Structurally and functionally integrated lightweight high-strength ferritic steel sheet and method of manufacturing the same

Abstract

The application relates to the technical field of metal materials, in particular to a structure-function integrated light high-strength ferrite steel plate and a manufacturing method thereof. The steel plate is composed of the following chemical components with the weight percentage: C: <=0.003%, Si: <=0.05%, Cu: 0.3%-0.8%, Al: 5%-8%, S: <=0.01%, P <=0.018%, N <=0.005%, and the balance of Fe and inevitable impurities. The yield strength of the steel plate is >=400 MPa, the tensile strength is >=550 MPa, and the elongation A50 after fracture is >=20%; the damping value delta is >=0.08; the steel plate has high mechanical properties, meets the requirements of structural materials, has excellent damping performance and corrosion resistance, and has moderate cost, so that the weight of equipment is reduced by more than 5%.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, specifically to a lightweight, high-strength ferritic steel plate with integrated structure and function and its manufacturing method. Background Technology

[0002] With increasing environmental awareness and pressure to peak carbon emissions, steel product users are no longer simply demanding high strength and high toughness from steel. They increasingly require traditional steel materials to possess not only basic mechanical properties but also specific special properties, such as vibration damping, corrosion resistance, and electromagnetic wave absorption. Structural-functional integrated steel materials possess structural material properties while also offering other functionalities, such as vibration damping, corrosion resistance, wave absorption, and lightweight properties. To meet the growing demands for specialized steel properties, structural-functional integrated steel materials will inevitably become a crucial development direction for the next generation of steel materials.

[0003] Chinese patent documents CN109266973B (published in the announcement number) disclose "Fe-Mn-Si-Ni-C system elasto-plastic damping steel and its manufacturing method and application," CN86102543A (published in the announcement number) discloses "Fe-chromium system multi-element silent vibration damping steel and its manufacturing method," and CN115074636A (published in the announcement number) disclose "A preparation method of high-carbon damping vibration damping steel and its smelting and casting device." While these patents improve the functionality of the steel, the alloy systems are complex and the costs are high. Chinese patent document CN108504929B (published in the announcement number) discloses "A high-performance elasto-plastic damping steel and its manufacturing method and application," which not only has high costs but is also difficult to implement in continuous casting production. Chinese patent document CN107338401A, which discloses "A composite low-alloy damping steel containing Nb and its preparation method", improves the damping performance of the steel, but seriously deteriorates the cold and hot working properties and comprehensive mechanical properties of the steel. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a lightweight, high-strength ferritic steel plate with integrated structural and functional properties and its manufacturing method. It has moderate cost and, while possessing high mechanical properties and meeting the requirements of structural materials, also exhibits excellent damping and corrosion resistance.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A lightweight, high-strength ferritic steel plate with integrated structural and functional properties is composed of the following chemical composition by weight percentage:

[0007] C: ≤0.003%, Si: ≤0.05%, Cu: 0.3%–0.8%, Al: 5%–8%, S: ≤0.01%, P: ≤0.018%, N: ≤0.005%, balance being Fe and unavoidable impurities.

[0008] Furthermore, the yield strength of the steel plate is ≥400MPa.

[0009] Furthermore, the tensile strength of the steel plate is ≥550MPa.

[0010] Furthermore, the elongation after fracture of the steel plate, A50, is ≥20%.

[0011] Furthermore, the damping value of the steel plate is δ≥0.08.

[0012] Furthermore, the microstructure of the steel plate is a single ferrite.

[0013] The manufacturing method of the above-mentioned structurally and functionally integrated lightweight high-strength ferritic steel plate specifically includes the following steps:

[0014] 1) Heating process:

[0015] The steel billet with the above chemical composition was heated in a heating furnace to 1100±50℃ and held at that temperature for 2±0.5 hours.

[0016] 2) Rolling process:

[0017] The process involves conventional rolling followed by water cooling. The final rolling temperature is 880±20℃, followed by water cooling to 560℃±20℃ for coiling, holding at that temperature for 3±0.5 hours, and then cooling in the furnace to room temperature.

[0018] Further, in step 1), the steel billet with the above chemical composition is heated to 1100±40℃ in a heating furnace and held at that temperature for 2±0.3 hours.

[0019] Furthermore, in step 2), the final rolling temperature is 880±10℃, the coil is water-cooled to 560℃±10℃ and held for 3±0.3 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. This invention improves the damping performance of steel by adding Cu and Al elements. The damping value of the steel plate δ≥0.08, which is more than 10 times that of ordinary steel materials, reducing the risk of mechanical vibration in automobiles and home appliances, as well as resonance instability in high-rise buildings and bridges. It can effectively reduce the noise generated by automobiles and mechanical equipment.

[0022] 2. This invention utilizes the precipitation strengthening effect of Cu to improve the strength of steel, thus enabling the invention to possess both high damping performance and good mechanical properties. It meets the mechanical performance requirements of steel for automobiles, home appliances, bridges, high-rise buildings, and machinery, and can also reduce equipment weight by more than 5%.

[0023] 3. This invention effectively improves the corrosion resistance of steel by adding Al and Cu in combination, thereby extending the service life of the equipment.

[0024] 4. By controlling the heating temperature (1100±50℃), this invention, under the composition system of the invented steel (without elements that are difficult to homogenize), can both ensure the homogenization of alloying elements and improve the surface quality of the steel plate and reduce oxidation loss.

[0025] 5. By controlling the final rolling temperature, the present invention can ensure that the copper element remains in a solid solution state at a final rolling temperature of 880±10℃. Water cooling can ensure that copper does not continuously precipitate during the cooling process (which reduces the strengthening effect and damping performance). Coiling at 560℃±10℃ can make copper precipitate uniformly, thereby improving strength and damping performance.

[0026] 6. The total alloy content of this invention is less than 10%, which is much lower than that of similar steels with similar performance. It also contains less expensive metals, resulting in a significant cost advantage.

[0027] In summary, the structurally integrated lightweight high-strength ferritic steel plate manufactured using this invention has a yield strength ≥400MPa, tensile strength ≥550MPa, elongation after fracture A50 ≥20%, and damping value δ ≥0.08. It possesses high mechanical properties, meets the requirements of structural materials, and exhibits excellent damping and corrosion resistance. Attached Figure Description

[0028] Figure 1 This is a metallographic diagram of the present invention. Detailed Implementation

[0029] This invention discloses a lightweight, high-strength ferritic steel plate with integrated structural and functional properties and its manufacturing method. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments, and those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0030] A lightweight, high-strength ferritic steel plate with integrated structural and functional properties is composed of the following chemical composition by weight percentage:

[0031] C: ≤0.003%, Si: ≤0.05%, Cu: 0.3%–0.8%, Al: 5%–8%, S: ≤0.01%, P: ≤0.018%, N: ≤0.005%, balance being Fe and unavoidable impurities.

[0032] Based on cost and the overall performance of the steel plate, the composition and main function of the steel plate in this invention are as follows:

[0033] C: Carbon is the most important solid solution strengthening element in steel, but solid solution carbon will significantly reduce the damping performance of steel plates, and increasing carbon will lead to the formation of non-ferrite structure in steel. Considering cost factors, the optimal range of carbon in this invention is ≤0.005%.

[0034] Si is a common element in steel. It can increase the strength of steel, but reduce its plasticity. Further reducing the Si content will increase the metallurgical cost. The silicon content in this invention is ≤0.05%.

[0035] Cu: Copper has both solid solution strengthening and precipitation strengthening effects, and copper precipitates can also improve the damping properties of steel. However, excessively high copper content will increase surface defects in cast billets and hot-rolled steel plates. Meanwhile, the maximum solid solubility of Cu in ferrite is approximately 0.8%, therefore, the Cu content in this invention is set at 0.3–0.8%.

[0036] Al: Aluminum can inhibit cementite precipitation, reduce steel density, fix nitrogen in steel, and play a certain role in refining grains. Furthermore, solid-solution aluminum promotes ferrite formation, indirectly improving damping performance. Considering lightweighting and the ease of billet casting, the aluminum content in this invention is 5-8%.

[0037] P: Although phosphorus can improve the strength of steel plates, it will seriously deteriorate the cold forming properties of steel, so its upper limit is set at ≤0.018%.

[0038] S: Sulfur is a harmful element in steel. It can form manganese sulfide, which reduces the performance of steel plates. Therefore, the lower the content, the better. The upper limit is set at 0.01%.

[0039] The manufacturing method of the aforementioned structurally and functionally integrated lightweight high-strength ferritic steel plate includes the following steps:

[0040] (1) Heating process: The qualified steel billet is heated to 1100±50℃ in a heating furnace and held for 2±0.5 hours. This allows the alloying elements to be fully dissolved and the composition to be uniform.

[0041] (2) Rolling process: Ordinary rolling + water cooling is adopted, the final rolling temperature is 880±20℃, water cooling to 560℃±20℃ simulates coiling, heat preservation for 3±0.5 hours, and furnace cooling to room temperature.

[0042] In the method for manufacturing the steel plate of the present invention:

[0043] The billet heating temperature is controlled at 1100±50℃ and the holding time is 2±0.5 hours. Since the invention does not contain any elements that are difficult to homogenize, and the aluminum and copper elements do not significantly increase the deformation resistance, it can ensure the homogenization of the composition without increasing the difficulty of rolling steel, while reducing oxidation loss and improving the surface quality of the steel plate.

[0044] Controlling the final rolling temperature at 880±20℃ allows for sufficient copper dissolution, ensuring adequate copper precipitation for strengthening.

[0045] The controlled cooling process of this invention involves water cooling to 560℃±20℃ to simulate coiling, holding at that temperature for 3±0.5 hours, and then cooling in the furnace to room temperature. Water cooling ensures that copper does not continuously precipitate during the cooling process (resulting in larger copper particles and less strengthening effect), while uniform precipitation occurs during the 560℃±20℃ holding period of 3±0.5 hours, maximizing copper precipitation strengthening and improving damping performance. Furnace cooling reduces the internal stress of the steel plate and improves its damping performance.

[0046] like Figure 1 As shown, the steel plate obtained by the above manufacturing method with the above chemical composition has a yield strength ≥400MPa, tensile strength ≥550MPa, elongation after fracture A50 ≥20%, damping value δ ≥0.08, and the microstructure of the steel plate is a single ferrite.

[0047]

Example

[0048] All embodiments of the present invention are manufactured according to the following process:

[0049] After cutting off the head and tail of an 80kg qualified billet, heat it to 1050±50℃ and hold it for 2±0.5 hours. Then, hot roll it to a final rolling temperature of 880±20℃, water cool it to 560℃±20℃ for simulated coiling, hold it for 3±0.5 hours, and then cool it to room temperature in the furnace.

[0050] The chemical composition (Wt%) of the embodiments of the present invention is shown in Table 1; the hot rolling process parameters of the embodiments of the present invention are shown in Table 2; and the mechanical property parameters of the embodiments of the present invention are shown in Table 3.

[0051] Table 1 Chemical composition (wt, %) of embodiments of the present invention

[0052]

[0053]

[0054] Table 2 Hot rolling process parameters of the present invention embodiment

[0055]

[0056] Table 3 Mechanical performance parameters of embodiments of the present invention

[0057]

[0058] As can be seen from Table 3, the structurally integrated lightweight high-strength ferritic steel plate manufactured using the present invention has a yield strength ≥400MPa, tensile strength ≥550MPa, elongation after fracture A50 ≥20%, and damping value δ ≥0.08. It has high mechanical properties, meets the requirements of structural materials, and has excellent damping performance and corrosion resistance.

[0059] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of manufacturing a structural and functional integration light high-strength ferrite steel sheet, characterized by, The steel plate is composed of the following chemical components with weight percentage: C: ≤0.003%, Si: ≤0.05%, Cu: 0.62%-0.8%, Al: 7.5%-8%, S: ≤0.01%, P ≤0.018%, N ≤0.005%, the balance being Fe and unavoidable impurities; The steel plate has a yield strength ≥400 MPa, a tensile strength ≥550 MPa, an elongation after fracture A50 ≥20%, and a damping value δ ≥0.08; and the microstructure of the steel plate is single ferrite; Specifically comprising the following steps: 1) heating process: The steel billet with the above chemical components is heated to 1100±40℃ in a heating furnace and is kept for 2±0.3 hours; 2) rolling process: Rolling+water cooling is adopted, the finish rolling temperature is 880±10℃, water cooling is performed to 560℃±10℃ for coiling, the temperature is kept for 3±0.3 hours, and the temperature is cooled to room temperature in the furnace.

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