel possesses good mechanical properties, meeting seismic requirements. The rate of mechanical property degradation of the reinforcing steel during service is reduced, extending the service life of the building structure and reducing maintenance costs.

[0029] In some embodiments, the chemical composition of the industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement includes, by weight percentage: C: 0.17wt%~0.21wt%, Mn: 1.08wt%~1.18wt%, Si: 0.46wt%~0.52wt%, Cr: 0.25wt%~0.32wt%, V: 0.025wt%~0.035wt%, Cu: 0.35wt%~0.38wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the balance being Fe and unavoidable impurities.

[0030] By further limiting the chemical composition ratio of the industrial atmospheric corrosion resistant and earthquake-resistant steel bars to the above range, the mechanical strength and corrosion resistance of the steel bars can be further improved, giving them higher resistance to industrial atmospheric corrosion and earthquake resistance.

[0031] Specifically, controlling the C content to 0.17wt%~0.21wt% balances the material's strength and toughness; adjusting the Mn content to 1.08wt%~1.18wt% improves hardenability and reduces hot cracking sensitivity; limiting the Si content to 0.46wt%~0.52wt% promotes deoxidation and enhances solid solution strengthening; optimizing the Cr content to 0.25wt%~0.32wt% facilitates the formation of a dense oxide film; controlling the Cu content to 0.35wt%~0.38wt% improves resistance to industrial atmospheric corrosion; maintaining the V content at 0.025wt%~0.035wt% refines the grains; maintaining the P content at 0.08wt%~0.10wt% improves corrosion resistance while avoiding cold brittleness; and limiting the S content to below 0.010wt% reduces sulfide inclusions.

[0032] In some embodiments, the yield strength of the industrial atmospheric corrosion resistant and earthquake-resistant steel bars is 430MPa-470MPa.

[0033] Yield strength is the yield limit of a metallic material when it undergoes yielding, which is the stress that resists slight plastic deformation. By adjusting the chemical composition ratio of industrial atmospheric corrosion-resistant seismic steel bars, the steel bars can have a higher yield strength, which is beneficial to further improving the seismic performance of industrial atmospheric corrosion-resistant seismic steel bars used in buildings.

[0034] In some embodiments, the tensile strength of the industrial atmospheric corrosion resistant and earthquake-resistant steel bars is 615MPa-655MPa.

[0035] By adjusting the chemical composition ratio of industrial atmospheric corrosion resistant seismic steel bars, the steel bars can have higher tensile strength, which is beneficial to further improve the seismic performance of industrial atmospheric corrosion resistant seismic steel bars in buildings.

[0036] In some embodiments, the strength-to-yield ratio of the industrial atmospheric corrosion-resistant and earthquake-resistant steel bars is 1.35-1.46.

[0037] The strength-to-yield ratio refers to the ratio of the measured tensile strength to the measured yield strength of steel bars. It can reflect the seismic performance of steel bars. By limiting the strength-to-yield ratio of industrial atmospheric corrosion-resistant seismic steel bars to the above range, the steel bars can have higher toughness and can withstand higher strain and stress, thereby improving the seismic performance of industrial atmospheric corrosion-resistant seismic steel bars.

[0038] In some embodiments, the elongation of the industrial atmospheric corrosion resistant and earthquake-resistant steel bars is 18%-26%.

[0039] Elongation refers to the increase in the length of a steel bar relative to its original length when subjected to a certain tensile force. It can be calculated by the ratio of the difference between the length of the steel bar under tension and its original length to the original length.

[0040] In some embodiments, the maximum total elongation of the industrial atmospheric corrosion-resistant seismic steel reinforcement is 12.5%-14.9%.

[0041] Maximum total elongation refers to the total elongation of a steel bar under tension up to its maximum force, reflecting its deformation capacity and tensile strength. By limiting the maximum total elongation of industrial atmospheric corrosion-resistant seismic steel bars to the aforementioned range, these bars can possess higher tensile strength, further improving their structural strength and stability when applied to buildings, and enhancing their seismic performance.

[0042] An embodiment of the second aspect of this application provides a method for preparing earthquake-resistant steel bars resistant to industrial atmospheric corrosion, comprising the following steps: S10 provides molten steel with the following chemical composition by mass percentage: C: 0.17wt%~0.21wt%, Mn: 0.95wt%~1.25wt%, Si: 0.35wt%~0.65wt%, Cr: 0.20wt%~0.40wt%, V: 0.025wt%~0.035wt%, Cu: 0.30wt%~0.50wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the remainder being Fe and unavoidable impurities; S20 involves sequentially refining molten steel in a converter, refining it using an LF furnace, and then continuously casting it to obtain a continuously cast billet. Molten iron with the aforementioned chemical composition is then refined in a converter and refined using an LF furnace before continuous casting to obtain another continuously cast billet. The casting speed can be 3.2 m / min to 3.8 m / min. The continuously cast billet is heated to 950℃ to 1210℃ and then tapped from the furnace. The heating time can be 40 min to 80 min.

[0043] Converter smelting is used for preliminary composition adjustment, while LF refining further removes impurities and precisely controls the content of alloying elements. During continuous casting, the solidification rate of the continuously cast billet affects the degree of internal segregation, requiring optimization of the solidification structure through casting speed control. The heating temperature and time of the continuously cast billet must be matched with the rolling process to ensure austenite homogenization.

[0044] S30 involves heating a continuously cast billet and then rolling and cooling it sequentially to obtain earthquake-resistant steel bars resistant to industrial atmospheric corrosion.

[0045] The industrial atmospheric corrosion-resistant and earthquake-resistant steel bars prepared according to the method of this application exhibit excellent mechanical and corrosion resistance properties. The yield strength of the steel bars reaches over 430 MPa, the tensile strength reaches over 615 MPa, the strength-to-yield ratio can reach between 1.35 and 1.46, the elongation can reach over 18%, and the total elongation at maximum force can reach over 12.5%. Simultaneously, the corrosion rate of the steel bars in the industrial atmospheric environment is significantly reduced, effectively extending their service life. Furthermore, due to the adoption of a reasonable chemical composition design and preparation process, the seismic performance of the steel bars is also improved, meeting the requirements for use in high-intensity earthquake zones.

[0046] Specifically, after being smelted in a converter, the molten steel enters the LF refining furnace. Bottom-blown argon gas is used to agitate and promote the flotation of inclusions. Simultaneously, alloy fine-tuning is added to ensure the content of each element reaches the target range. During continuous casting, a constant casting speed is used, and the solidification process of the continuously cast billet is controlled by secondary cooling water to reduce internal cracks and segregation. When heating the continuously cast billet, the temperature is set to 950℃~1010℃ for 40~80 minutes to ensure uniform temperature between the core and surface of the billet, eliminate casting stress, and complete austenitization. During rolling, a multi-pass deformation process breaks down the austenite grains. The final rolling temperature is higher than the Ar3 point to prevent premature ferrite precipitation. The final rolling speed and temperature are coordinated to control the degree of recrystallization. After rolling, air cooling or controlled cooling is used to transform the austenite into fine ferrite and dispersed pearlite, while simultaneously precipitating nano-sized V(C,N) particles, further improving strength and corrosion resistance. Through the synergistic effect of the above processes, the yield strength of the steel bars reaches 430~470MPa, the tensile strength is 615~655MPa, and the elongation is maintained at 18%~26%, meeting the dual requirements of earthquake resistance and resistance to industrial atmospheric corrosion.

[0047] Specifically, the heating temperature range controls austenite grain size to prevent coarsening, while the heating time range ensures sufficient diffusion of alloying elements. The final rolling temperature range maintains dynamic recrystallization conditions, and the final rolling speed range balances rolling deformation resistance and grain refinement. The synergistic control of heating temperature and time prevents excessively thick surface oxide layers; the combination of final rolling temperature and speed enables strain-induced precipitation, promoting uniform distribution of nanoscale carbides.

[0048] In some implementations, the final rolling temperature can be 960℃-1020℃, and the steel bar speed after final rolling can be 8.0m / s-12.5m / s.

[0049] Specifically, the heating stage utilizes a temperature range of 950℃-1210℃, allowing chromium to fully dissolve in the matrix and form a continuous passivation film. The heating time is controlled between 40 and 80 minutes to ensure uniform cross-sectional temperature while preventing excessive copper loss. During the rolling stage, the final rolling temperature is maintained at 960℃-1020℃, coupled with a rolling speed of 8-12.5 m / s, causing vanadium to precipitate as carbonitrides during deformation, pinning dislocations and increasing strength. This temperature-speed combination controls the degree of dynamic recrystallization, stabilizing the grain size within the 5-8 μm range, ensuring elongation meets targets while increasing tensile strength to the upper limit of 655 MPa.

[0050] In some implementations, after the heated continuously cast billet exits the furnace, it is continuously rolled using a 19-stand rolling mill with alternating horizontal and vertical sections. The continuous rolling can include roughing, intermediate rolling and finishing rolling, with 6 stands for roughing, 6 stands for intermediate rolling and 7 stands for finishing.

[0051] Through the above technical solutions, this application achieves full austenitization and uniform grain size in the internal structure of the continuously cast billet by precisely controlling the heating temperature and time, while avoiding oxidation loss caused by overheating. The coordinated adjustment of the final rolling temperature and rolling speed can effectively suppress abnormal grain growth after rolling, reduce banded structure and component segregation, thereby improving the density and uniformity of the internal structure while ensuring the surface quality of the steel bar, laying the foundation for obtaining stable corrosion resistance and mechanical properties in the future.

[0052] In some embodiments, the surface of the final rolled steel bar can be water-cooled, with a water pressure of 1.0MPa-1.5MPa and a water flow rate of 150m³ / h to 300m³ / h.

[0053] In some embodiments, the temperature of the cooled steel bars on the cooling bed can be 880℃-950℃.

[0054] In some embodiments, after the steel bars are air-cooled in a cooling bed, they are cut, packaged, and stored to obtain industrial atmospheric corrosion resistant seismic steel bars.

[0055] In some embodiments, the metallographic structure of the industrial atmospheric corrosion resistant and earthquake-resistant steel bar obtained by the above preparation method is ferrite and pearlite, and the grain size is greater than or equal to 10.5.

[0056] Example The following specific embodiments illustrate the present invention. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0057] Examples 1-3 A type of industrial atmospheric corrosion-resistant and earthquake-resistant steel bar, the chemical composition of which is shown in Table 1 (Fe and unavoidable impurities are not listed in Table 1), and the preparation parameters are shown in Table 2: Comparative Example 1 The chemical composition of the reinforcing steel is shown in Table 1, and the preparation parameters are shown in Table 2.

[0058] Table 1 Table 2 Test section The test results of the steel reinforcement performance in Examples 1-3 are detailed in Table 3.

[0059] Table 3 Based on the data in Table 3, the industrial atmospheric corrosion resistant and earthquake-resistant steel bars provided in this application embodiment have good surface quality, mechanical properties and cold bending performance.

[0060] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A type of industrial atmospheric corrosion-resistant and earthquake-resistant steel reinforcement, characterized in that, It includes the following components by weight percentage: C: 0.17wt%~0.21wt%, Mn: 0.95wt%~1.25wt%, Si: 0.35wt%~0.65wt%, Cr: 0.20wt%~0.40wt%, V: 0.025wt%~0.035wt%, Cu: 0.30wt%~0.50wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the balance being Fe and unavoidable impurities.

2. The industrial atmospheric corrosion resistant and earthquake-resistant steel bar according to claim 1, characterized in that, It includes the following components by weight percentage: C: 0.17wt%~0.21wt%, Mn: 1.08wt%~1.18wt%, Si: 0.46wt%~0.52wt%, Cr: 0.25wt%~0.32wt%, V: 0.025wt%~0.035wt%, Cu: 0.35wt%~0.38wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the balance being Fe and unavoidable impurities.

3. The industrial atmospheric corrosion-resistant and earthquake-resistant steel reinforcement according to claim 1 or 2, characterized in that, The yield strength of the industrial atmospheric corrosion resistant and earthquake-resistant steel bar is 430MPa-470MPa.

4. The industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement according to claim 1 or 2, characterized in that, The tensile strength of the industrial atmospheric corrosion resistant and earthquake-resistant steel bar is 615MPa-655MPa.

5. The industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement according to claim 1 or 2, characterized in that, The strength-to-yield ratio of the industrial atmospheric corrosion-resistant and earthquake-resistant steel bars is 1.35-1.

46.

6. The industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement according to claim 1 or 2, characterized in that, The elongation rate of the industrial atmospheric corrosion resistant and earthquake-resistant steel bars is 18%-26%.

7. The industrial atmospheric corrosion resistant and earthquake-resistant steel reinforcement according to claim 1 or 2, characterized in that, The maximum total elongation of the industrial atmospheric corrosion resistant and earthquake-resistant steel bars is 12.5%-14.9%.

8. A method for preparing industrial atmospheric corrosion-resistant and earthquake-resistant steel bars, characterized in that, Includes the following steps: Molten steel is provided, the chemical composition of which, by mass percentage, comprises: C: 0.17wt%~0.21wt%, Mn: 0.95wt%~1.25wt%, Si: 0.35wt%~0.65wt%, Cr: 0.20wt%~0.40wt%, V: 0.025wt%~0.035wt%, Cu: 0.30wt%~0.50wt%, P: 0.08wt%~0.10wt%, S≤0.010wt%, with the remainder being Fe and unavoidable impurities; The molten steel is sequentially smelted in a converter, refined in an LF furnace, and continuously cast to obtain a continuously cast billet. The continuously cast billet is heated and then rolled and cooled sequentially to obtain the reinforcing steel.

9. The preparation method according to claim 8, characterized in that, The continuous casting speed of the billet is 3.2m / min-3.8m / min.

10. The preparation method according to claim 8, characterized in that, The heating temperature of the continuously cast billet is 950℃-1210℃, and the heating time is 40min-80min; and / or The final rolling temperature is 960℃-1020℃, and the final rolling speed is 8m / s-12.5m / s.

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