Production method of cold-rolled dual-phase steel for stamping

Abstract

The invention discloses a production method of cold-rolled dual-phase steel for stamping. Main process parameters are as follows: (1) a smelting-continuous casting production process flow; (2) hot rolling production process flow; (3) pickling and cold rolling process flow; (4) continuous annealing process flow; the cold-rolled dual-phase steel for stamping is prepared from chemical components in percentage by mass as follows: 0.06%-0.08% of C, 0.15%-0.20% of S , 1.20%-1.30% of Mn, smaller than or equal to 0.018% of P, smaller than or equal to 0.005% of S, 0.002%-0.003% of T and the balance of Fe and inevitable impurities. The cold-rolled dual-phase steel for stamping has the characteristics of high strength, low yield ratio, high rigidity and high plasticity, greatly improves the cold forming performance of automobile sheets, and is a material widely applied to automobile reinforcements and structural members.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical plate production, and in particular relates to a production method of cold-rolled dual-phase steel for stamping. Background Art

[0002] In recent years, low-carbon alloy steel has taken yield strength ratio as an important indicator while pursuing high strength and high toughness, because the lower the yield strength ratio of steel, the higher the work hardening index and the higher the uniform elongation. As automobile steel, it can improve the cold forming performance of automobile sheets. In automobile manufacturing, stress-bearing structural parts and reinforcements such as automobile chassis and wheelchair brackets need to have good deformation resistance, that is, they need to have high yield strength, while for some stamping parts, a low yield strength ratio is required.

[0003] Dual-phase steel is a high-strength steel obtained by heat treatment of low carbon steel or low carbon alloy steel in critical area or controlled rolling process. In recent years, with the development of lightweight automobiles, DP steel has been widely used in automobile body manufacturing due to its excellent strength, high work hardening rate, good ductility, moderate hardenability and good welding performance. This type of cold-rolled plate is mainly used for strengthening structural parts such as frames, pillars, beams, etc. in small cars that have high requirements on material strength and formability. Summary of the invention

[0004] The purpose of the present invention is to provide a production method of cold-rolled dual-phase steel for stamping, which is designed under the C-Mn component system, and the strength loss caused by removing alloy elements is compensated by fine control of the annealing process. The products produced greatly reduce the alloy cost while meeting the standard requirements, and at the same time create a larger profit space for downstream customers, which has been well received by users. The cold-rolled dual-phase steel for stamping of the present invention has the characteristics of high strength, low yield strength ratio, high stiffness and high plasticity, which greatly improves the cold forming performance of automobile plates and is a material widely used in automobile reinforcements and structural parts.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a production method for cold-rolled dual-phase steel for stamping, and the main process parameters are as follows:

[0007] (1) Smelting-continuous casting production process: molten iron pretreatment-converter-LF refining-casting machine; LF slag desulfurization, and adding aluminum iron, ferrosilicon, and ferromanganese alloys according to the composition of the molten steel to adjust to the target composition range; calcium treatment is carried out after the LF treatment, and the soft blowing time is ensured to be more than 8 minutes after wire feeding; the casting machine adopts constant pulling speed control, and the pulling speed range is: 1.0~1.5m / min;

[0008] (2) Hot rolling production process: heating of ingot - rough rolling - finishing rolling - coiling; the temperature of ingot out of furnace is 1210±20°C, the rough rolling adopts 3+3 mode 2-stand rolling mill, the finishing rolling adopts 7-stand continuous variable crown rolling mill, the thickness of intermediate ingot is 45-60mm; the final rolling temperature of finishing rolling is 870±20°C, the thickness of hot rolled steel strip is 5mm; cooling adopts laminar cooling equipment, front dispersed cooling mode, and the coiling temperature is 580±20°C;

[0009] (3) Pickling and cold rolling process: The hot-rolled strip is pickled in a hydrochloric acid tank using the i-BOX technology to remove the surface oxide scale, and then cold-rolled in a 5-stand cold rolling mill with a cold rolling reduction of 54% to a target thickness of 2.3 mm.

[0010] (4) Continuous annealing process: After unwinding the cold hardened steel strip, heat it to 780±10℃, soak it for 220-280S, cool it to 670±10℃ at a rate of 3-5℃ / s, and then cool it to 280±10℃ at a cooling rate of 20-30℃ / s. The flattening elongation is set to 0.8%;

[0011] The chemical composition of the cold-rolled dual-phase steel for stamping is as follows: C: 0.06-0.08%, Si: 0.15-0.20%, Mn: 1.20-1.30%, P: ≤0.018%, S: ≤0.005%, Ti: 0.002-0.003%, and the rest is Fe and unavoidable impurities.

[0012] Furthermore, the chemical composition of the cold-rolled dual-phase steel for stamping is in percentage by weight: C: 0.07%, Si: 0.16%, Mn: 1.21%, P: 0.012%, S: 0.003%, Ti: 0.0021%, and the rest is Fe and unavoidable impurities.

[0013] Furthermore, the chemical composition of the cold-rolled dual-phase steel for stamping is in percentage by weight: C: 0.07%, Si: 0.17%, Mn: 1.28%, P: 0.014%, S: 0.004%, Ti: 0.0022%, and the rest is Fe and unavoidable impurities.

[0014] Furthermore, the chemical composition of the cold-rolled dual-phase steel for stamping is in percentage by weight: C: 0.07%, Si: 0.17%, Mn: 1.22%, P: 0.013%, S: 0.003%, Ti: 0.0021%, and the rest is Fe and unavoidable impurities.

[0015] Further, the molten iron is pre-treated for desulfurization, and the molten iron is dephosphorized and decarburized to obtain molten steel by top and bottom combined blowing converter smelting. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1628°C; the molten steel after converter smelting is then subjected to LF refining outside the furnace, and the refining temperature is ≥1560°C. The LF refining outside the furnace is performed for temperature measurement and composition fine-tuning; the slab continuous casting overheating degree is 25°C, after which the slab is cleaned, slowly cooled, and the quality of the continuous casting slab is inspected; the slab heating temperature is 1220°C, the heating time is 208min, and the heated slab is subjected to high-pressure water dephosphorization; the width is fixed by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are adopted; finishing The final rolling temperature is 880℃, and the finished product thickness is 5mm; the laminar cooling adopts front dispersed cooling, and the temperature of the steel strip is reduced to 580℃ for coiling; the hot-rolled strip is pickled in a hydrochloric acid tank, and after the surface oxide scale of the hot-rolled strip is removed, it is cold-rolled by a 5-stand UCM rolling mill, and the cold rolling reduction rate is 54%, and the target thickness is rolled to 2.3mm; the continuous annealing of the cold hard coil is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 85m / min, the soaking temperature is 780℃, the soaking time is 230S, the slow cooling temperature is 680℃, the rapid cooling rate is 28℃ / S, the rapid cooling temperature is 290℃, and the flat elongation is 0.8%; finally, the product performance test is carried out.

[0016] Further, the molten iron is pre-treated for desulfurization, and the molten iron is decarbonized and dephosphorized to obtain molten steel by top and bottom combined blowing converter smelting. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1630°C; the molten steel after converter smelting is then subjected to LF refining outside the furnace, and the refining temperature is ≥1560°C. The LF refining outside the furnace is performed for temperature measurement and composition fine-tuning; the slab continuous casting overheating degree is 22°C, after which the slab is cleaned, slowly cooled, and the quality of the continuous casting slab is inspected; the slab heating temperature is 1220°C, the heating time is 205min, and the heated slab is subjected to high-pressure water dephosphorization; the width is fixed by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are adopted; finishing The final rolling temperature is 875℃, and the finished product thickness is 5mm; the laminar cooling adopts front dispersed cooling, and the temperature of the steel strip is reduced to 583℃ for coiling; the hot-rolled strip is pickled in a hydrochloric acid tank, and after the surface oxide scale of the hot-rolled strip is removed, it is cold-rolled by a 5-stand UCM rolling mill, and the cold rolling reduction rate is 54%, and the target thickness is rolled to 2.3mm; the continuous annealing of the cold hard coil is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 95m / min, the soaking temperature is 780℃, the soaking time is 221S, the slow cooling temperature is 670℃, the rapid cooling rate is 29℃ / S, the rapid cooling temperature is 288℃, and the flat elongation is 0.8%; finally, the product performance test is carried out.

[0017] Further, the molten iron is pre-treated for desulfurization, and the molten iron is decarbonized and dephosphorized to obtain molten steel by top and bottom combined blowing converter smelting. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1648°C; the molten steel after converter smelting is then subjected to LF refining outside the furnace, and the refining temperature is ≥1560°C. The LF refining outside the furnace is performed for temperature measurement and composition fine-tuning; the slab continuous casting overheating degree is 25°C, after which the slab is cleaned, slowly cooled, and the quality of the continuous casting slab is inspected; the slab heating temperature is 1220°C, the heating time is 202min, and the heated slab is subjected to high-pressure water dephosphorization; the width is determined by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used; finishing The final rolling temperature is 870℃, and the finished product thickness is 5mm; the laminar cooling adopts front dispersed cooling, and the temperature of the steel strip is reduced to 583℃ for coiling; the hot-rolled strip is pickled in a hydrochloric acid tank, and after the surface oxide scale of the hot-rolled strip is removed, it is cold-rolled by a 5-stand UCM rolling mill, and the cold rolling reduction rate is 54%, and the target thickness is rolled to 2.3mm; the continuous annealing of the cold hard coil is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 78m / min, the soaking temperature is 780℃, the soaking time is 240S, the slow cooling temperature is 670℃, the rapid cooling rate is 26℃ / S, the rapid cooling temperature is 285℃, and the flat elongation is 0.8%; finally, the product performance test is carried out.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are:

[0019] The metallographic microstructure of the steel of the present invention is ferrite + a small amount of martensite, the martensite content is 5%-8%, and the grain size is between 11.0 and 11.5. The low yield ratio automotive structural steel produced by the method provided by the present invention has been subjected to stamping and use tests in automobile factories, and the surface quality and performance indicators have met the relevant technical standard requirements of automobile factories and met the use requirements of relevant automobile factories. The mechanical properties and process properties meet the relevant standards and user requirements. At the same time, the alloy of the present invention has low cost, simple preparation method, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] Figure 1 This is the microstructure diagram of Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The present invention is described in more detail below through specific examples. The examples are only descriptions of the best mode of implementation of the present invention and do not limit the scope of the present invention in any way.

[0023] Example 1

[0024] The molten iron is pre-treated for desulfurization, and the top and bottom combined blown converter is used to dephosphorize and decarbonize the molten iron to obtain molten steel. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1628℃. Then the molten steel after converter smelting is subjected to LF furnace refining, the refining in place temperature is ≥1560℃, the LF furnace refining is performed for temperature measurement and composition fine-tuning, and the chemical composition of the LF furnace refining for the casting machine is shown in Table 1. The overheat of the slab continuous casting is 25℃, and then the slab is cleaned, slowly cooled, and the quality of the continuous casting is checked. The slab heating temperature is 1220℃, the heating time is 208min, and the heated slab is dephosphorized by high-pressure water. The width is set by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used. The finishing rolling temperature is 880℃, and the finished product thickness is 5mm. Laminar cooling uses front dispersion cooling, and the steel strip temperature is reduced to 580℃ for coiling. The hot-rolled strip is pickled in a hydrochloric acid tank. The acid tank adopts the i-BOX technology newly developed by MH. The operation and maintenance are greatly simplified, saving energy and labor. After removing the surface oxide scale of the hot-rolled strip, it is cold-rolled by a 5-stand UCM rolling mill with a cold rolling reduction rate of 54% and rolled to a target thickness of 2.3mm. The continuous annealing of the cold-hardened coil is carried out in a continuous vertical annealing furnace with HGJC function. The steel strip runs at a speed of 85m / min, the soaking temperature is 780℃, the soaking time is 230S, the slow cooling temperature is 680℃, the rapid cooling rate is 28℃ / S, the rapid cooling temperature is 290℃, and the flat elongation is 0.8%. Finally, the product performance test is carried out.

[0025] Example 2

[0026] The molten iron is pre-treated for desulfurization, and the top and bottom combined blown converter is used to decarbonize and dephosphorize the molten iron to obtain molten steel. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1630℃. Then the molten steel after converter smelting is subjected to LF refining outside the furnace, and the refining temperature is ≥1560℃. The LF refining outside the furnace is used for temperature measurement and composition fine-tuning. The chemical composition of the LF refining casting machine is shown in Table 1. The overheat of the slab continuous casting is 22℃, and then the slab is cleaned, slowly cooled, and the quality of the continuous casting is checked. The slab heating temperature is 1220℃, the heating time is 205min, and the heated slab is dephosphorized by high-pressure water. The width is set by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used. The finishing rolling temperature is 875℃, and the finished product thickness is 5mm. Laminar cooling uses front dispersion cooling, and the steel strip temperature is reduced to 583℃ for coiling. The hot-rolled strip is pickled in a hydrochloric acid tank. The acid tank adopts the i-BOX technology newly developed by MH. The operation and maintenance are greatly simplified, saving energy and labor. After removing the surface iron oxide scale, the hot-rolled strip is cold-rolled by a 5-stand UCM rolling mill with a cold rolling reduction rate of 54% and rolled to a target thickness of 2.3mm. The continuous annealing of the cold-hardened coil is carried out in a continuous vertical annealing furnace with HGJC function. The steel strip runs at a speed of 95m / min, the soaking temperature is 780℃, the soaking time is 221S, the slow cooling temperature is 670℃, the rapid cooling rate is 29℃ / S, the rapid cooling temperature is 288℃, and the flat elongation is 0.8%. Finally, the product performance test is carried out.

[0027] Example 3

[0028] The molten iron is pre-treated for desulfurization, and the top and bottom combined blown converter is used to decarbonize and dephosphorize the molten iron to obtain molten steel. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1648℃. Then the molten steel after converter smelting is subjected to LF refining outside the furnace, and the refining temperature is ≥1560℃. The LF refining outside the furnace is used for temperature measurement and composition fine-tuning. The chemical composition of the LF refining casting machine is shown in Table 1. The overheat of the slab continuous casting is 25℃, and then the slab is cleaned, slowly cooled, and the quality of the continuous casting is checked. The slab heating temperature is 1220℃, the heating time is 202min, and the heated slab is dephosphorized by high-pressure water. The width is set by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used. The finishing rolling temperature is 870℃, and the finished product thickness is 5mm. Laminar cooling uses front dispersion cooling, and the steel strip temperature is reduced to 583℃ for coiling. The hot-rolled strip is pickled in a hydrochloric acid tank. The acid tank adopts the i-BOX technology newly developed by MH. The operation and maintenance are greatly simplified, saving energy and labor. After removing the surface oxide scale of the hot-rolled strip, it is cold-rolled by a 5-stand UCM rolling mill with a cold rolling reduction rate of 54% and rolled to a target thickness of 2.3mm. The continuous annealing of the cold-hardened coil is carried out in a continuous vertical annealing furnace with HGJC function. The steel strip runs at a speed of 78m / min, the soaking temperature is 780℃, the soaking time is 240S, the slow cooling temperature is 670℃, the rapid cooling rate is 26℃ / S, the rapid cooling temperature is 285℃, and the flat elongation is 0.8%. Finally, the product performance test is carried out.

[0029] Table 1 Chemical composition of Examples 1 to 3 of the present invention (wt%)

[0030] Example C Si Mn P S Ti 1 0.07 0.16 1.21 0.012 0.003 0.0021 2 0.07 0.17 1.28 0.014 0.004 0.0022 3 0.07 0.017 1.22 0.013 0.003 0.0021

[0031] The steel coils of Examples 1 to 3 of the present invention were tested for mechanical properties, and the test results are shown in Table 2.

[0032] Table 2 Mechanical properties of the steel coils of Examples 1 to 3 of the present invention

[0033]

[0034] It can be seen from the data in Table 2 that the mechanical properties and process properties of the low yield strength ratio automotive structural steel produced according to the method provided by the present invention meet the requirements of the agreement signed with the user.

[0035] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for producing cold-rolled dual-phase steel for stamping, characterized in that: The main process parameters are as follows: (1) Smelting-continuous casting production process: molten iron pretreatment-converter-LF refining-casting machine; LF slag desulfurization, and adding aluminum iron, ferrosilicon, and ferromanganese alloys according to the composition of the molten steel to adjust to the target composition range; calcium treatment is carried out after the LF treatment, and the soft blowing time is ensured to be more than 8 minutes after wire feeding; the casting machine adopts constant pulling speed control, and the pulling speed range is: 1.0~1.5m / min; (2) Hot rolling production process: heating of ingot - rough rolling - finishing rolling - coiling; the temperature of ingot out of furnace is 1210±20°C, the rough rolling adopts 3+3 mode 2-stand rolling mill, the finishing rolling adopts 7-stand continuous variable crown rolling mill, the thickness of intermediate ingot is 45-60mm; the final rolling temperature of finishing rolling is 870±20°C, the thickness of hot rolled steel strip is 5mm; cooling adopts laminar cooling equipment, front dispersed cooling mode, and the coiling temperature is 580±20°C; (3) Pickling and cold rolling process: The hot-rolled strip is pickled in a hydrochloric acid tank using the i-BOX technology to remove the surface oxide scale, and then cold-rolled in a 5-stand cold rolling mill with a cold rolling reduction of 54% to a target thickness of 2.3 mm. (4) Continuous annealing process: After unwinding the cold hardened steel strip, heat it to 780±10℃, soak it for 220-280S, cool it to 670±10℃ at a rate of 3-5℃ / s, and then cool it to 280±10℃ at a cooling rate of 20-30℃ / s. The flattening elongation is set to 0.8%; The chemical composition of the cold-rolled dual-phase steel for stamping is as follows: C: 0.06-0.08%, Si: 0.15-0.20%, Mn: 1.20-1.30%, P: ≤0.018%, S: ≤0.005%, Ti: 0.002-0.003%, and the rest is Fe and unavoidable impurities.

2. The method for producing cold-rolled dual-phase steel for stamping according to claim 1, characterized in that: The chemical composition of the cold-rolled dual-phase steel for stamping is as follows: C: 0.07%, Si: 0.16%, Mn: 1.21%, P: 0.012%, S: 0.003%, Ti: 0.0021%, and the rest is Fe and unavoidable impurities.

3. The method for producing cold-rolled dual-phase steel for stamping according to claim 1, characterized in that: The chemical composition of the cold-rolled dual-phase steel for stamping is as follows: C: 0.07%, Si: 0.17%, Mn: 1.28%, P: 0.014%, S: 0.004%, Ti: 0.0022%, and the rest is Fe and unavoidable impurities.

4. The method for producing cold-rolled dual-phase steel for stamping according to claim 1, characterized in that: The chemical composition of the cold-rolled dual-phase steel for stamping is as follows: C: 0.07%, Si: 0.17%, Mn: 1.22%, P: 0.013%, S: 0.003%, Ti: 0.0021%, and the rest is Fe and unavoidable impurities.

5. The method for producing cold-rolled dual-phase steel for stamping according to claim 2, characterized in that: The molten iron is pre-treated for desulfurization, and the top and bottom combined blowing converter is used to dephosphorize and decarbonize the molten iron to obtain molten steel. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1628℃; the molten steel after converter smelting is then subjected to LF refining outside the furnace, and the refining temperature is ≥1560℃. The LF refining outside the furnace is performed for temperature measurement and component fine-tuning; the slab continuous casting overheating degree is 25℃, after which the slab is cleaned, slowly cooled, and the quality of the continuous casting slab is checked; the slab heating temperature is 1220℃, the heating time is 208min, and the heated slab is subjected to high-pressure water dephosphorization; the width is fixed by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used; the finishing rolling is finished The rolling temperature is 880℃, and the finished product thickness is 5mm; the laminar cooling adopts front dispersed cooling, and the temperature of the steel strip is reduced to 580℃ for coiling; the hot-rolled strip is pickled in a hydrochloric acid tank, and after the surface oxide scale of the hot-rolled strip is removed, it is cold-rolled by a 5-stand UCM rolling mill, and the cold rolling reduction rate is 54%, and the target thickness is rolled to 2.3mm; the continuous annealing of the cold hard coil is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 85m / min, the soaking temperature is 780℃, the soaking time is 230S, the slow cooling temperature is 680℃, the rapid cooling rate is 28℃ / S, the rapid cooling temperature is 290℃, and the flat elongation is 0.8%; finally, the product performance test is carried out.

6. The method for producing cold-rolled dual-phase steel for stamping according to claim 3, characterized in that: The molten iron is pre-treated for desulfurization, and the top and bottom combined blowing converter is used to decarbonize and dephosphorize the molten iron to obtain molten steel. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1630℃; the molten steel after converter smelting is then subjected to LF refining outside the furnace, and the refining temperature is ≥1560℃. The LF refining outside the furnace is performed for temperature measurement and component fine-tuning; the slab continuous casting overheating degree is 22℃, after which the slab is cleaned, slowly cooled, and the quality of the continuous casting slab is checked; the slab heating temperature is 1220℃, the heating time is 205min, and the heated slab is subjected to high-pressure water dephosphorization; the width is fixed by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used; the finishing rolling is finished The rolling temperature is 875℃, and the finished product thickness is 5mm; the laminar cooling adopts front dispersed cooling, and the temperature of the steel strip is reduced to 583℃ for coiling; the hot-rolled strip is pickled in a hydrochloric acid tank, and after the surface oxide scale of the hot-rolled strip is removed, it is cold-rolled by a 5-stand UCM rolling mill, and the cold rolling reduction rate is 54%, and the target thickness is rolled to 2.3mm; the continuous annealing of the cold hard coil is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 95m / min, the soaking temperature is 780℃, the soaking time is 221S, the slow cooling temperature is 670℃, the rapid cooling rate is 29℃ / S, the rapid cooling temperature is 288℃, and the flat elongation is 0.8%; finally, the product performance test is carried out.

7. The method for producing cold-rolled dual-phase steel for stamping according to claim 4, characterized in that: The molten iron is pre-treated for desulfurization, and the top and bottom combined blowing converter is used to decarbonize and dephosphorize the molten iron to obtain molten steel. Argon is blown throughout the converter smelting process, scrap steel is added to the converter, and the converter tapping temperature is 1648℃; the molten steel after converter smelting is then subjected to LF refining outside the furnace, and the refining temperature is ≥1560℃. The LF refining outside the furnace is performed for temperature measurement and component fine-tuning; the slab continuous casting overheating degree is 25℃, after which the slab is cleaned, slowly cooled, and the quality of the continuous casting slab is checked; the slab heating temperature is 1220℃, the heating time is 202min, and the heated slab is subjected to high-pressure water dephosphorization; the width is fixed by a fixed width press, and 2-stand rough rolling and 7-stand CVC finishing rolling are used; the finishing rolling is finished The rolling temperature is 870℃, and the finished product thickness is 5mm; the laminar cooling adopts front dispersed cooling, and the temperature of the steel strip is reduced to 583℃ for coiling; the hot-rolled strip is pickled in a hydrochloric acid tank, and after the surface oxide scale of the hot-rolled strip is removed, it is cold-rolled by a 5-stand UCM rolling mill, and the cold rolling reduction rate is 54%, and the target thickness is rolled to 2.3mm; the continuous annealing of the cold hard coil is carried out in a continuous vertical annealing furnace with HGJC function, the steel strip running speed is 78m / min, the soaking temperature is 780℃, the soaking time is 240S, the slow cooling temperature is 670℃, the rapid cooling rate is 26℃ / S, the rapid cooling temperature is 285℃, and the flat elongation is 0.8%; finally, the product performance test is carried out.

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