A pattern plate and a method of manufacturing the same

Abstract

The application relates to the technical field of steel metallurgy, and particularly relates to a patterned plate and a preparation method thereof. The method comprises the following steps: using a protective slag with a set chemical composition to continuously cast molten steel, and controlling the casting speed of the continuous casting to obtain a casting blank; heating the casting blank to make the casting blank have a target temperature; rolling the heated casting blank to obtain a hot-rolled plate; wherein the rolling comprises: rough rolling the heated casting blank to obtain an intermediate blank with a target thickness; transversely magnetically inductively heating the intermediate blank, then fine rolling, and controlling the process parameters of the fine rolling; laminarly cooling the hot-rolled plate in a post-stage cooling mode, then coiling, and controlling the process parameters of the coiling to obtain a patterned plate. The method can continuously reduce the thickness specification of the patterned plate under the premise of ensuring rolling stability, can prepare a patterned plate with a specification of <=1.2 mm, and the quality of the steel strip caused by the flat coiling does not obviously fluctuate.

Description

Technical Field

[0001] This application relates to the field of iron and steel metallurgy technology, and in particular to a patterned plate and its preparation method. Background Technology

[0002] Currently, hot-rolled patterned steel sheets mainly include single-patterned sheets such as lentil-shaped, diamond-shaped, and round bean-shaped sheets, as well as simple combined patterned sheets (lentil + round bean). Due to the presence of the bean-shaped patterns on the surface, patterned steel sheets have good surface friction and excellent anti-slip properties, and are widely used in industries such as automotive flooring, construction, machinery manufacturing, transportation, and shipbuilding.

[0003] In particular, in recent years, with the continuous increase in the number of thin slab continuous casting and rolling production lines, coupled with changes in market demand and production enterprise cost control, higher, newer and stricter requirements have been put forward for the production of patterned plates, mainly in the following aspects: (1) larger patterned shape size, requiring both aesthetics and wear resistance; (2) lower production cost, mainly the consumption of rolls and roll processing costs and leveling costs in the production process; (3) expansion of thin-specification patterned plates, especially the development of specifications of 1.2mm and below.

[0004] However, due to the complex production process of patterned steel plates, the high requirements for the rolling stability of the rolling mill and the coil shape of the coiler, as well as the high processing cost and high roll consumption of the rolls, there are relatively few domestic enterprises with the ability to stably and mass-produce thin-specification patterned steel plates and conduct research. The output and variety of patterned steel plates cannot meet the market demand, indicating huge market potential. Summary of the Invention

[0005] This application provides a patterned plate and its preparation method to solve the technical problem that existing patterned plates cannot simultaneously achieve both thin specifications and good surface quality.

[0006] In a first aspect, this application provides a method for preparing a patterned plate, wherein the thickness of the patterned plate is ≤1.2mm, and the method includes:

[0007] Molten steel is continuously cast using a protective slag with a set chemical composition, and the casting speed is controlled to obtain a cast billet.

[0008] The billet is heated to bring it to a target temperature.

[0009] The heated billet is rolled to obtain a hot-rolled plate; wherein the rolling process includes:

[0010] The heated billet is rough rolled to obtain an intermediate billet with the target thickness;

[0011] The intermediate billet is subjected to transverse magnetic flux induction heating, followed by finish rolling, and the process parameters of the finish rolling are controlled.

[0012] The hot-rolled plate is subjected to laminar flow cooling using a post-cooling mode, followed by coiling, and the coiling process parameters are controlled to obtain a patterned plate.

[0013] Optionally, the specified chemical composition includes:

[0014] Calcium oxide, fixed carbon, total water, silicon dioxide, aluminum oxide, ferric oxide, fluoride ions, lithium oxide, magnesium oxide, and sodium oxide; wherein, by mass percentage,

[0015] The sodium oxide content is 8.20-9.20%, the fluoride ion content is 9.10-10.10%, the calcium oxide content is 29.80-35.80%, the fixed carbon content is 5.20-6.20%, the total water content is ≤0.50%, the silicon dioxide content is 21.50-27.50%, the aluminum oxide content is 5.30-6.30%, the ferric oxide content is ≤1%, the lithium oxide content is 0.90-1.90%, the magnesium oxide content is 3.50-4.50%, and the weight ratio of calcium oxide to silicon dioxide is 1.29-1.39.

[0016] Optionally, the casting speed is ≥4.9m / min.

[0017] Optionally, the target temperature is 1165-1195℃.

[0018] Optionally, the target thickness is 15-20 mm.

[0019] Optionally, the process parameters for finishing rolling include: finishing mill inlet temperature and finishing mill outlet temperature; wherein,

[0020] The inlet temperature of the finishing mill is 1190-1230℃.

[0021] The difference between the finishing mill inlet temperature and the finishing mill outlet temperature is 370-400℃.

[0022] Optionally, rolling the heated billet to obtain a hot-rolled plate includes:

[0023] The heated billet is rolled, and the descaling pressure during the rolling process is controlled to obtain a hot-rolled plate; wherein,

[0024] The phosphorus removal pressure is 320-340 MPa.

[0025] Optionally, rolling the heated billet to obtain a hot-rolled plate includes:

[0026] The heated billet is rolled, and the water usage mode of the rolling process is controlled to obtain a hot-rolled plate; wherein the water usage mode of the rolling process includes:

[0027] Anti-stripping water is activated on the work rolls of the second roughing mill stand, the work rolls of the second finishing mill stand, and the work rolls of the second finishing mill stand.

[0028] At the fine descaling inlet and outlet, the strip is cooled with 1 / 4 water flow.

[0029] Water spray is applied to the opening side of the third, fourth, and fifth finishing mill stands.

[0030] Optionally, the winding process parameters include:

[0031] The winding temperature, the diameter of the core section, the winding tension of the core section, and the pressure of the auxiliary winding rollers; among these,

[0032] The winding temperature is 550-580℃, the diameter of the hard core section is 820-845mm, the winding tension of the hard core section is 27.5-30KN, and the pressure of the auxiliary winding roller is 40-55KN.

[0033] Secondly, this application provides a patterned plate, which is prepared by the method described in any embodiment of the first aspect.

[0034] The technical solutions provided in this application have the following advantages compared with the prior art:

[0035] The method provided in this application optimizes and improves the production process, providing a method for preparing thin-gauge patterned plates. Under the premise of ensuring rolling stability, the thickness of the patterned plates is continuously reduced, and the ability to produce patterned plates with a specification of ≤1.2mm is achieved. Moreover, the quality of the strip steel caused by the flat coil does not fluctuate significantly, achieving good economic benefits. It also has strong guiding significance for other thin slab continuous casting and rolling production lines. Attached Figure Description

[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic flowchart illustrating a method for preparing a patterned plate according to an embodiment of this application;

[0039] Figure 2 This is a schematic diagram of the induction coil arrangement in an induction heating process provided in an embodiment of this application; wherein, A-longitudinal magnetic flux induction heating, and B-transverse magnetic flux induction heating;

[0040] Figure 3 This is a schematic diagram of an induction heater traverse vehicle provided in an embodiment of this application;

[0041] Figure 4 Mechanical property curves at different finishing mill inlet temperatures provided for embodiments of this application; wherein, A - yield strength curve, B - tensile strength curve, OS and DS represent the two sides of the strip, OS represents the operating side; DS represents the transmission side;

[0042] Figure 5 Microstructure morphology of patterned plates at different finishing rolling exit temperatures provided for embodiments of this application; wherein, A-820℃, B-825℃, C-830℃;

[0043] Figure 6 Mechanical property curves at different winding temperatures provided for embodiments of this application; wherein, A - yield strength curve, B - tensile strength curve, OS and DS represent the two sides of the strip, OS represents the operating side; DS represents the transmission side;

[0044] Figure 7 The mechanical properties of the inner ring, outer ring, and middle position of the patterned steel strip provided in this application embodiment; wherein, A-yield strength curve, B-tensile strength curve, OS and DS represent the two sides of the strip, OS represents the operating side; DS represents the transmission side;

[0045] Figure 8 A schematic diagram illustrating the fluctuation between the actual and set values ​​of the winding tension provided in the embodiments of this application;

[0046] Figure 9 A schematic diagram illustrating the change in the roll diameter position of the hard core segment provided in an embodiment of this application;

[0047] Figure 10 A schematic diagram of the coiling tension of the top section of the strip in a coiler provided in this application embodiment;

[0048] Figure 11 This is a surface quality diagram of the patterned steel strip provided in Embodiment 11 of this application;

[0049] Figure 12 A surface quality diagram of the patterned steel strip provided in Comparative Example 1 of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0052] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0053] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0054] Firstly, this application provides a method for preparing a patterned plate; please refer to [link to relevant documentation]. Figure 1 The thickness of the patterned plate is ≤1.2mm, and the method includes:

[0055] S1. Use a protective slag with a set chemical composition to continuously cast molten steel, and control the casting speed to obtain a billet;

[0056] In some embodiments, the specified chemical composition includes:

[0057] Calcium oxide, fixed carbon, total water, silicon dioxide, aluminum oxide, ferric oxide, fluoride ions, lithium oxide, magnesium oxide, and sodium oxide; wherein, by mass percentage,

[0058] The sodium oxide content is 8.20-9.20%, the fluoride ion content is 9.10-10.10%, the calcium oxide content is 29.80-35.80%, the fixed carbon content is 5.20-6.20%, the total water content is ≤0.50%, the silicon dioxide content is 21.50-27.50%, the aluminum oxide content is 5.30-6.30%, the ferric oxide content is ≤1%, the lithium oxide content is 0.90-1.90%, the magnesium oxide content is 3.50-4.50%, and the weight ratio of calcium oxide to silicon dioxide is 1.29-1.39. The melting point of this protective slag can be controlled at 1200-1400℃.

[0059] In this embodiment, the MCCR production line differs from traditional thin slab casting and rolling lines, employing an integrated casting and rolling process. Continuous casting and the rolling mill are rigidly connected via strip steel flow rate per second, placing high demands on casting stability. Therefore, for steel grades with higher production difficulty, a transitional casting mode is typically used. This involves selecting a low-risk steel grade for the first casting heat, and after a smooth transition, casting of patterned plates begins in the second heat. Due to differences in steel composition (the composition of dissimilar steel grades should be similar), the tundish tonnage and casting speed differ. Since the lower limit of carbon content in patterned plate is set at 0.175%, close to the peritectic region (0.08-0.17), the composition of the protective slag used in the continuous casting process is controlled to ensure casting stability.

[0060] The positive effects of controlling the sodium oxide (Na2O) content to 8.20-9.20% include: sodium oxide promotes the glassy transparency of the protective slag, effectively improving the lubrication function of the slag film. Excessive sodium oxide content can lead to a decrease in the basicity of the protective slag, causing it to degrade; conversely, insufficient sodium oxide content can result in excessively high basicity, affecting the slag's ability to adsorb inclusions. Specifically, the sodium oxide content can be 8.20%, 8.80%, 9.20%, etc.

[0061] Control of fluoride ions (F - The positive effects of a fluoride ion content of 9.10-10.10% include: lowering the melting point and viscosity of the protective slag, regulating crystallization properties, and improving the reaction mechanics between the slag and metal or between the slag and inclusions. It also acts as a flux and diluent. However, excessive fluoride ion content can increase costs and cause fluoride volatilization, which, if adsorbed, can affect human health. Insufficient fluoride ion content can negatively impact the melting performance of the protective slag, easily leading to slag entrapment. Specifically, the fluoride ion content can be 9.10%, 9.60%, 10.10%, etc.

[0062] The positive effect of controlling the calcium oxide (CaO) content to 29.80-35.80% is that it can enhance the ability of protective slag to dissolve inclusions. Specifically, the calcium oxide content can be 29.80%, 32.80%, 35.80%, etc.

[0063] The positive effects of controlling the fixed carbon (FC) content to 5.20-6.20% are as follows: Carbon in the protective slag exists as fixed carbon, which can prevent slag agglomeration, facilitate slag melting, and effectively control the melting rate of the protective slag. Specifically, the fixed carbon content can be 5.20%, 5.80%, 6.20%, etc.

[0064] The positive effects of controlling the total water (Mt) content to ≤0.50% are as follows: the lower the water content in the protective slag, the lower the [H] element content, which can reduce the instability of casting speed caused by excessive [H] element. Specifically, the total water content can be 0.50%, 0.40%, 0.30%, etc.

[0065] The positive effects of controlling the silica (SiO2) content to 21.50-27.50% are: SiO2 has a high melting point and compositional stability, thus maintaining the stability of the protective slag when used at high temperatures. Specifically, the silica content can be 21.50%, 25.50%, 27.50%, etc.

[0066] The positive effects of controlling the content of alumina (Al2O3) to 5.30-6.30% are as follows: Alumina mainly improves the fluidity of the protective slag, making it less prone to crusting and allowing it to be evenly coated on the top of the crystallizer. Specifically, the content of alumina can be 5.30%, 5.80%, 6.30%, etc.

[0067] The positive effect of controlling the content of ferric oxide (Fe2O3) to ≤1% is mainly to control the oxidizing properties of the protective slag. Specifically, the content of ferric oxide can be 1%, 0.8%, etc.

[0068] The positive effects of controlling the lithium oxide (Li2O) content to 0.90-1.90% include a significant impact on the viscosity of the protective slag, melting temperature, and glass properties. Specifically, the lithium oxide content can be 0.90%, 1.50%, 1.90%, etc.

[0069] The positive effects of controlling the magnesium oxide (MgO) content to 3.50-4.50% include: reducing the melting temperature and viscosity of the protective slag, while ensuring a faster melting rate, thus reducing the likelihood of cracking in the steel billet under higher drawing speeds. Specifically, the magnesium oxide content can be 3.50%, 4.0%, 4.5%, etc.

[0070] The weight ratio of calcium oxide to silicon dioxide is also the basicity R of the aforementioned protective slag. Controlling this ratio to 1.29-1.39 has the positive effect of reflecting the slag's ability to absorb inclusions in molten steel. If the basicity R is too high, it will increase the crystallization temperature of the slag, leading to an increase in the temperature of the molten steel. This not only increases the erosion of refractory materials such as tundishes but also leads to increased superheat, affecting casting. If the basicity R is too low, it will affect the slag's ability to adsorb inclusions. Specifically, the basicity R can be 1.29, 1.26, 1.39, etc.

[0071] In some embodiments, the casting speed is ≥4.9 m / min.

[0072] The positive effects of controlling the casting speed to ≥4.9 m / min in continuous casting and rolling production lines: The casting speed is the foundation of rolling. A stable casting speed of 4.9 m / min or higher can effectively ensure that the entry temperature of the finishing mill is within a reasonable range, effectively preventing the flattening of the patterned steel coil. If the casting speed is too low, it will lead to an excessively high entry temperature of the finishing mill, which in turn makes it difficult for phase transformation to occur, affecting the performance of the steel coil. Specifically, the casting speed can be 4.9 m / min, 5.0 m / min, 5.1 m / min, etc.

[0073] The continuous casting process also includes: the tundish baking temperature and time is 3.5-4.5h, and the baking temperature is 1100-1150℃. The temperature is controlled by a "narrow window" to avoid the tundish refractory material falling off due to excessive baking time, which would affect the quality of the molten steel.

[0074] Before pouring, ensure that there are no foreign objects in the tundish. During the entire pouring process, argon is blown at a flow rate of 80-120 L / min and a pressure of 0.4 MPa.

[0075] The weight of the tundish in each start-up furnace should be controlled at 30-35t, and the weight of the continuous casting furnace should be 38-42t. The temperature of the molten steel in the tundish should be 1529-1544℃, and the superheat should be 12-27℃.

[0076] During the casting process, the absolute value of the liquid level fluctuation in the crystallizer is 0-3mm.

[0077] S2. Heat the billet to bring it to a target temperature;

[0078] In some implementations, the target temperature is 1165-1195°C.

[0079] In this embodiment, the heating is carried out in a tunnel furnace, and the calorific value of the tunnel furnace gas is set at 2400 Kcal / m3. "Target temperature" represents the furnace exit temperature of the billet. Controlling the furnace exit temperature of the billet to 1165-1195℃ has the following positive effects: Low exit temperatures can easily lead to excessive temperature differences between the center and edges of the strip, causing peeling defects. Once peeling defects occur on the surface or edge of the strip, they will significantly affect the wear resistance of the patterned plate. Specifically, the furnace exit temperature of the billet can be 1165℃, 1185℃, 1195℃, etc.

[0080] S3. The heated billet is rolled to obtain a hot-rolled plate; wherein the rolling includes:

[0081] The heated billet is rough rolled to obtain an intermediate billet with the target thickness;

[0082] The intermediate billet is subjected to transverse magnetic flux induction heating, followed by finish rolling, and the process parameters of the finish rolling are controlled.

[0083] In some implementations, the target thickness is 15-20 mm.

[0084] The positive effects of controlling the thickness of the intermediate slab to 15-20mm are as follows: If the intermediate slab thickness is too large, although it increases the deformation during the finishing rolling process, it also slows down the temperature drop rate. Without the support of intermediate slab water cooling, this not only increases the waiting time and reduces production efficiency, but also significantly reduces the impact of excessive deformation on the final microstructure and properties. If the intermediate slab thickness is too small, the deformation degree in the roughing rolling stage increases, while the temperature drop in the finishing rolling stage is faster but the deformation degree is slightly smaller. This can lead to an unbalanced load distribution between the two mills (or the roughing and finishing rolling stages), potentially reducing the finishing rolling stage's impact on refining recrystallized austenite grains, increasing the effective grain boundary area, and promoting the transformation to ferrite. Moreover, a too-thin intermediate slab will result in excessive temperature drop at the slab edge, which will be further deepened after passing through the descaling mill, thus increasing the amount of rolled skin. Specifically, the thickness of the intermediate slab can be 15mm, 18mm, 20mm, etc. The rolling effect is optimal when the intermediate slab thickness is 18mm.

[0085] The positive effects of transverse magnetic flux induction heating on the intermediate billet: The induction heater (IH) is located between the roughing and finishing mills, and its main purpose is to heat the strip steel to ensure a certain rolling temperature and prevent the rolling load from causing a decrease in stability.

[0086] Depending on the arrangement of the induction coils, induction heating of strips can generally be divided into longitudinal flux induction heating (see [link to relevant documentation]). Figure 2 (A) and transverse flux induction heating (see also) Figure 2 (B)). In transverse magnetic flux induction heating, the magnetic flux generated by the alternating current in the same direction in the two symmetrically placed coils is perpendicular to the strip surface, and the eddy current is parallel to the strip. There is no problem of mutual cancellation, so the shortcomings of longitudinal magnetic flux induction heating can be avoided.

[0087] Induction heater coil (see) Figure 3 The schematic diagram of the induction heater traverse carriage shown indicates that the movement is achieved through the displacement of the trolley. The horizontal working position of the coil is determined by the width and thickness of the slab. The corresponding Q value, i.e., the relative distance between the edge of the slab and the edge of the IH coil, is selected using the slab specifications corresponding to the coil overlap range in Table 1. The heating output power of the IH coil is set according to different intermediate slab specifications (rolling speed, thickness, and width). Simultaneously, the temperature detection at the IH inlet and outlet areas is compared, and continuous adaptive adjustments are made. The IH heating control is a negative feedback temperature control loop, controlled by comparing the target temperature at the finishing mill inlet and the IH outlet temperature. The difference between the temperature setpoint and the feedback is used to correct the input power of the heating frequency converter. Currently, seven sets of induction heating devices are used, effectively ensuring the uniformity of the strip width.

[0088] Table 1. Overlap range of induction heater traverse car coil

[0089]

[0090] In some embodiments, the process parameters of the finishing mill include: the finishing mill inlet temperature and the finishing mill outlet temperature; wherein,

[0091] The inlet temperature of the finishing mill is 1190-1230℃.

[0092] The difference between the finishing mill inlet temperature and the finishing mill outlet temperature is 370-400℃.

[0093] Rolling temperature has a significant impact on the performance of patterned steel sheets. An improperly set temperature can lead to flattening and curling defects. Therefore, establishing a reasonable temperature regime has a decisive influence on product quality.

[0094] The positive effects of controlling the finishing mill inlet temperature (FET) to 1190-1230℃: Please refer to [link to relevant documentation]. Figure 4 The mechanical property curves shown are for different finishing mill inlet temperatures; where A is the yield strength curve, B is the tensile strength curve, OS and DS represent the two sides of the strip, OS represents the operating side, and DS represents the drive side; Figure 4 It can be seen that the strength decreases as the FET (Frost-Effect Temperature) decreases. In the width direction of the plate, there is a phenomenon of high strength in the middle and low strength at the edges, with the middle strength being approximately 20-30 MPa higher than the edges. Furthermore, the higher the FET temperature, the greater the performance difference between the middle and the edges, which clearly corresponds to the temperature non-uniformity of the steel plate. Specifically, the finishing mill inlet temperature can be 1190℃, 1210℃, 1230℃, etc.

[0095] The positive effects of controlling the temperature difference between the finishing mill inlet and the finishing mill outlet (FDT) to be 370-400℃: Please refer to [link to relevant documentation]. Figure 5 The microstructure of the patterned steel plate at different finishing rolling exit temperatures is shown in the diagrams; where A-820℃, B-825℃, and C-830℃. Figure 5 The C-patterned plate exhibits the best microstructure, reducing the FET temperature and the temperature drop from FET to FDT, thereby decreasing the original austenite grain size and improving the material strength at high temperatures. Specifically, the difference between the finishing mill inlet temperature and the finishing mill outlet temperature can be 370℃, 380℃, 390℃, 400℃, etc. A temperature difference of 380℃ between the FET and FDT is optimal.

[0096] In some embodiments, rolling the heated billet to obtain a hot-rolled plate includes:

[0097] The heated billet is rolled, and the descaling pressure during the rolling process is controlled to obtain a hot-rolled plate; wherein,

[0098] The phosphorus removal pressure is 320-340 MPa.

[0099] The positive effects of controlling descaling pressure at 320-340 MPa: Descaling includes coarse descaling and fine descaling. Compared to pickled plates and galvanized plates, patterned plates do not have very high surface requirements; it is only necessary to ensure that there are no obvious foreign objects pressed into the surface or iron pits. Therefore, coarse descaling adopts a single-row low-pressure mode. Fine descaling also adopts a single row, prioritizing the use of manifold #2. The fine descaling machine has two rows of manifolds. Manifold #1 is closer to the induction heater. Using manifold #1 allows descaling water to easily enter the induction heater, which will have a certain cooling effect on the strip surface, thus affecting the strip performance. Manifold #2 is closer to the F1 inlet. Using manifold #2 allows the strip to quickly enter the finishing mill stand for rolling after descaling. Under the premise of ensuring a good surface condition, rapid rolling of the strip can promote further deformation strengthening of the strip, which is beneficial to ensuring the strength of the patterned plate. Specifically, the descaling pressure can be 320 MPa, 330 MPa, 340 MPa, etc. More preferably, the dephosphorization pressure is 330 MPa.

[0100] In some embodiments, rolling the heated billet to obtain a hot-rolled plate includes:

[0101] The heated billet is rolled, and the water usage during rolling is controlled to obtain a hot-rolled plate; wherein,

[0102] The water usage mode for the rolling process includes:

[0103] Anti-stripping water is activated on the work rolls (H2), (F1), and (F2) of the second roughing mill stand;

[0104] At the fine descaling inlet and outlet, the strip is cooled with 1 / 4 water flow.

[0105] Side water spraying is activated on the third finishing mill stand (F3), the fourth finishing mill stand (F4), and the fifth finishing mill stand (F5).

[0106] In this embodiment, anti-stripping water mainly refers to the cooling water for the work rolls of the mill stand. Its function is to prevent the oxide film on the work rolls of the mill stand from peeling off, which would affect the quality of the strip steel. Currently, the anti-stripping water for stands H2, F1, and F2 is in the open state when rolling patterned steel sheets, and the anti-stripping water flow rate is 25m³ / h. 3 / Hour;

[0107] 1 / 4 Cooling Water: The 1 / 4 cooling water is located at the inlet and outlet of the fine descaling process. Its purpose is to prevent wavy patterns from appearing on both sides of the strip at the 1 / 4 mark. Uneven strip temperature not only affects the strip's shape quality but also its properties, especially at the 1 / 4 mark. If the properties at the 1 / 4 mark of the strip's cross-section meet requirements, the properties of the entire cross-section will also meet requirements. Turning on the 1 / 4 cooling water effectively alleviates uneven temperature distribution across the strip's cross-section.

[0108] Side-spray water: This refers to the side-spray water device between the finishing mill stands. Previously, the production line used dust removal water, similar to a descaling process. The water was sprayed obliquely onto the strip at a certain angle. Sometimes, the dust removal water would remain on the strip and enter the next stand with it, causing excessive temperature drop in the strip. As mentioned earlier, the temperature drop between FET and FDT cannot be too large. In addition, it also has a certain impact on the rolling stability of the strip. Based on this, the dust removal water of the F3 / F4 / F5 stands was modified to side-spray water, which cools the strip while preventing water from remaining on the strip surface.

[0109] S4. The hot-rolled plate is subjected to laminar flow cooling using a post-cooling mode, followed by coiling, and the coiling process parameters are controlled to obtain a patterned plate.

[0110] The positive effects of using a post-cooling mode for laminar flow cooling of the hot-rolled plate: Laminar cooling water is distributed between the finishing mill exit and the coiler, primarily to reduce the strip temperature and ensure good performance. However, when rolling patterned plates, the activation of laminar cooling water can lead to significant differences in strip properties. After coiling, the strip properties exhibit a pattern of inner ring > outer ring > middle, as shown in [reference needed]. Figure 7 The diagram shows the mechanical properties of the inner ring, outer ring, and middle section of the patterned steel strip. A represents the yield strength curve, B represents the tensile strength curve, and OS and DS represent the two sides of the strip, with OS representing the operating side and DS representing the transmission side. The yield strength of the inner ring is approximately 59-101 MPa higher than that of the middle section. Due to the difference in properties between the inner and outer rings, the middle section exhibits lower properties, resulting in flattening during coiling. Therefore, in the rolling of patterned steel strips, the laminar cooling mode is selected as the later stage cooling. Later stage cooling increases the air cooling time of the strip, inhibits the formation of proeutectoid ferrite, reduces the diffusion distance of carbon, avoids the formation of large carbon-rich structures, improves the uniformity of the microstructure distribution of hot-rolled products, and increases the deformation of the non-recrystallized austenite region in the finishing mill, which is beneficial to improving the performance uniformity of the product.

[0111] In some embodiments, the winding process parameters include:

[0112] Winding temperature, core section diameter, core section winding tension, and auxiliary winding roll pressure; among which,

[0113] The winding temperature is 550-580℃, the diameter of the hard core section is 820-845mm, the winding tension of the hard core section is 27.5-30KN, and the pressure of the auxiliary winding roller is 40-55KN.

[0114] The positive effects of controlling the winding temperature to 550-580℃ include: ensuring the yield strength and tensile strength of the patterned steel sheet; see [reference needed]. Figure 6 The diagram shows the mechanical property curves at different winding temperatures; where A represents the yield strength curve, B represents the tensile strength curve, and OS and DS represent the two sides of the strip, with OS representing the operating side and DS representing the transmission side. Specifically, the winding temperature can be 550℃, 560℃, 570℃, 580℃, etc.

[0115] The positive effects of controlling the core section diameter to 820-845mm and the core section winding tension to 27.5-30KN are as follows: After the coiler core shaft reaches the "fully expanded" state, a tension control relationship is established between the strip and the coiler. Furthermore, the coiler tension gradually decreases as the strip diameter increases, exhibiting a "stepped tension" control mode. The actual winding tension fluctuates by approximately 1KN from the set value. Please refer to [link / reference]. Figure 8 The diagram illustrates the fluctuation between the actual and set values ​​of the coiling tension. As the coil diameter increases during strip winding, the coiling tension is continuously adjusted. This explains the fluctuation in actual coiling tension within a certain range, as mentioned earlier. Because strip is prone to flattening, and the performance of the inner, middle, and outer coils differs, the core strength after winding may not be sufficient to support the entire weight of the strip, leading to flattening. To address this, increasing the diameter of the hard core section is proposed; see [reference needed]. Figure 9 The diagram illustrates the variation in the diameter of the core section. The core section refers to the strip that first contacts the mandrel; its larger diameter results in stronger core strength and reduces the likelihood of flattening. Specifically, the core section's diameter can be 820mm, 835mm, 845mm, etc., and its winding tension can be 27.5KN, 28.5KN, 30KN, etc.

[0116] The positive effects of controlling the auxiliary coiling roller pressure to 40-55KN: After the strip tail is sheared by the high-speed flying shear, the strip is guided into the mandrel for winding by the coiling machine's auxiliary coiling roller. To ensure a good coil shape, additional auxiliary coiling rollers are needed to assist in winding the steel coil in a "step control" manner. Therefore, the auxiliary coiling roller pressure also affects the strip shape, especially the strip tail. See the schematic diagram of the coiling tension in the top section of the strip in the coiling machine; specifically, the auxiliary coiling roller pressure can be 40KN, 45KN, 50KN, 55KN, etc.

[0117] Secondly, this application provides a patterned plate, which is prepared by the method described in any embodiment of the first aspect.

[0118] The patterned plate is realized based on the above-described patterned plate preparation method. The specific steps of the patterned plate preparation method can be referred to the above embodiments. Since the patterned plate adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0119] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0120] This application provides a method for preparing a patterned plate, wherein the thickness of the patterned plate is ≤1.2mm, and the method includes:

[0121] S1. Use a protective slag with a set chemical composition to continuously cast molten steel, and control the casting speed to obtain a billet;

[0122] S2. Heat the billet to bring it to a target temperature;

[0123] S3. The heated billet is rolled to obtain a hot-rolled plate; wherein the rolling includes:

[0124] The heated billet is rough rolled to obtain an intermediate billet with the target thickness;

[0125] The intermediate billet is subjected to transverse magnetic flux induction heating, followed by finish rolling, and the process parameters of the finish rolling are controlled.

[0126] S4. The hot-rolled plate is subjected to laminar flow cooling using a post-cooling mode, followed by coiling. The coiling process parameters are controlled to obtain a patterned plate. Specific process parameters are shown in Tables 2 and 3.

[0127] Table 2. Chemical composition (wt%) and melting point (°C) of protective slag.

[0128] Serial Number CaO FC Mt <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[Fe2O3]]> Example 1 29.80 5.20 0.40 21.50 5.30 0.8 Example 2 35.80 6.20 0.5 27.50 6.3 1.0 Example 3 33.0 5.80 0.46 25.0 6.0 0.9 Comparative Example 1 25.80 2.20 0.40 17.50 3.30 0.8 Serial Number R <![CDATA[F - ]]> <![CDATA[Li2O]]> MgO <![CDATA[Na2O]]> Melting point Example 1 1.39 9.10 0.90 3.50 8.20 1315 Example 2 1.30 10.10 1.90 4.50 9.20 1389 Example 3 1.32 9.60 1.50 4.0 8.70 1377 Comparative Example 1 1.45 5.7 0.6 2.8 7.2 1218

[0129] Table 3. Process parameters for preparing patterned plates

[0130]

[0131] As shown in Tables 2-3 above, while the production specifications of the patterned steel sheets that can be produced according to the embodiments of this application are continuously decreasing, the quality of the strip steel caused by the flat coils has not fluctuated significantly. (See Tables 2-3 above.) Figure 11 The surface quality diagram of the patterned steel strip shown in Example 1; however, the patterned steel strip prepared in Comparative Example 1 clearly exhibits flattening and curling problems, as can be seen in [reference needed]. Figure 12 The surface quality diagram of the patterned steel strip shown in Comparative Example 1.

[0132] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method of making a patterning plate, characterized by, The pattern plate has a thickness of ≤1.2 mm, and the method comprises: using a protective slag with a set chemical composition for continuous casting of molten steel, and controlling the casting speed of the continuous casting to be ≥4.9 m / min to obtain a casting blank; heating the casting blank to have a target temperature; rolling the heated casting blank to obtain a hot-rolled plate; wherein the rolling comprises: rough rolling the heated casting blank to obtain an intermediate blank with a target thickness; transversely magnetically inductively heating the intermediate blank, then finish rolling, and controlling the process parameters of the finish rolling; using a post-stage cooling mode to laminarly cool the hot-rolled plate, then coiling, and controlling the process parameters of the coiling to obtain a pattern plate; wherein the set chemical composition comprises, in terms of mass percentage, sodium oxide: 8.20-9.20%, fluoride ion: 9.10-10.10%, calcium oxide: 29.80-35.80%, fixed carbon: 5.20-6.20%, total water ≤0.50%, silicon dioxide: 21.50-27.50%, aluminum oxide: 5.30-6.30%, iron trioxide ≤1%, lithium oxide: 0.90-1.90%, magnesium oxide: 3.50-4.50%, and the weight ratio of calcium oxide to silicon dioxide is 1.29-1.39; the process parameters of the finish rolling comprise: the finish rolling inlet temperature is 1190-1230℃, and the difference between the finish rolling inlet temperature and the finish rolling outlet temperature is 370-400℃; the process parameters of the coiling comprise: the coiling temperature is 550-580℃, the coiling diameter of the hard core section is 820-845 mm, the coiling tension of the hard core coiling section is 27.5-30 KN, and the coiling roll pressure is 40-55 KN.

2. The method of claim 1, wherein, The target temperature is 1165-1195℃.

3. The method of claim 1, wherein, The target thickness is 15-20 mm.

4. The method according to claim 1 or 3, characterized in that, The rolling of the heated casting blank to obtain a hot-rolled plate comprises: rolling the heated casting blank, and controlling the phosphorus removal pressure in the rolling to obtain a hot-rolled plate; wherein, the phosphorus removal pressure is 320-340 MPa.

5. The method according to claim 1 or 3, characterized in that, The rolling of the heated casting blank to obtain a hot-rolled plate comprises: rolling the heated casting blank, and controlling the water use mode of the rolling to obtain a hot-rolled plate; wherein, the water use mode of the rolling comprises: turning on the anti-peeling water for the second rough rolling stand work roll, the first finish rolling stand work roll, and the second finish rolling stand work roll; turning on 1 / 4 cooling water for the strip steel at the finish descaling inlet and the finish descaling outlet; turning on side spray water for the third finish rolling stand, the fourth finish rolling stand, and the fifth finish rolling stand.

6. A patterning board characterized by The pattern plate is prepared by the method of any one of claims 1-5.

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