Production method of cold-rolled aluminum-zinc plated steel strip

Abstract

The invention discloses a production method of a cold-rolled aluminum-zinc-plated steel strip. The production method comprises the following steps: acquiring a hot-rolled steel plate at a set temperature as a cold-rolled base material; performing cold rolling processing on the cold-rolled base material to obtain a cold-rolled finished steel strip; the cold-rolled finished steel strip is subjected to plating solution treatment, and an aluminum-zinc-plated finished steel strip is obtained; winding the aluminum-zinc plated finished steel strip to form an aluminum-zinc plated finished steel coil; in the process of winding the aluminum and zinc plated finished steel strip to form the aluminum and zinc plated finished steel coil, the winding force applied to the steel strip meets the following relation: F = A * r * W; the tension coefficient of the steel strip is determined by the thickness h of the aluminum and zinc plated finished steel strip, and under the condition that h is larger than or equal to 1.5 mm and smaller than or equal to 2.5 mm, A is larger than or equal to 1.2 and smaller than or equal to 1.6; and the value of A is reduced along with the increase of the value of h. By the adoption of the technical scheme, the situation that transverse creases occur in the winding process of the aluminum-zinc plated finished steel strip is reduced, and the quality of the produced aluminum-zinc plated finished steel strip is improved.

Description

Technical Field

[0014]

[0001] This application relates to cold rolling processing technology, especially a production method of cold-rolled aluminized zinc steel strip. Background Art

[0002] When directly coiling cold-rolled thick-gauge strip steel using a mandrel, the deformation curvature is relatively large, the deformation amounts of the inner and outer surfaces of the steel plate are significantly different, and the stress concentration generated during the deformation process cannot be evenly released. After accumulating to a certain extent, obvious non-uniform plastic deformation will occur along the width direction of the steel coil, forming a transverse fold mark defect similar to the trace of origami. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a production method of cold-rolled aluminized zinc steel strip to overcome the problem of transverse fold mark defects generated during the coiling process of cold-rolled steel strip in the prior art solution.

[0004] To achieve at least one of the above purposes, this application provides the following technical solutions:

[0005] An embodiment of this application provides a production method of cold-rolled aluminized zinc steel strip, including the following steps:

[0006] Obtain a hot-rolled steel plate with a cooling temperature within a set range as the cold-rolling base material;

[0007] Cold-roll the cold-rolling base material to obtain a cold-rolled finished steel strip;

[0008] Perform plating solution treatment on the cold-rolled finished steel strip to obtain an aluminized zinc finished steel strip;

[0009] Wind the aluminized zinc finished steel strip to form an aluminized zinc finished steel coil;

[0010] During the process of winding the aluminized zinc finished steel strip to form an aluminized zinc finished steel coil, the winding force applied to the steel strip satisfies the following relationship: F = A × r × W;

[0011] Where, F is the magnitude of the tension applied to the steel strip, A is the steel strip tension coefficient, r is the thickness of the finished steel coil, W is the width of the steel strip, the measurement unit of F is kg, and the measurement units of r and W are mm;

[0012] The steel strip tension coefficient is determined by the thickness h of the aluminized zinc finished steel strip. When h satisfies 1.5 mm ≤ h ≤ 2.5 mm, A satisfies 1.2 ≤ A ≤ 1.6; and the value of A decreases as the value of h increases.

[0013] In some embodiments, when h is 1.5 mm, the corresponding tension coefficient A is set to 1.6;

[0014] When the thickness h satisfies 1.5 mm < h ≤ 1.

[0015] When the thickness h satisfies 1.7 mm < h ≤ 2 mm, the corresponding tension coefficient A is set to 1.4;

[0016] When the thickness h satisfies 2 mm < h ≤ 2.2 mm, the corresponding tension coefficient A is set to 1.3;

[0017] When the thickness h satisfies 2.2 mm < h ≤ 2.5 mm, the corresponding tension coefficient A is set to 1.2.

[0018] In some embodiments, obtaining the hot-rolled steel sheet with the cooling temperature within the set range as the cold-rolled base material is specifically: cooling the hot-rolled steel sheet by laminar flow cooling, and determining the cooling end temperature of the hot-rolled steel sheet according to the thickness of the hot-rolled steel sheet and the cooling water temperature of the laminar flow cooling. The three satisfy the following relationship:

[0019] 620 - 5×(T - 28) - 10×(t - 3) ≤ CT ≤ 640 - 5×(T - 28) - 10×(t - 3);

[0020] Where, CT is the cooling end temperature of the hot-rolled steel sheet, T is the cooling water temperature of the laminar flow cooling, t is the thickness of the hot-rolled steel sheet; the measurement units corresponding to CT and T are °C, and the measurement unit corresponding to t is mm.

[0021] In some embodiments, CT, T, and t satisfy the following relationship:

[0022] CT = 630 - 5×(T - 28) - 10×(t - 3).

[0023] In some embodiments, for the hot-rolled steel sheet with the thickness t of the hot-rolled steel sheet being 4 mm:

[0024] When T satisfies T ≤ 30 °C, the temperature CT of the hot-rolled steel sheet at the end of laminar flow cooling remains at 600 °C to 620 °C;

[0025] When T satisfies 30 °C < T ≤ 32 °C, the temperature CT of the hot-rolled steel sheet at the end of laminar flow cooling remains at 590 °C to 610 °C;

[0026] When T satisfies 32 °C < T ≤ 34 °C, the temperature CT of the hot-rolled steel sheet at the end of laminar flow cooling remains at 580 °C to 600 °C.

[0027] In some embodiments, winding the aluminized zinc finished steel strip to form an aluminized zinc finished steel coil is specifically using a winding device to wind the aluminized zinc finished steel strip;

[0028] The winding device includes a winding mechanism for winding the aluminized zinc finished steel strip and a central control mechanism signal-connected to the winding mechanism;

[0029] The central control mechanism is provided with an input terminal for inputting corresponding parameters;

[0030] The central control mechanism is used to control the speed at which the winding mechanism winds the galvanized finished steel strip and the tension applied to the galvanized finished steel strip.

[0031] In some embodiments, the central control mechanism further includes a size detection element fixedly connected to the winding mechanism, and the size element is signal-connected to the central control mechanism for transmitting size information of the aluminum-zinc coated finished steel coil to the central control mechanism.

[0032] In some embodiments, the size detection element is an infrared distance sensor.

[0033] In some embodiments, the cold-rolled finished steel strip is subjected to a plating solution treatment to obtain an galvanized finished steel strip, and then the temperature of the galvanized finished steel strip is reduced to no more than 70°C, and then the galvanized finished steel strip is wound to form an galvanized finished steel coil.

[0034] In the above technical solution, by limiting the temperature of the cold-rolled base material and at the same time limiting the tension coefficient of the coiled aluminum-zinc coated finished steel strip, on the one hand, the uniformity of the microstructure of the cold-rolled base material can be improved. Under the action of the microstructure genetic effect, the microstructure uniformity of the obtained aluminum-zinc coated finished steel strip is higher; in addition, determining the appropriate tension coefficient and determining the tension applied to the aluminum-zinc coated finished steel strip through the tension coefficient, the width of the steel strip and the thickness of the steel coil can reduce the occurrence of horizontal folding defects in the winding process of the aluminum-zinc coated finished steel strip, thereby improving the quality of the produced aluminum-zinc coated finished steel strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 Schematic diagram of a steel coil with horizontal fold defects;

[0037] Figure 2 A schematic diagram of a method for producing galvanized steel strip provided in some embodiments of the present application;

[0038] Figure 3 A schematic diagram of a winding device provided in some embodiments of the present application;

[0039] Figure 4 Schematic diagram of a steel coil for overcoming horizontal folding defects provided in some embodiments of the present application.

[0040] The reference numerals are as follows:

[0041] 1. Winding equipment, 11. Winding mechanism, 12. Central control mechanism, 121. Input end, 13. Size detection element. DETAILED DESCRIPTION

[0042] The present application will be further described in detail below through the accompanying drawings and examples, through which the features and advantages of the present application will become more clear and distinct.

[0043] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by technicians in the technical field to which this application belongs; the terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions.

[0044] The phrase "embodiment" mentioned in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive with other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0045] The term "exemplary" is used herein to mean "serving as an example, embodiment, or illustration." Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0046] In the description of this application, the technical terms "first", "second", "third", etc. are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary and secondary relationship of the indicated technical features.

[0047] In the description of this application, the technical term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0048] In the description of this application, the orientations or positional relationships indicated by technical terms such as "upper", "lower", "inside", "outside", "front", "back", "left", "right", "top", and "bottom" are orientations or positional relationships based on the working state of this application. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0049] In the description of this application, unless otherwise specified or limited, technical terms such as "mounted," "connected," "connect," and "fixed" should be understood broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0050] In the description of this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0051] In the description of the present application, “a plurality of” means two or more (including two), unless otherwise clearly and specifically defined.

[0052] In the description of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, and other dimensions of the integrated device shown in the drawings are merely illustrative and do not constitute any limitation on this application.

[0053] As part of the creative concept of this application, before describing the embodiments of this application, it is necessary to analyze the causes of the problem of horizontal fold defects in cold-rolled steel strips during the coiling process in related technologies, and obtain the technical solutions of the embodiments of this application through reasonable analysis.

[0054] In the related technology, cold-rolled strip steel has a wide range of applications. During the production process, the finished steel strip is wound on the winding core at the coiling stage. The steel strip has a certain degree of curvature, but there is a certain difference in the deformation of the inner and outer layers of the steel strip. As the coiling continues, the stress concentration generated during the deformation of the steel strip cannot be released evenly. When it accumulates to a certain extent, it will produce obvious uneven plastic deformation along the width direction of the steel coil, forming a horizontal fold defect similar to the traces of origami. Figure 1 This defect will damage the structural strength of the steel strip. Even if it is remedied through other treatment methods later, it will cause a certain decline in structural strength and other performance. In addition, some steel strips have production process limitations. For example, in order to ensure the integrity of the zinc spangles, galvanized steel strips are generally not passed through the skin-pass mill to eliminate the yield platform. The horizontal folding defect has a greater impact on the steel strip.

[0055] To this end, the present application provides a method for producing cold-rolled aluminum-zinc coated steel strip, thereby solving the technical problem in the prior art that horizontal folds are generated during the coiling process of the cold-rolled steel strip, affecting the structural strength of the steel strip.

[0056] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings. The technical features involved in the different implementation modes of the present application described below can be combined with each other as long as there is no conflict between them.

[0057] For ease of description of the following embodiments, this application uses galvanized steel strip as an example. Specifically, after the steel strip completes the cold rolling process, it is plated with an aluminum-zinc mixture. Of course, the production method provided in this application is applicable not only to galvanized steel strip, but also to various other cold-rolled steel strip products currently available in the art.

[0058] The embodiment of the present application provides a method for producing a cold-rolled galvanized steel strip, referring to Figure 2 , including the following steps:

[0059] Step 001: pre-processing the raw steel and hot rolling it;

[0060] Step 002: Cooling the hot-rolled product to obtain a cold-rolled base material at a set temperature;

[0061] Step 003: cold rolling the cold rolled base material to obtain a cold rolled finished steel strip;

[0062] Step 004: The cold-rolled finished steel strip is subjected to plating treatment to obtain an aluminum-zinc coated finished steel strip;

[0063] Step 005: Winding the galvanized steel strip to form a galvanized steel coil.

[0064] Specifically, step 001: desulfurize the raw steel, and subject the desulfurized steel to converter smelting, off-furnace refining, and continuous casting. Through the early processing process, impurities in the raw steel are removed, reducing the presence of more impurities in the steel during the hot rolling process, which may cause various problems such as cracking of the steel during the hot rolling process. It can also avoid the precipitation of more impurities during the hot rolling process, which requires frequent cleaning of the hot rolling equipment, and can provide greater convenience for actual production operations.

[0065] After completing the preliminary treatment, the steel is transported to the hot rolling equipment, where it is heated to the hot rolling temperature range and hot rolled. The number of hot rolling passes is adjusted as needed, and the compression rate of each rolling is maintained at around 10%. After multiple rolling passes, the size of the steel gradually reaches the set size. This avoids excessive compression in a single rolling pass, which can lead to problems such as cracking in the steel. The internal structure of the steel is gradually tightened during the multiple rolling processes, and the shape of the steel plate after rolling can be more easily controlled to avoid large deformation problems.

[0066] It should be noted that maintaining a compression rate of approximately 10% per rolling pass means that the steel is hot-rolled to the desired thickness in multiple passes, with each pass compressing the steel a certain amount. For example, if a 4mm thick steel billet is rolled into a 2mm thick steel plate, the thickness of the steel billet after the first rolling pass is 3.6mm, representing a compression rate of 10%. It should also be understood that the present embodiment does not strictly limit the compression rate per rolling pass to 10%, but rather allows it to fluctuate within a certain range around this value, for example, 8%-12%. In actual production, this value may be adjusted based on actual conditions.

[0067] Step 002: The steel is hot-rolled through hot rolling equipment to form steel plates of a set size. The steel plates conveyed from the hot rolling process are then cooled to maintain them in a suitable temperature range. The cooling process uses laminar cooling, that is, laminar water flow is used to cool the hot-rolled steel plates. Multiple laminar flow pipes are arranged along the conveying path of the hot-rolled steel plates, arranged on the upper and lower sides of the steel plates (the embodiment of this application takes the steel plates conveyed in a flat state as an example), forming a cooling belt extending along the conveying path of the hot-rolled steel plates. The upper and lower surfaces of the steel plates are cooled synchronously. After the temperature is cooled to the set temperature, it is used as a cold-rolled base material in the subsequent cold rolling process.

[0068] During the cooling process of hot-rolled steel plates, it is necessary to monitor the temperature of the steel plates in real time to control the temperature of the steel plates more conveniently and accurately. The temperature of the steel plates after laminar cooling can be adjusted accordingly according to the different thicknesses of the steel plates and the different temperatures of the cooling water used for laminar cooling. For example, the following relationship is satisfied among the three:

[0069] CT=630-5×(T-28)-10×(t-3).

[0070] Wherein, CT is the temperature of the hot-rolled steel plate at the end of cooling, T is the cooling water temperature of laminar cooling, and t is the thickness of the hot-rolled steel plate; the corresponding measurement units of CT and T are ℃, and the corresponding measurement unit of t is mm.

[0071] The thickness of hot-rolled steel sheets is already set during the hot-rolling process, so this thickness can be directly determined. A temperature sensor is installed in the water storage container of the laminar flow cooling equipment to monitor the cooling water temperature. Alternatively, the temperature sensor can be installed in a laminar flow pipe or other location, as long as it can determine the cooling water temperature.

[0072] In actual production, the temperature of hot-rolled steel plates is difficult to accurately control at a certain temperature value, but rather fluctuates within a certain range above and below the set temperature value. Therefore, in the relationship between CT, T, and t, when T and t are determined and CT is within the corresponding range, the three satisfy the following relationship:

[0073] 620-5×(T-28)-10×(t-3)≤CT≤640-5×(T-28)-10×(t-3).

[0074] The temperature sensor is connected to the control system signal, wherein the control system is connected to the signals of each device of the hot rolling production line for overall control of the hot rolling and cooling processes. For example, the control system can adjust the heating temperature, conveying speed, cooling water flow rate of laminar cooling, etc. of the hot-rolled steel plate.

[0075] The control system receives the detected cooling water temperature information and determines the target temperature of the hot-rolled steel plate based on the cooling water temperature. This information is then used to determine the cooling water flow rate for laminar cooling. The hot-rolled steel plate continues to cool while being transported at a set speed. Given a fixed cooling water temperature, a higher cooling water flow rate results in a lower temperature after cooling. Therefore, adjusting the cooling water flow rate allows for convenient temperature control of the hot-rolled steel plate.

[0076] In addition, in other embodiments, the flow rate of cooling water can also be set to remain unchanged, and the final temperature of the hot-rolled steel plate can be controlled by adjusting the conveying speed of the hot-rolled steel plate. However, regulating the conveying speed of the hot-rolled steel plate may affect the preceding processing steps of the hot-rolled steel plate. In actual production, the conveying speed of the hot-rolled steel plate should be adjusted without affecting the normal processing of other steps.

[0077] However, in the actual production process, the temperature of the cooling water in laminar flow cooling does not remain at a certain constant temperature for a long time, but may fluctuate within a certain range. If it is controlled in real time, the flow rate of the laminar flow cooling water will change at a high frequency, which will cause a large working burden on the flow control structure of the cooling water and easily lead to the problem of shortened service life.

[0078] Moreover, the laminar flow cooling equipment includes multiple laminar flow cooling pipes arranged along the conveying path of the hot-rolled steel plate. If the final temperature of the hot-rolled steel plate is adjusted according to the precise temperature point value of the cooling water, each laminar flow cooling pipe needs to be controlled separately. At least multiple laminar flow cooling pipes on the conveying path of the hot-rolled steel plate are divided into multiple intervals, and each interval is controlled separately, which greatly increases the control difficulty and makes it difficult to accurately control the final cooling temperature of the hot-rolled steel plate.

[0079] In order to conveniently control the temperature of the hot-rolled steel plate, in the actual production process, when the temperature of the laminar flow cooling water is in different intervals, the target temperature of the hot-rolled steel plate corresponding to each temperature interval is set, and it is ensured that the temperature of the hot-rolled steel plate at the end of laminar flow cooling is within a certain interval above and below the target temperature.

[0080] Exemplarily, for cold-rolled base materials with a thickness of 4 mm, when the temperature of the cooling water is in different intervals, the corresponding target temperatures of the hot-rolled steel plate are as follows:

[0081] When the laminar flow cooling water temperature T satisfies T ≤ 30 °C, the target temperature of the hot-rolled steel plate is 610 °C, and the temperature of the hot-rolled steel plate at the end of laminar flow cooling is maintained at 600 °C - 620 °C;

[0082] When the laminar flow cooling water temperature T satisfies 30 °C < T ≤ 32 °C, the target temperature of the hot-rolled steel plate is 600 °C, and the temperature of the hot-rolled steel plate at the end of laminar flow cooling is maintained at 590 °C - 610 °C;

[0083] When the laminar flow cooling water temperature T satisfies 32 °C < T ≤ 34 °C, the target temperature of the hot-rolled steel plate is 590 °C, and the temperature of the hot-rolled steel plate at the end of laminar flow cooling is maintained at 580 °C - 600 °C.

[0084] Step 003: The hot-rolled steel plate after cooling is the base material for the subsequent cold rolling process, hereinafter simply referred to as cold-rolled base material. After the cold-rolled base material is coiled, it is transported to the cold rolling production line.

[0085] In some other embodiments, the cold rolling production line and the hot rolling production line are arranged in the same area. In this case, the cold-rolled base material after laminar flow cooling can be directly transferred to the cold rolling production line for the subsequent cold rolling process, thus saving the intermediate coiling, transportation, and unrolling processes.

[0086] The compression ratio of the cold-rolled base material is maintained in the range of 40% to 60%. Of course, this limited range is an exemplary description. The specific cold rolling process is the rolling process conventionally adopted in this field, and this part will not be repeated in the embodiments of this application.

[0087] Step 004: The finished steel strip after cold rolling is cleaned and rust-removed to ensure surface cleanliness and smoothness. The treated finished steel strip is then transferred to a hot-dip process where a layer of aluminum-zinc alloy is applied to the surface. Hot-dip is a common treatment method in the art. The equipment, specific operations, and various parameter settings required for the hot-dip process are well known to those skilled in the art and will not be further described in detail in this embodiment.

[0088] After the hot-dip galvanizing is completed, the galvanized finished steel strip is cooled and then subjected to tensioning and straightening. The straightening process improves the plate shape. Specifically, it can eliminate the edge waves, middle waves and other wave defects of the steel strip to obtain a better plate shape. In addition, the tensioning and straightening process can also improve the processing performance of the steel strip. After stretching and bending, the steel strip has less or no yield platform in the subsequent deformation process, thereby improving the quality of the galvanized steel strip.

[0089] The galvanized steel strip is cooled to lower its temperature to ensure that the galvanized coating on the surface is completely solidified and tightly bonded to the steel strip, minimizing the risk of uneven coating or detachment. For example, the temperature of the galvanized steel strip is lowered to no higher than 70°C.

[0090] Step 005: After galvanizing and straightening, the steel strip is transported to the coiling process, where it is coiled into finished galvanized steel coils for subsequent transportation or storage. Coiling cold-rolled steel strip requires the use of appropriate coiling equipment. A section of the strip is connected to a reel, which rotates to coil the strip.

[0091] During the coiling process, it is necessary to ensure that the appropriate tension is applied to the steel strip. Specifically, the tension applied to the steel strip satisfies the following relationship: F ​​= A × r × W. Here, F is the tension applied to the steel strip, A is the tension coefficient of the steel strip, r is the thickness of the finished steel coil, and W is the width of the steel strip. The unit of measurement for F is kg, and the units of measurement for r and W are mm.

[0092] The process of steel strip winding needs to be assisted by corresponding winding equipment, refer to Figure 3The winding device 1 includes a winding mechanism 11 for winding a steel strip into a steel strip, and a central control mechanism 12 connected to the winding mechanism 11 by signal transmission. The central control mechanism 12 has an input terminal 121. For example, the input terminal 121 is a touch screen or a keyboard-like input structure, and is equipped with a display screen for displaying relevant data. A staff member inputs corresponding parameters through the input terminal 121, and the central control mechanism 12 controls the operation of the winding mechanism 11.

[0093] In the actual production process, the dimensions of the finished galvanized steel strips to be produced are all determined. Based on the obtained dimensions, the operator inputs the tension coefficient corresponding to the dimensions of the finished galvanized steel strips through the input terminal 121 of the central control mechanism 12, and the central control mechanism 12 calculates the corresponding tension. Alternatively, the corresponding relationship between the dimensional parameters of the finished galvanized steel strips and the tension coefficients can be pre-stored in the central control mechanism 12. The operator can directly input the dimensional parameters of the finished galvanized steel strips, and the central control mechanism 12 automatically determines the tension coefficient. This can avoid the problem of errors caused by the operator in determining the tension coefficient based on the dimensions of the finished galvanized steel strips.

[0094] In addition, as the winding process continues, the size of the galvanized steel coil formed by winding the galvanized steel strip (referring to the radial size of the cross-section of the steel coil) continues to increase, and the winding force required by the winding equipment is also greater. Therefore, the magnitude of the winding force is adjusted in real time according to the size of the galvanized steel coil, which can ensure that the force on the galvanized steel strip remains constant at different stages of the winding process.

[0095] refer to Figure 3 The winding device 1 further includes a size detection element 13 for real-time detection of the size of the galvanized steel coil. The element is connected to the central control mechanism 12 by a signal so as to transmit the real-time detected size information of the galvanized steel coil to the central control mechanism 12. Exemplarily, the size detection element 13 is an infrared distance sensor fixed to the winding mechanism 11. The element 13 detects the distance from its position to the outermost surface of the galvanized steel coil and transmits this size information to the central control mechanism 12. Since the infrared distance sensor is positioned accurately, the size of the galvanized steel coil can be obtained based on the distance from the infrared distance sensor to the outermost surface of the galvanized steel coil.

[0096] During the winding process, the central control mechanism 12 is also used to control the winding mechanism 11 to adjust the speed of the finished galvanized steel strip in real time. By adjusting the speed of the steel strip, the finished galvanized steel strip is transported at an appropriate speed. For example, the transport speed of the finished galvanized steel strip is controlled between 60 and 100 m / s to maintain the stability of the steel strip winding process and avoid excessive variations in transport speed that may cause stacking or stretching deformation of the steel strip.

[0097] The present invention designs an experiment to investigate the effects of different laminar cooling water temperatures, hot-rolled steel strip cooling endpoint temperatures, and tension coefficients on the quality of the final galvanized steel coils. Specific experimental results are shown in the table below:

[0098] Table 1

[0099]

[0100]

[0101] Table 2

[0102]

[0103]

[0104]

[0105] Based on the experimental results of Groups 1, 2, and 3 above, it can be determined that the suitable temperature range of the hot-rolled steel plate at the laminar cooling endpoint is different when the laminar cooling water temperature is different. In addition, when the laminar cooling water temperature is determined, the thickness of the hot-rolled steel plate will also affect its suitable temperature range at the laminar cooling endpoint. The influence of the hot-rolled steel plate thickness on the suitable laminar cooling endpoint temperature can be determined based on Groups 1, 12, and 15, 2, 13, and 16, and 3, 14, and 17, respectively. By combining the above laminar cooling temperature and the influence of the hot-rolled steel plate thickness on the laminar cooling endpoint temperature, the appropriate laminar cooling endpoint temperature can be determined.

[0106] By limiting the temperature of the hot-rolled steel plate at the end point of laminar cooling through the above correspondence, the uniformity of the microstructure of the hot-rolled steel plate can be improved. After that, the hot-rolled steel plate is cold-rolled. Through the genetic effect of the microstructure, the uniformity of the microstructure of the cold-rolled finished steel strip and the aluminum-zinc coated finished steel strip can be improved, which can effectively avoid the problem of stress concentration and uneven deformation caused by the hardness difference between the two phases during the coiling process of thick-gauge steel strip.

[0107] And taking into account the convenience in actual work and the feasibility of improving the control of the terminal temperature of the hot-rolled steel plate at the laminar cooling end point, on the premise of being able to eliminate the horizontal fold defects in the subsequent aluminum-zinc coated finished steel coils, the terminal temperature of the hot-rolled steel plate at the laminar cooling end point can be allowed to fluctuate within a certain range, which can simplify the process of temperature regulation in the production process.

[0108] The experimental data of Group 1-11 details the determination of appropriate tension coefficients under different thicknesses of aluminized zinc finished steel strips, in order to reduce the occurrence of transverse fold marks on the surface of the aluminized zinc finished steel strip after winding into a steel coil. When the thickness of the aluminized zinc finished steel strip is determined, the tension coefficient can be set to any value within a certain range. However, in actual production, to reduce the situation where different workers set different tension coefficients within the selectable range for aluminized zinc finished steel strips of the same thickness, the corresponding tension coefficient values for different thicknesses of aluminized zinc finished steel strips are set to reduce the problem of errors.

[0109] For ease of description, let the thickness of the aluminized zinc finished steel strip be h; when h satisfies 1.5mm ≤ h ≤ 2.5mm, A satisfies 1.2 ≤ A ≤ 1.6; and the value of A decreases as the value of h increases. Exemplarily, when h is 1.5mm, the corresponding tension coefficient A is set to 1.6;

[0110] When the thickness h satisfies 1.5mm < h ≤ 1.7mm, the corresponding tension coefficient A is set to 1.5;

[0111] When the thickness h satisfies 1.7mm < h ≤ 2mm, the corresponding tension coefficient A is set to 1.4;

[0112] When the thickness h satisfies 2mm < h ≤ 2.2mm, the corresponding tension coefficient A is set to 1.3;

[0113] When the thickness h satisfies 2.2mm < h ≤ 2.5mm, the corresponding tension coefficient A is set to 1.2.

[0114] In the actual production process, after the workers know the thickness of the aluminized zinc finished steel strip, they determine the corresponding tension coefficient according to the above-mentioned corresponding relationship between the thickness of the aluminized zinc finished steel strip and the tension coefficient, and input it into the central control mechanism of the coiling equipment; during the subsequent process of the coiling equipment winding the steel strip, the central control mechanism calculates the magnitude of the winding force exerted on the steel coil by the winding mechanism according to the tension coefficient, the width of the aluminized zinc finished steel strip, and the thickness of the steel coil, ensuring a good winding effect on the aluminized zinc finished steel strip and reducing the problem of transverse fold marks on the surface of the steel strip after winding; refer to Figure 4 , through the parameter limitation in the embodiments of this application, the produced aluminized zinc finished steel coils have no transverse fold mark defects.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for producing a cold-rolled galvanized steel strip, characterized in that: It includes the following steps: Obtain a hot-rolled steel plate at a set temperature as the cold-rolled base material; The cold-rolled base material is cold-rolled to obtain a cold-rolled finished steel strip; The cold-rolled finished steel strip is subjected to plating solution treatment to obtain an aluminized zinc finished steel strip; Wind the aluminized zinc finished steel strip to form an aluminized zinc finished steel coil; During the process of winding the aluminized zinc finished steel strip to form an aluminized zinc finished steel coil, the winding force applied to the steel strip satisfies the following relationship: F = A × r × W; Where, F is the magnitude of the tension applied to the aluminized zinc finished steel strip, A is the tension coefficient of the aluminized zinc finished steel strip, r is the finished thickness of the aluminized zinc finished steel coil, W is the width of the aluminized zinc finished steel strip, the measurement unit of F is kg, and the measurement units of r and W are mm; The steel strip tension coefficient is determined by the thickness h of the aluminized zinc finished steel strip. When h satisfies 1.5mm ≤ h ≤ 2.5mm, A satisfies 1.2 ≤ A ≤ 1.6; and the value of A decreases as the value of h increases.

2. The method for producing cold-rolled galvanized steel strip according to claim 1, characterized in that: When h is 1.5mm, the corresponding tension coefficient A is set to 1.6; When the thickness h satisfies 1.5mm < h ≤ 1.7mm, the corresponding tension coefficient A is set to 1.5; When the thickness h satisfies 1.7mm < h ≤ 2mm, the corresponding tension coefficient A is set to 1.4; When the thickness h satisfies 2mm < h ≤ 2.2mm, the corresponding tension coefficient A is set to 1.3; When the thickness h satisfies 2.2mm < h ≤ 2.5mm, the corresponding tension coefficient A is set to 1.

2.

3. The method for producing cold-rolled galvanized steel strip according to claim 1, characterized in that: The process of obtaining a hot-rolled steel plate with a cooling temperature in a set range as the cold-rolled base material is specifically: cooling the hot-rolled steel plate by laminar flow cooling, and determining the cooling end temperature of the hot-rolled steel plate according to the thickness of the hot-rolled steel plate and the cooling water temperature of the laminar flow cooling. The three satisfy the following relationship: 620 - 5×(T - 28) - 10×(t - 3) ≤ CT ≤ 640 - 5×(T - 28) - 10×(t - 3); Where, CT is the cooling end temperature of the hot-rolled steel plate, T is the cooling water temperature of the laminar flow cooling, t is the thickness of the hot-rolled steel plate; the measurement units corresponding to CT and T are °C, and the measurement unit corresponding to t is mm.

4. The method for producing cold-rolled galvanized steel strip according to claim 3, characterized in that: CT, T, and t satisfy the following relationship: CT = 630 - 5×(T - 28) - 10×(t - 3).

5. The method for producing cold-rolled galvanized steel strip according to claim 3, characterized in that: For the hot-rolled steel plate with a thickness t of 4mm of the hot-rolled steel plate: When T satisfies T ≤ 30°C, the temperature CT of the hot-rolled steel plate at the end of laminar flow cooling remains at 600°C - 620°C; When T satisfies 30°C < T ≤ 32°C, the temperature CT of the hot-rolled steel plate at the end of laminar flow cooling remains at 590°C - 610°C; When T satisfies 32°C < T ≤ 34°C, the temperature CT of the hot-rolled steel plate at the end of laminar flow cooling remains at 580°C - 600°C.

6. The method for producing cold-rolled galvanized steel strip according to claim 1, characterized in that: The process of winding the aluminized zinc finished steel strip to form an aluminized zinc finished steel coil is specifically using a coiling device to wind the aluminized zinc finished steel strip; The coiling device includes a coiling mechanism for winding the aluminized zinc finished steel strip and a central control mechanism signal-connected to the coiling mechanism; The central control mechanism is provided with an input end for inputting corresponding parameters; The central control mechanism is used to control the speed at which the winding mechanism winds the galvanized finished steel strip and the tension applied to the galvanized finished steel strip.

7. The method for producing cold-rolled galvanized steel strip according to claim 6, characterized in that: The central control mechanism also includes a size detection element fixedly connected to the winding mechanism. The size element is connected to the central control mechanism by signal and is used to transmit the size information of the aluminum-zinc coated finished steel coil to the central control mechanism.

8. The method for producing cold-rolled galvanized steel strip according to claim 7, characterized in that: The size detection element is an infrared distance sensor.

9. The method for producing cold-rolled galvanized steel strip according to claim 1, characterized in that: The cold-rolled finished steel strip is subjected to a plating solution treatment to obtain an galvanized finished steel strip, and then the temperature of the galvanized finished steel strip is reduced to no more than 70° C., and then the galvanized finished steel strip is wound to form an galvanized finished steel coil.

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