Building template galvanized sheet and preparation method thereof

Abstract

The invention relates to a building template galvanized sheet, which is characterized in that the smelting components for producing a hot rolled steel strip comprise the following components in percentage content: 0.05-0.10% of C, 0.02-0.05% of Si, 1.50-1.70% of Mn, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.025-0.045% of V, 0.045-0.055% of Nb, 0.110-0.160% of Ti, 0.35-0.45% of Mo, 0.25-0.45% of Als, less than or equal to 0.004% of N and the balance of iron and inevitable impurities, and the preparation method comprises the following steps: steelmaking, LF refining, RH vacuum and continuous casting to produce a casting blank, heating the casting blank in a heating furnace, and then carrying out hot rolling; the production process comprises the steps of pickling, flattening, galvanizing, finishing, passivating and coiling to form a galvanized coil. The production process is simple, the product implementation process is easy to control, waste of building materials can be reduced after the template is manufactured, and the construction cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of galvanized sheets, and in particular to a galvanized sheet for a building template and a preparation method thereof. Background Art

[0002] Formwork is an important construction material in the construction industry, and its quality directly affects the quality of building concrete structures. There are two commonly used formworks, one is aluminum material and the other is wood material. Aluminum material has good formability but high cost. Wood material has low cost but short service life, low strength, and easy to break, which has a great impact on the construction quality of building concrete. At present, there is an urgent need for a formwork with low cost, good product surface quality, high dimensional accuracy, strong coating bonding, high strength, and stable performance. Summary of the invention

[0003] The present invention provides a galvanized sheet for building formwork and a preparation method thereof. By reasonably regulating manufacturing process data, the strengthening effect of multiple alloy elements is fully utilized, and solid solution strengthening, precipitation strengthening, phase transformation strengthening and fine grain strengthening are adopted to obtain a galvanized product with good surface quality, high dimensional accuracy, strong coating bonding force, high strength and stable performance. The galvanized product has lower cost than aluminum formwork, higher strength than wooden formwork, longer service life and is not easy to break.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: A galvanized sheet for building templates, the production of hot-rolled steel strip smelting chemical composition and weight percentage are C: 0.05-0.10%, Si: 0.02-0.05%, Mn: 1.50-1.70%, P≤0.015%, S≤0.005%, V: 0.025-0.045%, Nb: 0.045-0.055%, Ti: 0.110-0.160%, Mo: 0.35-0.45%, Als: 0.25-0.45%, N≤0.004%, and the balance is iron and unavoidable impurities.

[0005] Preferably, the thickness of the galvanized sheet is 1.5-1.8 mm, the yield strength is ≥750 MPa, the tensile strength is ≥850 MPa, and the thickness of the double-sided zinc layer is 80 g / m 2 , bend 90 0 No cracking.

[0006] Preferably, the following steps are included: S1 hot rolling and S2 production step; S1. Hot rolling process includes: steelmaking, LF+RH vacuum refining, continuous casting, billet heating, high-pressure water descaling, controlled rolling, controlled rolling cooling and coiling process; S2. The production process includes: pickling, rinsing, leveling, galvanizing, and coiling into galvanized coils; The galvanizing process includes: annealing furnace, zinc pot / air knife, skin pass, straightening and passivation.

[0007] Preferably, the vacuum degree of the molten steel in S1 during the RH vacuum refining process is below 133 Pa, the treatment time in vacuum is 15-25 min, the pure degassing time is 5-10 min, and the standing time is 8-10 min.

[0008] Preferably, in the controlled rolling process described in S1, the time of the ingot in the soaking section in the heating furnace is 100-120min, the temperature difference between the head and tail of the ingot and the surface temperature difference are ±10°C, and after 5 rough rolling passes, the outlet temperature is 1110±20°C; the finishing outlet temperature is 880±20°C, the laminar cooling rate is 25-30°C / s, and the coiling temperature is 560±20°C.

[0009] Preferably, the pickling process in S2 requires: total acid concentration 175-190g / L, iron ion concentration in 1# acid tank 110-120g / L, iron ion concentration in 2# acid tank 50-65g / L, iron ion concentration in 3# acid tank 25-45g / L, and pickling temperature 78-85°C.

[0010] Preferably, in the leveling process described in S2, the leveling elongation is 0.9%-1.0%; and the pickling process speed is 95±5 m / min.

[0011] Preferably, in the annealing furnace process section in the galvanizing step described in S2, an induction heating furnace is used for heating: the temperature of the strip exiting the direct combustion section is 630-650°C, the temperature of the strip exiting the radiation tube section is 650-680°C, and the temperature of the strip entering the zinc pot is 450-460°C; the galvanizing speed is 65±5 m / min, and the dew point of the heating furnace is below -40°C.

[0012] Preferably, in the zinc pot / air knife process section, the zinc liquid composition in the zinc pot is: Zn mass content ≥ 99%, Al mass content 0.23 ± 0.03%; zinc liquid temperature: 452°C ± 2°C; The upper and lower air knife pressures are 45mbar-55mbar, the air knife height from the zinc liquid is 60mm-70mm, the air knife distance from the strip is 45mm-70mm, the air knife angle is controlled at -25° to -15°, and the air knife baffle is ≤2mm from the edge of the strip.

[0013] Preferably, in the skin-finishing process section, the skin-finishing machine elongation is 0.8-1.0%.

[0014] Beneficial effects of the present invention: The method of the present invention is invented by combining the use environment and use method of the building template to use galvanized templates to replace aluminum and wooden templates, which not only takes into account the building quality but also saves the construction cost. Because the galvanized sheet has an isolation effect and a cathodic protection effect on the steel matrix material, in tropical and cold environments, zinc has good corrosion resistance and is economical. The steel matrix adopts multi-element alloying to improve the template strength. The galvanized building template manufactured by combining the two has a beautiful appearance, high strength, and corrosion resistance. It is deeply trusted by the market. Therefore, it is crucial to develop high-strength, corrosion-resistant, low-cost, and green and environmentally friendly building templates to reduce construction costs in the construction industry.

[0015] The invention has a reliable design principle, a simple production process, an easy-to-control product realization process, high product strength, corrosion resistance, long service life, and is not easy to break when making building templates. It has a very wide application prospect. Based on the steelmaking, hot rolling, pickling, and galvanizing continuous production line, 1.5-1.8 mm galvanized sheet is produced. DETAILED DESCRIPTION

[0016] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention. Example 1

[0017] A manufacturing process for manufacturing galvanized sheet for building templates, wherein the hot rolling process includes: steelmaking, LF+RH vacuum refining, continuous casting, heating of ingots, high-pressure water descaling, controlled rolling, controlled rolling cooling and coiling process; Hot rolling process produces hot rolled steel strip melting composition: C: 0.05%, Si: 0.02%, Mn: 1.50%, P: 0.015%, S: 0.005%, V: 0.025%, Nb: 0.045%, Ti: 0.110%, Mo: 0.35%, Als: 0.25%, N: 0.0032%, the balance is iron and unavoidable impurities; The vacuum degree of RH vacuum treatment is 49Pa, the vacuum treatment time is 5min, the pure degassing time is 5min, and the static time is 8min. The time of the ingot produced by continuous casting in the heating furnace is 100min, the temperature difference between the head and tail of the ingot and the surface temperature difference is 7℃, and after 5 rough rolling, the outlet temperature is 1090℃.

[0018] The finishing exit temperature is 862°C, the laminar cooling rate is 28°C / s, and the coiling temperature is 548°C.

[0019] The production process includes: pickling, leveling, galvanizing, skin passivation, and coiling into hot-dip galvanized coils. The galvanizing process includes: annealing furnace, zinc pot / air knife, skin passivation, straightening and passivation; the pickling process requirements are: total acid concentration 175g / L, iron ion concentration of 1# acid tank 113g / L, iron ion concentration of 2# acid tank 52g / L, iron ion concentration of 3# acid tank 28g / L, pickling temperature 79°C; leveling process, leveling elongation 0.9%; pickling process speed is 93 m / min.

[0020] Heating adopts induction heating furnace: the temperature of strip steel out of direct combustion section is 633℃, the temperature of strip steel out of radiation tube section is 658℃, the temperature of strip steel into zinc pot is 451℃; galvanizing speed is 60 m / min, heating furnace dew point: -40℃; In the galvanizing process, the composition of the zinc liquid in the zinc pot is as follows: Zn content is 99%, Al content is 0.21%; the temperature of the zinc liquid is 450°C; in the skin-passing process, the elongation of the skin-passing machine is 0.8%.

[0021] During the galvanizing process, the upper and lower air knife pressures are 45mbar, the air knife is 60mm above the zinc liquid, the air knife is 60mm away from the strip, the air knife angle is controlled at -25°, and the air knife baffle is 1.5mm away from the edge of the strip. The 1.5 mm high-strength hot-dip galvanized sheet in Example 1 was obtained. Example 2

[0022] A manufacturing process for manufacturing galvanized sheet for building templates, wherein the hot rolling process includes: steelmaking, LF+RH vacuum refining, continuous casting, heating of ingots, high-pressure water descaling, controlled rolling, controlled rolling cooling and coiling process; the hot rolling process produces hot-rolled steel strip with melting composition of C: 0.10%, Si: 0.05%, Mn: 1.70%, P: 0.015%, S: 0.005%, V: 0.045%, Nb: 0.055%, Ti: 0.160%, Mo: 0.45%, Als: 0.45%, N: 0.0040%, and the balance is iron and unavoidable impurities; The vacuum degree of vacuum treatment is 130Pa, the vacuum treatment time is 25min, the pure degassing time is 10min, and the standing time is 10min. The time of the billet produced by continuous casting in the heating furnace is 120min, the temperature difference between the head and tail of the billet and the surface temperature difference is 10℃, and after 5 rough rolling, the outlet temperature is 1130℃. The outlet temperature of the finishing rolling is 900℃, and the laminar cooling rate is 29℃ / s. The coiling temperature is 575℃. The production process includes: pickling, leveling, galvanizing, skin passivation, and coiling into hot-dip galvanized coils. The galvanizing process includes: annealing furnace, zinc pot / air knife, skin passivation, straightening and passivation; the pickling process requirements are: total acid concentration 175g / L, iron ion concentration of 1# acid tank 119g / L, iron ion concentration of 2# acid tank 64g / L, iron ion concentration of 3# acid tank 43g / L, pickling temperature 83°C; leveling process, leveling elongation 1.0%; pickling process speed is 98 m / min. Heating adopts induction heating furnace: the temperature of strip steel out of direct combustion section is 647℃, the temperature of strip steel out of radiation tube section is 676℃, and the temperature of strip steel into zinc pot is 458℃; galvanizing speed is 69m / min, heating furnace dew point: -40℃; galvanizing process, zinc liquid composition in zinc pot: Zn content 99%, Al content 0.26%; zinc liquid temperature: 454℃; skin-passing process, skin-passing machine elongation 1.0%. In the galvanizing process, the upper and lower air knife pressure is 45mbar, the air knife height from zinc liquid is 70mm, the air knife distance from strip steel is 70mm, the air knife angle is controlled at -25°, and the air knife baffle is 2mm away from the edge of strip steel. The 1.8 mm high-strength hot-dip galvanized sheet in Example 2 was obtained. Example 3

[0023] A production process for producing galvanized sheet for building templates, the hot rolling process includes: steelmaking, LF+RH vacuum refining, continuous casting, heating of ingot, high-pressure water descaling, controlled rolling, controlled rolling cooling and coiling process; the hot rolling process produces hot-rolled steel strip with melting composition C: 0.08%, Si: 0.03%, Mn: 1.60%, P: 0.014%, S: 0.004%, V: 0.034%, Nb: 0.048%, Ti: 0.142%, Mo: 0.38%, Als: 0.37%, N: 0.0032%, and the balance is iron and unavoidable impurities; the vacuum degree of vacuum treatment is 121Pa, the vacuum treatment time is 19min, the pure degassing time is 7min, and the standing time is 9min.

[0024] The time of the ingot produced by continuous casting in the soaking section of the heating furnace is 118 minutes, the temperature difference between the head and tail of the ingot and the surface temperature difference are 8°C, and after 5 rough rolling, the outlet temperature is 1125°C. The outlet temperature of the finishing rolling is 894°C, and the laminar cooling rate is 27°C / s. The coiling temperature is 578°C. The production process includes: pickling, leveling, galvanizing, skin passivation, and coiling into hot-dip galvanized coils. The galvanizing process includes: annealing furnace, zinc pot / air knife, skin passivation, straightening and passivation; the pickling process requirements are: total acid concentration 177g / L, 1# acid tank iron ion concentration 119g / L, 2# acid tank iron ion concentration 62g / L, 3# acid tank iron ion concentration 35g / L, pickling temperature 81°C; leveling process, leveling elongation 0.95%; pickling process speed is 97 m / min. Heating adopts induction heating furnace: the temperature of strip steel out of direct combustion section is 644℃, the temperature of strip steel out of radiation tube section is 668℃, and the temperature of strip steel into zinc pot is 457℃; galvanizing speed is 66m / min, heating furnace dew point: -40℃; galvanizing process, zinc liquid composition in zinc pot: Zn content 99%, Al content 0.25%; zinc liquid temperature: 453℃; skin-passing process, skin-passing machine elongation 0.9%. In the galvanizing process, the upper and lower air knife pressure is 45mbar, the air knife height from zinc liquid is 70mm, the air knife distance from strip steel is 70mm, the air knife angle is controlled at -25°, and the air knife baffle is 1.5mm away from the edge of strip steel. The 1.6 mm high-strength hot-dip galvanized sheet in Example 3 was obtained.

[0025] Experimental data: The zinc layer inspection results of the galvanized sheets produced in Examples 1-3 are shown in Table 1 and the mechanical properties are shown in Table 2.

[0026] Table 1

[0027] Table 2

[0028] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A galvanized sheet for building formwork, characterized in that: The smelting chemical composition and weight percentage of the hot-rolled steel strip are C: 0.05-0.10%, Si: 0.02-0.05%, Mn: 1.50-1.70%, P≤0.015%, S≤0.005%, V: 0.025-0.045%, Nb: 0.045-0.055%, Ti: 0.110-0.160%, Mo: 0.35-0.45%, Als: 0.25-0.45%, N≤0.004%, and the balance is iron and unavoidable impurities.

2. A galvanized sheet for building formwork according to claim 1, characterized in that: The thickness of the galvanized sheet is 1.5-1.8 mm, the yield strength is ≥750 MPa, the tensile strength is ≥850 MPa, and the thickness of the double-sided zinc layer is 80 g / m 2 , bend 90 0 No cracking.

3. The method for preparing a galvanized sheet for building formwork according to claim 1 or 2, characterized in that: It includes the following processes: S1 hot rolling and S2 production process; S1. Hot rolling process includes: steelmaking, LF+RH vacuum refining, continuous casting, billet heating, high-pressure water descaling, controlled rolling, controlled rolling cooling and coiling process; S2. The production process includes: pickling, rinsing, leveling, galvanizing, and coiling into galvanized coils; The galvanizing process includes: annealing furnace, zinc pot / air knife, skin pass, straightening and passivation.

4. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: The vacuum degree of the molten steel in S1 during the RH vacuum refining process is below 133Pa, the vacuum treatment time is 15-25min, the pure degassing time is 5-10min, and the standing time is 8-10min.

5. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: In the controlled rolling process described in S1, the time for the ingot to be soaked in the heating furnace is 100-120 minutes, the temperature difference between the head and tail of the ingot and the surface temperature difference are ±10°C, and after 5 rough rolling passes, the outlet temperature is 1110±20°C; the outlet temperature of the finishing rolling is 880±20°C, the laminar cooling rate is 25-30°C / s, and the coiling temperature is 560±20°C.

6. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: The pickling process described in S2 requires: total acid concentration 175-190g / L, iron ion concentration in 1# acid tank 110-120g / L, iron ion concentration in 2# acid tank 50-65g / L, iron ion concentration in 3# acid tank 25-45g / L, and pickling temperature 78-85°C.

7. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: The flattening process described in S2 has a flattening elongation of 0.9%-1.0%; the pickling process speed is 95±5 m / min.

8. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: In the annealing furnace process section of the galvanizing process described in S2, an induction heating furnace is used for heating: the temperature of the strip exiting the direct combustion section is 630-650°C, the temperature of the strip exiting the radiation tube section is 650-680°C, and the temperature of the strip entering the zinc pot is 450-460°C; the galvanizing speed is 65±5 m / min, and the dew point of the heating furnace is below -40°C.

9. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: In the zinc pot / air knife process section, the zinc liquid composition in the zinc pot is: Zn mass content ≥ 99%, Al mass content 0.23 ± 0.03%; zinc liquid temperature: 452°C ± 2°C; The upper and lower air knife pressures are 45mbar-55mbar, the air knife height from the zinc liquid is 60mm-70mm, the air knife distance from the strip is 45mm-70mm, the air knife angle is controlled at -25° to -15°, and the air knife baffle is ≤2mm from the edge of the strip.

10. The method for preparing a galvanized sheet for building formwork according to claim 3, characterized in that: In the skin-finishing process section, the skin-finishing machine has an elongation of 0.8-1.0%.

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