490mpa grade anti-seismic fire-resistant steel plate and method for manufacturing the same

Abstract

The present invention provides a 490 MPa grade earthquake-resistant and fire-resistant steel plate and a preparation method thereof. The chemical composition of the fire-resistant steel plate includes: C: 0.02 - 0.18%, Si: 0.1 - 0.5%, Mn: 1.1 - 1.6%, P ≤ 0.015%, S ≤ 0.015%, Mo: 0.15 - 0.5%, Nb: 0.01 - 0.06%, V ≤ 0.13%, 0 < Ti ≤ 0.04%, and the balance is Fe and unavoidable impurities. The preparation method includes smelting molten steel for steelmaking; pre-treating the molten steel for steelmaking, removing impurities and then controlling the composition at the end of the converter, deoxidizing and alloying, and obtaining molten steel after refining; casting the molten steel into continuous casting billets, heating and then holding at a constant temperature, performing rough rolling and finish rolling, and obtaining a 490 MPa grade earthquake-resistant and fire-resistant steel plate after cooling. The fire-resistant steel plate of the present invention has high strength, good plasticity and toughness, excellent earthquake resistance and long-time fire resistance, which can not only meet the requirements of earthquake-resistant and fire-resistant performance, but also reduce production costs.

Description

Technical Field

[0001] The present invention relates to the field of fire-resistant steel plates for building structures, and more specifically, to a 490 MPa grade earthquake-resistant fire-resistant steel plate and a preparation method thereof. Background Art

[0002] Under the current background of economic development, there are more and more high-rise and super high-rise buildings at home and abroad. In high-rise buildings, there are dense crowds and numerous items. Once a fire breaks out, it will seriously endanger people's lives and property safety. The occurrence of the "9·11" incident in the United States has made countries around the world put forward urgent and strict requirements for the fire resistance performance of building steels, especially steels used in high-rise buildings. The high-temperature strength and fire resistance performance of building steels have become the focus of research and development in recent years. Summary of the Invention

[0003] Aiming at the deficiencies existing in the prior art, one of the purposes of the present invention is to solve one or more problems existing in the above-mentioned prior art. For example, one of the purposes of the present invention is to provide a 490 MPa grade earthquake-resistant fire-resistant steel plate for buildings with high strength, good plasticity and toughness, excellent earthquake resistance and long-time fire resistance.

[0004] One aspect of the present invention provides a 490 MPa grade earthquake-resistant fire-resistant steel plate, which may include the following chemical components by weight percentage: C: 0.02% - 0.18%, Si: 0.1% - 0.5%, Mn: 1.1% - 1.6%, P≤0.015%, S≤0.015%, Mo: 0.15% - 0.5%, Nb: 0.01% - 0.06%, V≤0.13%, 0<Ti≤0.04%, and the balance is Fe and unavoidable impurities.

[0005] Furthermore, the microstructure of the earthquake-resistant fire-resistant steel plate may include polygonal ferrite, granular bainite, and lath / needle martensite.

[0006] Furthermore, the yield strength of the earthquake-resistant fire-resistant steel plate may be greater than 490 MPa, the tensile strength may be greater than 580 MPa, the yield ratio may not be greater than 0.85, and the elongation after fracture may be greater than 15%.

[0007] Furthermore, the yield strength of the earthquake-resistant fire-resistant steel plate at 600°C may not be lower than 2 / 3 of the yield strength at room temperature.

[0008] On the other hand, the present invention provides a method for preparing a 490MPa-class earthquake-resistant and fire-resistant steel plate, which may include the following steps: smelting molten steel for steelmaking with a C content of 3.7% to 4.3% and an S content > 0.08% by weight percentage; performing pretreatment on the molten steel for steelmaking, removing impurities, controlling the composition at the end of the converter, and then performing deoxidation alloying. After refining, molten steel with the target chemical composition is obtained; casting the molten steel into continuous casting billets, heating and holding the continuous casting billets, subjecting them to rough rolling and finish rolling, and cooling to obtain a 490MPa-class earthquake-resistant and fire-resistant steel plate. Among them, the molten steel with the target chemical composition includes, by weight percentage: C: 0.02% - 0.18%, Si: 0.1% - 0.5%, Mn: 1.1% - 1.6%, P ≤ 0.015%, S ≤ 0.015%, Mo: 0.15% - 0.5%, Nb: 0.01% - 0.06%, V ≤ 0.13%, 0 < Ti ≤ 0.04%, and the balance is Fe and inevitable impurities.

[0009] Further, the heating temperature of the continuous casting billet can be 1100 - 1200°C, and the holding time can be not less than 120 min.

[0010] Further, the rough rolling temperature can be 1000 - 1100°C, and the finish rolling temperature can be 870 - 990°C.

[0011] Further, the rough rolling can be carried out for 3 - 6 passes, and the finish rolling can be carried out for 4 - 8 passes.

[0012] Further, during the rolling process, cooling can be first carried out by the laminar flow cooling method, the starting cooling temperature can be 800 - 870°C, and then air-cooled to room temperature.

[0013] Further, the steel billet can be cooled to 480 - 600°C to start coiling, and then air-cooled to room temperature.

[0014] Compared with the prior art, the beneficial effects of the present invention at least include: the fire-resistant steel plate of the present invention has high strength, good plasticity and toughness, excellent earthquake resistance and long-time fire resistance, which not only meets the requirements of earthquake-resistant and fire-resistant performance, but also can reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Through the following description in conjunction with the drawings, the above and other objects and features of the present invention will become clearer, wherein:

[0016] Figure 1 is the metallographic structure diagram of Example 1 of the present invention at 500× and 1000×;

[0017] Figure 2 is the SEM diagram of Example 1 of the present invention at 1000×;

[0018] Figure 3This is a fracture morphology diagram of Example 1 of the present invention after a tensile test at 600℃. Detailed Implementation

[0019] In the following, a 490MPa grade earthquake-resistant and fire-resistant steel plate and its preparation method according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0020] Specifically, this invention obtains a fire-resistant steel plate with an internal structure of ferrite + pearlite + granular bainite molybdenum-niobium-vanadium-titanium multi-alloy system by adjusting the amount of alloying elements added and controlling the rolling process parameters. This results in a building steel plate with high strength, good plasticity and toughness, excellent seismic resistance and long-term fire resistance, which meets the requirements of seismic and fire resistance performance while reasonably reducing production costs.

[0021] The design concept of the chemical composition and its mass percentage content of this invention is as follows:

[0022] Carbon: C is the main strengthening measure. Most of the C will form cementite or carbides in the steel. C can increase the hardenability of steel, making it easier for the steel to form bainite and martensite during the microstructure transformation process. However, too much C will affect the plasticity, toughness and weldability of the steel. Therefore, the mass percentage of C in this invention is controlled within the range of 0.02 to 0.18%.

[0023] Manganese (Mn): Derived from pig iron and ferromanganese in deoxidizers, Mn can react with sulfur (S) to form MnS, preventing hot brittleness in steel. It exists in steel as a substitute for solid solution atoms, playing a role in solid solution strengthening. Mn can also lower the austenite transformation temperature, increase the nucleation rate of ferrite, and inhibit its growth rate, thus playing a role in grain refinement strengthening. However, excessively high Mn content will increase the carbon equivalent of steel, thereby affecting its ductility and toughness. Therefore, this invention controls the mass percentage of Mn between 1.1% and 1.6%.

[0024] Silicon: The solid solution strengthening ability of Si is more than twice that of Mn. When the Si content is high, the ductile-brittle transition temperature of steel increases, which is not conducive to welding. Moreover, it will also cause the surface properties of the steel bars to deteriorate and make them more prone to rusting. Therefore, the mass percentage of Si in this invention is controlled between 0.1% and 0.5%.

[0025] Phosphorus and sulfur: P and S are generally harmful elements in steel, which can have an adverse effect on the mechanical properties of steel. The content of these two elements needs to be controlled at a low level. In this invention, the mass percentage of P is below 0.012% and the mass percentage of S is below 0.008%.

[0026] Molybdenum (Mo) plays two strengthening roles in refractory steel: solid solution strengthening and precipitation strengthening. Solid solution Mo accounts for 90% of the total added Mo content in steel. Mo has a relatively small effect on increasing the yield strength of steel at room temperature, but a significant effect on increasing the yield strength at high temperatures. Mo strengthens the ferrite matrix, readily segregating at grain boundaries, increasing the binding force at grain boundaries at high temperatures, preventing dislocation annihilation at high temperatures, maintaining the dislocation strengthening effect, and avoiding excessively rapid strength loss at high temperatures that could lead to steel failure. The addition of Mo can improve both the high-temperature performance and seismic resistance of steel. Mo also has a certain precipitation strengthening effect, reacting with C in steel to form MoC or Mo2C. Mo can also promote the precipitation of Nb, readily segregating around NbC, inhibiting the growth of NbC at high temperatures, thereby increasing the high-temperature yield strength of steel. However, excessive Mo can affect the hardenability of steel, worsening its weldability and brittleness, and directly increasing the cost per ton of steel. Therefore, the Mo mass percentage in this invention is within the range of 0.15% to 0.5%.

[0027] Niobium and Vanadium (Nb and V) also exhibit two strengthening mechanisms in steel: grain refinement and precipitation strengthening. Grain refinement strengthening: Austenite coarsens during heating and holding. Nb and V dissolved atoms and their fine, dispersed carbonitrides have a stabilizing effect on grain boundaries, hindering austenite grain migration and inhibiting austenite grain growth. During high-temperature rolling, the dissolved Nb and V have a dragging effect on grain boundaries, significantly inhibiting dynamic recrystallization of austenite, increasing the recrystallization temperature of the steel, and allowing the steel to enter the non-recrystallization zone earlier at high temperatures, thus significantly refining the grains. Precipitation strengthening: The higher the content of dissolved elements, the greater the precipitation during cooling, and the more pronounced the strengthening effect. For V microalloying, a small amount of nitrogen is added. V nitrides precipitate quickly, have low dispersion, low precipitation temperature, fine precipitate particles, and are less prone to aggregation and growth, resulting in a significant strengthening effect. Additionally, Mo-Nb microalloying can enhance the precipitation strengthening of Nb. In this invention, the mass percentage of Nb is 0.01–0.06%, and the mass percentage of V is ≤0.13%.

[0028] Titanium (Ti) in steel can combine with C and N to form carbonitrides, inhibiting grain growth and coarsening. However, excessive Ti can generate inclusions, reducing the steel's ductility and toughness. In this invention, the mass percentage of Ti is 0. <Ti≤0.04%。

[0029] One aspect of the present invention provides a 490 MPa grade earthquake-resistant and fire-resistant steel plate. In some embodiments, the earthquake-resistant and fire-resistant steel plate may include the following chemical components by weight percentage: C: 0.02% - 0.18%, Si: 0.1% - 0.5%, Mn: 1.1% - 1.6%, P ≤ 0.015%, S ≤ 0.015%, Mo: 0.15% - 0.5%, Nb: 0.01% - 0.06%, V ≤ 0.13%, 0 < Ti ≤ 0.04%, with the balance being Fe and unavoidable impurities. For example, the earthquake-resistant and fire-resistant steel plate may include the following chemical components by weight percentage: C: 0.05% - 0.13%, Si: 0.2% - 0.4%, Mn: 1.3% - 1.5%, P ≤ 0.012%, S ≤ 0.012%, Mo: 0.21% - 0.45%, Nb: 0.02% - 0.05%, V ≤ 0.11%, 0.01% ≤ Ti ≤ 0.03%, with the balance being Fe and unavoidable impurities; or may include the following chemical components by weight percentage: C: 0.08% - 0.10%, Si: 0.25% - 0.35%, Mn: 1.35% - 1.45%, P ≤ 0.008%, S ≤ 0.007%, Mo: 0.25% - 0.41%, Nb: 0.03% - 0.04%, V ≤ 0.08%, 0.02% ≤ Ti ≤ 0.025%, with the balance being Fe and unavoidable impurities; or a combination of the above ranges.

[0030] In some embodiments, the microstructure of the earthquake-resistant and fire-resistant steel plate may include ferrite, bainite, and martensite. Among them, the ferrite may be polygonal ferrite. The bainite may be granular bainite. The martensite may be lath and / or acicular martensite. Or, the microstructure of the earthquake-resistant and fire-resistant steel plate may be composed of ferrite, bainite, and martensite.

[0031] In some embodiments, the yield strength of the earthquake-resistant and fire-resistant steel plate may be greater than 490 MPa, the tensile strength may be greater than 580 MPa, the yield ratio may not be greater than 0.85, and the elongation after fracture may be greater than 15%. For example, the yield strength of the earthquake-resistant and fire-resistant steel plate is greater than 510 MPa, the tensile strength may be greater than 590 MPa, the yield ratio may be less than 0.75, and the elongation after fracture may be greater than 17%. For another example, the yield strength of the earthquake-resistant and fire-resistant steel plate is greater than 525 MPa, the tensile strength may be greater than 597 MPa, the yield ratio may be less than 0.71, and the elongation after fracture may be greater than 19%.

[0032] In some embodiments, the yield strength of the earthquake-resistant and fire-resistant steel plate at 600 °C is not lower than 2 / 3 of the yield strength at room temperature. For example, the yield strength of the earthquake-resistant and fire-resistant steel plate at 600 °C may be 7 / 10 of the yield strength at room temperature, or 4 / 5, or a combination of the above values.

[0033] In some embodiments, the thickness of the earthquake-resistant and fire-resistant steel plate can be 8 to 24 mm. For example, the thickness can be 12 to 20 mm, or 14 to 18 mm or a combination of the above ranges.

[0034] Another aspect of the present invention provides a method for preparing a 490 MPa grade earthquake-resistant and fire-resistant steel plate. In some embodiments, the preparation method may include:

[0035] S01, ironmaking in a blast furnace; smelting pig iron with a C content of 3.7% to 4.3% and an S content > 0.08% by weight percentage.

[0036] S02, steelmaking; pretreating the pig iron, removing impurities, controlling the composition at the end of the converter, and then performing deoxidation alloying. After refining, molten steel with the target chemical composition is obtained; wherein, the molten steel with the target chemical composition includes by weight percentage: C: 0.02% - 0.18%, Si: 0.1% - 0.5%, Mn: 1.1% - 1.6%, P ≤ 0.015%, S ≤ 0.015%, Mo: 0.15% - 0.5%, Nb: 0.01% - 0.06%, V ≤ 0.13%, 0 < Ti ≤ 0.04%, and the balance is Fe and unavoidable impurities.

[0037] S03, continuous casting and rolling; pouring the molten steel into a continuous casting billet, heating and holding the continuous casting billet, and then performing rough rolling and finish rolling. After cooling, a 490 MPa grade earthquake-resistant and fire-resistant steel plate is obtained.

[0038] In some embodiments, step S01 may include: adding iron ore, coke, and flux into the blast furnace in proportion, while blowing hot air and injecting pulverized coal, controlling the temperature and air permeability in the furnace, and obtaining pig iron with a C content between 3.7% and 4.3% and an S content > 0.08%. The proportions of the iron ore, coke, and flux, the control of the furnace temperature, the air blowing, and the coal injection can be achieved by conventional operations in the art and will not be elaborated here. For example, pig iron with a C content between 3.8% and 4.1% and an S content > 0.09% can be obtained; or pig iron with a C content between 3.9% and 4.0% and an S content > 0.085% can be obtained.

[0039] In some embodiments, step S02 may include: subjecting the molten iron obtained from blast furnace smelting in step S01 to pretreatment such as dephosphorization, desulfurization, and desiliconization, then pouring it into a converter, removing impurities through blowing, controlling the converter end point by the high-pull supplementary blowing method, and then pouring the molten steel and alloy into a ladle pre-baked and heated, and performing in-ladle deoxidation alloying. Further deoxidizing and slightly adjusting the composition of the molten steel in the LF refining furnace, taking a steel sample and measuring the temperature to obtain molten steel with the target chemical composition. Among them, the molten steel with the target chemical composition includes, by weight percentage: C: 0.02% - 0.18%, Si: 0.1% - 0.5%, Mn: 1.1% - 1.6%, P ≤ 0.015%, S ≤ 0.015%, Mo: 0.15% - 0.5%, Nb: 0.01% - 0.06%, V ≤ 0.13%, 0 < Ti ≤ 0.04%, and the balance is Fe and unavoidable impurities. The above-mentioned pretreatment, impurity removal, deoxidation alloying, and LF refining, etc. can use conventional methods in the art to control the chemical composition of the smelted molten steel within the target value.

[0040] In some embodiments, step S03 may include: casting the molten steel obtained in step S02 to obtain a continuous casting billet, putting the continuous casting billet into a heating furnace to heat it to a certain temperature and hold for a predetermined time, and then entering a continuous rolling mill for rough rolling and finish rolling. Control the temperature during the rolling process. The rolling process can first adopt the laminar flow cooling method for cooling to obtain a 490 MPa grade earthquake-resistant and fire-resistant steel plate.

[0041] In some embodiments, the heating temperature of the continuous casting billet can be 1100 - 1200 °C, and the holding time can be not less than 120 min. At the above heating temperature and holding time, the temperature of the steel billet can be evenly heated, and the added alloy can be fully dissolved. For example, the heating temperature of the continuous casting billet can be 1130 - 1190 °C, and the holding time is not less than 130 min. For another example, the heating temperature of the continuous casting billet can be 1150 - 1170 °C, and the holding time is not less than 125 min. For another example, the heating temperature of the continuous casting billet can be 1160 °C, and the holding time is 132 min.

[0042] In some implementations, the roughing temperature can be 1000–1100°C, and the roughing and finishing temperature can be 870–990°C. For example, the roughing temperature can be 1050–1080°C, and the roughing and finishing temperature can be 890–970°C. Another example is that the roughing temperature can be 1060–1070°C, and the roughing and finishing temperature can be 910–950°C. The roughing process can be performed in 3–6 passes, at which point austenite begins to crystallize inside the steel. The finishing process can be performed in 4–8 passes, at which point ferrite begins to form. Then, through the combination of laminar cooling and air cooling of this invention, molybdenum and vanadium carbides inside the steel precipitate during the process, pinning grain boundaries and inhibiting grain growth, forming a microstructure in which polygonal ferrite, granular bainite, and lath / acicular martensite coexist, thereby improving the strength of the reinforcing steel.

[0043] In some implementations, the rolling process can be initially cooled using laminar flow cooling at an initial temperature of 800–870°C, followed by air cooling to room temperature. For example, the initial cooling temperature can be 810–860°C, or 820–850°C, or 830–840°C, or a combination of these ranges.

[0044] In some implementations, the billet can be cooled to 480–600°C to begin coiling, and then air-cooled to room temperature. For example, the billet can be cooled to 510–580°C to begin coiling, or cooled to 525–565°C to begin coiling.

[0045] To better understand the present invention, specific examples are provided below to further illustrate the content of the present invention, but the content of the present invention is not limited to the examples below.

[0046] The 490MPa grade earthquake-resistant and fire-resistant steel plates of Examples 1-5 of the present invention were prepared by the following method:

[0047] Iron ore, coke, and flux are added to the blast furnace in proportion, while hot blast and pulverized coal are injected simultaneously. The furnace temperature and permeability are controlled. After blast furnace ironmaking, the molten steel is pretreated and then added to the converter. Impurities are removed by blowing, and the converter endpoint is controlled using a high-pressure blowing method. The molten steel and alloys are then poured into a preheated ladle for in-ladle deoxidation and alloying. The molten steel is further deoxidized and its composition is finely adjusted in the LF refining furnace. Steel samples are taken and the temperature is measured to obtain molten steel with the target chemical composition shown in Table 2.

[0048] The molten steel obtained in the previous step is cast into a continuous casting billet. The continuous casting billet is placed in a heating furnace and heated at the temperature and time described in Table 1. Then it undergoes rough rolling, finish rolling and coiling as described in Table 1. After cooling, a 490MPa grade earthquake-resistant and fire-resistant steel plate is obtained. The rolling process can first use laminar flow cooling (laminar cooling) to cool the billet. The initial cooling temperature can be 840℃, and then it can be air-cooled to room temperature.

[0049] Table 1 Rolling process parameters of various embodiments of the present invention

[0050]

[0051] Table 2 Chemical composition (wt, %) of various embodiments of the present invention

[0052]

[0053] The performance of the 490MPa grade earthquake-resistant and fire-resistant steel plates prepared by the above methods in each embodiment at room temperature and 600℃ is shown in Tables 3 and 4.

[0054] Table 3 Mechanical properties of various embodiments of the present invention at room temperature

[0055]

[0056] Table 4 Mechanical properties of various embodiments of the present invention at 600℃

[0057]

[0058]

[0059] The above data shows that the room temperature and high temperature performance (600℃) of the five embodiments of this invention meet the requirements of the national standard for Q460FR fire-resistant steel plates. The yield strength of the earthquake-resistant fire-resistant steel plate is greater than 490MPa, the tensile strength is greater than 580MPa, the yield ratio is not greater than 0.85, and the elongation after fracture is greater than 15%. The yield strength of the earthquake-resistant fire-resistant steel plate at 600℃ is not less than 2 / 3 of its yield strength at room temperature. Wherein, R... p0.2 -600 indicates the yield strength at 600℃, R p0.2 - "room" indicates the yield strength at room temperature. Furthermore, as can be seen from the data in Tables 3 and 4, the 490MPa grade earthquake-resistant fire-resistant steel plate of this invention exceeds the national standard and reaches the Q490FR level.

[0060] like Figure 1 The image shown is a metallographic image of Example 1 at 500× and 1000×. Figure 2 The image shown is a SEM image of Example 1 at 1000×. Figure 1 and Figure 2 This indicates that the microstructure of the 490MPa grade earthquake-resistant and fire-resistant steel plate of the present invention consists of polygonal ferrite, granular bainite, and lath / acicular martensite. The fracture morphology of Example 1 after a tensile test at 600℃ is as follows... Figure 3As shown, the 490MPa grade earthquake-resistant and fire-resistant steel plate prepared by this invention under high-temperature conditions exhibits high strength and good toughness. Its fracture morphology shows dimples of varying sizes, with a second phase present within these dimples, indicating that some dimples nucleate at the interface between the second phase and the matrix. In ductile fracture, due to the significant difference in deformability between the inclusions and the steel matrix, stress concentration occurs around the inclusions, leading to fracture. Slip lines are visible on the inner walls of the dimples.

[0061] Although the invention has been described above in conjunction with exemplary embodiments, those skilled in the art will understand that various modifications and changes can be made to the exemplary embodiments of the invention without departing from the spirit and scope defined by the claims.

Claims

1. A method for manufacturing a 490 MPa grade seismic fire resistant steel sheet, characterized in that, The method comprises the following steps: melting the molten steel with a C content of 3.7-4.3% and a S content of >0.08% by weight percentage; pretreating the molten steel, decarburizing in a converter, removing S and P, and controlling the end composition of the converter, then deoxidizing and alloying, and obtaining the molten steel with the target chemical composition after refining; casting the molten steel into a continuous casting billet, heating and holding the continuous casting billet, rough rolling and finish rolling, and obtaining the 490MPa-grade anti-seismic fire-resistant steel plate after cooling, wherein the 490MPa-grade anti-seismic fire-resistant steel plate comprises the following components by weight percentage: C: 0.13-0.18%, Si: 0.4-0.5%, Mn: 1.1-1.6%, P≤0.015%, S≤0.015%, Mo: 0.15-0.50%, Nb: 0.01-0.06%, V: 0.08-0.13%, Ti≤0.04%, and the balance of Fe and inevitable impurities; the rough rolling temperature is 1000-1100℃, and the finish rolling temperature is 870-990℃; the rolling process is cooled by using the laminar flow cooling method first, and the open cooling temperature is 800-870℃, and then air cooling to room temperature.

2. The method of manufacturing a 490 MPa grade seismic fire resistant steel plate according to claim 1, characterized in that, The microstructure of the anti-seismic fire-resistant steel plate comprises polygonal ferrite, granular bainite and lath / needle-shaped martensite.

3. The method of producing a 490 MPa grade anti-seismic fire-resistant steel plate according to claim 1, characterized by, The yield strength of the anti-seismic fire-resistant steel plate is greater than 490MPa, the tensile strength is greater than 580MPa, the yield strength ratio is not greater than 0.85, and the elongation after fracture is greater than 15%.

4. The method of producing a 490 MPa grade anti-seismic fire-resistant steel plate according to claim 1, characterized by, The yield strength of the anti-seismic fire-resistant steel plate at 600℃ is not less than 2 / 3 of the yield strength at room temperature.

5. The method of producing a 490 MPa grade anti-seismic fire-resistant steel plate according to claim 1, characterized by, The heating temperature of the continuous casting billet is 1100-1200℃, and the holding time is not less than 120min.

6. The method of producing a 490 MPa grade anti-seismic fire-resistant steel plate according to claim 1, characterized by, The rough rolling is 3-6 passes, and the finish rolling is 4-8 passes.

7. The method of producing a 490 MPa grade anti-seismic fire-resistant steel plate according to claim 1, characterized by, The steel plate is coiled at 480-600℃, and then air cooled to room temperature.

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