Manufacturing method of high-strength shock-resistant weather-resistant fire-resistant H-shaped steel with uniform indoor high-temperature performance

Abstract

The invention provides a manufacturing method of high-strength anti-seismic weather-resistant fire-resistant H-shaped steel with uniform indoor high-temperature performance, and relates to the technical field of building steel production processes. The method comprises the following steps: carrying out vacuum smelting according to set components of fireproof H-shaped steel to obtain H-shaped steel liquid, and casting to obtain an H-shaped steel blank; then first-stage multi-pass hot rolling is carried out, then the whole surface is rapidly water-cooled until the surface temperature is lower than the initial rolling temperature of first-stage hot rolling by 260-370 DEG C, a core-surface temperature difference is formed, second-stage multi-pass hot rolling is immediately carried out after water cooling, and the hot-rolled H-shaped steel is obtained; and the flanges are subjected to water mist cooling and then integrally air-cooled to the room temperature, and the high-strength anti-seismic weather-resistant fire-resistant H-shaped steel with uniform room-temperature and high-temperature performance is obtained. According to the invention, delivery is carried out in a hot rolling state, a complex heat treatment process is not needed, a wide process window is provided, different parts have excellent room high-temperature mechanical properties and corrosion resistance, and the material can be widely applied to the fields of buildings, bridges and the like which simultaneously require shock resistance, high strength and certain high-temperature resistance and weather resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of construction steel production technology, in particular to a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room-temperature performance. Background Art

[0002] Currently, there is significant room for growth in the application of prefabricated buildings. As prefabricated buildings become increasingly popular, H-shaped steel for construction, which offers excellent comprehensive performance, is gaining increasing attention. In particular, demand for H-shaped steel that offers high strength, multifunctionality, and homogenized performance is expected to increase significantly.

[0003] Existing H-shaped steels for construction mostly adopt hot rolling process, and the rheological behavior of the material varies greatly in the flange and web areas. The flange usually experiences greater tensile deformation when subjected to stress, while the web mainly experiences shear deformation. In addition, the two have different thicknesses and surface areas, and different cooling rates, which can easily lead to large differences in their organizational properties, seriously affecting their use. Therefore, it is very necessary and urgent to solve the problem of performance uniformity of high-strength H-shaped steel for construction.

[0004] For example, Chinese patent CN118166292A discloses a method for manufacturing weather-resistant and shock-resistant hot-rolled H-shaped steel. The steel composition is selected with relatively few alloy elements added, and the preparation method is rough rolling and finish rolling. The cooling method is water-controlled cooling. Therefore, the yield strength and tensile strength of the prepared steel are relatively low, the elongation is high, and the low-temperature impact performance is high.

[0005] Chinese patent CN111519095A discloses a method for preparing a multiphase microstructured, earthquake-resistant, weather-resistant, and fire-resistant H-shaped steel. The steel's composition selection involves the addition of a relatively large number of alloying elements, and the preparation process is complex, difficult to operate, and results in high production costs and low efficiency, making it unsuitable for industrial production. The prepared steel has low yield strength and tensile strength, high Charpy impact energy, and low high-temperature strength.

[0006] Chinese patent CN117587315A discloses a method for producing high-strength weather-resistant and earthquake-resistant hot-rolled H-shaped steel for prefabricated steel structure buildings. The preparation process is still complicated and the production cost is high. However, the yield strength and tensile strength of the prepared steel are still not high, and the low-temperature impact performance is not high either.

[0007] Chinese patent CN111996453A discloses a multi-precipitation-enhanced, seismic-resistant, corrosion-resistant and fire-resistant H-shaped steel and its preparation method, which obtains a dual-phase structure of ferrite and bainite. The yield strength and tensile strength of the prepared steel are still not high, and the high-temperature yield strength after being kept at 600°C for 3 hours is also the same. Although the relative corrosion rate is slightly lower than that of the comparative example, the reduction is not large, and the relative corrosion rate is higher than 50%. Summary of the Invention

[0008] In order to solve the technical problems of the existing technology of functional composite H-beam, such as complex process, narrow process window, and difficulty in uniform room temperature and high temperature performance at different locations, the present invention proposes a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-beam that can solve the above technical problems. The technical solution is as follows:

[0009] A method for manufacturing high-strength, earthquake-resistant, weather-resistant, and fire-resistant H-shaped steel with uniform room-temperature and high-temperature performance, comprising vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and post-rolling cooling. The specific process is as follows:

[0010] S1. Vacuum smelting and casting into billets: According to the set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-beam, vacuum smelting is used to obtain H-beam molten steel, and then casting is performed to obtain H-beam billets;

[0011] S2, hot rolling and cooling between rolling passes: The H-beam billet of S1 is subjected to a first-stage multi-pass hot rolling, and then the entire surface is rapidly water-cooled to a surface temperature lower than the first-stage hot rolling start temperature of 260-370°C. After water cooling, the second-stage multi-pass hot rolling is immediately carried out to obtain a hot-rolled H-beam;

[0012] S3, multi-stage post-hot rolling cooling: The flanges of the hot-rolled H-shaped steel plates of S2 are spray-cooled, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0013] Optionally, the composition of the medium- and high-strength earthquake-resistant, weather-resistant and fire-resistant H-shaped steel S1 is set to be calculated by mass percentage: C 0.05-0.10%, Mn 1.0-1.5%, Si 0.1-0.3%, Cr 0.2-0.6%, Mo0.35-0.5%, Ti 0.08-0.12%, V 0.05-0.08%, Nb 0.03-0.05%, Cu 0.2-0.5%, Ni 0.2-0.5%, Al 0.01-0.06%, P≤0.012%, S≤0.006%, and the rest is iron and inevitable trace chemical elements.

[0014] The main chemical components of the present invention are limited for the following reasons:

[0015] Carbon: Carbon significantly affects the strength, toughness, and weldability of steel. Reducing the carbon content not only ensures excellent plasticity and toughness in the alloy steel, but also effectively improves the steel's cold and hot deformation capabilities. Furthermore, as the carbon content decreases, the alloy steel maintains good weldability and a low brittle transition temperature. Therefore, to ensure excellent overall performance, the carbon content of the present invention is 0.05-0.10% by weight.

[0016] Manganese: Manganese has deoxidizing and desulfurizing properties, reacting with sulfur in steel to form MnS, which prevents hot brittleness. Furthermore, manganese interacts with nitrogen at around 450°C, which improves high-temperature tensile strength but negatively impacts high-temperature ductility and can also cause temper brittleness. Increasing the manganese content reduces carbon diffusion and refines carbides. Therefore, the manganese content in the present invention is 1.0-1.5% by weight.

[0017] Silicon: A deoxidizing element in steel, silicon improves the steel's corrosion resistance and is often added to stainless steel, low-alloy steel, and corrosion-resistant alloys to enhance their corrosion resistance, imparting resistance to chloride stress corrosion cracking, pitting, hot concentrated nitric acid, oxidation, and seawater corrosion. However, excessive amounts can deteriorate the steel's toughness and weldability. Silicon also has a strong solid solution strengthening effect, but excessive amounts can also deteriorate the steel's toughness and weldability. Therefore, the silicon content in the present invention is 0.1-0.3% by weight.

[0018] Chromium: Chromium improves steel's strength, hardness, and atmospheric corrosion resistance, and its effects are particularly pronounced when added to other alloying elements. Chromium slows the decomposition of austenite, significantly improving the steel's hardenability and providing secondary hardening, but it also increases the steel's tendency to temper brittleness. However, excessive chromium content can reduce the toughness of the base material and the heat-affected zone. Therefore, the chromium content of the present invention is 0.2-0.6% by weight.

[0019] Molybdenum: Molybdenum significantly improves the hardenability of steel, is conducive to the formation of bainite or martensite, reduces temper brittleness, and improves the delayed fracture resistance of steel. Molybdenum also has a solid solution strengthening effect on ferrite, can improve the stability of carbides, reduce the coarsening tendency, and can also improve high-temperature strength through the enrichment of Mo2C and Mo. Excessive molybdenum will deteriorate low-temperature toughness and welding performance, and the cost of molybdenum is relatively high. Therefore, the weight percentage of the molybdenum element content in the present invention is 0.2-0.5%.

[0020] Titanium: Titanium has a low solid solubility in steel and easily precipitates in austenite, pinning it to grain boundaries, preventing grain growth and recrystallization and thus refining the grains. Furthermore, titanium is a strong deoxidizer in steel, densifying the internal structure, reducing aging sensitivity and cold brittleness, and improving weldability. Furthermore, due to its low solid solubility, titanium easily precipitates as an interphase during the austenite-to-ferrite transition, enhancing high-temperature strength. Therefore, the titanium content in the present invention is 0.08-0.12% by weight.

[0021] Vanadium: Vanadium has a low full solution temperature and is essentially fully dissolved during soaking. This dissolved state during rolling effectively improves hardenability and recrystallization temperature. During post-rolling air cooling, vanadium readily precipitates as it transforms from austenite to ferrite, forming interphase precipitation. During tempering, vanadium precipitates independently in ferrite and bainite, or in combination with niobium and molybdenum, enhancing high-temperature strength. Therefore, the weight percentage of vanadium in the present invention is 0.05-0.08%.

[0022] Niobium: Niobium dissolved in austenite during rolling and the deformation-induced precipitation of niobium carbonitride particles significantly raises the austenite pre-recrystallization temperature, refines the austenite grains, and subsequently refines the grains of ferrite and other phases, thereby improving strength. Niobium dissolved in austenite also enhances hardenability. Niobium carbide particles precipitated during tempering, or combined with vanadium and molybdenum to form a secondary phase, enhance high-temperature strength. Therefore, the niobium content of the present invention is 0.03-0.05% by weight.

[0023] Copper: Copper improves the hardenability and atmospheric corrosion resistance of steel and is also one of the austenitizing stabilizing elements. The nano-scale copper phase particles precipitated during aging have a certain precipitation strengthening effect. However, copper-containing steel is prone to hot brittleness due to selective surface oxidation. Therefore, in addition to the high copper content, nickel (0.5 times or more) is also added. Therefore, the weight percentage of the copper element in the present invention is 0.2-0.5%.

[0024] Nickel: Nickel is an austenite stabilizing element, which is beneficial for obtaining metastable austenite and improving the toughness and plasticity of steel. In addition, nickel, when combined with copper, can greatly improve the hardenability and atmospheric corrosion resistance of steel. However, nickel is relatively expensive. Considering the cost and the comprehensive performance of steel, the weight percentage of nickel in the present invention is 0.2-0.5%.

[0025] Aluminum: Aluminum is a strong deoxidizing element and can also combine with nitrogen to form aluminum nitride, which plays a role in refining grains. Therefore, the weight percentage of the aluminum element content in the present invention is 0.01-0.06%.

[0026] Phosphorus and sulfur: Phosphorus and sulfur are unavoidable harmful impurities in steel. High phosphorus levels can cause segregation, affecting steel microstructure uniformity and reducing plasticity. Sulfur easily forms sulfide inclusions, which are detrimental to low-temperature toughness, cause anisotropy in properties, and severely impact steel strain aging. Therefore, the phosphorus and sulfur contents in steel should be strictly limited. In this invention, the phosphorus content is controlled to ≤0.012% by weight, and the sulfur content is controlled to ≤0.006% by weight.

[0027] Optionally, the vacuum smelting temperature in S1 is 1550-1650°C, the smelting time is 2-4h, and the cross-sectional shape of the H-shaped steel plate blank obtained by casting is I-shaped, with a flange width of 200-600mm, a web height of 100-400mm, a flange thickness of 20-60mm, and a web thickness of 10-40mm.

[0028] Optionally, the starting rolling temperature of the first stage multi-pass hot rolling in S2 is 1100-1170° C., the rolling is performed in 2-4 passes, the rolling reduction in a single pass is 15-20%, and the total rolling reduction is 40-60%.

[0029] Optionally, in S2, the entire surface is rapidly water-cooled to a surface temperature of 800-840°C, with the cooling rate controlled at above 40°C / s. Immediately after cooling, the second stage of multi-pass hot rolling is carried out, with the start rolling temperature being 800-840°C, 5-10 passes being rolled, the single-pass rolling reduction being 10-15%, and the total rolling reduction being 45-80%.

[0030] Optionally, in S3, the flange is cooled by water mist to below 400°C, and the cooling rate is controlled at above 10°C / s.

[0031] Optionally, the high-strength seismic, weathering and fire-resistant H-shaped steel with uniform room temperature and high temperature performance in S3 has different microstructures at different positions. The microstructure at the flange is mainly composed of ferrite with a volume fraction of 0-10% and bainite with a volume fraction of 90-100%; the microstructure at the web is mainly composed of ferrite with a volume fraction of 10-70% and bainite with a volume fraction of 30-90%, and there are also a large amount of MC-type carbides containing Mo / Nb / V / Ti.

[0032] Optionally, different parts (flanges, webs, etc.) of the high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel in S3 with uniform room temperature and high temperature performance have a yield strength ≥550 MPa, a tensile strength of 700-840 MPa, an elongation after fracture ≥18%, a KV2 ≥69 J at -20°C, and a yield strength ratio <0.80, a yield strength (≥367 MPa) after insulation at 600°C for 3 hours that is not less than 2 / 3 of the yield strength at room temperature, and a relative corrosion rate (based on Corten A) that is less than 50%.

[0033] The technical principle of the present invention is as follows: utilizing the different deformation amounts of different parts of the H-shaped steel and the different cooling rates will promote the formation of different types and proportions of microstructures and precipitations, and utilizing the regulation effect of the ratio of bainite and ferrite and precipitation to promote uniform room temperature and high temperature performance.

[0034] To address the shortcomings of existing technologies, a method for manufacturing high-strength, seismic-resistant, weather-resistant, and fire-resistant H-beams with uniform room-temperature and high-temperature performance is provided, based on rational composition design and produced solely through controlled rolling, controlled inter-pass cooling, and post-rolling cooling. Through controlled composition and process, a multiphase structure of ferrite and bainite is achieved, with significant precipitation within the structure. Delivered in a TMCP state, the steel eliminates the need for complex heat treatment processes, offers a wide process window, and maintains uniform performance across different parts. It is widely applicable in applications such as buildings and bridges, where seismic resistance, high strength, and certain high-temperature and weather resistance properties are simultaneously required.

[0035] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0036] The above scheme, the present invention proposes a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room and high temperature performance, which can solve the technical problems of the existing technology such as complex process, narrow process window, and difficulty in uniform room and high temperature performance at different positions of functional composite H-shaped steel.

[0037] The invention adds a certain amount of alloy elements to H-shaped steel for construction, firstly rolls the steel through the recrystallization zone to obtain fine austenite grains, and then undergoes a surface rapid cooling treatment, in order to prevent the austenite grains from growing.

[0038] In order to form a temperature gradient between the surface and the core, the present invention then refines the grains after rolling compared to conventional rolling and causes accumulation of deformation in the core where the thickness is thicker, thereby increasing nucleation points and promoting further phase transformation in a higher temperature range.

[0039] The invention uses flange water mist to quickly cool the steel after rolling, thereby obtaining a larger proportion of bainite structure, and simultaneously the rapid cooling reduces the time in the precipitation temperature range.

[0040] Although the air cooling treatment at the web position of the present invention is affected by the heat conduction of the water mist cooling at the flange position, its cooling rate will be slower and a smaller proportion of bainite structure will be obtained; however, it will stay in the precipitation temperature range for a longer time, and a large amount of MC-type carbides mainly composed of Mo\Ti\V\Nb will be formed in the ferrite, thereby improving the room temperature strength while maintaining the high temperature strength.

[0041] The present invention promotes the uniformity of room temperature and high temperature properties of the entire steel plate thickness direction due to the differential strain fields at different positions during the rolling process and the differential temperature fields during the phase change process, by utilizing different tissue types and proportions, and different amounts of precipitation strengthening within the tissue.

[0042] The present invention utilizes the regulation of rolling and cooling to refine the grains, and there are differences in the phase ratio and tissue type at different positions. By utilizing the differences in temperature and strain, different amounts of precipitation are obtained at different positions, and the strength, yield strength ratio, plasticity, etc. are regulated to achieve the best combination of strength and plasticity and toughness, thereby improving the room temperature mechanical properties and enhancing the high temperature resistance of different tissue types. At the same time, the addition of corrosion-resistant elements can effectively improve the corrosion resistance.

[0043] In summary, compared with other traditional methods, the method of the present invention prepares high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance through vacuum smelting and casting into billets, hot rolling forming and cooling between rolling passes, and multi-stage hot rolling post-cooling; the preparation method is simple and easy to operate, green and environmentally friendly, low in cost, short in process, and high in efficiency, which is conducive to large-scale industrial production and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 This is a process flow chart of a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to the present invention;

[0046] Figure 2 This is a metallographic diagram of the flange of an H-shaped steel prepared by the method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room-temperature performance according to Example 1 of the present invention;

[0047] Figure 3 This is a metallographic diagram of the web of an H-shaped steel prepared by a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature performance in Example 1 of the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0049] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0050] In the embodiments of the present invention, “image” and “picture” may sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are the same.

[0051] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0052] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0053] A method for manufacturing high-strength, earthquake-resistant, weather-resistant, and fire-resistant H-shaped steel with uniform room-temperature and high-temperature performance, comprising vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and post-rolling cooling. The specific process is as follows:

[0054] S1. Vacuum smelting and casting into billets: According to the set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-beam, vacuum smelting is used to obtain H-beam molten steel, and then casting is performed to obtain H-beam billets;

[0055] S2, hot rolling and cooling between rolling passes: The H-beam billet of S1 is subjected to a first-stage multi-pass hot rolling, and then the entire surface is rapidly water-cooled to a surface temperature lower than the first-stage hot rolling start temperature of 260-370°C. After water cooling, the second-stage multi-pass hot rolling is immediately carried out to obtain a hot-rolled H-beam;

[0056] S3, multi-stage post-hot rolling cooling: The flanges of the hot-rolled H-shaped steel plates of S2 are spray-cooled, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0057] In particular, the S1 medium-high strength earthquake-resistant, weather-resistant and fire-resistant H-shaped steel has the following set composition by mass percentage: C 0.05-0.10%, Mn 1.0-1.5%, Si 0.1-0.3%, Cr 0.2-0.6%, Mo0.35-0.5%, Ti 0.08-0.12%, V 0.05-0.08%, Nb 0.03-0.05%, Cu 0.2-0.5%, Ni 0.2-0.5%, Al 0.01-0.06%, P≤0.012%, S≤0.006%, and the rest are iron and inevitable trace chemical elements.

[0058] In particular, the vacuum smelting temperature in S1 is 1550-1650°C, the smelting time is 2-4 hours, and the cross-sectional shape of the H-shaped steel plate blank obtained by casting is I-shaped, with a flange width of 200-600 mm, a web height of 100-400 mm, a flange thickness of 20-60 mm, and a web thickness of 10-40 mm.

[0059] In particular, the starting rolling temperature of the first stage multi-pass hot rolling in S2 is 1100-1170° C., the rolling is performed in 2-4 passes, the rolling reduction in a single pass is 15-20%, and the total rolling reduction is 40-60%.

[0060] In particular, the entire surface in S2 is rapidly water-cooled to a surface temperature of 800-840°C, with the cooling rate controlled at above 40°C / s. Immediately after cooling, the second stage of multi-pass hot rolling is carried out, with the start rolling temperature of 800-840°C, 5-10 passes of rolling, a single-pass rolling reduction of 10-15%, and a total rolling reduction of 45-80%.

[0061] In particular, the flange in S3 is cooled by water mist to below 400°C, and the cooling rate is controlled above 10°C / s.

[0062] In particular, the high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel S3 with uniform room temperature and high temperature performance has different microstructures at different positions. The microstructure at the flange is mainly composed of ferrite with a volume fraction of 0-10% and bainite with a volume fraction of 90-100%; the microstructure at the web is mainly composed of ferrite with a volume fraction of 10-70% and bainite with a volume fraction of 30-90%, and there are also a large amount of MC-type carbides containing Mo / Nb / V / Ti.

[0063] In particular, different parts of the high-strength, seismic, weather-resistant and fire-resistant H-shaped steel in S3, which has uniform room temperature and high temperature performance (flanges, webs, etc.), have a yield strength ≥550MPa, a tensile strength of 700-840MPa, an elongation after fracture ≥18%, a KV2 ≥69J at -20°C, and a yield strength ratio of <0.80. The yield strength after insulation at 600°C for 3 hours (≥367MPa) is not less than 2 / 3 of the yield strength at room temperature, and the relative corrosion rate (based on Corten A) is less than 50%.

[0064] Example 1

[0065] The present embodiment provides a method for manufacturing high-strength, earthquake-resistant, weather-resistant, and fire-resistant H-shaped steel with uniform room-temperature and high-temperature performance. The method comprises vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and cooling after rolling. The specific process is as follows:

[0066] S1. Vacuum smelting and casting into billets: The set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel is calculated by mass percentage as follows: C 0.087%, Mn 1.42%, Si 0.26%, Cr 0.43%, Mo 0.44%, Ti 0.11%, V 0.068%, Nb 0.043%, Cu 0.45%, Ni 0.43%, Al 0.018%, P 0.006%, S 0.003%, and the remainder is iron and inevitable trace chemical elements; according to the set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel, vacuum smelting is used to obtain H-shaped steel liquid, the vacuum smelting temperature is 1550°C, and the smelting time is 2.5 hours; the cross-sectional shape of the cast H-shaped steel plate billet is I-shaped, with a flange width of 500 mm, a web height of 350 mm, a flange thickness of 55 mm, and a web thickness of 35 mm;

[0067] S2, hot rolling forming and cooling between rolling passes: The H-beam billet of S1 is subjected to the first stage multi-pass hot rolling, the starting rolling temperature of the first stage multi-pass hot rolling is 1145℃, and the rolling is performed in 3 passes, with a rolling reduction of 20% in each pass and a total rolling reduction of 60%;

[0068] After that, the entire surface is rapidly water-cooled to a surface temperature of 817°C, with the cooling rate controlled at above 40°C / s. Immediately after water-cooling, the second stage of multi-pass hot rolling is carried out, with the starting rolling temperature at 815°C, 7 passes, a rolling reduction of 10%, and a total reduction of 70%, to obtain hot-rolled H-beam.

[0069] S3, multi-stage post-hot rolling cooling: The flange of the hot-rolled H-shaped steel plate of S2 is spray-cooled to 385℃, and the cooling rate is controlled at more than 10℃ / s, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0070] The high-strength, earthquake-resistant, weather-resistant, and fire-resistant H-beam produced in this example, with uniform room-temperature and high-temperature performance, contains 3% ferrite and 97% bainite at the flange quarter. The steel exhibits a yield strength of 602.2 MPa, a tensile strength of 813.8 MPa, an elongation of 18.7%, a -20°C KV2 of 78.5 J, and a yield-to-tensile ratio of 0.74. After holding at 600°C for 3 hours, the steel exhibits a yield strength of 434.2 MPa, a high-temperature / room-temperature yield strength ratio of 72.1%, and a relative corrosion rate (based on Corten A) of 45%.

[0071] The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this embodiment contains a ferrite structure with a volume fraction of 39% and a bainite structure with a volume fraction of 61% at 1 / 4 of the web; the yield strength is 584.5 MPa, the tensile strength is 749.4 MPa, the elongation after fracture is 19.4%, the KV2 at -20°C is 89.5 J and the yield strength ratio is 0.78. The yield strength after insulation at 600°C for 3 hours is 399.8 MPa, the high temperature / room temperature yield strength is 68.4%, and the relative corrosion rate (based on Corten A) is 46%.

[0072] Example 2

[0073] The present embodiment provides a method for manufacturing high-strength, earthquake-resistant, weather-resistant, and fire-resistant H-shaped steel with uniform room-temperature and high-temperature performance. The method comprises vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and cooling after rolling. The specific process is as follows:

[0074] S1. Vacuum smelting and casting into billets: The set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel is calculated by mass percentage as follows: C 0.078%, Mn 1.35%, Si 0.20%, Cr 0.51%, Mo 0.43%, Ti 0.09%, V 0.072%, Nb 0.035%, Cu 0.38%, Ni 0.40%, Al 0.022%, P 0.007%, S 0.004%, and the remainder is iron and inevitable trace chemical elements; according to the set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel, vacuum smelting is used to obtain H-shaped steel liquid, the vacuum smelting temperature is 1600°C, and the smelting time is 3h; the cross-sectional shape of the cast H-shaped steel plate billet is I-shaped, with a flange width of 450mm, a web height of 300mm, a flange thickness of 45mm, and a web thickness of 30mm;

[0075] S2. Hot rolling and cooling between rolling passes: The H-beam billet of S1 is subjected to the first stage of multi-pass hot rolling. The starting rolling temperature of the first stage of multi-pass hot rolling is 1130°C, and the rolling is performed in 3 passes. The rolling reduction of each pass is 15%, and the total rolling reduction is 45%;

[0076] After that, the entire surface is rapidly water-cooled to a surface temperature of 821°C, with the cooling rate controlled at above 40°C / s. Immediately after water-cooling, the second stage of multi-pass hot rolling is carried out, with the starting rolling temperature at 1150°C, 5 passes, a rolling reduction of 11%, and a total reduction of 55%, to obtain hot-rolled H-beam.

[0077] S3, multi-stage post-hot rolling cooling: The flange of the hot-rolled H-shaped steel plate of S2 is spray-cooled to 391°C, with the cooling rate controlled at above 10°C / s, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0078] The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this embodiment contains a ferrite structure with a volume fraction of 3% and a bainite structure with a volume fraction of 97% at 1 / 4 of the flange; the yield strength is 596.7 MPa, the tensile strength is 795.6 MPa, the elongation after fracture is 18.9%, the KV2 at -20°C is 84.2 J, and the yield strength ratio is 0.75. The yield strength after insulation at 600°C for 3 hours is 423.1 MPa, the high temperature / room temperature yield strength is 70.9%, and the relative corrosion rate (based on Corten A) is 44%.

[0079] The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this embodiment contains a ferrite structure with a volume fraction of 32% and a bainite structure with a volume fraction of 68% at 1 / 4 of the web; the yield strength is 579.2 MPa, the tensile strength is 742.6 MPa, the elongation after fracture is 19.6%, the KV2 at -20°C is 102.1 J and the yield strength ratio is 0.78, the yield strength after insulation at 600°C for 3 hours is 395.0 MPa, the high temperature / room temperature yield strength is 68.2%, and the relative corrosion rate (based on Corten A) is 45%.

[0080] Example 3

[0081] S1. Vacuum smelting and casting into billets: The set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel is calculated by mass percentage as follows: C 0.073%, Mn 1.46%, Si 0.28%, Cr 0.39%, Mo 0.40%, Ti 0.10%, V 0.078%, Nb 0.045%, Cu 0.44%, Ni 0.38%, Al 0.023%, P 0.007%, S 0.005%, and the remainder is iron and inevitable trace chemical elements; according to the set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel, vacuum smelting is used to obtain H-shaped steel liquid, the vacuum smelting temperature is 1650°C, and the smelting time is 4 hours; the cross-sectional shape of the cast H-shaped steel plate billet is I-shaped, with a flange width of 500 mm, a web height of 320 mm, a flange thickness of 45 mm, and a web thickness of 30 mm;

[0082] S2, hot rolling forming and cooling between rolling passes: The H-beam billet of S1 is subjected to the first stage multi-pass hot rolling, the starting rolling temperature of the first stage multi-pass hot rolling is 1162°C, and the rolling is performed in 2 passes, with a rolling reduction of 20% in each pass and a total rolling reduction of 40%;

[0083] After that, the entire surface is rapidly water-cooled to a surface temperature of 809°C, with the cooling rate controlled at above 40°C / s. Immediately after water-cooling, the second stage of multi-pass hot rolling is carried out, with the starting rolling temperature at 840°C, 8 passes, a rolling reduction of 10%, and a total reduction of less than 80%, to obtain hot-rolled H-shaped steel.

[0084] S3, multi-stage post-hot rolling cooling: The flange of the hot-rolled H-shaped steel plate of S2 is spray-cooled to 382°C, with the cooling rate controlled at above 10°C / s, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0085] The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this embodiment contains a ferrite structure with a volume fraction of 7% and a bainite structure with a volume fraction of 93% at 1 / 4 of the flange; the yield strength is 588.4 MPa, the tensile strength is 795.1 MPa, the elongation after fracture is 19.1%, the KV2 at -20°C is 89.2 J, and the yield strength ratio is 0.74. The yield strength after insulation at 600°C for 3 hours is 409.5 MPa, the high temperature / room temperature yield strength is 69.6%, and the relative corrosion rate (based on Corten A) is 47%.

[0086] The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this embodiment contains a ferrite structure with a volume fraction of 45% and a bainite structure with a volume fraction of 55% at 1 / 4 of the web; the yield strength is 569.6 MPa, the tensile strength is 721.0 MPa, the elongation after fracture is 20.0%, the KV2 at -20°C is 96.4 J and the yield strength ratio is 0.79, the yield strength after insulation at 600°C for 3 hours is 386.2 MPa, the high temperature / room temperature yield strength is 67.8%, and the relative corrosion rate (based on Corten A) is 46%.

[0087] Comparative Example 1

[0088] The comparative example provides a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance. The method comprises vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and cooling after rolling. The specific process is as follows:

[0089] S1. Vacuum smelting and casting into billets: The set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel is calculated by mass percentage as follows: C 0.083%, Mn 1.28%, Si 0.24%, Cr 0.52%, Mo 0.40%, Ti 0.05%, V 0.038%, Nb 0.038%, Cu 0.48%, Ni 0.28%, Al 0.021%, P 0.005%, S 0.003%, and the remainder is iron and inevitable trace chemical elements; according to the set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel, vacuum smelting is used to obtain H-shaped steel liquid, the vacuum smelting temperature is 1600°C, and the smelting time is 3h; the cross-sectional shape of the cast H-shaped steel plate billet is I-shaped, with a flange width of 550mm, a web height of 380mm, a flange thickness of 55mm, and a web thickness of 35mm;

[0090] S2, hot rolling forming and cooling between rolling passes: The H-beam billet of S1 is subjected to the first stage multi-pass hot rolling. The starting rolling temperature of the first stage multi-pass hot rolling is 1124°C, and the rolling is performed in 3 passes. The rolling reduction of each pass is 15%, and the total rolling reduction is 45%;

[0091] After that, the entire surface is rapidly water-cooled to a surface temperature of 814°C, with the cooling rate controlled at above 40°C / s. Immediately after water-cooling, the second stage of multi-pass hot rolling is carried out, with the starting rolling temperature at 810°C, 7 passes, a rolling reduction of 10%, and a total rolling reduction of 70%, to obtain hot-rolled H-beam.

[0092] S3, multi-stage post-hot rolling cooling: The flange of the hot-rolled H-shaped steel plate of S2 is spray-cooled to below 392°C, with the cooling rate controlled at above 10°C / s, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0093] The high-strength, seismic, weathering and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this comparative example contains a ferrite structure with a volume fraction of 5% and a bainite structure with a volume fraction of 95% at 1 / 4 of the flange; the yield strength is 558.3 ​​MPa, the tensile strength is 715.8 MPa, the elongation after fracture is 19.7%, the KV2 at -20°C is 102.6 J and the yield strength ratio is 0.78, the yield strength after insulation at 600°C for 3 hours is 366.8 MPa, the high temperature / room temperature yield strength is 65.7%, and the relative corrosion rate (based on Corten A) is 47%.

[0094] The high-strength, seismic, weathering and fire-resistant H-shaped steel web with uniform room temperature and high temperature performance prepared in this comparative example contains a ferrite structure with a volume fraction of 42% and a bainite structure with a volume fraction of 58% at 1 / 4; the yield strength is 535.6 MPa, the tensile strength is 686.7 MPa, the elongation after fracture is 20.6%, the KV2 at -20°C is 105.4 J and the yield strength ratio is 0.78, the yield strength after insulation at 600°C for 3 hours is 344.4 MPa, the high temperature / room temperature yield strength is 64.3%, and the relative corrosion rate (based on Corten A) is 47%.

[0095] Comparative Example 2

[0096] The comparative example provides a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance. The method comprises vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and cooling after rolling. The specific process is as follows:

[0097] S1. Vacuum smelting and casting into billets: The high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel has the following set composition by mass percentage: C 0.080%, Mn 1.37%, Si 0.22%, Cr 0.45%, Mo 0.46%, Ti 0.10%, V 0.059%, Nb 0.044%, Cu 0.41%, Ni 0.40%, Al 0.029%, P 0.007%, S 0.004%, and the remainder is iron and inevitable trace chemical elements; according to the set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel, vacuum smelting is used to obtain H-shaped steel liquid, the vacuum smelting temperature is 1550°C, and the smelting time is 4 hours; the cross-sectional shape of the cast H-shaped steel plate billet is I-shaped, with a flange width of 350 mm, a web height of 200 mm, a flange thickness of 30 mm, and a web thickness of 20 mm;

[0098] S2, hot rolling forming and cooling between rolling passes: The H-beam billet of S1 is subjected to the first stage multi-pass hot rolling, the starting rolling temperature of the first stage multi-pass hot rolling is 1157°C, and the rolling is performed in 2 passes, with a rolling reduction of 20% in each pass and a total rolling reduction of 40%;

[0099] Then the entire surface is air-cooled to a surface temperature of 835°C, the starting rolling temperature is 835°C, and rolling is performed for 5 passes with a rolling reduction of 15% and a total reduction of 75% to obtain hot-rolled H-beam;

[0100] S3, multi-stage post-hot rolling cooling: The flange of the hot-rolled H-shaped steel plate of S2 is spray-cooled to below 396°C, with the cooling rate controlled at above 10°C / s, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0101] The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this comparative example contains 8% ferrite structure and 8% bainite structure by volume at 1 / 4 of the flange, with a yield strength of 563.4 MPa, a tensile strength of 731.7 MPa, an elongation at break of 19.8%, a KV2 of 76.4 J at -20°C and a yield strength ratio of 0.77. The yield strength after insulation at 600°C for 3 hours is 387.6 MPa, the high temperature / room temperature yield strength is 68.8%, and the relative corrosion rate (based on Corten A) is 49%.

[0102] The high-strength, seismic, weathering and fire-resistant H-shaped steel web with uniform room temperature and high temperature performance prepared in this comparative example contains a ferrite structure with a volume fraction of 24% and a bainite structure with a volume fraction of 76% at 1 / 4; the yield strength is 542.3 MPa, the tensile strength is 723.1 MPa, the elongation after fracture is 21.9%, the KV2 at -20°C is 73.6 J and the yield strength ratio is 0.75, the yield strength after insulation at 600°C for 3 hours is 369.8 MPa, the high temperature / room temperature yield strength is 68.2%, and the relative corrosion rate (based on Corten A) is 48%.

[0103] Comparative Example 3

[0104] The comparative example provides a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance. The method comprises vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and cooling after rolling. The specific process is as follows:

[0105] S1. Vacuum smelting and casting into billets: The set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel is calculated by mass percentage as follows: C 0.087%, Mn 1.32%, Si 0.20%, Cr 0.47%, Mo 0.39%, Ti 0.09%, V 0.068%, Nb 0.036%, Cu 0.35%, Ni 0.25%, Al 0.027%, P 0.005%, S 0.003%, and the remainder is iron and inevitable trace chemical elements; according to the set composition of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel, vacuum smelting is used to obtain H-shaped steel liquid, the vacuum smelting temperature is 1650°C, and the smelting time is 3h; the cross-sectional shape of the cast H-shaped steel plate billet is I-shaped, with a flange width of 400mm, a web height of 250mm, a flange thickness of 35mm, and a web thickness of 25mm;

[0106] S2, hot rolling forming and cooling between rolling passes: The H-beam billet of S1 is subjected to the first stage multi-pass hot rolling, the starting rolling temperature of the first stage multi-pass hot rolling is 1142°C, and the rolling is performed in 3 passes, with a rolling reduction of 20% in each pass and a total rolling reduction of 60%;

[0107] After that, the entire surface is rapidly water-cooled to a surface temperature of 823°C, with the cooling rate controlled at above 40°C / s. Immediately after water-cooling, the second stage of multi-pass hot rolling is carried out, with the starting rolling temperature at 823°C, 6 passes, a rolling reduction of 10%, and a total rolling reduction of 60%, to obtain hot-rolled H-shaped steel.

[0108] S3, multi-stage post-hot rolling cooling: The hot-rolled H-shaped steel plate of S2 is air-cooled to room temperature as a whole, with the air cooling starting temperature being 801°C, to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

[0109] The high-strength, seismic, weathering and fire-resistant H-shaped steel with uniform room temperature and high temperature performance prepared in this comparative example contains a ferrite structure with a volume fraction of 33% and a bainite structure with a volume fraction of 67% at 1 / 4 of the flange; the yield strength is 543.2 MPa, the tensile strength is 687.6 MPa, the elongation after fracture is 21.6%, the KV2 at -20°C is 88.4 J and the yield strength ratio is 0.79, the yield strength after insulation at 600°C for 3 hours is 359.4 MPa, the high temperature / room temperature yield strength is 67.1%, and the relative corrosion rate (based on Corten A) is 49%.

[0110] The high-strength, seismic, weathering and fire-resistant H-shaped steel web with uniform room temperature and high temperature performance prepared in this comparative example contains a ferrite structure with a volume fraction of 48% and a bainite structure with a volume fraction of 52% at 1 / 4; the yield strength is 561.5 MPa, the tensile strength is 719.9 MPa, the elongation after fracture is 20.8%, the KV2 at -20°C is 85.1 J and the yield strength ratio is 0.78, the yield strength after insulation at 600°C for 3 hours is 379.0 MPa, the high temperature / room temperature yield strength is 67.5%, and the relative corrosion rate (based on Corten A) is 49%.

[0111] Comparison of Comparative Examples 1-3 with Examples 1-3 reveals that the strength, plasticity, toughness, yield strength ratio, high-temperature performance, and corrosion performance of the steel products of the examples of the present invention all meet the requirements of the invention. However, since the composition, etc. of Comparative Example 1 do not meet the requirements of the claims and the precipitation amount does not meet the requirements of the present invention, the room temperature strength and high-temperature performance of the web thereof do not meet the requirements. In Comparative Example 2, water cooling before the second stage of rolling is not performed, and rolling is performed directly by air cooling to 835°C, which is not likely to cause a large temperature difference between the core and the surface. During the rolling process, the deformation of the core is small, and the deformation accumulation is small, especially the deformation at the web position is small, which makes it difficult to refine the structure during the subsequent phase transformation. At the same time, if the steel product stays in the high temperature section for too long, it will cause grain growth, which will affect the size and performance of the structure after the phase transformation. In Comparative Example 3, water mist cooling is not performed on the flange after the second stage of rolling, and it is directly air cooled to room temperature. This makes it difficult to accelerate the cooling rate of the flange to obtain more bainite structure, which will cause uneven overall performance, and therefore does not meet the requirements of the present invention.

[0112] The above scheme, the present invention proposes a method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room and high temperature performance, which can solve the technical problems of the existing technology such as complex process, narrow process window, and difficulty in uniform room and high temperature performance at different positions of functional composite H-shaped steel.

[0113] The invention adds a certain amount of alloy elements to H-shaped steel for construction, firstly rolls the steel through the recrystallization zone to obtain fine austenite grains, and then undergoes a surface rapid cooling treatment, in order to prevent the austenite grains from growing.

[0114] In order to form a temperature gradient between the surface and the core, the present invention then refines the grains after rolling compared to conventional rolling and causes accumulation of deformation in the core where the thickness is thicker, thereby increasing nucleation points and promoting further phase transformation in a higher temperature range.

[0115] The invention uses flange water mist to quickly cool the steel after rolling, thereby obtaining a larger proportion of bainite structure, and simultaneously the rapid cooling reduces the time in the precipitation temperature range.

[0116] Although the air cooling treatment at the web position of the present invention is affected by the heat conduction of the water mist cooling at the flange position, its cooling rate will be slower and a smaller proportion of bainite structure will be obtained; however, it will stay in the precipitation temperature range for a longer time, and a large amount of MC-type carbides mainly composed of Mo\Ti\V\Nb will be formed in the ferrite, thereby improving the room temperature strength while maintaining the high temperature strength.

[0117] The present invention promotes the uniformity of room temperature and high temperature properties of the entire steel plate thickness direction due to the differential strain fields at different positions during the rolling process and the differential temperature fields during the phase change process, by utilizing different tissue types and proportions, and different amounts of precipitation strengthening within the tissue.

[0118] The present invention utilizes the regulation of rolling and cooling to refine the grains, and there are differences in the phase ratio and tissue type at different positions. By utilizing the differences in temperature and strain, different amounts of precipitation are obtained at different positions, and the strength, yield strength ratio, plasticity, etc. are regulated to achieve the best combination of strength and plasticity and toughness, thereby improving the room temperature mechanical properties and enhancing the high temperature resistance of different tissue types. At the same time, the addition of corrosion-resistant elements can effectively improve the corrosion resistance.

[0119] In summary, compared with other traditional methods, the method of the present invention prepares high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance through vacuum smelting and casting into billets, hot rolling forming and cooling between rolling passes, and multi-stage hot rolling post-cooling; the preparation method is simple and easy to operate, green and environmentally friendly, low in cost, short in process, and high in efficiency, which is conducive to large-scale industrial production and promotion.

[0120] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0121] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0122] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0123] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance, characterized in that: The manufacturing method of the high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance comprises vacuum smelting, casting into billets, hot rolling forming, cooling between rolling passes, and cooling after rolling. The specific process is as follows: S1. Vacuum smelting and casting into billets: According to the set composition of high-strength, earthquake-resistant, weather-resistant and fire-resistant H-beam, vacuum smelting is used to obtain H-beam molten steel, and then casting is performed to obtain H-beam billets; S2, hot rolling and cooling between rolling passes: The H-beam billet of S1 is subjected to a first-stage multi-pass hot rolling, and then the entire surface is rapidly water-cooled to a surface temperature lower than the first-stage hot rolling start temperature of 260-370°C. After water cooling, the second-stage multi-pass hot rolling is immediately carried out to obtain a hot-rolled H-beam; S3, multi-stage post-hot rolling cooling: The flanges of the hot-rolled H-shaped steel plates of S2 are spray-cooled, and then the whole is air-cooled to room temperature to obtain high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform room temperature and high temperature performance.

2. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: The set composition of S1 medium and high strength earthquake-resistant, weather-resistant and fire-resistant H-shaped steel is calculated by mass percentage: C 0.05-0.10%, Mn 1.0-1.5%, Si 0.1-0.3%, Cr 0.2-0.6%, Mo 0.35-0.5%, Ti 0.08-0.12%, V 0.05-0.08%, Nb 0.03-0.05%, Cu 0.2-0.5%, Ni 0.2-0.5%, Al 0.01-0.06%, P≤0.012%, S≤0.006%, and the rest are iron and inevitable trace chemical elements.

3. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: The vacuum smelting temperature in S1 is 1550-1650°C, the smelting time is 2-4 hours, and the cross-sectional shape of the H-shaped steel plate blank obtained by casting is I-shaped, with a flange width of 200-600mm, a web height of 100-400mm, a flange thickness of 20-60mm, and a web thickness of 10-40mm.

4. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: The starting rolling temperature of the first stage multi-pass hot rolling in S2 is 1100-1170℃, with 2-4 passes, a single pass rolling reduction of 15-20%, and a total rolling reduction of 40-60%.

5. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: In S2, the entire surface is quickly water-cooled to a surface temperature of 800-840°C, and the cooling rate is controlled at above 40°C / s. Immediately after cooling, the second stage of multi-pass hot rolling is carried out, with the starting rolling temperature of 800-840°C, 5-10 passes, a single-pass rolling reduction of 10-15%, and a total rolling reduction of 45-80%.

6. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: The yield strength of hot-rolled H-beam in S2 is ≥550MPa, the tensile strength is 700-840MPa, the yield strength ratio is <0.80, and the elongation after fracture is ≥18%.

7. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: In S3, the flange is cooled by water mist to below 400°C, and the cooling rate is controlled above 10°C / s.

8. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: The high-strength, seismic-resistant, weather-resistant and fire-resistant H-shaped steel S3 with uniform room temperature and high temperature performance has different microstructures at different positions. The microstructure at the flange is mainly composed of ferrite with a volume fraction of 0-10% and bainite with a volume fraction of 90-100%; the microstructure at the web is mainly composed of ferrite with a volume fraction of 10-70% and bainite with a volume fraction of 30-90%, and there are also a large amount of MC-type carbides containing Mo / Nb / V / Ti.

9. The method for manufacturing high-strength, earthquake-resistant, weather-resistant and fire-resistant H-shaped steel with uniform high-temperature performance according to claim 1, characterized in that: The high-strength, seismic, weathering and fire-resistant H-shaped steel in S3, with uniform room temperature and high temperature performance, has a yield strength ≥550MPa, a tensile strength of 700-840MPa, an elongation ≥18%, a KV2 ≥69J at -20℃, and a yield strength ratio <0.

80. The yield strength after holding at 600℃ for 3h (≥367MPa) is not less than 2 / 3 of the yield strength at room temperature, and the relative corrosion rate (based on Corten A) is less than 50%.

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