Preparation method of galvanized household appliance steel

Abstract

The invention discloses a preparation method of galvanized household appliance steel. The preparation method comprises the following steps: 1) smelting process; 2) a hot rolling process; 3) an annealing process; the galvanized household appliance steel comprises the following chemical components in percentage by mass: 0.025-0.060% of C, less than or equal to 0.03% of S , 0.15-0.35% of Mn, less than or equal to 0.020% of P, less than or equal to 0.020% of S, 0.020-0.070% of Al < t >, less than or equal to 0.0045% of N, less than or equal to 0.0030% of O and the balance of Fe and inevitable impurities. The galvanized household electrical appliance steel provided by the invention has good corrosion resistance, heat and humidity resistance, fingerprint resistance and coating performance, chemical components and mechanical properties meet the use requirements of excellent hot-galvanized fingerprint-resistant plates for high-end household electrical appliances, and can be applied to high-end household electrical appliance outer plates such as computers, servers, film and television sound equipment, automatic office systems and the like; and the stable batch supply capability is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgical plate production, and particularly relates to a preparation method of galvanized household appliance steel. BACKGROUND

[0002] With the continuous development of the national economy, new requirements for green steel are put forward in China. Green steel refers to high-quality steel produced by green and environmentally friendly process, which can reduce the use of fossil fuels, reduce carbon dioxide emissions, achieve clean production, and has high environmental protection and sustainability.

[0003] The household appliance industry has increasingly high requirements for "green steel", and major host factories have proposed a carbon reduction roadmap for household appliance steel. Although scrap steel is not green steel, the recycling of scrap steel is also crucial to achieving the goal of sustainable development. Scrap steel recycling can effectively reduce the production of new steel, save energy, reduce CO2 emissions, and not only contribute to environmental protection, but also promote the sustainable development of the steel industry.

[0004] Converter smelting scrap steel usage requirements: the proportion of scrap steel added to the furnace should be greater than or equal to 50% of the total charge, and the scrap steel added to the furnace is composed of pre-consumption recycled materials and post-consumption recycled materials. The proportion of post-consumption recycled materials added during production should be greater than or equal to 5% of the total charge. The green steel BTRC50 for hot galvanizing household appliances is developed, and through research on equipment, process and quality problems in the smelting, hot rolling and cold rolling process, especially optimization and improvement of various performance, stable batch production of the product is ensured. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of galvanized household appliance steel. The galvanized household appliance steel provided by the present application has good corrosion resistance, moisture resistance, fingerprint resistance and coating performance, and the chemical composition and mechanical properties meet the use requirements of high-end household appliance hot galvanizing fingerprint-resistant plates, and can be applied to high-end household appliance outer plate parts such as computers, servers, audio-visual systems and automatic office systems, and has stable batch supply capacity.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a preparation method of galvanized household appliance steel, which comprises the following steps:

[0008] 1. Smelting process

[0009] (1) KR desulfurization: KR hot metal desulfurization technology is adopted, and the final sulfur content after deep desulfurization is required to be within 0.002%. KR desulfurization is carried out by mechanical stirring method, desulfurizer is added into the hot metal, and the desulfurizer and sulfur in the hot metal react to remove the sulfur content in the hot metal under continuous stirring. After desulfurization is completed, the desulfurization slag is thoroughly removed to prevent high-sulfur slag from being mixed into the converter to cause resulfurization. The stability of the hot metal temperature is controlled to ensure that the hot metal temperature is above 1300℃, which is beneficial to the stable control of the converter smelting process and improves the hit rate of the converter final temperature;

[0010] (2) Converter smelting:

[0011] Converter hot metal is mixed with scrap steel according to the Si content, and the scrap steel addition ratio is required to be greater than or equal to 50% of the total charge. The scrap steel is composed of pre-consumption and post-consumption recycled materials. The proportion of post-consumption recycled materials added during production is required to be greater than or equal to 5% of the total charge. Temperature control is required during the smelting process, and the converter tapping temperature should be greater than 1660℃;

[0012] (3) RH vacuum treatment: Decarburization treatment is carried out according to the composition and temperature of the converter supplied to the RH; After decarburization is completed, aluminum particles are added for deoxidization and alloying according to the oxygen content, and manganese iron and other alloys are added for 4 minutes to adjust the composition of the molten steel to the target value; After the composition is adjusted, the vacuum circulation time is ensured to be not less than 6 minutes; The temperature and composition of the molten steel are homogenized, which is beneficial to the floating of inclusions in the molten steel and improves the cleanliness of the molten steel;

[0013] (4) Continuous casting: The continuous casting is at a constant speed, and the speed range is 1.0-1.8 m / min; The liquidus temperature is controlled at 1532℃, and the superheat during pouring is controlled between 30-45℃ to avoid the formation of cold steel during the pouring process, which is beneficial to the floating of inclusions and realizes multi-heat pouring;

[0014] 2). Hot rolling process

[0015] The cast blank is heated by a walking beam furnace, the rough rolling is carried out by double rack R1 and R2 reciprocating rolling, the rough rolling mode is 3+3, the finish rolling is carried out by F1-F7 continuous rolling process, the finish rolling temperature is 915±15℃, the austenite single-phase zone rolling is ensured, the coiling temperature is 620±15℃, the normal precipitation of carbonitride is ensured, and the deep drawing performance is improved;

[0016] Casting blank heating system:

[0017]

[0018] Rolling process:

[0019]

[0020] 3). Annealing process

[0021] Annealing uses vertical continuous annealing furnace, furnace adopts reducing atmosphere and nitrogen hydrogen mixed protective atmosphere cooling; heating section and soaking section temperature target 750℃, ensure grain completely recrystallization, heating furnace each section outlet temperature control condition see table, flat machine elongation different thickness control condition see table;

[0022] Annealing process:

[0023]

[0024] Flat machine elongation:

[0025]

[0026]

[0027] The galvanized household appliance steel has the following chemical composition in mass percent: C: 0.025-0.060%, Si: ≤0.03%, Mn: 0.15-0.35%, P: ≤0.020%, S: ≤0.020%, Alt: 0.020-0.070%, N: ≤0.0045%, O: ≤0.0030%, and the rest is Fe and inevitable impurities.

[0028] Further, the galvanized household appliance steel has the following chemical composition in mass percent: C: 0.035%, Si: 0.008%, Mn: 0.28%, P: 0.008%, S: 0.005%, Alt: 0.033%, N: 0.0020%, O: 0.0021%, and the rest is Fe and inevitable impurities.

[0029] Further, the galvanized household appliance steel has the following chemical composition in mass percent: C: 0.040%, Si: 0.010%, Mn: 0.25%, P: 0.010%, S: 0.006%, Alt: 0.042%, N: 0.0020%, O: 0.0029%, and the rest is Fe and inevitable impurities.

[0030] Further, the galvanized household appliance steel has the following chemical composition in mass percent: C: 0.038%, Si: 0.005%, Mn: 0.25%, P: 0.007%, S: 0.005%, Alt: 0.037%, N: 0.0012%, O: 0.0020%, and the rest is Fe and inevitable impurities.

[0031] Further, specifically including: molten iron desulfurization pretreatment, control the converter tapping temperature 1690 ℃, in the converter process adding scrap galvanized household appliance steel preparation method, adding scrap steel ratio for total load of 52%; then the converter smelting after the molten steel is refined outside RH, refining just in place temperature 1635 ℃, RH outside refining temperature and composition fine tuning; slab continuous casting superheat is 45 ℃, slab heating temperature is 1175 ℃, the heating time is 177 min, the heated slab is high pressure water phosphorus removal; through the fixed width press fixed width, using 2 rack rough rolling, 7 rack CVC finishing rolling; finishing rolling finish rolling temperature is 890 ℃, finished product thickness 5.5 mm; laminar flow cooling adopts front dispersion cooling, steel strip temperature reduces to 650 ℃ and is coiled; after the hot rolled strip is pickled in hydrochloric acid tank to remove the surface iron oxide scale, it is cold rolled through 5 rack UCM rolling mill, the cold rolling reduction is 70%, and is rolled to target thickness 1.5 mm; cold hard coil continuous annealing is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 145 m / min, the soaking temperature is 742 ℃, the slow cooling temperature is 654 ℃, and the skin pass elongation is 1.453-1.457%.

[0032] Further, specifically including: molten iron desulfurization pretreatment, control the converter tapping temperature 1690 ℃, in the converter process adding scrap galvanized household appliance steel preparation method, adding scrap steel ratio for total load of 52%; then the converter smelting after the molten steel is refined outside RH, refining just in place temperature 1635 ℃, RH outside refining temperature and composition fine tuning; slab continuous casting superheat is 45 ℃, slab heating temperature is 1175 ℃, the heating time is 177 min, the heated slab is high pressure water phosphorus removal; through the fixed width press fixed width, using 2 rack rough rolling, 7 rack CVC finishing rolling; finishing rolling finish rolling temperature is 890 ℃, finished product thickness 5.5 mm; laminar flow cooling adopts front dispersion cooling, steel strip temperature reduces to 650 ℃ and is coiled; after the hot rolled strip is pickled in hydrochloric acid tank to remove the surface iron oxide scale, it is cold rolled through 5 rack UCM rolling mill, the cold rolling reduction is 70%, and is rolled to target thickness 1.5 mm; cold hard coil continuous annealing is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 145 m / min, the soaking temperature is 742 ℃, the slow cooling temperature is 654 ℃, and the skin pass elongation is 1.453-1.457%.

[0033] Further, specifically comprising: molten iron is subjected to desulphurization pretreatment, the converter tapping temperature is controlled to 1690 DEG C, the preparation method of the converter process adding scrap steel galvanized household appliance steel, the proportion of scrap steel added is 63% of the total amount; the converter tapping temperature is 1688 DEG C; then the molten steel after converter smelting is subjected to RH furnace outside refining, the refining in-place temperature is 1635 DEG C, the RH furnace outside refining is subjected to temperature measurement and component fine adjustment; the slab continuous casting superheat is 45 DEG C, the slab heating temperature is 1175 DEG C, and the heating time is 177 min; the heated slab is subjected to high-pressure water dephosphorization; the width is fixed by fixed-width press; 2-rack rough rolling and 7-rack CVC finish rolling are adopted; the finish rolling final rolling temperature is 920 DEG C, and the finished product thickness is 5.5 mm; the laminar flow cooling adopts front dispersion cooling, and the steel strip temperature is reduced to 680 DEG C for coiling; after the hot-rolled strip steel is pickled in a hydrochloric acid tank to remove the surface iron oxide scale, the steel strip is cold-rolled by 5-rack UCM rolling mill, the cold rolling reduction is 70%, and the target thickness is 1.5 mm; the cold hard coiling continuous annealing is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 145 m / min, the soaking temperature is 742 DEG C, the slow cooling temperature is 654 DEG C, and the flattening elongation is 1.453-1.527%.

[0034] Compared with the prior art, the beneficial technical effects of the present application are:

[0035] The metallographic microstructure grain size of the cold-rolled galvanized household appliance steel of the present application is 6-9.5, the yield strength of the thickness 0.50 < t ≤ 2.50 mm is 200-320 MPa, the tensile strength is 270-420 MPa, and the elongation A50 is ≥30.0%. The performance of the cold-rolled galvanized household appliance steel produced by the method provided by the present application all meets the requirements of the relevant technical standards. BRIEF DESCRIPTION OF DRAWINGS

[0036] The present application will be further described below in combination with the description of the drawings.

[0037] Figure 1 It is the metallographic structure photo of the galvanized household appliance steel of the present application example 1. DETAILED DESCRIPTION

[0038] The present application will be further described below in combination with the description of the drawings.

[0039] Example 1

[0040] Molten iron undergoes desulfurization pretreatment, and the converter tapping temperature is controlled at 1690℃. Self-collected scrap steel (a mixture of pre-consumption and post-consumption recycled materials) is added during the converter process, accounting for 52% of the total charge. The molten steel after converter smelting is then subjected to RH ladle refining at a set temperature of 1635℃. Temperature measurement and composition fine-tuning are performed during RH ladle refining. The chemical composition supplied to the casting machine after RH ladle refining is shown in Table 1. The slab continuous casting superheat is 45℃, the slab heating temperature is 1175℃, and the heating time is 177 minutes. The heated slab is then subjected to high-pressure water descaling. Width is determined using a width-fixing press, and a 2-stand roughing mill and a 7-stand CVC finishing mill are used. The finishing mill final rolling temperature is 890℃, and the finished product thickness is 5.5mm. Laminar flow cooling uses pre-dispersion cooling, and the strip temperature is reduced to 650℃ before coiling. After hot-rolled strip steel is pickled in a hydrochloric acid bath to remove surface iron oxide scale, it is cold-rolled on a 5-stand UCM mill with a cold rolling reduction of 70% to a target thickness of 1.5 mm. The cold-rolled coil undergoes continuous annealing in a continuous vertical annealing furnace with HGJC functionality. The strip running speed is 145 m / min, the soaking temperature is 742℃, the slow cooling temperature is 654℃, and the leveling elongation is 1.453–1.457%. Finally, product performance testing is performed.

[0041] Example 2

[0042] Molten iron undergoes desulfurization pretreatment, and the converter tapping temperature is controlled at 1690℃. Self-collected scrap steel (a mixture of pre-consumption and post-consumption recycled materials) is added during the converter process, accounting for 58% of the total charge. The molten steel after converter smelting is then subjected to RH ladle refining at a set temperature of 1635℃. Temperature measurement and composition fine-tuning are performed during RH ladle refining. The chemical composition supplied to the casting machine after RH ladle refining is shown in Table 1. The slab continuous casting superheat is 45℃, the slab heating temperature is 1175℃, and the heating time is 177 minutes. The heated slab is then subjected to high-pressure water descaling. Width is determined using a width-fixing press, and a 2-stand roughing mill and a 7-stand CVC finishing mill are used. The finishing mill final rolling temperature is 900℃, and the finished product thickness is 5.5mm. Laminar flow cooling uses pre-dispersion cooling, and the strip temperature is reduced to 620℃ before coiling. After hot-rolled strip steel is pickled in a hydrochloric acid bath to remove surface iron oxide scale, it is cold-rolled on a 5-stand UCM mill with a cold rolling reduction of 70% to a target thickness of 1.5 mm. The cold-rolled coil undergoes continuous annealing in a continuous vertical annealing furnace with HGJC functionality. The strip running speed is 145 m / min, the soaking temperature is 750℃, the slow cooling temperature is 654℃, and the leveling elongation is 1.453–1.459%. Finally, product performance testing is performed.

[0043] Example 3

[0044] The molten iron undergoes desulfurization pretreatment, and the converter tapping temperature is controlled at 1690℃. Self-collected scrap steel (a mixture of pre-consumption and post-consumption recycled materials) is added during the converter process, accounting for 63% of the total charge. The converter tapping temperature is 1688℃. The molten steel after converter smelting is then subjected to RH ladle refining at a set temperature of 1635℃. Temperature measurement and composition fine-tuning are performed during RH ladle refining. The chemical composition supplied to the casting machine after RH ladle refining is shown in Table 1. The slab continuous casting superheat is 45℃, the slab heating temperature is 1175℃, and the heating time is 177 minutes. The heated slab is then subjected to high-pressure water descaling. Width is determined using a width-fixing press, and a 2-stand roughing mill and a 7-stand CVC finishing mill are used. The finishing mill final rolling temperature is 920℃, and the finished product thickness is 5.5mm. Laminar flow cooling uses pre-dispersion cooling, and the strip temperature is reduced to 680℃ before coiling. After hot-rolled strip steel is pickled in a hydrochloric acid bath to remove surface iron oxide scale, it is cold-rolled on a 5-stand UCM mill with a cold rolling reduction of 70% to a target thickness of 1.5 mm. The cold-rolled coil undergoes continuous annealing in a continuous vertical annealing furnace with HGJC functionality. The strip running speed is 145 m / min, the soaking temperature is 742℃, the slow cooling temperature is 654℃, and the leveling elongation is 1.453–1.527%. Finally, product performance testing is performed.

[0045] Table 1. Chemical composition (wt%) of Examples 1-3 of the present invention

[0046] Examples C Si Mn P S Alt N O 1 0.035 0.008 0.28 0.008 0.005 0.033 0.0020 0.0021 2 0.040 0.010 0.25 0.010 0.006 0.042 0.0020 0.0029 3 0.038 0.005 0.25 0.007 0.005 0.037 0.0012 0.0020

[0047] The mechanical properties of the steel coils in Examples 1 to 3 of the present invention were tested, and the test results are shown in Table 2.

[0048] Table 2 Mechanical properties of steel coils from Examples 1-3 of the present invention

[0049]

[0050] As can be seen from Table 2, the mechanical properties of the galvanized household appliance steel produced by this invention all meet the mechanical property requirements for household appliance steel products.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for producing a galvanised household appliance steel, characterised in that: Comprise: 1). Smelting process (1) KR desulfurization: KR hot metal desulfurization technology is adopted, and the final sulfur content is required to be within 0.002% after deep desulfurization. KR desulfurization is carried out by mechanical stirring method, desulfurizer is added into hot metal, and desulfurizer and sulfur in hot metal react to remove sulfur content in hot metal in continuous stirring. After desulfurization is completed, desulfurization slag is thoroughly removed to prevent high-sulfur slag from being mixed into the converter to cause resulfurization. The stability of the temperature of the hot metal into the furnace is controlled to ensure that the temperature of the hot metal is above 1300℃, which is beneficial to the stable control of the converter smelting process and improves the hit rate of the final temperature of the converter. (2) Converter smelting: The converter hot metal is mixed with scrap steel according to the Si content, and the proportion of scrap steel into the furnace is required to be greater than or equal to 50% of the total charge. The scrap steel into the furnace is composed of pre-consumption recycled material and post-consumption recycled material. The proportion of post-consumption recycled material added during production is required to be greater than or equal to 5% of the total charge. Temperature control is required during the smelting process, and the converter tapping temperature should be greater than 1660℃. (3) RH vacuum treatment: According to the composition and temperature of the converter for RH molten steel, decarburization treatment is carried out. After decarburization is completed, aluminum particles are added for deoxidization and alloying according to the oxygen content, and manganese iron and other alloys are added for 4 minutes to adjust the composition of the molten steel to the target value. After the composition is adjusted, the vacuum circulation is ensured to be not less than 6 minutes. The temperature and composition of the molten steel are uniformized, which is beneficial to the floating of inclusions in the molten steel and improves the cleanliness of the molten steel. (4) Continuous casting: The continuous casting is at a constant speed, and the speed range is 1.0-1.8 m / min. The liquidus temperature is controlled at 1532℃, and the superheat is controlled at 30-45℃ during the casting process to avoid the formation of cold steel during the casting process, which is beneficial to the floating of inclusions and realizes multi-ladle casting. 2). Hot rolling process The cast blank is heated by using a walking beam furnace, coarse rolling is carried out by using double rack R1 and R2 reciprocating rolling, the coarse rolling mode is 3+3, fine rolling is carried out by using F1-F7 continuous rolling process, the fine rolling temperature is 915±15℃, the austenite single-phase zone is ensured to be rolled, the coiling temperature is 620±15℃, the carbonitride is ensured to be normally precipitated, and the deep drawing performance is improved. Casting blank heating system: Rolling process: 3). Annealing process Annealing uses a vertical continuous annealing furnace, and a reducing atmosphere and a nitrogen-hydrogen mixed protective atmosphere are used for cooling; the target temperature of the heating section and the soaking section is 750℃, which ensures complete recrystallization of the grains, the outlet temperature control of each section of the heating furnace is shown in the table below, and the elongation control of the temper mill for different thicknesses is shown in the table below. Annealing process: Temper mill elongation: The galvanized household appliance steel has a mass percentage of chemical components of C: 0.025-0.060%, Si: ≤0.03%, Mn: 0.15-0.35%, P: ≤0.020%, S: ≤0.020%, Alt: 0.020-0.070%, N: ≤0.0045%, O: ≤0.0030%, and the rest is Fe and unavoidable impurities.

2. The method for producing a galvanized home appliance steel according to claim 1, characterized in that: The galvanized household appliance steel has the following chemical composition in mass percent: C: 0.035%, Si: 0.008%, Mn: 0.28%, P: 0.008%, S: 0.005%, Alt: 0.033%, N: 0.0020%, O: 0.0021%, and the balance of Fe and inevitable impurities.

3. The method of producing a galvanized household appliance steel according to claim 1, characterized in that: The galvanized household appliance steel has the following chemical composition in mass percent: C: 0.040%, Si: 0.010%, Mn: 0.25%, P: 0.010%, S: 0.006%, Alt: 0.042%, N: 0.0020%, O: 0.0029%, and the balance of Fe and inevitable impurities.

4. The method of producing a galvanized household appliance steel according to claim 1, characterized in that: The galvanized household appliance steel has the following chemical composition in mass percent: C: 0.038%, Si: 0.005%, Mn: 0.25%, P: 0.007%, S: 0.005%, Alt: 0.037%, N: 0.0012%, O: 0.0020%, and the balance of Fe and inevitable impurities.

5. The method of producing a galvanized home appliance steel according to claim 1, characterized in that: Specifically comprising: The molten iron is pretreated by desulfurization, and the tapping temperature of the converter is controlled at 1690 DEG C. The scrap steel is added in the converter process, and the proportion of the scrap steel is 52% of the total amount. Then the molten steel after the converter smelting is refined by RH furnace, the on-site temperature of the refining is 1635 DEG C, and the temperature measurement and composition fine adjustment are performed by the RH furnace. The slab continuous casting superheat is 45 DEG C, the slab heating temperature is 1175 DEG C, and the heating time is 177 min. The high-pressure water is used to remove phosphorus after the heated slab. The width is fixed by the fixed-width press, the rough rolling is performed by 2 racks, and the fine rolling is performed by 7 racks of CVC. The final rolling temperature is 890 DEG C, and the finished product thickness is 5.5 mm. The laminar cooling is performed by front dispersion cooling, and the steel strip temperature is reduced to 650 DEG C for coiling. After the hot-rolled strip is pickled by the hydrochloric acid tank to remove the surface iron oxide scale, the cold rolling is performed by 5 racks of UCM rolling mill, the cold rolling reduction is 70%, and the target thickness is 1.5 mm. The continuous annealing of the cold hard coil is performed in the continuous vertical annealing furnace with HGJC function, the steel strip running speed is 145 m / min, the soaking temperature is 742 DEG C, the slow cooling temperature is 654 DEG C, and the flattening elongation is 1.453-1.457%.

6. The method of producing a galvanized home appliance steel according to claim 1, characterized in that: Specifically comprising: The molten iron is pretreated by desulphurization, the temperature of the molten steel tapped from the converter is controlled at 1690 DEG C, the preparation method of the galvanized household appliance steel by adding scrap steel in the converter process, the proportion of the scrap steel added is 58% of the total amount; then the molten steel after the converter smelting is subjected to RH external refining, the in-place temperature of the refining is 1635 DEG C, the temperature measurement and composition fine adjustment are performed in the RH external refining; the slab continuous casting superheat is 45 DEG C, the slab heating temperature is 1175 DEG C, the heating time is 177 min, the high-pressure water is used to remove phosphorus from the heated slab; the width is fixed by a fixed-width press, 2-stand rough rolling and 7-stand CVC finishing rolling are adopted; the finishing rolling final rolling temperature is 900 DEG C, the finished product thickness is 5.5 mm; the laminar flow cooling is performed by front dispersion cooling, the steel strip temperature is reduced to 620 DEG C for coiling; after the hot-rolled strip steel is pickled in a hydrochloric acid tank to remove the surface iron oxide scale, the steel is cold-rolled by 5-stand UCM rolling mill, the cold rolling reduction is 70%, and the steel is rolled to the target thickness of 1.5 mm; the cold hard coil continuous annealing is performed in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 145 m / min, the soaking temperature is 750 DEG C, the slow cooling temperature is 654 DEG C, and the skin pass elongation is 1.453-1.459%.

7. The method of producing a galvanized home appliance steel according to claim 1, characterized in that: Specifically comprising: The molten iron is pretreated by desulphurization, the temperature of the molten steel tapped from the converter is controlled at 1690 DEG C, the preparation method of the galvanized household appliance steel by adding scrap steel in the converter process, the proportion of the scrap steel added is 58% of the total amount; the temperature of the molten steel tapped from the converter is 1688 DEG C; then the molten steel after the converter smelting is subjected to RH external refining, the in-place temperature of the refining is 1635 DEG C, the temperature measurement and composition fine adjustment are performed in the RH external refining; the slab continuous casting superheat is 45 DEG C, the slab heating temperature is 1175 DEG C, the heating time is 177 min, the high-pressure water is used to remove phosphorus from the heated slab; the width is fixed by a fixed-width press, 2-stand rough rolling and 7-stand CVC finishing rolling are adopted; the finishing rolling final rolling temperature is 920 DEG C, the finished product thickness is 5.5 mm; the laminar flow cooling is performed by front dispersion cooling, the steel strip temperature is reduced to 680 DEG C for coiling; after the hot-rolled strip steel is pickled in a hydrochloric acid tank to remove the surface iron oxide scale, the steel is cold-rolled by 5-stand UCM rolling mill, the cold rolling reduction is 70%, and the steel is rolled to the target thickness of 1.5 mm; the cold hard coil continuous annealing is performed in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 145 m / min, the soaking temperature is 742 DEG C, the slow cooling temperature is 654 DEG C, and the skin pass elongation is 1.453-1.527%.

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