A steel for thin gauge battery can and a method of manufacturing the same and use thereof

Abstract

The present application belongs to the technical field of steel preparation, and particularly relates to a thin-gauge steel for battery shell and a preparation method and application thereof. The preparation method comprises the following steps: 1) mixing raw materials, smelting and continuous casting to obtain a continuous casting blank; 2) heating, hot rolling, cooling and coiling the continuous casting blank to obtain a hot-rolled blank, wherein the relationship between the final rolling temperature of the hot rolling and the carbon content in the continuous casting blank is T = 1066 * 2 (0.4 - M * 100) ± 10 DEG C, T is the final rolling temperature, and M is the mass percentage of carbon in the continuous casting blank; 3) after the hot-rolled blank is uncoiled, pickling and cold rolling are performed to obtain a cold-rolled blank; and 4) annealing the cold-rolled blank at 800-850 DEG C, then performing segmented cooling, aging treatment and water quenching to obtain the thin-gauge steel for battery shell. When the thin-gauge steel for battery shell prepared by the preparation method is used to prepare a battery shell, the sand hole and lug forming phenomena can be simultaneously avoided, the obtained steel has moderate strength and good forming performance, and is suitable for multi-pass stamping requirements.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of steel production, and particularly relates to a thin-gauge steel for battery shell and a preparation method and application thereof. BACKGROUND

[0002] With the development of domestic new energy vehicles, especially the rapid promotion of electric buses, electric buses and other models, the demand for power batteries is increasing. In the production and manufacturing process of the battery, the steel battery shell plays an important role in ensuring the quality and safety of the battery, therefore, the quality of the steel battery shell is very important. The battery shell is produced by multi-pass stamping, and the forming depth is deep. The battery shell after stamping requires high strength and high surface quality to ensure the safety of the battery, so the comprehensive performance of the steel strip is very high. At the same time, with the increase of product demand, the production efficiency of the product is improved, the stamping speed is rapidly improved, and the existing thin-gauge battery shell is usually made of low-carbon steel. However, the existing low-carbon steel, although the sand hole and ear are reduced, the strength is too high, which will be limited after the rapid improvement of the stamping speed, resulting in poor forming performance and large wear of the die. SUMMARY

[0003] Therefore, the technical problem to be solved by the present application is to overcome the defects that the existing thin-gauge battery shell steel cannot simultaneously realize no sand hole, no ear, and poor forming performance and large wear of the die due to high strength, so as to provide a thin-gauge battery shell steel and a preparation method and application thereof.

[0004] The present application provides a preparation method of a thin-gauge battery shell steel, comprising the following steps:

[0005] 1) mixing raw materials, smelting and continuous casting to obtain a continuous casting billet;

[0006] The continuous casting billet, by mass percentage, comprises: C: 0.02-0.03%, Si: 0.01-0.03%, Mn: 0.10-0.25%, P≤0.015%, S≤0.015%, Als: 0.05-0.07%, Ti: 0.021-0.040%, and the rest is iron element and inevitable impurity element;

[0007] 2) heating, hot rolling, cooling and coiling the continuous casting billet obtained in step 1) to obtain a hot rolled billet;

[0008] The relationship between the final rolling temperature of the hot rolling and the carbon content in the continuous casting billet is T=1066*2(0.4-M*100)±10℃, wherein T is the final rolling temperature, and M is the mass percentage of carbon in the continuous casting billet;

[0009] 3) after uncoiling the hot rolled billet obtained in step 2), pickling and cold rolling to obtain a cold rolled billet;

[0010] 4) annealing the cold-rolled blank obtained in step 3) at 800-850℃, then subcooling, aging treatment, and water quenching treatment to obtain the steel for the thin-gauge battery shell.

[0011] Preferably, the smelting in step 1) comprises converter smelting and refining;

[0012] The converter smelting temperature is 1640-1680℃, and the converter smelting time is 40-60min;

[0013] The continuous casting speed in step 1) is 1.0-1.5m / min;

[0014] The continuous casting blank thickness is 180-220mm;

[0015] Optionally, the refining comprises LF refining and RH refining;

[0016] The LF refining tapping temperature is 1600-1640℃, and the LF refining time is 35-55min;

[0017] The RH refining tapping temperature is 1570-1620℃, and the RH refining time is 8-12min.

[0018] Preferably, in step 2), the continuous casting blank obtained in step 1) is heated to a continuous casting blank tapping temperature of 1130-1180℃ before hot rolling;

[0019] The hot rolling comprises rough rolling and finish rolling;

[0020] Optionally, the rough rolling reduction is 75%-85%;

[0021] Optionally, in step 2), the heating step further comprises a continuous casting blank surface scaling treatment.

[0022] Preferably, the hot-rolled blank thickness is 1.8-3.0mm;

[0023] Optionally, in step 2), the cooling is layer cooling to a temperature of 680-740℃;

[0024] In step 2), the coiling temperature is 660-720℃;

[0025] Preferably, in step 3), the pickling agent is an aqueous hydrochloric acid solution;

[0026] Optionally, the mass concentration of hydrochloric acid in the aqueous hydrochloric acid solution is 10-20%;

[0027] The present application does not specifically limit the composition of the aqueous hydrochloric acid solution, which can be a used aqueous hydrochloric acid solution, a partially used aqueous hydrochloric acid solution, or a mixed aqueous hydrochloric acid solution obtained by mixing a recovered aqueous hydrochloric acid solution obtained by recycling and regenerating treatment.

[0028] Preferably, the cold rolling reduction rate in step 3) is 75-87.5%;

[0029] The cold rolling is lubricated using an emulsion, and the saponification value of the emulsion is 180-190 mgKOH / g;

[0030] Optionally, the temperature of the emulsion during cold rolling is 45-70℃;

[0031] Further optionally, the temperature of the emulsion during cold rolling is 50-55℃;

[0032] Optionally, the rolling environment temperature during cold rolling is 0-50℃. For example, the rolling environment temperature during cold rolling can be room temperature.

[0033] Optionally, the thickness of the cold rolling blank is ≤0.4mm;

[0034] Optionally, step 3) further comprises a coiling step after the cold rolling step;

[0035] Optionally, the coiling temperature is 0-45℃, for example, the coiling can be carried out at room temperature.

[0036] Optionally, after uncoiling the hot rolling blank obtained in step 2), step 3) further comprises a hot rolling blank welding process; post-treatment after welding the hot rolling blank can effectively reduce unnecessary loss of steel during preparation.

[0037] Preferably, the annealing time in step 4) is 60-360s;

[0038] The stepwise cooling in step 4) comprises a slow cooling segment and a fast cooling segment;

[0039] The slow cooling segment has a cooling rate of 2-5℃ / s, and the slow cooling segment is cooled to 680-700℃;

[0040] The fast cooling segment has a cooling rate of 40-60℃ / s, and the fast cooling segment is cooled to 380-420℃;

[0041] The aging treatment temperature in step 4) is 380-420℃, and the aging treatment time is 220-300s;

[0042] After the aging treatment in step 4) is completed, a cooling treatment is further included, and the cooling is to 100-140℃ before water quenching treatment is carried out;

[0043] Optionally, before the annealing step in step 4), a cleaning step is further included.

[0044] Optionally, before the annealing step in step 4), a cleaning step is further included. Optionally, after the water quenching step in step 4), a flattening, oiling and coiling step is further included.

[0045] Optionally, the flattening reduction is 1.0-1.5%.

[0046] Optionally, the oiling amount is 300-500 mg / m 2 The oiling is double-sided oiling.

[0047] Optionally, the coiling temperature is 0-45℃. Optionally, the coiling is carried out at room temperature.

[0048] The present application provides a thin-gauge battery shell steel prepared by the preparation method of the thin-gauge battery shell steel.

[0049] The present application further provides an application of the thin-gauge battery shell steel in a battery shell.

[0050] The technical scheme of the present application has the following advantages:

[0051] 1. The preparation method of the thin specification battery shell steel provided by the present application comprises the following steps: 1) mixing raw materials, smelting and continuous casting to obtain a continuous casting billet; the components of the continuous casting billet, by mass percentage, are: C: 0.02-0.03%, Si: 0.01-0.03%, Mn: 0.10-0.25%, P≤0.015%, S≤0.015%, Als: 0.05-0.07%, Ti: 0.021-0.040%, and the rest is iron elements and inevitable impurity elements; 2) heating, hot rolling, cooling and coiling the continuous casting billet obtained in step 1) to obtain a hot rolled blank; the relationship between the final rolling temperature of the hot rolling and the carbon content in the continuous casting billet is T=1066*2(0.4-M*100)±10℃, wherein T is the final rolling temperature and M is the mass percentage of carbon in the continuous casting billet; 3) after uncoiling the hot rolled blank obtained in step 2), carrying out pickling and cold rolling to obtain a cold rolled blank; 4) annealing the cold rolled blank obtained in step 3) at 800-850℃, then carrying out segmented cooling, aging treatment and water quenching treatment to obtain the thin specification battery shell steel. The continuous casting billet with specific components can effectively reduce the sand eye and ear phenomenon in the steel; according to the carbon content in the continuous casting billet and the specific relationship between the final rolling temperature of the hot rolling and the carbon content in the continuous casting billet, the final rolling temperature of the hot rolling is determined, at which the iron oxide scale pressing defect can be effectively reduced, the sand eye is reduced, and the strength of the low-carbon steel product can be controlled; then, a specific annealing temperature of 800-850℃ is selected after the cold rolling, and then segmented cooling, aging treatment and water quenching treatment are carried out, which can cooperate with the final rolling temperature of the hot rolling to eliminate the mixed crystal defects, improve the anisotropy of the product, and effectively reduce the generation of ears. By using the continuous casting billet with specific components, controlling the relationship between the carbon content in the continuous casting billet and the final rolling temperature of the hot rolling, and cooperating with the specific cold rolling process, the specific annealing temperature and the specific treatment after annealing, the thin specification battery shell steel obtained by the present application can realize no sand eye and ear phenomenon when preparing the battery shell, the strength of the steel is moderate (lower than the original low-carbon steel), the forming performance is good, the mold wear is small, and the use requirements of the battery shell steel multi-pass stamping can be perfectly matched.

[0052] 2. The preparation method of the thin specification battery shell steel provided by the present application, wherein the cold rolling uses emulsion lubrication, and the saponification value of the emulsion is 180-190mgKOH / g; under the lubrication of the emulsion with the saponification value, the rolling force can be reduced and the strip surface finish can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to illustrate the technical solutions in the specific embodiments of the present application or the prior art more clearly, the accompanying drawings needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0054] Figure 1 The metallographic phase diagram of the hot-rolled blank after hot rolling in the embodiment 1 of the present application;

[0055] Figure 2 The metallographic phase diagram of the thin-gauge battery shell steel in the embodiment 2 of the present application;

[0056] Figure 3 The metallographic phase diagram of the thin-gauge battery shell steel in the embodiment 3 of the present application;

[0057] Figure 4 The metallographic phase diagram of the thin-gauge battery shell steel in the comparative example 1 of the present application. DETAILED DESCRIPTION

[0058] The following examples are provided to better further understand the present application, and are not limited to the best mode, and do not limit the content and protection scope of the present application. Any person under the inspiration of the present application or the combination of the present application with other prior art features can obtain any product same or similar to the present application, which falls within the protection scope of the present application.

[0059] The specific experimental steps or conditions are not indicated in the examples, and can be operated according to the conventional experimental steps or conditions described in the literature in the art. The reagents or instruments used are not indicated by the manufacturer, and are conventional reagent products that can be obtained by market purchase.

[0060] Example 1

[0061] The present embodiment provides a preparation method of a thin-gauge battery shell steel, which comprises the following steps:

[0062] 1) mixing raw materials, converter smelting at 1652℃ for 51min, refining including LF refining at 1611℃ for 36min and RH refining at 1584℃ for 9min, then continuous casting at a casting speed of 1.2m / min to obtain a continuous casting billet with a thickness of 220mm; the continuous casting billet comprises, by mass percent: C: 0.026%, Si: 0.03%, Mn: 0.15%, P: 0.013%, S: 0.0019%, Als: 0.052%, Ti: 0.024%, and the balance being iron and inevitable impurities;

[0063] 2) performing surface peeling treatment on the continuous casting billet obtained in step 1), then heating treatment, the discharge temperature of the continuous casting billet after heating treatment is 1150℃, then hot rolling, the final rolling temperature T is determined according to the carbon content in the continuous casting billet, i.e. T = 1066*2(0.4-0.026%*100)±10℃, i.e. the final rolling temperature of the hot rolling is 804℃, the hot rolling includes rough rolling and finish rolling, the reduction rate of the rough rolling is 83%, after rolling, the continuous casting billet is layer cooled, then coiling at 692℃ to obtain a hot rolling billet with a thickness of 2mm; the metallographic image of the hot rolling billet is shown in Figure 1 ;

[0064] 3) unwinding the hot rolling billet obtained in step 2), welding the hot rolling billet, then continuously cold rolling at room temperature after pickling with hydrochloric acid aqueous solution, the mass concentration of hydrochloric acid in the hydrochloric acid aqueous solution is 18%, the cold rolling is lubricated with emulsion, the temperature of the emulsion is 55℃, the saponification value of the emulsion is 181.75mgKOH / g, the cold rolling reduction rate is 85%, then coiling at room temperature to obtain a cold rolling billet with a thickness of 0.3mm;

[0065] 4) unwinding the cold rolling billet obtained in step 3), washing with water, annealing at 835℃ for 75s, then performing step cooling, i.e. slow cooling to 680℃ at a cooling speed of 2℃ / s, then fast cooling to 420℃ at a cooling speed of 45℃ / s, then aging treatment at 420℃ for 230s, then cooling to 120℃, then water quenching in a water quenching tank, then flattening and double-side oiling at room temperature, the flattening reduction is 1.2%, the oiling amount is 400mg / m 2 , then coiling at room temperature to obtain the steel for thin-gauge battery shell.

[0066] Example 2

[0067] The embodiment provides a preparation method of a steel for thin-gauge battery shell, comprising the following steps:

[0068] 1) mixing raw materials, converter smelting at a temperature of 1658℃ for 48 min, and refining including LF refining at a temperature of 1620℃ for 36 min and RH refining at a temperature of 1578℃ for 8 min, then continuous casting at a casting speed of 1.1 m / min to obtain a continuous casting billet with a thickness of 220 mm, wherein the continuous casting billet contains, by mass percent, C: 0.021%, Si: 0.02%, Mn: 0.22%, P: 0.009%, S: 0.0028%, Als: 0.066%, Ti: 0.034%, and the balance of iron and inevitable impurities;

[0069] 2) performing surface peeling treatment on the continuous casting billet obtained in step 1), then heating treatment, the heating treatment being performed at a temperature of 1140℃, hot rolling after the heating treatment, the final rolling temperature T being determined according to the carbon content in the continuous casting billet, i.e. T = 1066*2(0.4-0.021%*100)±10℃, i.e. the final rolling temperature of the hot rolling being determined as 811℃, the hot rolling including rough rolling and finish rolling, wherein the rough rolling is performed at a reduction rate of 79%, and the hot rolled billet with a thickness of 2.5 mm is obtained by coiling at 701℃ after the layer cooling after the rolling;

[0070] 3) unwinding the hot rolled billet obtained in step 2), welding the hot rolled billet, then continuously cold rolling at room temperature after pickling with hydrochloric acid aqueous solution, the mass concentration of hydrochloric acid in the hydrochloric acid aqueous solution being 18%, the cold rolling being lubricated with emulsion, the temperature of the emulsion being 53℃, the saponification value of the emulsion being 181.75 mgKOH / g, the cold rolling being performed at a reduction rate of 85%, and the cold rolled billet with a thickness of 0.3 mm is obtained by coiling at room temperature;

[0071] 4) unwinding the cold rolled billet obtained in step 3), washing with water, annealing at a temperature of 835℃ for 75 s, then performing step cooling, i.e. slow cooling to 700℃ at a cooling speed of 3℃ / s, then fast cooling to 410℃ at a cooling speed of 40℃ / s, then aging treatment at a temperature of 410℃ for 260 s, then cooling to 110℃, then water quenching in a water quenching tank, then flattening and double-side oiling at room temperature, the flattening reduction being 1.5%, and the oiling amount being 350 mg / m 2 , and then coiling at room temperature to obtain the steel for thin-gauge battery shell. Figure 2

[0072] Example 3

[0073] The present embodiment provides a method for preparing a steel for thin-gauge battery shell, comprising the following steps: ​

[0074] 1) mixing raw materials, converter smelting at a temperature of 1642℃ for 42min, and refining including LF refining at a temperature of 1603℃ for 35min and RH refining at a temperature of 1580℃ for 12min, then continuous casting at a casting speed of 1.2m / min to obtain a continuous casting billet with a thickness of 220mm, wherein the continuous casting billet contains, by mass percent, C: 0.02%, Si: 0.01%, Mn: 0.10%, P: 0.008%, S: 0.003%, Als: 0.07%, Ti: 0.040%, and the balance of iron and inevitable impurities;

[0075] 2) performing surface peeling treatment on the continuous casting billet obtained in step 1), then heating treatment, the heating treatment being performed at a billet discharge temperature of 1140℃, then hot rolling after discharge, the final rolling temperature of hot rolling being determined according to the carbon content in the continuous casting billet, i.e. T = 1066*2(0.4-0.02%*100)±10℃, i.e. the final rolling temperature of hot rolling being determined as 820℃, the hot rolling including rough rolling and finish rolling, wherein the reduction rate of rough rolling is 83.6%, and the hot rolled billet with a thickness of 2mm is obtained after layer cooling after finish rolling and coiling at 680℃;

[0076] 3) unwinding the hot rolled billet obtained in step 2), welding the hot rolled billet, then continuously cold rolling at room temperature after pickling using hydrochloric acid aqueous solution, the mass concentration of hydrochloric acid in the hydrochloric acid aqueous solution being 18%, the cold rolling being lubricated using emulsion, the temperature of the emulsion being 55℃, the saponification value of the emulsion being 190.00mgKOH / g, the cold rolling reduction rate being 87.5%, and the cold rolled billet with a thickness of 0.25mm being obtained after coiling at room temperature;

[0077] 4) unwinding the cold rolled billet obtained in step 3), washing with water, annealing at a temperature of 800℃ for 130s, then performing step cooling, i.e. slow cooling to 700℃ at a cooling speed of 3℃ / s, then fast cooling to 410℃ at a cooling speed of 55℃ / s, then aging treatment at a temperature of 410℃ for 300s, then cooling to 120℃, then water quenching in a water quenching tank, then flattening and double-side oiling at room temperature, the flattening reduction being 1.0%, and the oiling amount being 500mg / m 2 , and then coiling at room temperature to obtain the thin-gauge battery shell steel, the metallographic diagram of the thin-gauge battery shell steel being shown in Figure 3 .

[0078] Example 4

[0079] The present embodiment provides a preparation method of a thin-gauge battery shell steel, comprising the following steps:

[0080] 1) mixing raw materials, converter smelting at a temperature of 1680℃ for 60 min, and refining including LF refining at a temperature of 1640℃ for 55 min and RH refining at a temperature of 1620℃ for 8 min, then continuous casting at a casting speed of 1.4 m / min to obtain a continuous casting billet with a thickness of 220 mm; the continuous casting billet has the following components in mass percent: C: 0.03%, Si: 0.03%, Mn: 0.25%, P: 0.015%, S: 0.005%, Als: 0.05%, Ti: 0.021%, and the balance being iron and inevitable impurities;

[0081] 2) surface peeling treatment of the continuous casting billet obtained in step 1), then heating treatment, the billet has a discharge temperature of 1180℃ after heating treatment, hot rolling after discharge, the final rolling temperature T = 1066*2(0.4-0.03%*100) ± 10℃ is determined according to the carbon content in the continuous casting billet, i.e. the final rolling temperature of hot rolling is determined as 782℃, the hot rolling includes rough rolling and finish rolling, the reduction rate of rough rolling is 78.2%, the billet is layer cooled after rolling, then coiling at 720℃ to obtain a hot rolled billet with a thickness of 2.5 mm;

[0082] 3) unwinding the hot rolled billet obtained in step 2), welding the hot rolled billet, then continuous cold rolling at room temperature after pickling with hydrochloric acid aqueous solution, the mass concentration of hydrochloric acid in the hydrochloric acid aqueous solution is 18%, the cold rolling uses emulsion lubrication, the temperature of the emulsion is 55℃, the saponification value of the emulsion is 180.00 mgKOH / g, the cold rolling reduction rate is 84%, then coiling at room temperature to obtain a cold rolled billet with a thickness of 0.4 mm;

[0083] 4) unwinding the cold rolled billet obtained in step 3), water cleaning, annealing at a temperature of 850℃ for 130 s, then step cooling, slow cooling to 680℃ at a cooling rate of 4℃ / s, then fast cooling to 420℃ at a cooling rate of 45℃ / s, then aging treatment at a temperature of 420℃ for 220 s, then cooling to 140℃, water quenching in a water quenching tank, then flattening and double-side oiling at room temperature, the flattening reduction is 1.5%, the oiling amount is 500 mg / m 2 , then coiling at room temperature to obtain the steel for thin gauge battery shell.

[0084] Comparative Example 1

[0085] This comparative example provides a preparation method of a steel for thin gauge battery shell, which is different from Example 1 in that the final rolling temperature of hot rolling in step 2) is 860℃.

[0086] The metallographic diagram of the thin-gauge battery shell steel obtained is shown in Figure 4 .

[0087] Comparative Example 2

[0088] The present comparative example provides a preparation method of a thin-gauge battery shell steel, which is different from Example 1 in that the annealing temperature in step 4) is 770℃.

[0089] Comparative Example 3

[0090] The present comparative example provides a preparation method of a thin-gauge battery shell steel, which is different from Example 1 in that the cold-rolled blank obtained in step 3) is uncoiled, washed with water, annealed, the annealing temperature is 835℃, the annealing time is 75s, after the annealing, the layer is cooled to room temperature, then flattened, double-sided oiled, the flattening reduction is 1.2%, the oiling amount is 400mg / m 2 , and the thin-gauge battery shell steel is obtained by coiling at room temperature.

[0091] Comparative Example 4

[0092] The present comparative example provides a preparation method of a thin-gauge battery shell steel, which is different from Example 1 in that the continuous casting blank in step 1) has the following components in mass percentage: C: 0.0023%, Si: 0.012%, Mn: 0.38%, P: 0.011%, S: 0.004%, Als: 0.058%, Ti: 0.051%, and the rest is iron and inevitable impurities.

[0093] Test Example

[0094] The thin-gauge battery shell steels obtained in Examples 1-4 and Comparative Examples 1-4 are tested, the determination of the lower yield strength, tensile strength and elongation after fracture in the forming property refers to the standard GB / T228-2021, and the test results are shown in Table 1. The higher the elongation after fracture, the better the forming property; the thin-gauge battery shell steels obtained in Examples 1-4 and Comparative Examples 1-4 are tested for △r value, the test refers to the standard GB / T228-2021, and the test results are shown in Table 1 in absolute value. The smaller the absolute value of △r, the better, indicating that the material has uniform performance in all directions, and is more uniform during stamping deformation, and is less likely to produce "ear" defects. When the absolute value of △r exceeds 0.3, it is more likely to produce "ear" defects.

[0095] The thin-gauge battery can shell steels obtained in Examples 1-4 and Comparative Examples 1-4 were placed on a battery can shell mold to be punched into cylindrical battery can shells with a diameter of 65 cm, under the condition of a punching speed of 100 strokes / min, 9 strokes were punched to reach a punching depth of 6.5 cm. The thin-gauge battery can shell steels obtained in Examples 1-4 and Comparative Examples 1-4 were punched into 10,000 cylindrical battery can shells, respectively, and the surface scratch rate, crack rate, sand hole rate and burr rate of the 10,000 cylindrical battery can shells corresponding to Examples 1-4 and Comparative Examples 1-4 were counted in real time, and the detection results are shown in Table 1. The lower the crack rate, the better the forming performance and the smaller the wear on the mold.

[0096] Table 1

[0097]

[0098]

[0099] Obviously, the above examples are merely illustrative and not limiting. Based on the above description, those skilled in the art can make other different forms of changes or variations. It is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for producing a steel for a thin gauge battery can, characterized by, The method comprises the following steps: 1) mixing raw materials, smelting and continuous casting to obtain a continuous casting billet; The continuous casting billet comprises the following components in percentage by mass: C: 0.02-0.03%, Si: 0.01-0.03%, Mn: 0.10-0.25%, P≤0.015%, S≤0.015%, Als: 0.05-0.07%, Ti: 0.021-0.040%, and the rest is iron and inevitable impurities; 2) heating, hot rolling, cooling and coiling the continuous casting billet obtained in step 1) to obtain a hot-rolled billet; The relationship between the final rolling temperature of the hot rolling and the carbon content in the continuous casting billet is T=1066*2(0.4-M*100)±10℃, wherein T is the final rolling temperature and M is the mass percentage of carbon in the continuous casting billet; 3) after uncoiling the hot-rolled billet obtained in step 2), carrying out pickling and cold rolling to obtain a cold-rolled billet; 4) annealing the cold-rolled billet obtained in step 3) at 800-850℃, then carrying out step-by-step cooling, aging treatment and water quenching treatment to obtain the steel for the thin-gauge battery shell; The annealing time in step 4) is 60-360s; The step-by-step cooling in step 4) comprises slow cooling and fast cooling; The slow cooling rate is 2-5℃ / s, and the slow cooling is to 680-700℃; The fast cooling rate is 40-60℃ / s, and the fast cooling is to 380-420℃; The aging treatment temperature in step 4) is 380-420℃, and the aging treatment time is 220-300s; After the aging treatment in step 4), the method further comprises cooling treatment, and the cooling is to 100-140℃ before water quenching treatment.

2. The method of producing a steel sheet for a thin-size battery case according to claim 1, wherein The smelting in step 1) comprises converter smelting and refining; The converter smelting temperature is 1640-1680℃, and the converter smelting time is 40-60min; The continuous casting speed in step 1) is 1.0-1.5m / min; The thickness of the continuous casting billet is 180-220mm; The refining comprises LF refining and RH refining; The LF refining temperature is 1600-1640℃, and the LF refining time is 35-55min; The RH refining temperature is 1570-1620℃, and the RH refining time is 8-12min.

3. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, In step 2), the heating treatment of the continuous casting billet obtained in step 1) is carried out at a discharge temperature of 1130-1180℃, and then hot rolling is carried out after the discharge; The hot rolling comprises rough rolling and finish rolling.

4. The method for preparing thin-gauge battery casing steel according to claim 3, characterized in that, The reduction rate of the rough rolling is 75%-85%.

5. The method of claim 3, wherein the steel for a thin-type battery case is prepared by adding 0.01 to 0.1% by weight of Ti and 0.01 to 0.1% by weight of Zr to the steel composition of claim 3. In step 2), the heating step further comprises surface peeling treatment of the continuous casting billet.

6. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, In step 2), the thickness of the hot-rolled billet is 1.8-3.0mm; In step 2), the coiling temperature is 660-720℃.

7. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, In step 3), the pickling agent for the pickling is hydrochloric acid aqueous solution.

8. The method for preparing thin-gauge battery casing steel according to claim 7, characterized in that, The mass concentration of hydrochloric acid in the hydrochloric acid aqueous solution is 10-20%.

9. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, In step 3), the reduction rate of the cold rolling is 75-87.5%; The emulsion lubricant used in the cold rolling has a saponification value of 180-190mgKOH / g.

10. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, The thickness of the cold-rolled billet is ≤0.4mm.

11. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, The cold rolling step in step 3) is followed by a coiling step.

12. The method of producing a steel sheet for a thin-size battery case according to claim 1 or 2, wherein The annealing step in step 4) is preceded by a cleaning step.

13. The method for preparing thin-gauge battery casing steel according to claim 1 or 2, characterized in that, The water quenching step in step 4) is followed by a tempering, oiling and coiling step.

14. A steel for a thin gauge battery can, characterized by, The thin gauge steel for battery case is prepared by the method of any one of claims 1-13.

15. Use of the thin gauge steel for battery case according to claim 14 in a battery case.

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