CN112226681A - Low-cost high-strength galvanized sheet SGC570 for structure and production method thereof - Google Patents

Low-cost high-strength galvanized sheet SGC570 for structure and production method thereof Download PDF

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CN112226681A
CN112226681A CN202010985944.4A CN202010985944A CN112226681A CN 112226681 A CN112226681 A CN 112226681A CN 202010985944 A CN202010985944 A CN 202010985944A CN 112226681 A CN112226681 A CN 112226681A
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rolling
temperature
steel
cold
percent
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李鹏
王少炳
黄利
惠鑫
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Baotou Iron and Steel Group Co Ltd
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Baotou Iron and Steel Group Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips

Abstract

The invention discloses a low-cost high-strength galvanized sheet SGC570 for a structure and a production method thereof, wherein the chemical components of the provided low-cost high-strength galvanized sheet SGC570 for the structure comprise the following components in percentage by mass: c: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent, and the balance of Fe and inevitable impurities. The production method of the galvanized sheet SGC570 provided by the invention can ensure that the galvanized sheet SGC570 has high strength and obviously reduces the production cost.

Description

Low-cost high-strength galvanized sheet SGC570 for structure and production method thereof
Technical Field
The invention belongs to the technical field of metallurgical plate production, and particularly relates to a low-cost high-strength galvanized sheet SGC570 for a structure and a production method thereof.
Background
Along with the rapid development of national economy and the optimization and adjustment of industrial structures, the energy-saving and environment-friendly consciousness of people is gradually enhanced, the demand of galvanized plates shows a high-speed growth situation in recent years, and the plates for the galvanized structure gradually replace the plates for the cold-rolled structure and are increasingly developed to high reinforcement. The high-strength galvanized sheet is used as a high-added-value steel product, is widely applied to industries such as buildings, light industry, automobiles, agriculture and pasturing, and has the characteristics of strong corrosion resistance, good surface quality, contribution to deep processing, economy and applicability and the like, and is well favored by wide users.
The structural high-strength galvanized sheet SGC570 is a structural sheet with the highest strength level in Japanese Standard JISG3302 series products of hot galvanized steel sheets and steel strips, has higher yield strength, tensile strength and good corrosion resistance, and has no replaceable requirements mainly in places such as supporting pieces, steel structures, steel for building bottom plates and the like due to the strength characteristics. The production of the high-strength galvanized sheet needs to consider the requirements of the standard on mechanical properties and also needs to consider the production and manufacturing costs, and the maximization of per ton steel profit is realized as much as possible. At present, the production of high-strength galvanized plates for structures mostly adopts common carbon steel to increase Mn alloy to improve the product strength, or for ultrahigh-strength galvanized plates (the yield strength is more than 500MPa), in order to ensure the forming performance of the ultrahigh-strength galvanized plates, other alloy elements or alloy elements (such as Nb, Cr and the like) are added to improve the strength of final finished products and ensure certain elongation, so that the production cost is increased, the galvanizing performance is deteriorated, even more expensive quick cooling equipment is added, and the equipment cost and the maintenance cost are increased.
CN101956126A discloses a cold-base high-strength galvanized sheet and a production method thereof, wherein the cold-base high-strength galvanized sheet comprises the following chemical components: 0.17-0.23%; mn: 0.65-0.85%; si: less than or equal to 0.15 percent; p: less than or equal to 0.015 percent; s: less than or equal to 0.012 percent; and Als: 0.015-0.030%. The Mn content (0.65-0.85%) in the component design is higher, the production cost of each ton of steel is increased, and the welding performance of the steel strip is influenced due to the high Mn content.
CN101348880A discloses a production method of a structural high-strength galvanized plate, which comprises the following chemical components: 0.16-0.20%; mn: 0.9-1.1%; si is less than or equal to 0.05 percent; p is less than or equal to 0.020%; s is less than or equal to 0.020%; and Als: 0.02-0.06%. In the component design, the Mn content (0.9-1.1%) is higher, the cost of steel per ton is increased, and the welding performance of a steel strip is influenced due to the high Mn content.
CN106756521A discloses a production process of a hot-dip galvanized plate for a high-strength structure, which comprises the following chemical components: 0.08-0.20%; mn: 0.25-0.60%; si: 0.01-0.03%; p: 0.02-0.04%; s: 0.03-0.05%; ni: 0.05-0.10%; cr: 0.08 to 0.12 percent. The invention contains Ni element and Cr element in the component design, has high content (0.05-0.10% of Ni and 0.08-0.12% of Cr), has high Ni and Cr alloy cost, and increases the cost of steel per ton.
Disclosure of Invention
In view of one or more of the problems in the prior art, an aspect of the present invention provides a structural low-cost high-strength galvanized sheet SGC570, which comprises the following chemical components by mass percent: c: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent, and the balance of Fe and inevitable impurities.
In another aspect, the present invention provides a method for producing the low-cost high-strength galvanized sheet SGC570 for structure, which comprises the following steps: smelting, continuous casting, hot rolling, acid pickling and cold rolling, and hot galvanizing; wherein:
the smelting-continuous casting process comprises the following steps: pretreatment of molten iron, converter, LF refining and casting machine; wherein the molten steel for casting machine comprises the following components: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent;
the hot rolling process comprises the following steps: heating a casting blank, rough rolling, finish rolling and coiling; wherein the tapping temperature of the casting blank is 1200 +/-20 ℃, the rough rolling is performed by adopting a 3+3 mode 2-stand rolling mill, the finish rolling is performed by adopting a 7-stand continuous variable-crown rolling mill, and the thickness of the intermediate blank is 40-45 mm; the initial rolling temperature of the finish rolling is 1020 +/-30 ℃, and the final rolling temperature of the finish rolling is 870 +/-15 ℃; after finish rolling, cooling by adopting laminar cooling equipment and a post-dispersion cooling mode, wherein the cooling speed is 20 +/-5 ℃/s, and the coiling temperature is 650 +/-20 ℃;
the pickling cold rolling process specifically comprises the following steps: pickling the hot-rolled strip steel, removing surface iron oxide scales, and cold-rolling by a 5-stand cold rolling mill to obtain a cold-hard coiled steel strip;
the hot galvanizing process specifically comprises the following steps: uncoiling the cold-hard coil steel strip, heating, wherein the heating temperature and the soaking temperature are both 530 +/-20 ℃, the heating time is 80-120S, the soaking time is 80-120S, the slow cooling temperature is 490 +/-10 ℃, the fast cooling temperature is 465 +/-10 ℃, and the temperature of putting the cold-hard coil steel strip into a zinc pot is 460 +/-10 ℃.
The thickness of the hot rolled steel strip in the hot rolling process is 5.0 mm; in the pickling cold rolling process, the cold rolling reduction rate is 70%, and the steel is rolled to the target thickness of 1.5 mm.
The leveling elongation in the hot galvanizing process is 0.3%.
The chemical components of the low-cost high-strength galvanized plate SGC570 for the structure provided by the technical scheme are designed by adopting basic C-Mn structural components, the content of the added Mn element is only 0.15-0.25%, the Mn content is obviously lower than that of steel used for the high-strength galvanized plate structure in the prior art, and other alloy elements (such as Nb, Cr and the like) are not added, so that the production cost of the steel used for the structure can be obviously reduced, meanwhile, on the basis of reducing the Mn content in the components, the high-strength galvanized plate SGC570 provided by the invention improves the strength by optimizing the content of the chemical components and optimizing and controlling production process parameters (particularly hot galvanizing process parameters) and the like, can also ensure that the steel used for the structure has high yield strength and tensile strength, meets the requirements of JIS G3302 on mechanical properties, meets the requirements of high-strength structural members, and is suitable for industrial production.
Drawings
FIG. 1 is a microstructure diagram of SGC570 of a low-cost high-strength galvanized sheet for construction produced in example 1.
Detailed Description
Aiming at the defect of high production cost of structural steel in the prior art, the invention aims to provide a structural low-cost high-strength galvanized sheet SGC570 with low cost, high yield strength and high tensile strength and a production method thereof. The method is realized by the following technical scheme.
The chemical components of the SGC570 of the provided low-cost high-strength galvanized sheet for the structure comprise the following components in percentage by mass: c: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent, and the balance of Fe and inevitable impurities.
The production method of the SGC570 of the low-cost high-strength galvanized sheet for the structure comprises the following process steps: smelting, continuous casting, hot rolling, acid pickling and cold rolling, and hot galvanizing; wherein:
the smelting-continuous casting process comprises the following steps: pretreatment of molten iron, converter, LF refining and casting machine; wherein the molten steel for casting machine comprises the following components: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent;
the hot rolling process comprises the following steps: heating a casting blank, rough rolling, finish rolling and coiling; wherein the tapping temperature of the casting blank is 1200 +/-20 ℃, the rough rolling is performed by adopting a 3+3 mode 2-frame rolling mill, the finish rolling is performed by adopting a 7-frame continuous variable crown (cvc) rolling mill, and the thickness of the intermediate blank is 40-45 mm; the initial rolling temperature of the finish rolling is 1020 +/-30 ℃, the finish rolling temperature of the finish rolling is 870 +/-15 ℃, and the thickness of the hot rolled steel strip is 5.0 mm; after finish rolling, cooling by adopting laminar cooling equipment and a post-dispersion cooling mode, wherein the cooling speed is 20 +/-5 ℃/s, and the coiling temperature is 650 +/-20 ℃;
the pickling cold rolling process specifically comprises the following steps: pickling the hot-rolled strip steel by using a hydrochloric acid tank of an i-BOX technology, removing surface iron oxide scales, cold-rolling the strip steel by using a 5-stand cold rolling mill until the cold-rolling reduction rate is 70 percent and the target thickness is 1.5mm to obtain a cold-hard coil strip steel;
the hot galvanizing process specifically comprises the following steps: uncoiling the cold-hard coil steel strip, heating, wherein the heating temperature and the soaking temperature are both 530 +/-20 ℃, the heating time is 80-120 s, the soaking time is 80-120 s, the slow cooling temperature is 490 +/-10 ℃, the fast cooling temperature is 465 +/-10 ℃, the temperature of a zinc pot is 460 +/-10 ℃, and the flattening elongation is 0.3%.
The present invention will be described in detail below with reference to specific examples, which are intended to facilitate understanding of the present invention and are not intended to limit the present invention.
Example 1
Carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization on the molten iron by adopting a top-bottom combined blown converter to obtain molten steel, blowing argon in the whole process of the converter smelting, adding scrap steel into the converter, and tapping the steel at the converter at the temperature of 1640 ℃. And then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is more than or equal to 1560 ℃, carrying out temperature measurement and component fine adjustment on the LF external refining, and the chemical components of the ladle casting machine for the LF external refining are shown in Table 1. The superheat degree of the slab continuous casting is 20 ℃, and then slab cleaning, slow cooling and quality inspection of the continuous casting slab are carried out. The heating temperature of the plate blank is 1235 ℃, the heating time is 220min, and the heated plate blank is subjected to high-pressure water dephosphorization. The width is fixed by a width fixing press, 2 frames are adopted for rough rolling, and 7 frames are adopted for CVC finish rolling. The initial rolling temperature of the finish rolling is 1030 ℃, the finish rolling temperature is 870 ℃, and the thickness of the finished product is 5.0 mm. And post-dispersion cooling is adopted in laminar cooling, the cooling speed is 20 ℃/s, and the temperature of the steel strip is reduced to 650 ℃ for coiling. The hot-rolled strip steel is pickled by a hydrochloric acid tank, the acid tank adopts an i-BOX technology newly developed by MH, the operation and maintenance are greatly simplified, the energy and labor force are saved, after the surface oxide scale of the hot-rolled strip steel is removed, the hot-rolled strip steel is cold-rolled by a 5-frame UCM rolling mill, the cold-rolling reduction rate is 70 percent, and the target thickness is 1.5 mm. The cold-hard coil galvanizing process is carried out in a vertical annealing furnace by adopting a American steel combination method galvanizing production process, the running speed of a steel strip in a furnace zone is 80m/min, the heating temperature and the soaking temperature are both 530 ℃, the heating time is 80-120 s, and the soaking time is 80-120 s; slowly cooling at 490 ℃ for 11-15 s; the rapid cooling temperature is 465 ℃ and the time is 8-12 s; putting the mixture into a zinc pot at the temperature of 460 ℃ for 22-35 s; the flat elongation is 0.3%, and finally, the product performance is tested, as shown in the following table 2. As shown in fig. 1, a microstructure diagram of a low-cost high-strength galvanized sheet SGC570 for a structure obtained in this example is shown, and it is seen that the microstructure is ferrite + pearlite.
Example 2
The method comprises the following steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization on the molten iron by adopting a top-bottom combined blown converter to obtain molten steel, blowing argon in the whole process of the converter smelting, adding scrap steel into the converter, and carrying out tapping at 1630 ℃. And then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is more than or equal to 1560 ℃, carrying out temperature measurement and component fine adjustment on the LF external refining, and the chemical components of the ladle casting machine for the LF external refining are shown in Table 1. The superheat degree of the slab continuous casting is 20 ℃, and then slab cleaning, slow cooling and quality inspection of the continuous casting slab are carried out. The heating temperature of the plate blank is 1230 ℃, the heating time is 225min, and the heated plate blank is subjected to high-pressure water dephosphorization. The width is fixed by a width fixing press, 2 frames are adopted for rough rolling, and 7 frames are adopted for CVC finish rolling. The initial rolling temperature of the finish rolling is 1030 ℃, the finish rolling temperature is 870 ℃, and the thickness of the finished product is 5.0 mm. And post-dispersion cooling is adopted in laminar cooling, the cooling speed is 20 ℃/s, and the temperature of the steel strip is reduced to 650 ℃ for coiling. The hot-rolled strip steel is pickled by a hydrochloric acid tank, the acid tank adopts an i-BOX technology newly developed by MH, the operation and maintenance are greatly simplified, the energy and labor force are saved, after the surface oxide scale of the hot-rolled strip steel is removed, the hot-rolled strip steel is cold-rolled by a 5-frame UCM rolling mill, the cold-rolling reduction rate is 70 percent, and the target thickness is 1.5 mm. The cold-hard coil galvanizing process is carried out in a vertical annealing furnace by adopting a American steel combination method galvanizing production process, the running speed of a steel strip in a furnace zone is 80m/min, the heating temperature and the soaking temperature are both 520 ℃, the heating time is 80-120 s, and the soaking time is 80-120 s; slowly cooling at 490 ℃ for 11-15 s; the rapid cooling temperature is 465 ℃ and the time is 8-12 s; putting the mixture into a zinc pot at the temperature of 460 ℃ for 22-35 s; the flat elongation is 0.3%, and finally, the product performance is tested, as shown in the following table 2.
Example 3
The method comprises the following steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization on the molten iron by adopting a top-bottom combined blown converter for smelting to obtain molten steel, blowing argon in the whole process of the converter smelting, adding scrap steel into the converter, and carrying out tapping temperature of the converter at 1650 ℃. And then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is more than or equal to 1560 ℃, carrying out temperature measurement and component fine adjustment on the LF external refining, and the chemical components of the ladle casting machine for the LF external refining are shown in Table 1. The superheat degree of the slab continuous casting is 20 ℃, and then slab cleaning, slow cooling and quality inspection of the continuous casting slab are carried out. The heating temperature of the plate blank is 1220 ℃, the heating time is 235min, and the heated plate blank is subjected to high-pressure water dephosphorization. The width is fixed by a width fixing press, 2 frames are adopted for rough rolling, and 7 frames are adopted for CVC finish rolling. The initial rolling temperature of the finish rolling is 1030 ℃, the finish rolling temperature is 870 ℃, and the thickness of the finished product is 5.0 mm. And front cooling is adopted in laminar cooling, the cooling speed is 20 ℃/s, and the temperature of the steel strip is reduced to 650 ℃ for coiling. The hot-rolled strip steel is pickled by a hydrochloric acid tank, the acid tank adopts an i-BOX technology newly developed by MH, the operation and maintenance are greatly simplified, the energy and labor force are saved, after the surface oxide scale of the hot-rolled strip steel is removed, the hot-rolled strip steel is cold-rolled by a 5-frame UCM rolling mill, the cold-rolling reduction rate is 70 percent, and the target thickness is 1.5 mm. The cold-hard coil galvanizing process is carried out in a vertical annealing furnace by adopting a American steel combination method galvanizing production process, the running speed of a steel strip in a furnace zone is 80m/min, the heating temperature and the soaking temperature are both 540 ℃, the heating time is 80-120 s, and the soaking time is 80-120 s; slowly cooling at 490 ℃ for 11-15 s; the rapid cooling temperature is 465 ℃ and the time is 8-12 s; putting the mixture into a zinc pot at the temperature of 460 ℃ for 22-35 s; the flat elongation is 0.3%, and finally, the product performance is tested, as shown in the following table 2.
Example 4
Carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization on the molten iron by adopting a top-bottom combined blown converter to obtain molten steel, blowing argon in the whole process of the converter smelting, adding scrap steel into the converter, and tapping the steel at the converter at the temperature of 1640 ℃. And then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is more than or equal to 1560 ℃, carrying out temperature measurement and component fine adjustment on the LF external refining, and the chemical components of the ladle casting machine for the LF external refining are shown in Table 1. The superheat degree of the slab continuous casting is 20 ℃, and then slab cleaning, slow cooling and quality inspection of the continuous casting slab are carried out. The heating temperature of the plate blank is 1235 ℃, the heating time is 230min, and the heated plate blank is subjected to high-pressure water dephosphorization. The width is fixed by a width fixing press, 2 frames are adopted for rough rolling, and 7 frames are adopted for CVC finish rolling. The initial rolling temperature of the finish rolling is 1030 ℃, the finish rolling temperature is 870 ℃, and the thickness of the finished product is 5.0 mm. And post-dispersion cooling is adopted in laminar cooling, the cooling speed is 20 ℃/s, and the temperature of the steel strip is reduced to 650 ℃ for coiling. The hot-rolled strip steel is pickled by a hydrochloric acid tank, the acid tank adopts an i-BOX technology newly developed by MH, the operation and maintenance are greatly simplified, the energy and labor force are saved, after the surface oxide scale of the hot-rolled strip steel is removed, the hot-rolled strip steel is cold-rolled by a 5-frame UCM rolling mill, the cold-rolling reduction rate is 70 percent, and the target thickness is 1.5 mm. The cold-hard coil galvanizing process is carried out in a vertical annealing furnace by adopting a American steel combination method galvanizing production process, the running speed of a steel strip in a furnace zone is 80m/min, the heating temperature and the soaking temperature are both 530 ℃, the heating time is 80-120 s, and the soaking time is 80-120 s; slowly cooling at 490 ℃ for 11-15 s; the rapid cooling temperature is 465 ℃ and the time is 8-12 s; putting the mixture into a zinc pot at the temperature of 460 ℃ for 22-35 s; the flat elongation is 0.3%, and finally, the product performance is tested, as shown in the following table 2.
Example 5
The method comprises the following steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization on the molten iron by adopting a top-bottom combined blown converter to obtain molten steel, blowing argon in the whole process of the converter smelting, adding scrap steel into the converter, and carrying out tapping at 1630 ℃. And then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is more than or equal to 1560 ℃, carrying out temperature measurement and component fine adjustment on the LF external refining, and the chemical components of the ladle casting machine for the LF external refining are shown in Table 1. The superheat degree of the slab continuous casting is 20 ℃, and then slab cleaning, slow cooling and quality inspection of the continuous casting slab are carried out. The heating temperature of the plate blank is 1230 ℃, the heating time is 225min, and the heated plate blank is subjected to high-pressure water dephosphorization. The width is fixed by a width fixing press, 2 frames are adopted for rough rolling, and 7 frames are adopted for CVC finish rolling. The initial rolling temperature of the finish rolling is 1030 ℃, the finish rolling temperature is 870 ℃, and the thickness of the finished product is 5.0 mm. And post-dispersion cooling is adopted in laminar cooling, the cooling speed is 20 ℃/s, and the temperature of the steel strip is reduced to 650 ℃ for coiling. The hot-rolled strip steel is pickled by a hydrochloric acid tank, the acid tank adopts an i-BOX technology newly developed by MH, the operation and maintenance are greatly simplified, the energy and labor force are saved, after the surface oxide scale of the hot-rolled strip steel is removed, the hot-rolled strip steel is cold-rolled by a 5-frame UCM rolling mill, the cold-rolling reduction rate is 70 percent, and the target thickness is 1.5 mm. The cold-hard coil galvanizing process is carried out in a vertical annealing furnace by adopting a American steel combination method galvanizing production process, the running speed of a steel strip in a furnace zone is 80m/min, the heating temperature and the soaking temperature are both 520 ℃, the heating time is 80-120 s, and the soaking time is 80-120 s; slowly cooling at 490 ℃ for 11-15 s; the rapid cooling temperature is 465 ℃ and the time is 8-12 s; putting the mixture into a zinc pot at the temperature of 460 ℃ for 22-35 s; the flat elongation is 0.3%, and finally, the product performance is tested, as shown in the following table 2.
Example 6
The method comprises the following steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization on the molten iron by adopting a top-bottom combined blown converter for smelting to obtain molten steel, blowing argon in the whole process of the converter smelting, adding scrap steel into the converter, and carrying out tapping temperature of the converter at 1650 ℃. And then, carrying out LF external refining on the molten steel smelted by the converter, wherein the refining in-place temperature is more than or equal to 1560 ℃, carrying out temperature measurement and component fine adjustment on the LF external refining, and the chemical components of the ladle casting machine for the LF external refining are shown in Table 1. The superheat degree of the slab continuous casting is 20 ℃, and then slab cleaning, slow cooling and quality inspection of the continuous casting slab are carried out. The heating temperature of the plate blank is 1220 ℃, the heating time is 235min, and the heated plate blank is subjected to high-pressure water dephosphorization. The width is fixed by a width fixing press, 2 frames are adopted for rough rolling, and 7 frames are adopted for CVC finish rolling. The initial rolling temperature of the finish rolling is 1030 ℃, the finish rolling temperature is 870 ℃, and the thickness of the finished product is 5.0 mm. And front cooling is adopted in laminar cooling, the cooling speed is 20 ℃/s, and the temperature of the steel strip is reduced to 650 ℃ for coiling. The hot-rolled strip steel is pickled by a hydrochloric acid tank, the acid tank adopts an i-BOX technology newly developed by MH, the operation and maintenance are greatly simplified, the energy and labor force are saved, after the surface oxide scale of the hot-rolled strip steel is removed, the hot-rolled strip steel is cold-rolled by a 5-frame UCM rolling mill, the cold-rolling reduction rate is 70 percent, and the target thickness is 1.5 mm. The cold-hard coil galvanizing process is carried out in a vertical annealing furnace by adopting a American steel combination method galvanizing production process, the running speed of a steel strip in a furnace zone is 80m/min, the heating temperature and the soaking temperature are both 540 ℃, the heating time is 80-120 s, and the soaking time is 80-120 s; slowly cooling at 490 ℃ for 11-15 s; the rapid cooling temperature is 465 ℃ and the time is 8-12 s; putting the mixture into a zinc pot at the temperature of 460 ℃ for 22-35 s; the flat elongation is 0.3%, and finally, the product performance is tested, as shown in the following table 2.
Table 1: chemical Components (wt%) of examples 1 to 6 of the present invention
Figure BDA0002689268300000061
Table 2: mechanical properties of Steel coils according to embodiments 1 to 6 of the present invention
Examples Yield strength Rel/MPa Tensile strength Rm/MPa Elongation A50/％ Yield ratio
Example 1 602 650 14 0.93
Example 2 593 645 12 0.92
Example 3 587 643 13 0.91
Example 4 583 641 14 0.91
Example 5 649 698 14 0.93
Example 6 594 647 13 0.92
JIS G 3302 ≥560 ≥570 — —
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (4)

1. The SGC570 of the low-cost high-strength galvanized plate for the structure is characterized in that the SGC570 comprises the following chemical components in percentage by mass: c: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent, and the balance of Fe and inevitable impurities.
2. The method for producing the SGC570 low-cost high-strength galvanized sheet for structures as recited in claim 1, which comprises the following process steps: smelting, continuous casting, hot rolling, acid pickling and cold rolling, and hot galvanizing; wherein:
the smelting-continuous casting process comprises the following steps: pretreatment of molten iron, converter, LF refining and casting machine; wherein the molten steel for casting machine comprises the following components: 0.03-0.05%, Si: less than or equal to 0.03 percent, Mn: 0.15-0.25%, P: less than or equal to 0.020%, S: less than or equal to 0.010 percent, Alt: 0.020 to 0.050%, Ca: 0.0008 to 0.0020 percent;
the hot rolling process comprises the following steps: heating a casting blank, rough rolling, finish rolling and coiling; wherein the tapping temperature of the casting blank is 1200 +/-20 ℃, the rough rolling is performed by adopting a 3+3 mode 2-stand rolling mill, the finish rolling is performed by adopting a 7-stand continuous variable-crown rolling mill, and the thickness of the intermediate blank is 40-45 mm; the initial rolling temperature of the finish rolling is 1020 +/-30 ℃, and the final rolling temperature of the finish rolling is 870 +/-15 ℃; after finish rolling, cooling by adopting laminar cooling equipment and a post-dispersion cooling mode, wherein the cooling speed is 20 +/-5 ℃/s, and the coiling temperature is 650 +/-20 ℃;
the pickling cold rolling process specifically comprises the following steps: pickling the hot-rolled strip steel, removing surface iron oxide scales, and cold-rolling by a 5-stand cold rolling mill to obtain a cold-hard coiled steel strip;
the hot galvanizing process specifically comprises the following steps: uncoiling the cold-hard coil steel, heating, wherein the heating temperature and the soaking temperature are both 530 +/-20 ℃, the heating time is 80-120S, the soaking time is 80-120S, the slow cooling temperature is 490 +/-10 ℃, the fast cooling temperature is 465 +/-10 ℃, and the temperature of putting the cold-hard coil steel into a zinc pot is 460 +/-10 ℃.
3. The production method according to claim 2, wherein the hot-rolled steel strip in the hot rolling process has a thickness of 5.0 mm; in the pickling cold rolling process, the cold rolling reduction rate is 70%, and the steel is rolled to the target thickness of 1.5 mm.
4. The production method according to claim 2 or 3, wherein the temper rolling elongation in the hot galvanizing process is 0.3%.
CN202010985944.4A 2020-09-18 2020-09-18 Low-cost high-strength galvanized sheet SGC570 for structure and production method thereof Pending CN112226681A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116334470A (en) * 2023-03-31 2023-06-27 包头钢铁（集团）有限责任公司 Production method of high-strength structural steel SGC570
CN116623082A (en) * 2023-05-17 2023-08-22 包头钢铁（集团）有限责任公司 250 MPa-grade hot galvanizing high-strength structural steel for container barrels and production method thereof

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Publication number Priority date Publication date Assignee Title
JP2003231944A (en) * 2002-02-12 2003-08-19 Nippon Steel Corp Steel thin-sheet for press and manufacturing method therefor
CN101348885A (en) * 2008-09-11 2009-01-21 北京科技大学 1000MPa grade cold rolling hot dip galvanizing two-phase steel and manufacturing method thereof
CN103469060A (en) * 2013-08-30 2013-12-25 内蒙古包钢钢联股份有限公司 Cold-rolled steel plate for stamping household appliances and manufacturing method thereof
CN106148823A (en) * 2016-08-30 2016-11-23 唐山钢铁集团有限责任公司 550Mpa high strength structure level galvanized steel strip and production method thereof

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Publication number Priority date Publication date Assignee Title
JP2003231944A (en) * 2002-02-12 2003-08-19 Nippon Steel Corp Steel thin-sheet for press and manufacturing method therefor
CN101348885A (en) * 2008-09-11 2009-01-21 北京科技大学 1000MPa grade cold rolling hot dip galvanizing two-phase steel and manufacturing method thereof
CN103469060A (en) * 2013-08-30 2013-12-25 内蒙古包钢钢联股份有限公司 Cold-rolled steel plate for stamping household appliances and manufacturing method thereof
CN106148823A (en) * 2016-08-30 2016-11-23 唐山钢铁集团有限责任公司 550Mpa high strength structure level galvanized steel strip and production method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116334470A (en) * 2023-03-31 2023-06-27 包头钢铁（集团）有限责任公司 Production method of high-strength structural steel SGC570
CN116623082A (en) * 2023-05-17 2023-08-22 包头钢铁（集团）有限责任公司 250 MPa-grade hot galvanizing high-strength structural steel for container barrels and production method thereof

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Application publication date: 20210115