Production method of steel plate for container plate and steel plate

Abstract

The invention provides a production method of a steel plate for a container plate and the steel plate, and the production method comprises the following steps: heating a plate blank to 1235-1275 DEG C to obtain a heated plate blank; wherein the plate blank comprises the Cu element with the mass content of 0.25%-0.3%, the heating treatment comprises a secondary heating section, and the time of solution treatment of the secondary heating section under the condition that the temperature is higher than 1200 DEG C is 25-45 min; rolling the heated plate blank to obtain a rolled plate; and the rolled plate is cooled and coiled, so that the steel plate is obtained, and the coiling temperature is 602-648 DEG C. The surface quality of the steel plate produced by the production method is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of steel manufacturing, and in particular relates to a production method and a steel plate for container plates. Background Art

[0002] The market demand for container boards has shown a strong growth trend, and the performance requirements for container boards have also increased. In particular, with the rapid development of emerging fields such as cross-border e-commerce and cold chain logistics, the demand for flexibility and customization of containers has continued to increase, further promoting the expansion of the container board market.

[0003] In the related art, there are many surface cracks on the steel plates used for container plates, which affect the surface quality of the steel plates and reduce the yield rate of the steel plates, so improvements are needed. Summary of the invention

[0004] The embodiments of the present application provide a production method of a steel plate for a container plate and a steel plate, so as to improve the surface quality of the steel plate for a container plate.

[0005] In a first aspect, an embodiment of the present application provides a method for producing a steel plate for a container plate, comprising:

[0006] The slab is heated to 1235 to 1275° C. to obtain a heated slab; wherein the slab includes a Cu element with a mass content of 0.25% to 0.3%, and the heating treatment includes a second heating stage, and the second heating stage is a solution treatment at a temperature greater than 1200° C. for 25 to 45 minutes;

[0007] rolling the heated slab to obtain a rolled plate;

[0008] The rolled plate is cooled and coiled to obtain a steel plate, wherein the coiling temperature is 602 to 648°C.

[0009] In some optional embodiments, the slab includes the following chemical elements in mass percentage: 0.06% to 0.095% C, 0.25% to 0.3% Cu, 0.3% to 0.4% Si, 0.38% to 0.5% Cr, 0.58%-0.75% Mn, and the balance is Fe and unavoidable impurity elements.

[0010] In some optional embodiments, the heating process further includes a recovery preheating section, a heating section and a soaking section in sequence, and the second heating section is located between the first heating section and the soaking section.

[0011] In some optional embodiments, the furnace atmosphere temperature of the recovery preheating section is 1050±50°C, and the slab temperature is 900±70°C.

[0012] In some alternative embodiments, the furnace atmosphere temperature in the first heating section is 1170 ± 30 °C, and the slab temperature is 1150 ± 30 °C.

[0013] In some alternative embodiments, the furnace atmosphere temperature in the second heating section is 1230 ± 30 °C, and the slab temperature is 1200 ± 20 °C.

[0014] In some alternative embodiments, the furnace atmosphere temperature in the soaking section is 1270 ± 20 °C, and the slab temperature is 1255 ± 20 °C.

[0015] In some alternative embodiments, the total in-furnace time of the heating treatment is 150 to 300 min, and the end temperature of the heating treatment is 1255 ± 20 °C.

[0016] In some alternative embodiments, rolling includes finish rolling, and the method further includes:

[0017] Adjusting the finish rolling force of the slab according to the deformation resistance and the calculation formula, where the calculation formula is as shown in Equation (1):

[0018] Rf Cal (i) = Fw Cal ·Km Cal (i)·Ld Cal (i)·Qp Cal (i) / 1000 Equation (1)

[0019] Where: Rf Cal (i) represents the finish rolling force, with the unit of kN;

[0020] Fw Cal represents the average width of the finish rolling slab, with the unit of kmm;

[0021] Km Cal (i) represents the deformation resistance, with the unit of kN / mm 2 ;

[0022] Ld Cal (i) represents the contact arc length between the roll and the slab, with the unit of kmm;

[0023] Qp Cal (i) represents the rolling force function, and the rolling force calculation function is as shown in the following formula:

[0024]

[0025] Where,

[0026] RdCal(i) represents the flat roll radius of the current stand, with the unit of mm;

[0027] HCal(i) represents the exit thickness of the current stand, with the unit of mm.

[0028] In some optional embodiments, in formula (1), Km Cal (i) is calculated by the following formula:

[0029]

[0030] n = 0.41 - 0.07·Cnt Pdi (1);

[0031]

[0032] m = {-0.019·Cnt Pdi (1) + 0.126}·t + {0.075·Cnt Pdi (1) - 0.050};

[0033]

[0034] t s = t + (t d - t)·0.7;

[0035]

[0036] wherein, Km Cal (i) represents the deformation resistance of the i-th stand, with the unit of kN / mm 2 ;

[0037] Akm Lay (j) represents the deformation resistance parameter for the j-th chemical composition; Cnt Pdi (j) represents the mass content of the j-th chemical composition;

[0038] t represents the temperature of the steel plate, with the unit of °C;

[0039] td represents the recrystallization transformation temperature of the steel grade, with the unit of °C;

[0040] σ f represents the conversion compensation factor;

[0041] g represents the deformation gain factor;

[0042] Str Cal (i) represents the strain rate of the i-th stand, with the unit of 1 / s;

[0043] St Cal (i) represents the strain of the i-th stand;

[0044] Lcr Cal (i) represents the rolling force learning coefficient of a certain stand;

[0045] n represents the strain factor exponent;

[0046] i represents the stand number;

[0047] j represents the chemical composition;

[0048] N represents the chemical composition number.

[0049] In some alternative embodiments, rolling is performed using seven stands F1 - F7 and a thickness reduction distribution mode, and the method further includes:

[0050] Adjust the reduction rate of a single stand according to Equation (2):

[0051]

[0052] Rr Cal represents the reduction rate; H Cal (i) represents the exit thickness of the current i - th stand, in mm; In some alternative embodiments, the method further includes:

[0053] Adjust the forward slip rate of a single stand according to Equation (3):

[0054]

[0055] where, Fs Cal represents the forward slip rate; Afs Lay represents the forward slip rate model parameter of the finish rolling of the 1580 - line hot continuous rolling; Rr Cal represents the reduction rate; H Cal (i) represents the exit thickness of the current i - th stand, in mm; H Cal (0) = Feh Cal, H Cal (7) = Fdh Cal ; R Hmi (i) represents the roll radius, in mm; Lcf Cal represents the built - in coefficient of forward slip rate self - learning.

[0056] In some alternative embodiments, the thickness of the steel plate ≤ 6 mm; the yield strength of the steel plate is 550 - 650 MPa, and the tensile strength is 600 - 700 MPa.

[0057] In a second aspect, an embodiment of the present application provides a steel plate for container plates, which is prepared by the method of the first aspect.

[0058] In the production method of the steel plate according to the embodiment of the present application, the solution treatment time of the second heating stage at a temperature greater than 1200°C is 25 - 45 min. On the one hand, the copper content in the slab is relatively high, and it is not suitable to store it at high temperature in the heating furnace for a long time to avoid the surface enrichment of copper, which may cause surface cracks on the steel plate. On the other hand, the solution treatment time being greater than or equal to 25 min is beneficial to the grain refinement of the slab and is conducive to improving the surface quality of the steel plate during the subsequent rolling and coiling processes. Therefore, by adopting appropriate heating treatment and coiling temperature, the surface cracks of the steel plate after coiling can be reduced, and the surface quality of the steel plate can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0060] Figure 1 It is a schematic flow chart of the production method of the steel plate for container plates provided by an embodiment of the present application;

[0061] Figure 2 It shows a schematic diagram of the production process flow of the 1580 production line of Lianyuan Steel in the embodiment of the present application.

[0062] Description of the reference numerals:

[0063] 1. Slab; 2. Heating furnace; 3. Rough rolling descaling machine; 4. Two-high reversing rough rolling mill; 5. Four-high reversing rough rolling mill; 6. Crop flying shear device; 7. Finish rolling descaling machine; 8. Vertical roll of finish rolling mill; 9. Seven-stand finish rolling mill; 10. Cooling; 11. Coiling. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0064] The following will describe in detail the features and exemplary embodiments of various aspects of the present application. In order to make the purpose, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present application, rather than to limit the present application. For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only intended to provide a better understanding of the present application by showing examples of the present application.

[0065] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0066] The steel for thin-specification container plates is widely used in container plates. However, in the production process, the steel for thin-specification container plates has the advantage of light weight, but pits and cracks on the steel plate surface affect the surface quality of the steel plate and subsequent painting and aesthetics. Therefore, after heat treatment, the steel plate should ensure both high mechanical properties and high surface quality.

[0067] To solve the problems of the prior art, the embodiments of the present application provide a production method and a steel plate for a steel plate used for container plates. First, the pickling method of the strip steel provided by the embodiments of the present application will be introduced below.

[0068] Figure 1 The flowchart of the production method of the steel plate for container plates provided by an embodiment of the present application is shown. As Figure 1 shown, the embodiments of the present application provide a production method for a steel plate used for container plates, which may include the following steps: Step 100 to Step 300.

[0069] The specific implementation manners of each step will be described in detail below.

[0070] Step 1, heat-treat the slab to 1235 to 1275 °C to obtain a heated slab; wherein, the slab includes 0.25% to 0.3% by mass of Cu element, and the heat treatment includes two heating segments, and the solution treatment time of the two heating segments at a temperature greater than 1200 °C is 25 - 45 min.

[0071] In this step, when the copper content in the slab is within the above range, such steel plates should not be stored at high temperature in the heating furnace for a long time to avoid the surface enrichment of copper, which may cause cracks on the steel plate surface. Once a breakdown occurs and rolling stops, if the stoppage time is expected to exceed 20 minutes, it will more seriously affect the surface quality and production efficiency of the steel plate. Therefore, the solution treatment time of the second heating section at a temperature higher than 1200 °C is 25 - 45 min. On the one hand, it can refine the grains in the steel plate and reduce surface cracking during subsequent rolling and coiling; on the other hand, it can avoid surface enrichment of copper and reduce cracks on the steel plate surface.

[0072] In some alternative embodiments, the slab comprises the following chemical elements by mass percentage: 0.06% to 0.095% C, 0.25% to 0.3% Cu, 0.3% to 0.4% Si, 0.38% to 0.5% Cr, 0.58% - 0.75% Mn, with the balance being iron and inevitable impurity elements.

[0073] Step 2: Roll the heated slab to obtain a rolled plate.

[0074] In some alternative embodiments, the heated slab is rolled under the condition of a reducing atmosphere in the furnace to obtain a rolled plate.

[0075] In this step, rolling may include rough rolling and finish rolling. The rough rolling may pass through one pass of R1 and five passes of R2. For example, the heated slab can be rolled into an intermediate slab with a thickness of 32 mm after rough rolling.

[0076] During the rolling process, rolling oil can be turned on, and loop height adjustment can be performed through the loop. The thickness of the finished rolled steel plate can be less than 6 mm, such as 2.2 mm. The width of the finished rolled steel plate can be 500 to 1300 mm, such as 900 mm.

[0077] Step 3: Cool and coil the rolled plate to obtain a steel plate, where the coiling temperature is 602 to 648 °C.

[0078] In some alternative embodiments, the cooling includes: the cooling rate of 1 - 10 groups of cooling headers is approximately 1.5 °C per square unit; the cooling rate of 11 - 20 groups of cooling headers is approximately 6.5 °C per square unit.

[0079] In this step, post-section centralized cooling mode can be adopted for cooling.

[0080] In this step, surface cracking of the rolled plate may occur during coiling. Therefore, on the basis of refining grains in the early stage, adjusting the appropriate coiling temperature can further reduce surface cracking caused by coiling and further improve the surface quality.

[0081] The coiling temperature can be any value among 602°C, 603°C, 604°C, 605°C, 606°C, 607°C, 608°C, 609°C, 610°C, 615°C, 620°C, 625°C, 630°C, 635°C, 640°C, 641°C, 642°C, 643°C, 644°C, 645°C, 646°C, 647°C, 648°C.

[0082] According to the production method of the embodiments of the present application, the steel plate can be a copper-containing steel, such as LGC550 copper-containing steel and LGC450 copper-containing steel.

[0083] Figure 2 The schematic diagram of the production process flow of the 1580 line of Liugang in the embodiments of the present application is shown. As Figure 2 shown, the production method of the steel plate for container plates can be carried out using a 1580 production line. 1. The slab 1 is heated in the heating furnace 2, and then rolling is carried out. The rolling includes rough rolling and finish rolling. In rough rolling, the scale on the surface of the slab can be removed first by the rough rolling descaling machine 3, and then the rough rolling is carried out using the two-high reversing roughing mill 4 and the four-high reversing roughing mill 5. After the rough rolling process, the head and tail of the slab or the parts with seriously unqualified quality can be removed by using the crop flying shear device 6. In finish rolling, the scale generated or remaining in the previous process can be removed by the finish rolling descaling machine 7. For example, the pressure of finish rolling descaling can be ≥22 Mpa; then the finish rolling is carried out using the vertical rolls 8 of the finish rolling mill and the seven-stand finish rolling mill 9, and then cooling 10 and coiling 11 are carried out to obtain the finished steel plate. The steel plate can be stored in the form of a steel coil.

[0084] In some alternative embodiments, in step 100, the heating treatment further sequentially includes a recovery preheating section, a first heating section, and a soaking section, and the second heating section is located between the first heating section and the soaking section.

[0085] In some alternative embodiments, in step 100, the furnace atmosphere temperature of the recovery preheating section is 1050 ± 50°C, and the slab temperature is 900 ± 70°C. In the initial stage of the heating treatment, when the furnace atmosphere temperature of the recovery preheating section is within the above range, the surface and internal temperatures of the slab can be gradually increased, and the temperature difference between the furnace atmosphere temperature and the slab can be reduced. This helps to reduce the risk of cracks generated in the slab due to excessive thermal stress during subsequent heating.

[0086] In some alternative embodiments, in step 100, the furnace atmosphere temperature of the first heating section is 1170 ± 30°C, and the slab temperature is 1150 ± 30°C. The slab is rapidly heated to a certain temperature range. By precisely controlling the furnace atmosphere temperature and the heating rate of the slab, the internal structure of the slab can begin to change, preparing for subsequent further heating and rolling, and can promote the uniform growth of grains inside the slab and reduce the tissue inhomogeneity.

[0087] In some alternative embodiments, in step 100, the furnace atmosphere temperature in the two-step heating section is 1230 ± 30 °C, and the slab temperature is 1200 ± 20 °C. The furnace atmosphere temperature and the slab temperature in the two-step heating section can further refine the grains inside the slab. The fine grain structure can significantly improve the strength, hardness, and toughness of the steel plate; it can also eliminate these stresses to a certain extent, avoid the adverse effects of stress concentration on the performance of the steel plate, and improve the quality of the steel plate.

[0088] In some alternative embodiments, in step 100, the furnace atmosphere temperature in the soaking section is 1270 ± 20 °C, and the slab temperature is 1255 ± 20 °C. By controlling the furnace atmosphere temperature and the slab temperature, it is ensured that the temperature difference between different parts of the slab is within a very small range, guaranteeing uniform deformation of the steel plate during rolling, enabling sufficient tissue transformation inside the slab, and improving the dimensional accuracy and mechanical property uniformity of the steel plate.

[0089] In some alternative embodiments, in step 100, the total in-furnace time for the heat treatment is 150 to 300 min, and the end temperature of the heat treatment is 1255 ± 20 °C.

[0090] In some alternative embodiments, in step 200, when the thickness h of the steel plate ≤ 3 mm, the end temperature of finish rolling is 875 to 915 °C; when the thickness h of the steel plate: 3 mm < h ≤ 4 mm, the end temperature of finish rolling is 880 ± 15 °C; when the thickness h of the steel plate: 4 mm < h ≤ 6 mm, the end temperature of finish rolling is 870 ± 15 °C.

[0091] The heat dissipation of steel plates with different thicknesses is different during rolling. Thinner steel plates dissipate heat quickly, and the temperature drops rapidly during finish rolling; thicker steel plates dissipate heat relatively slowly. Determining the end temperature of finish rolling according to the final thickness of the steel plate can enable the steel plate to be rolled within a suitable temperature range, promote the recrystallization of austenite grains, and obtain a uniform and fine grain structure. Thus, by using the above-mentioned end temperatures of finish rolling corresponding to the thickness, defects such as cracks on the steel plate surface and scale pressing-in can be avoided.

[0092] In some alternative embodiments, step 200 specifically includes: The rolling includes finish rolling, and the method further includes:

[0093] Step 400, adjusting the finish rolling force on the slab according to the deformation resistance and the calculation formula, where the calculation formula is as shown in Equation (1):

[0094] Rf Cal (i) = Fw Cal ·Km Cal (i)·Ld Cal (i)·Qp Cal (i) / 1000 Equation (1)

[0095] Where: RfCal (i) represents the finish rolling force, with the unit of kN;

[0096] Fw Cal represents the average width of finish rolling, with the unit of kmm;

[0097] Km Cal (i) represents the deformation resistance, with the unit of kN / mm 2 ;

[0098] Ld Cal (i) represents the contact arc length, with the unit of kmm;

[0099] Qp Cal (i) represents the rolling force function, and the rolling force calculation function is shown in the following formula:

[0100]

[0101] where RdCal(i) represents the flat roll radius of the current stand, with the unit of mm; HCal(i) represents the exit thickness of the current stand, with the unit of mm.

[0102] According to the embodiments of the present application, the finish rolling force of the slab is adjusted according to the deformation resistance and the calculation formula.

[0103] In some alternative embodiments, in formula (1), Km Cal (i) is calculated by the following formula:

[0104]

[0105] n = 0.41 - 0.07·Cnt Pdi (1)

[0106]

[0107] m = {-0.019·Cnt Pdi (1) + 0.126}·t + {0.075·Cnt Pdi (1) - 0.050}

[0108]

[0109] t s = t + (t d - t)·0.7

[0110]

[0111] where Km Cal (i) represents the deformation resistance of the i-th stand, with the unit of kN / mm 2 ;

[0112] Akm Lay (j) represents the deformation resistance parameter for j chemical components; Cnt Pdi (j) represents the mass content of j chemical components;

[0113] t represents the temperature of the steel plate, in °C;

[0114] td represents the recrystallization transformation temperature of the steel grade, in °C;

[0115] σ f represents the conversion compensation factor;

[0116] g represents the deformation gain factor;

[0117] Str Cal (i) represents the strain rate of the i-th stand, in 1 / sec;

[0118] St Cal (i) represents the strain of the i-th stand;

[0119] Lcr Cal (i) represents the rolling force learning coefficient of a certain stand;

[0120] n represents the strain factor exponent;

[0121] i represents the stand number;

[0122] j represents the chemical component, (j = 1: carbon);

[0123] N represents the chemical component number.

[0124] In some alternative embodiments, rolling is performed using seven stands F1 - F7 and a thickness reduction distribution mode, and the method further includes:

[0125] Step 410, adjusting the single-stand reduction ratio according to Equation (2):

[0126]

[0127] Rr Cal represents the reduction ratio; H Cal (i) represents the exit thickness of the current i-th stand, in mm;

[0128] In some alternative embodiments, the method further includes:

[0129] Step 420, adjusting the single-stand forward slip rate according to Equation (3):

[0130]

[0131] where, Fs Cal represents the forward slip rate; AfsLay Represents the front slip rate model parameters of the finish rolling section of the 1580 hot continuous rolling line; Rr Cal Represents the reduction ratio; H Cal (i) represents the exit thickness of the current i-th stand, in mm; H Cal (0) = Feh Cal, H Cal (7) = Fdh Cal ; R Hmi (i) represents the roll radius, in mm; Lcf Cal Represents the built-in coefficient of front slip rate self-learning.

[0132] In a second aspect, an embodiment of the present application provides a steel plate for container boards, which is prepared by the method of the first aspect.

[0133] In some alternative embodiments, the thickness of the steel plate ≤ 6 mm; the yield strength of the steel plate is 550 to 650 MPa, and the tensile strength is 600 to 700 MPa.

[0134] Embodiment

[0135] The following describes the embodiments of the present application. The embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those not specified in the embodiments regarding specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in the field or according to the product instructions. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchases.

[0136] Embodiment 1

[0137] This embodiment provides a production method for a steel plate for container boards, including the following steps:

[0138] Heat the slab in the heating furnace to 1255 °C, ensure that the temperature in the second heating and discharging section is greater than 1200 °C, and the solution time is 28 minutes. The slab includes 0.085% C, 0.28% Cu, 0.35% Si, 0.45% Cr, 0.65% Mn by mass, and the balance is iron and inevitable impurity elements.

[0139] Roll the heated slab. After rolling through one pass of rough rolling R1 + five passes of R2, roll it into an intermediate slab with an intermediate slab thickness of 32 mm.

[0140] Through seven stands of finish rolling F1 - F7, adjust the opening of the rolling oil and the loop formation, and roll the finished product to a thickness of 2.2 mm.

[0141] After passing through the post-section centralized cooling mode, control the coiling temperature CT to 630 °C, and coil it with a coiler to obtain a 2.2 mm high-strength container coil that meets the performance requirements.

[0142] Since the rolling force of this steel grade is significantly different from that of ordinary plates, the finishing rolling force is checked according to the deformation resistance calculation formula. As mentioned above, the finishing rolling force of the slab is adjusted according to the deformation resistance and the calculation formula. Among them, the calculation formula is shown in Equation (1):

[0143] Rf Cal (i) = Fw Cal ·Km Cal (i)·Ld Cal (i)·Qp Cal (i) / 1000 Equation (1)

[0144] Among them: Rf Cal (i) represents the finishing rolling force, with the unit of kN;

[0145] Fw Cal represents the average finishing width, with the unit of kmm;

[0146] Km Cal (i) represents the deformation resistance, with the unit of kN / mm 2 ;

[0147] Ld Cal (i) represents the contact arc length, with the unit of kmm;

[0148] Qp Cal (i) represents the rolling force function, and the rolling force calculation function is shown in the following formula:

[0149]

[0150] Among them, RdCal(i) represents the flat roll radius of the current stand, with the unit of mm; HCal(i) represents the exit thickness of the current stand, with the unit of mm;

[0151] Adjust the front slip rate of a single stand according to Equation (3):

[0152]

[0153] Among them, Fs Cal represents the front slip rate; Afs Lay represents the front slip rate model parameter of the finishing mill of the 1580 hot strip mill; Rr Cal represents the reduction ratio; H Cal (i) represents the exit thickness of the current i-th stand, with the unit of mm; H Cal (0) = Feh Cal ,H Cal (7) = Fdh Cal ; R Hmi (i) represents the roll radius, with the unit of mm; Lcf CalIndicates the built-in coefficient of forward slip self-learning.

[0154] Example 2

[0155] The difference between this example and Example 1 is as follows: For this steel grade, the rolling force is the same as that of ordinary steel plates. When the thickness of the intermediate billet is 32 mm, the relative reduction ratios of the F1-F7 rolling mills are set at 42%, 38%, 33%, 27%, 20%, 16%, and 10% respectively. At the same time, the roll gap is preset in a way that decreases proportionally from F1 to F7.

[0156] Example 3

[0157] The difference between this example and Example 1 is that the coiling temperature is 635 degrees Celsius.

[0158] Example 4

[0159] The difference between this example and Example 1 is that the coiling temperature is 628 degrees Celsius.

[0160] Example 5

[0161] The difference between this example and Example 1 is to ensure that the temperature in the second plus out section is greater than 1200 °C and the solution time is 26 minutes. The mass content of the Cu element is 0.22%.

[0162] Example 6

[0163] The difference between this example and Example 1 is to ensure that the temperature in the second plus out section is greater than 1200 °C and the solution time is 35 minutes. The mass content of the Cu element is 0.32%.

[0164] Comparative Example 1

[0165] The difference between this comparative example and Example 1 is that the solution time when the temperature in the second plus out section is greater than 1200 °C is 20 minutes.

[0166] Comparative Example 2

[0167] The difference between this comparative example and Example 1 is that the solution time when the temperature in the second plus out section is greater than 1200 °C is 20 minutes, and the coiling temperature is 608 degrees Celsius.

[0168] Performance detection

[0169] The finished steel plates prepared in the examples and comparative examples were tested according to the method of GB14977 national standard, and the results of measuring the mechanical properties of the steel plates are shown in Table 1. 550 - 650 600 - 700

[0170] Table 1

[0171]

[0172]

[0173] It should be clear that the present application is not limited to the specific configurations and processes described above and illustrated in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and illustrated as examples. However, the method process of the present application is not limited to the specific steps described and illustrated, and those skilled in the art can make various changes, modifications, and additions, or change the order between steps after understanding the spirit of the present application.

[0174] It should also be noted that the exemplary embodiments mentioned in the present application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above steps, that is, the steps can be executed in the order mentioned in the embodiments, or different from the order in the embodiments, or several steps can be executed simultaneously.

[0175] As described above, the above is only the specific implementation manner of the present application. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, modules, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be repeated here. It should be understood that the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should all be covered within the protection scope of the present application.

Claims

1. A production method of steel plates for container boards, characterized in that, Including: The slab is heated to 1235 to 1275 °C to obtain a heated slab; wherein, the slab includes 0.25% to 0.3% by mass of Cu element, and the heating treatment includes a two-step addition section, and the solution treatment time of the two-step addition section at a temperature greater than 1200 °C is 25 - 45 min; The heated slab is rolled to obtain a rolled sheet; The rolled sheet is cooled and coiled to obtain the steel sheet, wherein the coiling temperature is 602 to 648 °C.

2. The method according to claim 1, characterized in that The slab includes the following chemical elements by mass percentage: 0.06% to 0.095% of C, 0.25% to 0.3% of Cu, 0.3% to 0.4% of Si, 0.38% to 0.5% of Cr, 0.58% to 0.75% of Mn, and the balance is iron and inevitable impurity elements.

3. The method according to claim 1, wherein The heating treatment further sequentially includes a recovery preheating section, a first addition section, and a soaking section. The two-step addition section is located between the first addition section and the soaking section. The heating treatment satisfies one or more of the following conditions: (1) The furnace atmosphere temperature of the recovery preheating section is 1050 ± 50 °C, and the slab temperature is 900 ± 70 °C; (2) The furnace atmosphere temperature of the first addition section is 1170 ± 30 °C, and the slab temperature is 1150 ± 30 °C; (3) The furnace atmosphere temperature of the two-step addition section is 1230 ± 30 °C, and the slab temperature is 1200 ± 20 °C; (4) The furnace atmosphere temperature of the soaking section is 1270 ± 20 °C, and the slab temperature is 1255 ± 20 °C.

4. The method according to claim 1, characterized in that, The total in-furnace time of the heating treatment is 150 to 300 min, and the end temperature of the heating treatment is 1255 ± 20 °C.

5. The method according to claim 1, characterized in that The rolling includes finish rolling, and the method further includes: Adjusting the finish rolling force of the slab according to the deformation resistance and the calculation formula, wherein the calculation formula is shown in Formula (1): Rf Cal (i) = Fw Cal ·Km Cal (i)·Ld Cal (i)·Qp Cal (i) / 1000 Equation (1) Wherein: Rf Cal (i) represents the finish rolling force, with the unit of kN; Fw Cal represents the average width of the finish rolling slab, with the unit of kmm; Km Cal (i) represents the deformation resistance, with the unit of kN / mm 2 ; Ld Cal (i) represents the contact arc length between the roll and the slab, in kmm; Qp Cal (i) represents the rolling force calculation function, and the rolling force calculation function is as shown in the following formula: Wherein, RdCal(i) represents the flat roll radius of the current stand, with the unit of mm; HCal(i) represents the exit thickness of the current stand, with the unit of mm.

6. The method according to claim 5, wherein In formula (1), Km Cal (i) is calculated by the following formula: n = 0.41 - 0.07·Cnt Pdi (1); m = {-0.019·Cnt Pdi (1) + 0.126}·t + {0.075·Cnt Pdi (1) - 0.050}; t s = t + (t d - t)·0.7; Among them, Km Cal (i) represents the deformation resistance of the i-th stand, with the unit of kN / mm 2 ; Akm Lay (j) represents the deformation resistance parameter for j types of chemical components; Cnt Pdi (j) represents the mass content of the j-th chemical component; t represents the temperature of the steel sheet, with the unit of °C; td represents the recrystallization transformation temperature of this steel grade, with the unit of °C; σ f represents a conversion compensation factor; g represents the deformation gain factor; Str Cal (i) represents the strain rate of the i-th stand, with the unit of 1 / s; St Cal (i) represents the strain of the i-th stand; Lcr Cal (i) represents the learning coefficient of the rolling force of a certain stand; n represents the strain factor index; i represents the stand number; j represents the chemical composition, (j = 1: carbon); N represents the chemical composition number.

7. The method according to claim 1, characterized in that The rolling is carried out using seven stands of F1 - F7, and a thickness reduction distribution mode is adopted. The method further includes: Adjusting the single-stand reduction rate according to Formula (2); Rr Cal represents the reduction ratio; H Cal (i) represents the exit thickness of the current i-th stand, in mm.

8. The method according to claim 7, wherein The method further includes: Adjusting the single-stand forward slip rate according to Formula (3); Among them, Fs Cal represents the forward slip rate; Afs Lay represents the forward slip rate model parameters of the finish rolling before the 1580 line. Rr Cal represents the reduction ratio; H Cal (i) represents the exit thickness of the current i-th stand, in mm; H Cal (0) = Feh Cal, H Cal (7) = Fdh Cal ; R Hmi (i) represents the roll radius, in mm; Lcf Cal represents the built-in coefficient of forward slip self-learning.

9. The method according to any one of claims 1 to 8, characterized in that The thickness of the steel sheet ≤ 6 mm; the yield strength of the steel sheet is 550 to 650 MPa, and the tensile strength is 600 to 700 MPa.

10. A steel plate for container boards, characterized in that, Prepared by the method according to any one of claims 1 - 7.

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