A continuous quenching heat treatment method and system for 2~8mm high-strength thin steel plates

Abstract

The present invention discloses a continuous quenching heat treatment method for high-strength thin steel plates with a thickness of 2 to 8 mm. During the continuous quenching heat treatment process, the transfer time, quenching water volume, quenching cooling time, and quenching tension of the thin steel plates are controlled. The transfer time of the thin steel plates from the quenching heating furnace to the quenching machine is determined based on the thickness of the thin steel plates, and the speed of the drive roller group is set. The quenching water volume in the quenching machine is determined based on the percentage of each element in the thin steel plates. The quenching cooling time in the quenching machine is determined based on the quenching water volume, the thickness of the thin steel plates, the heating temperature of the thin steel plates in the quenching heating furnace, and the temperature of the thin steel plates after cooling in the quenching machine. The number of starting zones in the quenching machine is set based on the quenching cooling time. The quenching tension of the thin steel plates during the continuous quenching heat treatment process is determined based on the thickness of the thin steel plates, and the quenching tension is set using a force roller. Steel plates produced using the heat treatment technology of the present invention have the advantages of high performance, good plate quality, and low internal stress.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment, in particular to a continuous quenching heat treatment method and system for 2-8 mm thin steel plates. Background Art

[0002] High-strength steel sheets are widely used in defense, transportation, equipment manufacturing, petrochemicals, and other fields, such as armored vehicle armor plates and automotive body panels. With the rapid development of these sectors, the demand for high-strength steel sheets is increasing. For example, Zoomlion's demand for high-strength steel sheets reaches 300,000 tons per year.

[0003] To achieve high strength, thin steel sheets must be quenched to achieve a martensitic structure. Therefore, thin steel sheets must be cooled rapidly during the quenching process. Rapid cooling rates result in large residual stresses during the quenching process. Thin steel sheets, however, have weak rigidity. If residual stresses are not regulated or constrained during the quenching process, they can easily develop significant quenching deformations, such as wavy deformation, buckling, and tortoise-back deformation. High-strength thin steel sheets, with strengths exceeding 1000 MPa, are extremely difficult to straighten. Even after straightening in a high-tonnage straightening machine, significant residual stresses can remain in the steel sheets. During cutting, these internal stresses can be released, leading to accidents such as damage to cutting equipment and injuries to operators. If deformed thin steel sheets are not straightened, they will not meet service requirements, resulting in scrap and failure to meet the demand for high-quality development in these sectors.

[0004] Therefore, it is urgent for steel manufacturing companies to realize the quenching heat treatment production of high-strength thin steel plates with little or no deformation. Summary of the Invention

[0005] In view of the above problems in the prior art, the present application provides a continuous quenching method and system for 2-8 mm high-strength thin steel plates, so as to reduce or even eliminate the deformation of 2-8 mm high-strength thin steel plates during the quenching heat treatment process and improve the plate shape quality of ultra-strong thin steel plates.

[0006] To achieve the above objectives, the present application proposes a continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates, which adopts the following technical solutions:

[0007] During the continuous quenching heat treatment process, the transfer time of the thin steel plate, the amount of quenching water, the quenching cooling time and the quenching tension are controlled, among which:

[0008] According to the thickness of the thin steel plate, the transfer time of the thin steel plate from the quenching heating furnace 6 to the quenching machine 7 is determined, and the speed of the driving roller group 12 is set according to the transfer time;

[0009] Determine the amount of quenching water in the quenching machine 7 according to the percentage of each element in the thin steel plate;

[0010] The quenching cooling time in the quenching machine 7 is determined according to the quenching water volume, the thickness of the thin steel plate, the heating temperature of the thin steel plate in the quenching heating furnace 6 and the temperature of the thin steel plate after cooling in the quenching machine 7, and the number of starting zones in the quenching machine 7 is set according to the quenching cooling time;

[0011] The quenching tension of the thin steel plate during the continuous quenching heat treatment is determined according to the thickness of the thin steel plate, and the quenching tension is set by the force applying roller 9.

[0012] As described above, the continuous quenching heat treatment method primarily comprises control methods for transfer time, quenching water volume, quenching cooling time, and quenching tension. Taking into account the composition and thickness characteristics of the high-strength thin steel plate, the transfer time parameters, quenching water volume parameters, quenching tension parameters, and quenching cooling time control parameters are coupled and controlled. By precisely controlling the cooling method parameters and stress method parameters of the thin steel plate during the continuous quenching heat treatment process, a continuous and deformation-free quenching heat treatment process for high-strength thin steel plate with a thickness of 2 to 8 mm is achieved.

[0013] Alternatively, the transfer time may be determined as follows:

[0014] Δt=10.2788-7.2556*H+1.9845*H*H-0.1222*H*H*H, H∈[2, 8];

[0015] Wherein, Δt is the transfer time, the unit of which is s, and H is the thickness of the steel plate, the unit of which is mm.

[0016] From the above, by calculating the transfer time in advance, the rotation speed of the driving roller group 12 is set; the time for the thin steel plate to enter the quenching machine 7 from the quenching heating furnace 6 (called transfer time) is finely controlled to avoid the thin steel plate staying in the air for too long, which reduces the final strength of the thin steel plate.

[0017] Optionally, the water pressure of the quenching water is 0.2-0.25 MPa, and the amount of quenching water sprayed onto the thin steel plate can be determined according to the following three formulas:

[0018]

[0019] Where W is the amount of quenching water sprayed onto the thin steel plate, in m 3 / (m 2 *min), W Cr is the mass percentage of chromium element, W Mn is the mass percentage of manganese element, W Si is the mass percentage of silicon element, W Ni is the mass percentage of nickel element, W Mois the mass percentage of molybdenum element, W W is the mass percentage of tungsten element, W V is the mass percentage of vanadium element, W Ti is the mass percentage of titanium element, W Nb is the mass percentage of niobium element, W N is the mass percentage of nitrogen, W Al is the mass percentage of aluminum element, W B is the mass percentage of boron element, W C is the mass percentage of carbon element, W P is the mass percentage of phosphorus, W S is the mass percentage of sulfur element, W Cn is the mass percentage of cobalt element, in %, M and E are dimensionless intermediate variables.

[0020] As described above, quenching water volume control is achieved by precisely controlling the volume and pressure of quenching water sprayed onto the thin steel plate in quenching machine 7. This prevents significant quenching deformation of the thin steel plate due to excessive cooling rates and reduces its strength due to insufficient cooling rates. Quenching water volume control is established within the cooling system of quenching machine 7. The various elements in this control include, but are not limited to, C, Mn, Si, and Cr.

[0021] Optionally, the quenching cooling time is determined by the following two formulas:

[0022]

[0023] t 终 =539-423*W C -30.4*W Mn -17.7*W Ni -12.1*W Cr -7.5*W Mo -215;

[0024] Among them, t is the quenching cooling time, the unit is s, t 初 is the heating temperature of the thin steel plate in the quenching heating furnace 6, in °C, t 终 is the temperature of the thin steel plate after cooling in the quenching machine, in °C, and W is the amount of quenching water sprayed onto the thin steel plate, in m 3 / (m 2 *min), H is the thickness of the steel plate in mm, W C is the mass percentage of carbon element, W Mn is the mass percentage of manganese element, W Ni is the mass percentage of nickel element, W Cr is the mass percentage of chromium element, W Mo is the mass percentage of molybdenum element, in %.

[0025] As mentioned above, the control of quenching cooling time refers to the cooling time of the thin steel plate in the quenching machine 7 (called quenching time). This is to avoid reducing the strength of the thin steel plate due to too short cooling time, and to avoid wasting quenching water due to too long cooling time. The quenching cooling time is set by controlling the number of starting zones in the cooling system of the quenching machine 7.

[0026] Alternatively, the quenching tension can be determined according to the following formula:

[0027] σ=-0.0024*H*H+1.2024*H-0.9857, H∈[2, 8];

[0028] Among them, σ is the quenching tension in tons, and H is the thickness of the thin steel plate in mm.

[0029] As described above, quenching tension control involves continuously applying tension to the steel sheet along its length during the continuous quenching heat treatment process to prevent the steel sheet from sagging and deforming due to its own weight. This tension, applied along the length of the steel sheet, can also partially offset the quenching stress, thereby reducing deformation. The quenching tension is set by the force roller 9.

[0030] Optionally, the end of the current thin steel plate is welded to the beginning of the next thin steel plate as a whole by the front end butt welding equipment 3; and the thin steel plate that has been continuously heated is sheared into a plate size that meets the standard by the rear end shearing equipment 14.

[0031] As described above, before welding, the uneven surface of the new steel coil is flattened by the leveling equipment 2, and then the end of the current thin steel plate is welded to the beginning of the next thin steel plate by the butt welding equipment 3, realizing the continuous quenching heat treatment process of the thin steel plates; after the quenching heat treatment is completed, the continuous thin steel plates are sheared into sizes that meet national / international standards by the shearing equipment 14, and finally the continuous quenching treatment of 2-8 mm high-strength thin steel plates is completed.

[0032] Optionally, the running speed of the thin steel plate is determined according to the distance between the quenching heating furnace 6 and the quenching machine 7, and the transfer time, and the rotation speed of the driving roller group 12 is set; the number of starting zones of the quenching heating furnace 6 is set according to the preset quenching heating time and the running speed of the thin steel plate.

[0033] From the above, the transfer time of the thin steel plate can be obtained by substituting the thickness of the thin steel plate into the transfer time formula. The running speed of the thin steel plate in the entire continuous quenching heat treatment process is calculated by the calculation formula of the spacing and transfer time. The running speed is controlled by the rotation speed of the driving roller group; the quenching heating furnace 6 is composed of a certain number of single zones, and the length of each zone is equal and fixed. By pre-setting the quenching heating time and the running speed of the thin steel plate, the length that the quenching heating furnace 6 needs to heat is calculated, and then the number of zones that the quenching heating furnace 6 needs to start is determined, so as to make full use of thermal energy and save energy.

[0034] Optionally, the number of starting zones of the tempering heating furnace 8 is set according to the preset tempering heating time and the running speed of the thin steel plate.

[0035] From the above, by presetting the tempering heating time and the running speed of the thin steel plate, the length that needs to be heated in the tempering heating furnace 8 is calculated, and then the number of zones that need to be started in the tempering heating furnace 8 is determined, and the heating devices of each zone of the tempering heating furnace 8 are controlled separately, so as to make full use of thermal energy, save energy and avoid unnecessary waste.

[0036] Optionally, the movable rollers are moved in the horizontal direction to provide welding time and shearing time for the thin steel plates during the continuous quenching heat treatment process.

[0037] As shown above, active rollers are set at two places. The first active roller 5 is set after passing the butt welding equipment 3, and the second active roller 11 is set before passing the driving roller group 12. When replacing a new steel coil, the entire heat treatment device is still in operation, and the steel plate needs to be transported to the quenching heating furnace 6. At this time, the first active roller 5 is moved to provide thin steel plates for the quenching heating furnace 6, and also provides time for new welding on the thin steel plates. After the shearing equipment 14 shears the thin steel plates to a certain number of plates, it needs to be removed. At this time, it is necessary to provide sufficient time for the plate transfer by moving the second active roller 11.

[0038] The present application also provides a continuous quenching heat treatment system for 2-8 mm high-strength thin steel plates, which comprises:

[0039] A transfer time control module, which is used to determine the transfer time of the thin steel plate from the quenching heating furnace 6 to the quenching machine 7 according to the thickness of the thin steel plate, and set the rotation speed of the driving roller group 12 according to the transfer time;

[0040] A quenching water quantity control module, which is used to determine the quenching water quantity in the quenching machine 7 according to the percentage of each element in the thin steel plate;

[0041] A quenching cooling time control module is used to determine the quenching cooling time in the quenching machine 7 according to the quenching water volume, the thickness of the thin steel plate, the heating temperature of the thin steel plate in the quenching heating furnace 6 and the temperature of the thin steel plate after cooling in the quenching machine 7, and to set the number of starting zones in the quenching machine 7 according to the quenching cooling time;

[0042] The quenching tension control module is used to determine the quenching tension of the thin steel plate during the continuous quenching heat treatment according to the thickness of the thin steel plate, and set the quenching tension through the force roller 9.

[0043] As described above, in the transfer time control module, the heating devices in each zone of the quenching heating furnace 6 are controlled separately, and in the quenching water volume control module and the quenching cooling time control module, the quenching water control system in each zone of the quenching machine 7 is controlled separately; through the comprehensive and precise control of the transfer time, quenching water volume, quenching cooling time and quenching tension of the thin steel plate by each module, a continuous deformation-free quenching heat treatment production process of 2 to 8 mm high-strength thin steel plates is realized.

[0044] The beneficial effects of the present invention are as follows: by comprehensively and precisely regulating the amount of quenching water and the tensioning force of the quenching machine sprayed onto the thin steel plate during the continuous quenching heat treatment process, the deformation of the thin steel plate during the quenching heat treatment process is reduced or even eliminated, the plate shape and heat treatment residual stress of the thin steel plate are improved, and the heat treatment quality of the thin steel plate is improved. By controlling the transfer time, the formation of ferrite and pearlite structures in the thin steel plate is avoided, thereby ensuring the strength and toughness of the thin steel plate. By controlling the amount of quenching water sprayed onto the thin steel plate, the thin steel plate obtains a martensitic structure and reduces quenching stress, while avoiding the waste of quenching cooling water. By controlling the quenching cooling time, the waste of quenching cooling water is avoided. By controlling the tensioning force, wave deformation, buckling deformation, turtle back deformation, etc. are effectively avoided, and the tensioning force offsets part of the stress formed during the heat treatment process, further improving the plate shape of the thin steel plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The various technical features of the present invention and the relationships between them are further explained below with reference to the accompanying drawings. The accompanying drawings are exemplary, and some technical features are not shown in actual proportion. In addition, some drawings may omit technical features that are commonly used in the technical field to which the present invention belongs and are not essential for understanding and implementing the present invention, or additional technical features that are not essential for understanding and implementing the present invention may be shown. In other words, the combination of the various technical features shown in the accompanying drawings is not intended to limit the present invention. In addition, throughout the present invention, the same figure numerals refer to the same content. The specific description of the drawings is as follows:

[0046] Figure 1 Schematic diagram of a method for continuous quenching heat treatment of a 2-8 mm high-strength thin steel plate according to the present invention;

[0047] Figure 2 This is a diagram of a continuous heat treatment equipment scheme for implementing a continuous quenching heat treatment system for 2-8 mm high-strength thin steel plates in the present invention;

[0048] Figure 3This is a module diagram of a continuous quenching heat treatment system for 2-8 mm high-strength thin steel plates implemented in the present invention.

[0049] Description of Reference Numerals

[0050] 1-Original steel coil; 2-Opening equipment; 3-Butt welding equipment; 4-Transition roller; 5-First movable roller; 6-Quenching heating furnace; 7-Quenching machine; 8-Tempering heating furnace; 9-Force roller; 10-Follower roller; 11-Second movable roller; 12-Drive roller group; 13-Support roller; 14-Shearing equipment; 15-High-strength thin steel plate.

[0051] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0052] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0053] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present application.

[0054] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, the elements defined by the phrase "comprising..." do not exclude the presence of other identical elements in the process, method, article, or device comprising the elements.

[0055] The following describes in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems using specific embodiments. The specific embodiments described below can be combined with each other to form new embodiments. The same or similar ideas or processes described in one embodiment may not be repeated in other embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0056] [Example of continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates]

[0057] Figure 1 The steps of continuous quenching heat treatment of 2-8mm high strength thin steel plate are shown, such as Figure 1 As shown in the figure, during the continuous quenching heat treatment process, the transfer time, quenching water volume, quenching cooling time and quenching tension of the thin steel plate are controlled, where:

[0058] S101: Determine the transfer time of the thin steel plate from the quenching heating furnace 6 to the quenching machine 7 according to the thickness of the thin steel plate, and set the rotation speed of the driving roller group 12 according to the transfer time;

[0059] S102: Determine the amount of quenching water in the quenching machine 7 according to the percentage of each element in the thin steel plate;

[0060] S103: Determine the quenching cooling time in the quenching machine 7 based on the quenching water volume, the thickness of the thin steel plate, the heating temperature of the thin steel plate in the quenching heating furnace 6, and the temperature of the thin steel plate after cooling in the quenching machine 7, and set the number of starting zones in the quenching machine 7 based on the quenching cooling time;

[0061] S104: determining the quenching tension of the thin steel plate during the continuous quenching heat treatment according to the thickness of the thin steel plate, and setting the quenching tension through the force roller 9.

[0062] Specifically, the continuous quenching heat treatment method primarily involves controlling the transfer time, quenching water volume, quenching cooling time, and quenching tension. Taking into account the composition and thickness characteristics of the high-strength thin steel plate, the transfer time parameters, quenching water volume parameters, quenching tension parameters, and quenching cooling time control parameters are coupled and controlled. By precisely controlling the cooling method parameters and stress method parameters of the thin steel plate during the continuous quenching heat treatment process, a continuous, deformation-free quenching heat treatment process for high-strength thin steel plates with a thickness of 2 to 8 mm is achieved.

[0063] It should be noted that, throughout this application, the numbers representing the steps, such as S101, S102, etc., do not necessarily mean that the steps must be executed in this manner. If permitted, the order of the previous and next steps can be interchanged, or they can be executed simultaneously.

[0064] Alternatively, the transfer time may be determined as follows:

[0065] Δt=10.2788-7.2556*H+1.9845*H*H-0.1222*H*H*H, H∈[2,8] Formula 1;

[0066] Wherein, Δt is the transfer time, the unit of which is s, and H is the thickness of the steel plate, the unit of which is mm.

[0067] Specifically, the thickness of the thin steel plate is substituted into Formula 1, the transfer time is calculated in advance, and then the rotation speed of the driving roller group 12 is set; the time for the thin steel plate to enter the quenching machine 7 from the quenching heating furnace 6 (called the transfer time) is finely controlled to avoid the thin steel plate staying in the air for too long, which reduces the final strength of the thin steel plate.

[0068] Optionally, the water pressure of the quenching water is 0.2-0.25 MPa, and the amount of quenching water sprayed onto the thin steel plate can be determined according to the following three formulas:

[0069]

[0070]

[0071]

[0072] Where W is the amount of quenching water sprayed onto the thin steel plate, in m 3 / (m 2 *min), W Cr is the mass percentage of chromium element, W Mn is the mass percentage of manganese element, W Si is the mass percentage of silicon element, W Ni is the mass percentage of nickel element, W Mo is the mass percentage of molybdenum element, W W is the mass percentage of tungsten element, W V is the mass percentage of vanadium element, W Ti is the mass percentage of titanium element, W Nb is the mass percentage of niobium element, W N is the mass percentage of nitrogen, W Al is the mass percentage of aluminum element, W B is the mass percentage of boron element, W C is the mass percentage of carbon element, W P is the mass percentage of phosphorus, W S is the mass percentage of sulfur element, W Cn is the mass percentage of cobalt element, in %, M and E are dimensionless intermediate variables.

[0073] Specifically, the quenching water volume is controlled by precisely controlling the volume and pressure of quenching water sprayed onto the thin steel plates in the quenching machine 7. This prevents significant quenching deformation of the thin steel plates due to excessive cooling rates, and reduces their strength due to insufficient cooling rates. The quenching water volume is controlled within the cooling system of the quenching machine 7.

[0074] Optionally, the quenching cooling time is determined by the following two formulas:

[0075]

[0076] t 终 =539-423*W C -30.4*W Mn -17.7*W Ni -12.1*W Cr -7.5*W Mo -215 Formula 6;

[0077] Among them, t is the quenching cooling time, the unit is s, t 初 is the heating temperature of the thin steel plate in the quenching heating furnace 6, in °C, t 终 is the temperature of the thin steel plate after cooling in the quenching machine, in °C, and W is the amount of quenching water sprayed onto the thin steel plate, in m 3 / (m 2 *min), H is the thickness of the steel plate in mm, W C is the mass percentage of carbon element, W Mn is the mass percentage of manganese element, W Ni is the mass percentage of nickel element, W Cr is the mass percentage of chromium element, W Mo is the mass percentage of molybdenum element, in %.

[0078] Specifically, the quenching cooling time refers to the cooling time of the thin steel plate in the quenching machine 7 (called the quenching time). This is to avoid reducing the strength of the thin steel plate due to a too short cooling time, and to avoid wasting quenching water due to an excessive cooling time. The quenching cooling time is set by controlling the number of start zones in the cooling system of the quenching machine 7.

[0079] Alternatively, the quenching tension can be determined according to the following formula:

[0080] σ=-0.0024*H*H+1.2024*H-0.9857, H∈[2, 8] Formula 7;

[0081] Among them, σ is the quenching tension in tons, and H is the thickness of the thin steel plate in mm.

[0082] Specifically, the quenching tension is controlled by continuously applying a tension force along the length of the steel plate during the continuous quenching heat treatment process to prevent the steel plate from sagging and deforming due to its own weight. By applying the tension along the length of the steel plate, some of the quenching stress generated can be offset, thereby reducing deformation. The quenching tension is set by the force roller 9.

[0083] Optionally, the running speed of the thin steel plate is determined according to the distance between the quenching heating furnace 6 and the quenching machine 7, and the transfer time, and the rotation speed of the driving roller group 12 is set; the number of starting zones of the quenching heating furnace 6 is set according to the preset quenching heating time and the running speed of the thin steel plate.

[0084] Specifically, the thickness of the thin steel plate is substituted into the transfer time formula to obtain the transfer time of the thin steel plate. The running speed of the thin steel plate in the entire continuous quenching heat treatment process is calculated by the calculation formula of the spacing and transfer time. The running speed is controlled by the rotation speed of the driving roller group; the quenching heating furnace 6 is composed of a certain number of single zones, and the length of each zone is equal and fixed. By pre-setting the quenching heating time and the running speed of the thin steel plate, the length that the quenching heating furnace 6 needs to heat is calculated, and then the number of zones that the quenching heating furnace 6 needs to start is determined, so as to make full use of thermal energy and save energy.

[0085] Optionally, the number of starting zones of the tempering heating furnace 8 is set according to the preset tempering heating time and the running speed of the thin steel plate.

[0086] Specifically, by presetting the tempering heating time and the running speed of the thin steel plate, the length that needs to be heated in the tempering heating furnace 8 is calculated, and then the number of zones that need to be started in the tempering heating furnace 8 is determined, and the heating devices in each zone of the tempering heating furnace 8 are controlled separately to make full use of thermal energy, save energy, and avoid unnecessary waste.

[0087] In a specific embodiment, a high-strength thin steel plate with a thickness of 6 mm and a width of 2000 mm (chemical composition as shown in Table 1) is selected as an example, and Figure 2 The invention discloses a continuous heat treatment equipment for a continuous quenching heat treatment method for a high-strength thin steel plate, and describes a specific implementation method for a continuous quenching heat treatment method for a 2-8 mm high-strength thin steel plate.

[0088] Table 1 Chemical composition of high-strength steel plates studied in the specific embodiment (mass percentage, wt%)

[0089] element C Si Mn Cr Mo Ni P S Fe content 0.15 0.6 2.0 0.4 0.25 0.25 0.005 0.003 Bal.

[0090] Figure 2 It is a continuous heat treatment equipment for continuous quenching heat treatment of high strength thin steel plate, wherein the quenching heating furnace 6 has a total of 20 zones (i.e. Figure 2 N1 is 20), the length of each zone is 2.5m, the heating device of each zone is controlled separately, the distance between the quenching heating furnace 6 and the quenching machine 7 is 500mm, and the quenching machine 7 has a total of 8 zones (i.e. Figure 2 N2 is 8), the length of each zone is 0.5m, the quenching water control system of each zone is controlled separately, and the tempering heating furnace 8 has a total of 40 zones (i.e. Figure 2 N3 is 40), the length of each zone is 2.5m, and the heating device of each zone is controlled separately.

[0091] In a specific embodiment, the high-strength thin steel plate is made of low-carbon low-alloy steel material, and the heating temperature in the quenching heating furnace 6 is 920°C, that is, t in formula 5 初 It is 920℃.

[0092] In the above specific embodiment, first, according to Formulas 1 to 7, Table 1 and the thickness of the thin steel plate, the specific values of each parameter are obtained as shown in Table 2.

[0093] Table 2 Specific values of various parameters obtained according to formulas 1 to 7, Table 1 and the thickness of the steel plate

[0094] parameter Δt, s <![CDATA[W,m 3 / (m 2 *min)]]> t,s σ, ton result 12 0.5 10 6.5

[0095] In this specific embodiment, since Δt is xs and the distance between the quenching heating furnace 6 and the quenching machine 7 is 500 mm, it can be seen that the thin steel plate Figure 1 The running speed in the continuous heat treatment equipment is 500mm / 12S=42mm / s.

[0096] The quenching heating time for a high-strength thin steel plate with a thickness of 6 mm and a width of 2000 mm is approximately 15 minutes. Since the running speed of the steel plate is 42 mm / s, it can be seen that the length that needs to be heated by the quenching heating furnace 6 is 42 mm / s*15*60s=37800 mm=37.8 m. The length of each zone of the quenching heating furnace 6 is 2.5 m. When processing the thin steel plate in the embodiment, the quenching heating furnace 6 only needs to heat the last sixteen zones, and the heating system does not need to be started for the first four zones of the quenching heating furnace 6.

[0097] The quenching cooling time t of the high-strength plate with a thickness of 6 mm and a width of 2000 mm is 10 s. Since the running speed of the steel plate is 42 mm / s, it can be seen that the cooling length of the high-strength plate in the quenching machine 7 is 42 mm / s*10 s=420 mm=0.42 m. The length of each zone in the quenching machine 7 is 0.5 m. Therefore, when processing the steel plate in the embodiment, only the first zone is opened in the cooling system of the quenching machine, and the cooling system of the last seven zones of the quenching machine 7 does not need to be started.

[0098] The tempering heating time of the high-strength thin steel plate of the embodiment with a thickness of 6 mm and a width of 2000 mm is about 30 minutes, and the heating temperature is 200°C. As above, the tempering heating furnace 8 only needs to heat the first 32 zones, and the heating system does not need to be started for the last eight zones of the tempering heating furnace 8.

[0099] Optionally, the end of the current thin steel plate is welded to the beginning of the next thin steel plate as a whole by the front end butt welding equipment 3; and the thin steel plate that has been continuously heated is sheared into a plate size that meets the standard by the rear end shearing equipment 14.

[0100] Specifically, before welding, the uneven surface of the new steel coil is flattened by the flattening equipment 2, and then the end of the current thin steel plate is welded to the beginning of the next thin steel plate by the butt welding equipment 3, thereby realizing the continuous quenching heat treatment process of the thin steel plate; after the quenching heat treatment is completed, the continuous thin steel plate is sheared into a size that meets national / international standards by the shearing equipment 14, and finally the continuous quenching process of the 2-8 mm high-strength thin steel plate is completed.

[0101] Optionally, the movable rollers are moved in the horizontal direction to provide welding time and shearing time for the thin steel plates during the continuous quenching heat treatment process.

[0102] Specifically, active rollers are set at two places. The first active roller 5 is set after passing the butt welding equipment 3, and the second active roller 11 is set before passing the driving roller group 12. When replacing a new steel coil, the entire heat treatment device is still in operation, and the steel plate needs to be transported to the quenching heating furnace 6. At this time, the first active roller 5 is moved to provide thin steel plates for the quenching heating furnace 6, and also provides time for new welding on the thin steel plates. After the shearing equipment 14 shears the thin steel plates to a certain number of plates, it needs to be removed. At this time, it is necessary to provide sufficient time for the plate transfer by moving the second active roller 11.

[0103] [Example of a continuous quenching heat treatment system for 2-8mm high-strength thin steel plates]

[0104] exist Figure 2 In the continuous heat treatment equipment of the continuous quenching heat treatment system for 2-8 mm high-strength thin steel plates shown, the original steel coil 1 passes through the leveling equipment 2, the butt welding equipment 3, the transition roller 4, and the first movable roller 5 in sequence, and then enters the quenching heating furnace 6, the quenching machine 7 and the tempering heating furnace 8 for heating, cooling and tempering. Then, under the action of the force roller 9, the follower roller 10, the second movable roller 11, the drive roller group 12, the support roller 13 and the shearing equipment 14, a certain amount of high-strength thin steel plates 15 are produced.

[0105] Figure 3 A schematic diagram of a continuous quenching heat treatment system for 2-8 mm high-strength thin steel plates is shown, which includes:

[0106] The transfer time control module 301 is used to determine the transfer time of the thin steel plate from the quenching heating furnace 6 to the quenching machine 7 according to the thickness of the thin steel plate, and to set the rotation speed of the driving roller group 12 according to the transfer time;

[0107] A quenching water quantity control module 302 is used to determine the quenching water quantity in the quenching machine 7 according to the percentage of each element in the thin steel plate;

[0108] The quenching cooling time control module 303 is used to determine the quenching cooling time in the quenching machine 7 based on the quenching water volume, the thickness of the thin steel plate, the heating temperature of the thin steel plate in the quenching heating furnace 6, and the temperature of the thin steel plate after cooling in the quenching machine 7, and to set the number of starting zones in the quenching machine 7 according to the quenching cooling time;

[0109] The quenching tension control module 304 is used to determine the quenching tension of the thin steel plate during the continuous quenching heat treatment according to the thickness of the thin steel plate, and set the quenching tension through the force roller 9.

[0110] Specifically, in the transfer time control module 301, the heating devices in each zone of the quenching heating furnace 6 are controlled separately, and in the quenching water volume control module 302 and the quenching cooling time control module 303, the quenching water control system in each zone of the quenching machine 7 is controlled separately; through the comprehensive and precise control of the transfer time, quenching water volume, quenching cooling time and quenching tension of the thin steel plate by each module, a continuous deformation-free quenching heat treatment production process of 2 to 8 mm high-strength thin steel plates is realized.

[0111] In a specific embodiment, combining Figure 2 The continuous quenching heat treatment equipment in the embodiment is based on an original steel coil 1 with a thickness of 6 mm and a width of 2000 mm. Referring to the parameters in Tables 1 and 2, the specific implementation method of this embodiment is as follows:

[0112] Step (1): Start the heating system of the last sixteen zones of the quenching furnace 6 and heat the quenching furnace to 920°C. At the same time, start the heating system of the first thirty-two zones of the tempering furnace 8 and heat the tempering furnace to 200°C.

[0113] Step (2): The steel coil (1) of the embodiment with a thickness of 6 mm and a width of 2000 mm passes through the flattening equipment 2 and is then welded to the original steel plate of the continuous heat treatment equipment through the butt welding equipment 3 to form a whole.

[0114] Step (3): Apply a tensioning force of σ=6.5 tons to the steel plate through the force roller 9, and apply a tensioning force of 6.5 tons to the steel plate during the production process.

[0115] Step (4): The steel plate is driven by the driving roller group 12 to pass through the transition roller 4 and the first movable roller 5 in sequence at a speed of 42 mm / s and enter the quenching heating furnace 6 for heating;

[0116] Step (5): The steel plate that has been heated in the quenching heating furnace 6 comes out of the quenching heating furnace, and the cooling system of the quenching machine 7 is started at the same time. After 12 seconds, the steel plate enters the quenching machine 7 for quenching cooling;

[0117] Step (6): the thin steel plate after quenching and cooling enters the tempering heating furnace for tempering treatment;

[0118] Step (7): The tempered steel plate passes through the force roller 9, the follower roller 10, the movable roller 11, the drive roller group 12, and the support roller 13 in sequence and arrives in front of the shearing equipment 14;

[0119] Step (8): The steel plate is sheared by shearing equipment 14 to obtain a high-strength steel plate of the required length.

[0120] The steel plate obtained by the above method has a tensile strength of up to 1300MPa, an elongation of 10%, and a deformation of 1mm / m 2 , the internal residual stress of the steel plate is about 40MPa, which has the advantages of high performance, good plate quality and less internal stress.

[0121] The method and the module are based on the same concept. Since the principles of problem solving by the method and the module are similar, the implementation of the module and the method can refer to each other, and the repetitions will not be repeated.

[0122] In summary, by precisely controlling the amount of quenching water sprayed onto the thin steel plate during the continuous quenching heat treatment, deformation during the quenching heat treatment process can be reduced or even eliminated, improving the plate's shape, residual stresses during heat treatment, and overall heat treatment quality. Controlling the transfer time prevents the formation of ferrite and pearlite in the thin steel plate, ensuring its strength and toughness. Controlling the amount of quenching water sprayed onto the thin steel plate allows the plate to acquire a martensitic structure and reduce quenching stresses, while also avoiding waste of quenching cooling water. Controlling the quenching cooling time also avoids waste of quenching cooling water. Controlling the tension effectively prevents wavy, buckling, and turtleback deformations. The tension offsets some of the stresses formed during heat treatment, further improving the plate's shape.

[0123] Unless otherwise defined, all technical and scientific terms used in this application are the same as those commonly understood by those skilled in the art to which this application belongs. In the event of any inconsistency, the meaning described in the full text of this application or the meaning derived from the content recorded in the full text of this application shall prevail. In addition, the terms used in this description are only for the purpose of describing the embodiments of the present application and are not intended to limit this application.

[0124] In addition, the functions of the module can be implemented by executing a program (software) by a processor, or by hardware such as LSI (Large Scale Integration) and ASIC (Application Specific Integrated Circuit), or by a combination of software and hardware.

[0125] The term "comprising" used throughout this application should not be interpreted as limiting the contents listed thereafter; it does not exclude other structural elements or steps. Therefore, it should be interpreted as specifying the presence of the technical features, integers, steps or components mentioned, but does not exclude the presence or addition of one or more other technical features, integers, steps or components and groups thereof.

[0126] It can be understood that those skilled in the art can combine the features mentioned in one or more embodiments mentioned throughout the present application with the features of other embodiments in any appropriate manner to implement the present application.

[0127] Note that the above are only preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the technical concept of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates, characterized in that: During the continuous quenching heat treatment process, the transfer time, quenching water volume, quenching cooling time and quenching tension of the thin steel plate are controlled, including: Determining the transfer time of the thin steel plate from the quenching heating furnace (6) to the quenching machine (7) according to the thickness of the thin steel plate, and setting the rotation speed of the driving roller group (12) according to the transfer time; Determining the amount of quenching water in the quenching machine (7) according to the percentage of each element in the thin steel plate; Determining the quenching cooling time in the quenching machine (7) based on the quenching water volume, the thickness of the thin steel plate, the heating temperature of the thin steel plate in the quenching heating furnace (6), and the temperature of the thin steel plate after cooling in the quenching machine (7), and setting the number of starting zones in the quenching machine (7) based on the quenching cooling time; Determining the quenching tension of the thin steel plate during the continuous quenching heat treatment according to the thickness of the thin steel plate, and setting the quenching tension by a force-applying roller (9); The water pressure of the quenching water is 0.2-0.25 MPa, and the amount of quenching water sprayed onto the thin steel plate can be determined according to the following three formulas: ， ， ， Wherein, W is the amount of quenching water sprayed onto the thin steel plate, in m 3 / (m 2 *min), W Cr is the mass percentage of chromium element, W Mn is the mass percentage of manganese element, W Si is the mass percentage of silicon element, W Ni is the mass percentage of nickel element, W Mo is the mass percentage of molybdenum element, W W is the mass percentage of tungsten element, W V is the mass percentage of vanadium element, W Ti is the mass percentage of titanium element, W Nb is the mass percentage of niobium element, W N is the mass percentage of nitrogen, W Al is the mass percentage of aluminum element, W B is the mass percentage of boron element, W C is the mass percentage of carbon element, W P is the mass percentage of phosphorus, W S is the mass percentage of sulfur element, W Cu is the mass percentage of copper element, in %, M and E are dimensionless intermediate variables.

2. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 1, characterized in that: The transfer time can be determined according to the following formula: ，H∈[2，8]； Where ∆t is the transfer time in seconds, and H is the thickness of the steel plate in mm.

3. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 1, characterized in that: The quenching cooling time is determined by the following two formulas: ，H∈[2,8]， ； Wherein, t is the quenching cooling time, in seconds, t 初 is the heating temperature of the thin steel plate in the quenching heating furnace (6), in °C, t 终 is the temperature of the thin steel plate after cooling in the quenching machine, in °C, W is the amount of quenching water sprayed onto the thin steel plate, in m 3 / (m 2 *min), H is the thickness of the steel plate in mm, W C is the mass percentage of carbon element, W Mn is the mass percentage of manganese element, W Ni is the mass percentage of nickel element, W Cr is the mass percentage of chromium element, W Mo is the mass percentage of molybdenum element, in %.

4. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 1, characterized in that: The quenching tension can be determined according to the following formula: ，H∈[2，8]； Wherein, σ is the quenching tension, in tons, and H is the thickness of the thin steel plate, in mm.

5. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 1, characterized in that: Welding the end of the current thin steel plate to the beginning of the next thin steel plate into a whole by using the front end butt welding equipment (3); The thin steel plate that has been continuously heated is sheared into a plate size that meets the standard by the rear end shearing equipment (14).

6. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 1, characterized in that: Determining the running speed of the thin steel plate according to the distance between the quenching heating furnace (6) and the quenching machine (7), and the transfer time, and setting the rotation speed of the driving roller group (12); The number of starting zones of the quenching heating furnace (6) is set according to the preset quenching heating time and the running speed of the thin steel plate.

7. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 6, characterized in that: The number of start-up zones of the tempering heating furnace (8) is set according to the preset tempering heating time and the running speed of the thin steel plate.

8. The continuous quenching heat treatment method for 2-8 mm high-strength thin steel plates according to claim 1, characterized in that: The movable rollers move in the horizontal direction, providing welding time and shearing time for the thin steel plates during the continuous quenching heat treatment process.

9. A continuous quenching heat treatment system for 2~8mm high-strength thin steel plates, characterized in that: The 2-8 mm high-strength thin steel plate continuous quenching heat treatment system implements the 2-8 mm high-strength thin steel plate continuous quenching heat treatment method according to any one of claims 1 to 8, and the 2-8 mm high-strength thin steel plate continuous quenching heat treatment system comprises: a transfer time control module for determining the transfer time of the thin steel plate from the quenching heating furnace (6) to the quenching machine (7) according to the thickness of the thin steel plate, and setting the rotation speed of the driving roller group (12) according to the transfer time; a quenching water volume control module, which is used to determine the quenching water volume in the quenching machine (7) according to the percentage of each element in the thin steel plate; a quenching cooling time control module, which is used to determine the quenching cooling time in the quenching machine (7) based on the quenching water volume, the thickness of the thin steel plate, the heating temperature of the thin steel plate in the quenching heating furnace (6) and the temperature of the thin steel plate after cooling in the quenching machine (7), and to set the number of start zones in the quenching machine (7) based on the quenching cooling time; A quenching tension control module is used to determine the quenching tension of the thin steel plate during the continuous quenching heat treatment process according to the thickness of the thin steel plate, and to set the quenching tension through a force roller (9).

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