Preparation method of copper-containing steel plate for stamping

Abstract

The invention provides a preparation method of a copper-containing steel plate for stamping, which comprises the following steps: a heating step: heating a casting blank at the temperature of 980-1100 DEG C for 110-130 minutes, the casting blank comprises the following chemical components in percentage by mass: 0.003-0.10% of C, 0.10-1.00% of Si, 0.10-2.00% of Mn, 0.01-0.50% of A1, 0.2-2.0% of Cu, less than or equal to 0.1% of Ni, less than or equal to 0.1% of P, less than or equal to 0.1% of S and the balance of Fe and inevitable impurities; the balance is Fe and a small amount of inevitable impurity elements; the hot rolling step comprises rough rolling and finish rolling, the rough rolling step comprises rolling a casting blank for 5-7 passes, the rough rolling outlet temperature is 880-940 DEG C, the finish rolling step comprises controlling the finish rolling inlet temperature to 820-870 DEG C, and controlling the finish rolling outlet temperature to 760-810 DEG C. According to the preparation method, the copper-containing steel plate for stamping, which is good in surface quality, can be prepared on the basis of considering the mechanical properties of the copper-containing steel plate for stamping.

Description

Technical Field

[0001] The present disclosure relates to a method for preparing a copper-containing steel sheet for stamping. Background Art

[0002] The copper-containing steel sheet for stamping has characteristics such as high strength, good toughness and anti-deformation ability, and is commonly used in body structural parts and engine components. Copper has good corrosion resistance. Adding copper element to the steel sheet can enhance the resistance of the steel sheet to the atmosphere, water and some chemical substances, and reduce the occurrence of rust and corrosion. This is very important for the long-term use of the parts after stamping in different environments, especially in some humid or corrosive medium environments, which can extend the service life of the parts and reduce the maintenance cost.

[0003] The copper content in the copper-containing steel sheet for stamping is generally ≥0.2%, and the melting point of copper is 1083°C. Due to the low melting point of copper, surface quality defects of the steel sheet caused by copper brittle cracks are likely to occur during the hot rolling process. The current common process is to add nickel element to inhibit the generation of copper brittleness, which increases the production cost. Therefore, there is an urgent need for improvement. Summary of the Invention

[0004] The present disclosure provides a method for preparing a copper-containing steel sheet for stamping, which can prepare a copper-containing steel sheet for stamping with good surface quality while taking into account the mechanical properties of the copper-containing steel sheet for stamping.

[0005] In a first aspect, the present disclosure provides a method for preparing a copper-containing steel sheet for stamping, and the preparation method includes:

[0006] A heating step, including heating the slab at a temperature of 980°C to 1100°C, and the heating time is 110 min to 130 min. Wherein, the slab includes the following chemical components in mass percentage: C: 0.003% to 0.10%, Si: 0.10% to 1.00%, Mn: 0.10% to 2.00%, A1: 0.01% to 0.50%, Cu: 0.2% to 2.0%, Ni≤0.1%, P≤0.1%, S≤0.1%, and the rest is Fe and a small amount of impurity elements inevitably generated;

[0007] A hot rolling step, including rough rolling and finish rolling. The rough rolling includes rolling the slab for 5 to 7 passes, and the rough rolling exit temperature is 880°C to 940°C. The finish rolling includes controlling the finish rolling inlet temperature to be 820°C to 870°C and controlling the finish rolling exit temperature to be 760°C to 810°C.

[0008] In some optional embodiments, after the hot rolling step, the preparation method further includes: a coiling step, including coiling the slab that has undergone the hot rolling step to obtain the copper-containing steel sheet for stamping.

[0009] In some alternative embodiments, the coiling temperature is 680°C to 730°C.

[0010] In some alternative embodiments, before the coiling step, the preparation method further includes: cooling the slab that has undergone the hot rolling step in an air cooling mode, and the time for treating the slab in the air cooling mode is 8 to 15 s.

[0011] In some alternative embodiments, the thickness of the copper-containing steel sheet for stamping is 1.2 - 6.0 mm.

[0012] In some alternative embodiments, the heating step includes heating the slab at a temperature of 1040°C to 1080°C, and the heating time is 118 min to 128 min.

[0013] In some alternative embodiments, the rough rolling exit temperature is 910°C to 940°C, the finish rolling entry temperature is 830°C to 860°C, and the finish rolling exit temperature is 770°C to 800°C.

[0014] In some alternative embodiments, the slab includes the following chemical components by mass percentage: C: 0.003% to 0.10%, Si: 0.10% to 1.00%, Mn: 0.10% to 2.00%, A1: 0.01% to 0.50%, Cu: 0.3% to 1.0%, Ni ≤ 0.1%, P ≤ 0.1%, S ≤ 0.1%, and the balance is Fe and a small amount of inevitable impurity elements.

[0015] In a second aspect, the present disclosure provides a method for preparing a copper-containing steel sheet for stamping, which is obtained by the preparation method of the first aspect.

[0016] In some alternative embodiments, the mechanical properties of the copper-containing steel sheet for stamping meet the following: the tensile strength is 400 - 620 Mpa, the yield strength is 300 - 550 Mpa, and the elongation is 15% - 30%.

[0017] This application has at least the following beneficial effects: The hot rolling process of the embodiment of the present application uses low-temperature heating at 980°C to 1100°C, rough rolling at 880°C to 940°C, and finish rolling in the ferritic region with an entry temperature of 820°C to 870°C, which greatly reduces the energy consumption and roll consumption in the production process. At the same time, without adding nickel elements on the premise of not affecting the properties such as the impact toughness, corrosion resistance, and tensile strength of the product, the alloy cost is reduced, and the copper embrittlement crack defects in the production process are effectively eliminated. Description of the Drawings

[0018] To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the accompanying drawings required in the embodiments of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on the drawings without creative efforts.

[0019] Figure 1 Shows the test diagram of the on-line surface detector for the copper-containing steel plate in Embodiment 1

[0020] Figure 2 Shows the test diagram of the on-line surface detector for the copper-containing steel plate in Comparative Example 1. Detailed implementation manners

[0021] Hereinafter, the embodiments of the surfactant, its preparation method and application disclosed in the present disclosure will be specifically described in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where the detailed descriptions of well-known matters are omitted and the repeated descriptions of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily long and to facilitate the understanding of those skilled in the art. In addition, the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0022] The "range" disclosed in the present disclosure is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a specific range. The range defined in this way can include the end values or not include the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 - 120 and 80 - 110 are listed for a specific parameter, ranges of 60 - 110 and 80 - 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1 - 3, 1 - 4, 1 - 5, 2 - 3, 2 - 4, and 2 - 5. In the present disclosure, unless otherwise specified, the numerical range "a - b" represents the abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" have been fully listed herein, and "0 - 5" is only the abbreviated representation of these numerical combinations. Additionally, when stating that a certain parameter is an integer ≥2, it is equivalent to disclosing that the parameter is, for example, the integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure content of the present disclosure.

[0024] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure content of the present disclosure.

[0025] Unless otherwise specified, all steps of the present disclosure can be carried out sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) carried out sequentially, or may also include steps (b) and (a) carried out sequentially. For example, it is mentioned that the method may further include step (c), indicating that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or may also include steps (a), (c), and (b), or may also include steps (c), (a), and (b), etc.

[0026] Unless otherwise specified, in the present disclosure, terms such as "first", "second", etc. are used to distinguish different objects, rather than to describe a specific order or primary-secondary relationship.

[0027] The functions of copper in steel mainly include improving the strength, impact toughness, corrosion resistance and antibacterial properties of steel. The addition of copper can effectively improve the strength and impact toughness of steel, while enhancing its corrosion resistance and antibacterial properties. These characteristics enable copper-containing steel to be widely used in many fields, especially in weathering steel, high-strength steel and antibacterial steel. However, due to the relatively low melting point temperature of copper at 1083 °C, it is easy to accumulate in large amounts along the grain boundaries during the hot rolling process, resulting in copper embrittlement crack defects on the surface of the steel.

[0028] Copper embrittlement crack defects are likely to occur during the hot rolling process. The current common process is to inhibit the generation of copper embrittlement by adding nickel elements, which increases the production cost. Through research, it is found that by adopting the ferritic hot rolling process, on the basis of not adding nickel elements, the defects of easy brittleness and cracking of copper-containing steel plates can be effectively solved. At the same time, the energy consumption and roll consumption during the production process are reduced, and the surface quality and processing performance of the steel plates are improved.

[0029] In a first aspect, the present disclosure provides a method for preparing a copper-containing steel plate for stamping, the preparation method comprising:

[0030] Heating step, including heating the slab at a temperature of 980°C to 1100°C, and the heating time is 110 min to 130 min. Among them, the slab includes the following chemical components by mass percentage: C: 0.003% to 0.10%, Si: 0.10% to 1.00%, Mn: 0.10% to 2.00%, Al: 0.01% to 0.50%, Cu: 0.2% to 2.0%, Ni ≤ 0.1%, P ≤ 0.1%, S ≤ 0.1%, and the rest is Fe and a small amount of impurity elements inevitably generated.

[0031] Optionally, the temperature of the slab can be any temperature among 980°C, 990°C, 1000°C, 1010°C, 1020°C, 1030°C, 1040°C, 1050°C, 1060°C, 1070°C, 1080°C, 1090°C, 1100°C for heating. The heating time can be any time among 110 min, 115 min, 120 min, 125 min, 130 min.

[0032] In this step, heating the slab to a lower temperature level avoids subsequent rolling at the melting point temperature of copper. In this step, the initial thickness of the slab can be 190 to 230 mm.

[0033] Hot rolling step, including rough rolling and finish rolling. The rough rolling includes rolling the slab for 5 to 7 passes, and the rough rolling exit temperature is 880°C to 940°C. The finish rolling includes controlling the finish rolling entry temperature to be 820°C to 870°C and controlling the finish rolling exit temperature to be 760°C to 810°C.

[0034] In this step, the rough rolling exit temperature can be any value among 880°C, 890°C, 900°C, 910°C, 920°C, 930°C, 940°C. The finish rolling entry temperature can be any value among 820°C, 830°C, 840°C, 850°C, 860°C, 870°C. The finish rolling exit temperature can be any value among 760°C, 770°C, 780°C, 790°C, 800°C, 810°C.

[0035] In this step, austenite rolling is used for rough rolling and ferrite rolling is used for finish rolling. In this step, the thickness of the intermediate billet at the end of rough rolling is 25 to 40 mm. The reduction ratio of rough rolling is 80 to 90%. The finish rolling can be 5 to 7 passes.

[0036] The heating step and rough rolling adopted in the method of the embodiment of the present application effectively avoid the melting point temperature of copper, 1083°C, and prevent a large amount of copper from enriching along the grain boundaries to generate crack defects. The finish rolling temperature is the key temperature for ferrite rolling, which effectively reduces the rolling load of finish rolling.

[0037] In this embodiment, for the Cu element, when the content is 0.2% - 2.0%, through solution strengthening and subsequent precipitation of Cu particles, the atmospheric corrosion resistance is significantly improved; if Cu < 0.2%, the corrosion resistance is insufficient; if Cu > 2.0%, "copper embrittlement" defects are likely to occur during hot working, affecting the surface quality.

[0038] Coordinated control of C and Mn: When the C content is 0.003% - 0.10%, welding brittleness is avoided, and when the Mn content is 0.10% - 2.00%, it cooperates with Al to refine the grains and at the same time ensures the optimization of the texture after cold rolling and annealing. Under this composition system, after stamping, the hole expansion rate (λ≥1.8) of the steel plate meets the requirements of complex stamped parts.

[0039] According to the embodiment of the present application, the high - copper - content billet is heated to a relatively low temperature of 980°C - 1100°C and then sent to the rolling mill, so that the rolled piece completes the transformation from austenite to ferrite before entering the finish rolling, and the rough rolling and finish rolling processes are completely carried out within the ferrite temperature range to complete the finish rolling; therefore, the method of the embodiment of the present application utilizes the excellent effect of the copper element, adopts a composition design without adding nickel element, and through the hot - rolling process of low - temperature heating, low - temperature rough rolling, and finish rolling in the ferrite region, effectively solves the generation of copper - brittle crack defects in copper - containing steel. This preparation method can reduce the energy consumption during the heating process, the rolling force and roll consumption during the rolling process; it can also improve the stamping performance and surface quality of the copper - containing steel plate for stamping.

[0040] In some alternative embodiments, the heating step includes heating the billet at a temperature of 1040°C - 1080°C, and the heating time is 118 min - 128 min.

[0041] In some alternative embodiments, the rough - rolling exit temperature is 910°C to 940°C, the finish - rolling entry temperature is 830°C to 860°C, and the finish - rolling exit temperature is 770°C to 800°C.

[0042] When the heating temperature is 1040°C - 1080°C, through the gradient design of the rough - rolling exit temperature (910 - 940°C) and the finish - rolling entry temperature (830 - 860°C), combined with the control of the finish - rolling exit temperature (770 - 800°C), the balance between the dynamic recrystallization and the non - recrystallized zone is achieved, and the grain size is optimized.

[0043] In some alternative embodiments, the billet includes the following chemical components by mass percentage: C: 0.003% - 0.10%, Si: 0.10% - 1.00%, Mn: 0.10% - 2.00%, Al: 0.01% - 0.50%, Cu: 0.3% - 1.0%, Ni≤0.1%, P≤0.1%, S≤0.1%, and the rest is Fe and a small amount of impurity elements inevitably generated.

[0044] In some alternative embodiments, after the hot rolling step, the preparation method further includes: a coiling step, which includes coiling the slab that has undergone the hot rolling step to obtain the copper-containing steel sheet for stamping.

[0045] In some alternative embodiments, the coiling temperature is 680°C to 730°C. In this step, hot coiling is adopted. Optionally, the coiling temperature can be any value among 680°C, 690°C, 700°C, 710°C, 720°C, and 730°C.

[0046] The coiling temperature directly affects the grain structure and residual stress distribution of the steel sheet. If the temperature is lower than 680°C, it will cause excessive grain refinement, reduce the ductility of the material, and be unfavorable for subsequent stamping forming; if the temperature is higher than 730°C, the grains will coarsen, resulting in a decrease in strength and an increase in surface oxidation. By limiting the coiling temperature to 680°C to 730°C, appropriate toughness can be retained while ensuring fine grain strengthening, enabling the steel sheet to have both a high yield strength (≥350 MPa) and an elongation rate (≥25%), significantly improving the stamping forming qualification rate. Thus, the above coiling process is beneficial to the mechanical properties and processing performance of the copper-containing steel sheet for stamping.

[0047] In some alternative embodiments, before the coiling step, the preparation method further includes: cooling the slab that has undergone the hot rolling step in an air cooling mode, and the time for the air cooling mode to process the slab is 8 to 15 s. Exemplarily, the time for the air cooling mode to process the slab can be 8 s, 9 s, 10 s, 11 s, 12 s, 13 s, 14 s, 15 s, etc.

[0048] The air cooling time and the coiling temperature act synergistically to regulate the phase transformation process. If the air cooling time is less than 8 s, the cooling rate is too fast, and it is easy to form martensite hard phase, increasing the risk of stamping cracking; if it exceeds 15 s, the cooling is insufficient, resulting in the precipitation of grain boundary carbides, reducing the corrosion resistance and the mechanical properties of the steel sheet.

[0049] The air cooling time of 8 to 15 s matches the coiling temperature of 680°C to 730°C, which can inhibit the formation of harmful phases, make the microstructure of the steel sheet mainly ferrite (accounting for ≥85%), and at the same time uniformly distribute nano-scale Cu precipitation phases (size ≤50 nm), improving the corrosion resistance. Thus, controlling the time for the air cooling mode to process the slab is beneficial to the homogenization of ferrite during hot rolling, avoiding damage to the surface quality of the steel sheet, and also beneficial to the subsequent processing performance.

[0050] The above air cooling mode and coiling temperature are used to adjust the strength of the steel coil to facilitate the subsequent processing of the product.

[0051] In some alternative embodiments, the thickness of the copper-containing steel sheet for stamping is 1.2 - 6.0 mm. Optionally, the thickness of the copper-containing steel sheet for stamping can be any value among 1.0 mm, 2.0 mm, 3.0 mm, 4.0 mm, 5.0 mm, 6.0 mm or a range composed of them.

[0052] In a second aspect, the present disclosure provides a copper-containing steel sheet for stamping, which is obtained by the preparation method of the first aspect.

[0053] In some alternative embodiments, the mechanical properties of the copper-containing steel sheet for stamping satisfy: the tensile strength is 400 - 620 Mpa, the yield strength is 300 - 550 Mpa, and the elongation is 15% - 30%.

[0054] Embodiment

[0055] The following embodiments more specifically describe the content disclosed in the present disclosure. These embodiments are only for illustrative purposes, because various modifications and changes within the scope of the disclosed content of the present disclosure are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized according to conventional methods and can be used directly without further treatment, and all instruments used in the embodiments are commercially available.

[0056] Example 1

[0057] The present disclosure provides a preparation method of a copper-containing steel sheet for stamping, and the preparation method includes:

[0058] Prepare a casting blank according to the chemical components set in Table 1. The chemical components of the casting blank are C, Si, Mn, Cr, Al, and the rest are Fe and inevitable impurities. Specifically as shown in Table 1, and heat, rough roll, finish roll, and coiling the casting blank.

[0059] Table 1 Chemical components of the casting blank

[0060]

[0061] The specific procedures are as follows:

[0062] 1) Heating: The continuous casting slab has a thickness of 210 mm, and is heated in a heating furnace at a temperature of 1040 °C for 118 minutes;

[0063] 2) Rough rolling: The rough rolling process is carried out for 7 passes, the thickness of the intermediate billet is 36 mm, and the rough rolling exit temperature is 910 °C;

[0064] 3) Finish rolling: Finish rolling for 7 passes, the finish rolling entry temperature is 830 °C, and the finish rolling exit temperature is 770 °C;

[0065] 4) Coiling: Before coiling, the laminar cold rolling is carried out without water, and the air cooling mode is adopted. The time for treating the continuous casting billet in the air cooling mode is 10 s, the coiling temperature is 680 °C, and the thickness of the hot rolled steel coil is 2.5 mm.

[0066] Example 2

[0067] The difference between this example and Example 1 is as follows:

[0068] 1) Heating: The thickness of the continuous casting slab is 210 mm, the heating temperature in the heating furnace is 1080 °C, and the heating time is 118 minutes;

[0069] 2) Rough rolling: The rough rolling process is carried out for 7 passes, the thickness of the intermediate billet is 36 mm, and the rough rolling exit temperature is 940 °C;

[0070] 3) Finish rolling: The finish rolling is carried out for 7 passes, the finish rolling inlet temperature is 860 °C, and the finish rolling exit temperature is 800 °C;

[0071] 4) Coiling: Before coiling, the laminar cold rolling is carried out without water, and the air cooling mode is adopted. The time for treating the continuous casting billet in the air cooling mode is 15 s. The coiling temperature is 730 °C, and the thickness of the hot rolled steel coil is 4.5 mm.

[0072] Example 3

[0073] The difference between this example and Example 1 is that the mass content of Cu element in the continuous casting billet is different, and the mass content of Cu element is 2.2%.

[0074] Example 4

[0075] The difference between this example and Example 1 is that the mass content of Cu element in the continuous casting billet is different, and the mass content of Cu element is 0.22%.

[0076] Example 5

[0077] The difference between this example and Example 1 is as follows:

[0078] 1) Heating: The thickness of the continuous casting slab is 210 mm, the heating temperature in the heating furnace is 1080 °C, and the heating time is 128 minutes;

[0079] 2) Rough rolling: The rough rolling process is carried out for 7 passes, the thickness of the intermediate billet is 36 mm, and the rough rolling exit temperature is 1120 °C;

[0080] 3) Finish rolling: The finish rolling is carried out for 7 passes, the finish rolling inlet temperature is 1020 °C, and the finish rolling exit temperature is 890 °C;

[0081] 4) Coiling: After the laminar cold rolling before coiling, the post-section cooling mode is adopted, that is, direct cooling with cold water is used. The coiling temperature is 640 °C, and the thickness of the hot rolled steel coil is 4.5 mm.

[0082] Comparative Example 1

[0083] The differences between this comparative example and Example 1 are as follows:

[0084] 1) Heating: The thickness of the continuous casting slab is 210 mm, the heating temperature in the heating furnace is 1250 °C, and the heating time is 128 minutes;

[0085] 2) Rough rolling: The rough rolling process is carried out for 7 passes, the thickness of the intermediate billet is 36 mm, and the rough rolling exit temperature is 1120 °C;

[0086] 3) Finish rolling: Finish rolling for 7 passes, the finish rolling entry temperature is 1020 °C, and the finish rolling exit temperature is 890 °C;

[0087] 4) Coiling: The post-zone cooling mode is adopted for the laminar cold rolling before coiling, that is, directly cooled with cold water, the coiling temperature is 640 °C, and the thickness of the hot-rolled steel coil is 4.5 mm.

[0088] Comparative Example 2

[0089] The differences between this comparative example and Example 1 are as follows: Ni element is added to the cast billet, the mass content of Cu element is 0.35%, and the mass content of Ni element is 0.26%.

[0090] 1) Heating: The thickness of the continuous casting slab is 210 mm, the heating temperature in the heating furnace is 1200 °C, and the heating time is 128 minutes;

[0091] 2) Rough rolling: The rough rolling process is carried out for 7 passes, the thickness of the intermediate billet is 36 mm, and the rough rolling exit temperature is 1100 °C;

[0092] 3) Finish rolling: Finish rolling for 7 passes, the finish rolling entry temperature is 1020 °C, and the finish rolling exit temperature is 890 °C;

[0093] 4) Coiling: The post-zone cooling mode is adopted for the laminar cold rolling before coiling, that is, directly cooled with cold water, the coiling temperature is 640 °C, and the thickness of the hot-rolled steel coil is 4.5 mm.

[0094] Comparative Example 3

[0095] The differences between this comparative example and Example 1 are as follows: Ni element is added to the cast billet, the mass content of Cu element is 2.18%, and the mass content of Ni element is 1.92%.

[0096] 1) Heating: The thickness of the continuous casting slab is 210 mm, the heating temperature in the heating furnace is 1250 °C, and the heating time is 128 minutes;

[0097] 2) Rough rolling: The rough rolling process is carried out for 7 passes, the thickness of the intermediate billet is 36 mm, and the rough rolling exit temperature is 1120 °C;

[0098] 3) Finish rolling: 7 passes of finish rolling, the entry temperature of finish rolling is 1020 °C, and the exit temperature of finish rolling is 890 °C;

[0099] 4) Coiling: The laminar cold rolling before coiling adopts the post-section cooling mode, the coiling temperature is 640 °C, and the thickness of the hot-rolled steel coil is 4.5 mm.

[0100] Performance test

[0101] (1) Surface quality test of copper-containing steel sheet for stamping: The surface quality is tested by an on-line surface detector.

[0102] (2) Mechanical property test of copper-containing steel sheet for stamping: According to GB / T228.1-2010 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature", the steel sheets of the examples or comparative examples are sampled accordingly, and a tensile test is carried out using a tensile testing machine. The displacement speed is 2 mm / min, and test data such as the tensile strength, yield limit, and elongation rate of the material are obtained by computer drawing to obtain the test results.

[0103] The test results are shown in Table 2.

[0104] Table 2

[0105]

[0106]

[0107] It can be seen from the test results of Examples 1 to 4 and Comparative Examples 1-2 that by adopting a hot rolling process with low-temperature heating at 980 °C to 1100 °C, rough rolling at 880 °C to 940 °C, and finish rolling in the ferritic region with an entry temperature of 820 °C to 870 °C, the energy consumption and roll consumption in the production process are significantly reduced. At the same time, without adding nickel elements, the alloy cost is reduced on the premise of not affecting the properties such as the impact toughness, corrosion resistance, and tensile strength of the product, and the copper brittle crack defects in the production process are effectively eliminated.

[0108] Figure 1 The on-line surface detector test diagram of the copper-containing steel sheet of Example 1 is shown, and its surface has no cracks and its mechanical properties are better. Figure 2 The on-line surface detector test diagram of the copper-containing steel sheet of Comparative Example 1 is shown, and its surface has cracks and the product quality is unqualified.

[0109] Comparative Examples 2-3 adopted a conventional process of adding nickel elements. Compared with Examples 1-5, the temperature is higher and the energy consumption is larger in processes such as heating.

[0110] Calculated at a copper price of 60,000 yuan per ton, the copper addition cost per ton of steel is 180 - 600 yuan per ton.

[0111] (0.3% - 1.0%). Process additional cost: Copper is prone to "copper embrittlement" during hot processing, and temperature control or coating processes need to be added. The additional cost is about 200 - 500 yuan / ton. Even adding 0.1% nickel increases the cost by about 140 yuan / ton; if the nickel content reaches 0.5%, the cost increase can exceed 700 yuan / ton.

[0112] It can be seen from this that the cost per ton of steel of the steel plate containing nickel element prepared by the prior art, i.e., Comparative Examples 2 - 3, increases by 364 to 2688 yuan compared with the steel plate prepared in Examples 1 - 5.

[0113] It should be noted that the present disclosure is not limited to the above embodiments. The above embodiments are only examples, and embodiments having the same structure in essence as the technical idea and achieving the same effect within the scope of the technical solution of the present disclosure are all included in the technical scope of the present disclosure. In addition, within the scope not departing from the gist of the present disclosure, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways constructed by combining some constituent elements in the embodiments are also included in the scope of the present disclosure.

Claims

1. A method for preparing a copper-containing steel plate for stamping, characterized in that: The preparation method comprises: The heating step comprises heating the ingot at a temperature of 980° C. to 1100° C. for a heating time of 110 min to 130 min, wherein the ingot comprises the following chemical components by mass percentage: C: 0.003% to 0.10%, Si: 0.10% to 1.00%, Mn: 0.10% to 2.00%, A1: 0.01% to 0.50%, Cu: 0.2% to 2.0%, Ni≤0.1%, P≤0.1%, S≤0.1%, and the rest is Fe and a small amount of impurity elements that are inevitably produced; The hot rolling step includes rough rolling and finish rolling. The rough rolling includes rolling the ingot for 5 to 7 passes. The outlet temperature of the rough rolling is 880°C to 940°C. The finish rolling includes controlling the inlet temperature of the finish rolling to 820°C to 870°C and the outlet temperature of the finish rolling to 760°C to 810°C.

2. The preparation method according to claim 1, characterized in that: After the hot rolling step, the preparation method further includes: a coiling step, including coiling the ingot after the hot rolling step to obtain the copper-containing steel plate for stamping.

3. The preparation method according to claim 2, characterized in that: The coiling temperature is 680°C to 730°C.

4. The preparation method according to claim 2 or 3, characterized in that: Before the coiling step, the preparation method further comprises: cooling the ingot after the hot rolling step in an air cooling mode, and the time for treating the ingot in the air cooling mode is 8 to 15 seconds.

5. The preparation method according to any one of claims 1 to 3, characterized in that: The thickness of the copper-containing steel plate for stamping is 1.2-6.0 mm.

6. The preparation method according to any one of claims 1 to 3, characterized in that: The heating step comprises heating the ingot at a temperature of 1040° C. to 1080° C., and the heating time is 118 min to 128 min.

7. The preparation method according to any one of claims 1 to 3, characterized in that: The rough rolling outlet temperature is 910°C to 940°C, the finishing rolling inlet temperature is 830°C to 860°C, and the finishing rolling outlet temperature is 770°C to 800°C.

8. The preparation method according to any one of claims 1 to 3, characterized in that: The ingot includes the following chemical components by mass percentage: C: 0.003% to 0.10%, Si: 0.10%~1.00%, Mn: 0.10%~2.00%, A1: 0.01%~0.50%, Cu: 0.3%~1.0%, Ni≤0.1%, P≤0.1%, S≤0.1%, and the rest are Fe and a small amount of impurity elements that are inevitably produced.

9. A copper-containing steel sheet for stamping, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 8.

10. The copper-containing steel sheet for stamping according to claim 9, characterized in that: The mechanical properties of the copper-containing steel plate for stamping meet the following requirements: tensile strength of 400-620 MPa, yield strength of 300-550 MPa, and elongation of 15%-30%.

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