A laminar flow cooling control method for stainless steel cooling

Abstract

This invention discloses a laminar flow cooling control method for stainless steel, relating to the field of steel rolling technology. The method includes: determining the type and thickness of the stainless steel to be laminar flow cooled, and the target laminar flow cooling temperature; calculating the upper and lower valves to be opened and the cooling water volume required to reach the determined target laminar flow cooling temperature based on preset non-cooling valves that do not produce watermarks corresponding to different target laminar flow cooling temperatures, preset valve opening and cooling sequence corresponding to different target laminar flow cooling temperatures, and preset maximum cooling water volume of valves in the strong cooling zone corresponding to different stainless steel types and thicknesses; during actual rolling, dynamically increasing or decreasing the opened valves and their cooling water volume in sequence or in reverse sequence, and opening the corresponding blow valves according to preset blow valve opening rules based on the finally opened upper and lower valves. This invention can avoid laminar flow cooling watermarks on stainless steel, improve the shape of the cooled stainless steel sheet, and reduce the height of the double-sided wave.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and in particular to a laminar flow cooling control method for stainless steel cooling. Background Technology

[0002] refer to Figure 1 The existing 1549mm hot continuous rolling production line includes a furnace area, a roughing mill area, a finishing mill area, a laminar flow cooling area, and a coiling area arranged in sequence. The furnace area includes four heating furnaces arranged in sequence. The roughing mill area includes a high-pressure water descaling box, a roughing vertical roll mill (VE0), a roughing horizontal roll mill (R0), and a heat insulation cover arranged in sequence. The finishing mill area includes a rotary drum-type flying shear, a 7-stand finishing mill, a crown gauge and a straightness gauge, as well as a width gauge and a thickness gauge arranged in sequence. The laminar flow cooling area is equipped with laminar flow cooling equipment. The coiling area has two coilers (C1, C2). The main production process of the 1549mm hot continuous rolling production line is as follows: The slab is first heated in a heating furnace at the temperature specified by the process. After being heated to the target temperature, it enters the roughing mill for rolling. The vertical rolls of the roughing mill control the width, and the horizontal rolls control the thickness. Reversible rolling is carried out in the roughing mill, generally in 5 to 7 passes. After the rolling of the roughing mill, the strip steel reaches the preset target thickness, width and temperature. Then it enters the finishing mill for seven-stand horizontal roll continuous rolling, so that the strip steel reaches the preset target thickness and temperature. After that, the strip steel is cooled by laminar flow control to reach the target coiling temperature. Finally, the strip steel is formed into a steel coil by the coiler.

[0003] refer to Figure 2 In the appendix Figure 2 In the diagram, 1 represents the finishing mill temperature measurement point, 2 represents the upper valve, 3 represents the lower valve, 4 represents the side-blowing valve, and 5 represents the laminar flow cooling target temperature measurement point. The existing laminar flow cooling equipment is equipped with upper valves, lower valves, and side-blowing valves. The upper valves are located at the top, the lower valves are directly below the upper valves, and the side-blowing valves are located to the left of the upper valves. There are a total of 48 valve groups (01# to 48#), with each group consisting of an upper valve and a lower valve. There are also 25 side-blowing valves.

[0004] The laminar flow cooling equipment is divided into three zones: a strong cooling zone, a coarse adjustment zone, and a fine adjustment zone.

[0005] The forced cooling zone includes valves 01# to 24#, and the maximum water flow rate of both the upper and lower valves of valves 01# to 24# is 150m³. 3 / h, both the upper and lower valves are regulating valves, and the water spray volume during rolling can be adjusted arbitrarily within the maximum water volume;

[0006] The coarse adjustment zone includes valves #25 to #40. The maximum water flow rate for both the upper and lower valves of valves #25 to #40 is 66.6 m³. 3 / h, both the upper and lower valves are on / off valves, the water spray is at the maximum water volume and cannot be adjusted;

[0007] The fine-tuning zone includes valves 41# to 48#, and the maximum water flow rate of both the upper and lower valves of valves 41# to 48# is 33.3m³. 3 / h, both the upper and lower valves are on / off valves, the water spray is at the maximum water volume and cannot be adjusted;

[0008] The maximum water flow of the side-blowing valve is 5m³. 3 / h is the on / off valve, which sprays water at the maximum flow rate and cannot be adjusted.

[0009] Based on the above-mentioned laminar flow cooling equipment, the traditional laminar flow cooling water spray control method for stainless steel is as follows: The laminar flow cooling area is divided into two parts: a feedforward zone and a feedback zone. The feedforward zone refers to the strong cooling zone and the coarse adjustment zone, i.e., valves 01# to 40#. The feedback zone refers to the fine adjustment zone, i.e., valves 41# to 48#. In the feedback zone, four valves are pre-opened at the top and bottom of the eight valves, i.e., valves 41#, 43#, 45#, and 47# are pre-opened at the top and bottom respectively. In the feedforward zone, water is sprayed from front to back according to the "1010" strategy, i.e., starting from the first valve, water is sprayed in the order of "open, close, open, close...", i.e., water is sprayed according to the valve opening sequence of one valve at a time. The same strategy is used for the upper and lower valves until the target temperature is reached. For each valve opened in the upper spray, water is sprayed from the side spray nozzles before and after that valve. In the strong cooling zone, 300 series stainless steel is given 100% water volume, and 400 series stainless steel is given 70% water volume. The target temperature is calculated as follows: First, the temperature drop of the four valves in the feedback zone is calculated; then, the temperature drop of the feedforward zone is calculated according to the valve opening method and valve opening sequence, starting from the finishing mill exit temperature, until the cooling reaches the laminar cooling target temperature.

[0010] However, in practical applications, when laminar flow cooling is controlled using the above-mentioned water spraying method, the cooled stainless steel usually exhibits the following problems:

[0011] The problem of batch surface watermark defects has occurred, and when the defects are severe, they cannot be eliminated even after cold rolling and pickling, making the stainless steel unusable; obvious double-sided waves exist during the cold rolling process after the stainless steel is cooled, with wave heights exceeding 60mm, which affects the stability of cold rolling. Summary of the Invention

[0012] To address some or all of the technical problems existing in the prior art, the present invention provides a laminar flow cooling control method for stainless steel cooling.

[0013] The technical solution of the present invention is as follows:

[0014] A laminar flow cooling control method for stainless steel cooling is provided, the method being used in a 1549mm hot continuous rolling production line, comprising:

[0015] Determine the type and thickness of the stainless steel to be subjected to laminar flow cooling, as well as the target temperature for laminar flow cooling;

[0016] Based on the preset valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures, and the preset maximum cooling water volume of the valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel, the upper and lower valves that need to be opened to reach the determined laminar flow cooling target temperature, as well as the cooling water volume of the upper and lower valves, are calculated. Among them, based on the laminar flow cooling target temperature of stainless steel, and the preset non-cooling valves that do not produce watermarks corresponding to different laminar flow cooling target temperatures, the valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures is preset according to the principle of sparse first and dense later, and the upper valve cooling is stronger than the lower valve cooling.

[0017] In the actual rolling process, based on the calculated upper and lower valves required to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves, and according to the difference between the actual laminar cooling temperature and the laminar cooling target temperature, the valves and their cooling water volume are dynamically increased or decreased in sequence according to the preset upper and lower valve opening cooling sequence and the preset maximum cooling water volume of the valves in the strong cooling zone. Based on the finally opened upper and lower valves, the corresponding blow valves are opened according to the preset blow valve opening rules. The blow valve opening rules include: for each upper valve opened, the blow valve adjacent to the current upper valve is opened, and the two blow valves adjacent to the current upper valve are opened.

[0018] Furthermore, in some optional embodiments, the non-cooling valves that do not produce watermarks corresponding to different laminar flow cooling target temperatures are as follows:

[0019] Laminar flow cooling target temperature (°C) non-cooling valve <650 [38#，48#] 650～680 [41#，48#] 680～710 [43#，48#] ≥710 [45#，48#]

[0020] To take control;

[0021] When the target temperature for laminar flow cooling is a range value, the target temperature for laminar flow cooling includes the lower boundary value but does not include the upper boundary value. The non-cooled valves include all valves, including the first and last valves in the given range, and include the upper valve and the lower valve.

[0022] Furthermore, in some optional embodiments, the upper valves 01# to 48# are numbered sequentially as 1 to 48, and the lower valves 01# to 48# are numbered sequentially as 101 to 148. Based on the above numbering, the valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures is as follows:

[0023]

[0024] To take control;

[0025] When the target temperature for laminar flow cooling is a range value, the target temperature for laminar flow cooling includes the lower boundary value but does not include the upper boundary value.

[0026] Furthermore, in some optional embodiments, the maximum cooling water volume of the valve in the strong cooling zone corresponding to different types and thicknesses of stainless steel is as follows:

[0027]

[0028] To take control;

[0029] When the thickness is a range value, the thickness value includes the lower boundary value but does not include the upper boundary value. The maximum cooling water volume of the valve is expressed as a percentage of the maximum water volume of the valve. When the maximum cooling water volume is a range value, the maximum cooling water volume value includes the lower boundary value but does not include the upper boundary value.

[0030] Further, in some optional embodiments, the step of calculating the upper and lower valves that need to be opened to reach the determined laminar cooling target temperature, and the cooling water volume of the upper and lower valves, based on the preset valve opening and cooling sequence corresponding to different laminar cooling target temperatures and the preset maximum cooling water volume of the valves in the strong cooling zone corresponding to different stainless steel types and thicknesses, includes:

[0031] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, according to the preset upper and lower valve opening cooling sequence and the preset maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially and the corresponding laminar cooling temperature values ​​are calculated until the calculated laminar cooling temperature reaches the laminar cooling target temperature. Then, the currently determined valves used for cooling water spray and the cooling water volume of the valves are used as the upper and lower valves that need to be opened to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves.

[0032] Specifically, when adding valves for cooling water spray that belong to the strong cooling zone (valve #01 to #24), the cooling water flow rate is increased sequentially from 1% of the maximum flow rate in increments of 0.1% of the maximum flow rate, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate or a value before the maximum cooling water flow rate reaches the laminar cooling target temperature, then the currently determined valves for cooling water spray and their cooling water flow rates are considered as the valves that need to be opened to reach the determined laminar cooling target temperature. The cooling water volume of the upper and lower valves, and the cooling water volume of the upper and lower valves; if the calculated laminar cooling temperature value when the maximum cooling water volume is increased does not reach the laminar cooling target temperature, then continue to sequentially increase the valves used for cooling water spray and calculate the corresponding laminar cooling temperature value until the calculated laminar cooling temperature value reaches the laminar cooling target temperature. The currently determined valves used for cooling water spray and the cooling water volume of the valves are used as the upper and lower valves, and the cooling water volume of the upper and lower valves, that need to be opened to reach the determined laminar cooling target temperature.

[0033] Furthermore, in some optional embodiments, the step of dynamically increasing or decreasing the number of valves opened and their cooling water volume in sequence or in reverse sequence according to the difference between the actual laminar cooling temperature and the target laminar cooling temperature, based on the preset valve opening and cooling sequence and the maximum cooling water volume of the valves in the preset strong cooling zone, includes:

[0034] When the actual temperature of laminar cooling is higher than the target temperature of laminar cooling, the valves used for cooling water spray are added sequentially according to the preset valve opening sequence of the upper and lower valves and the maximum cooling water volume of the valves in the preset strong cooling zone, and the corresponding laminar cooling temperature value is calculated until the calculated laminar cooling temperature value reaches the target temperature of laminar cooling. Then, the upper and lower valves that are finally opened, as well as the cooling water volume of the upper and lower valves, are determined.

[0035] Specifically, when adding valves for cooling water spray that belong to valves 01# to 24# in the strong cooling zone, the cooling water flow rate is increased sequentially from 1% of the maximum flow rate in increments of 0.1% of the maximum flow rate until the maximum cooling water flow rate is reached, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate or a value before the maximum cooling water flow rate reaches the laminar cooling target temperature, then the currently determined valves for cooling water spray and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate does not reach the laminar cooling target temperature, then the process of sequentially adding valves for cooling water spray and calculating the corresponding laminar cooling temperature value continues until the calculated laminar cooling temperature value reaches the laminar cooling target temperature, and the currently determined valves for cooling water spray and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves.

[0036] Furthermore, in some optional embodiments, the step of dynamically increasing or decreasing the number of valves opened and their cooling water volume in sequence or in reverse sequence according to the difference between the actual laminar cooling temperature and the target laminar cooling temperature, based on a preset valve opening and cooling sequence and the maximum cooling water volume of the valves in the preset strong cooling zone, further includes:

[0037] If the actual temperature of laminar cooling is lower than the target temperature of laminar cooling, the valves used for cooling water spray are reduced in reverse order according to the preset valve opening sequence of the upper and lower valves and the maximum cooling water volume of the valves in the preset strong cooling zone, and the corresponding laminar cooling temperature value is calculated until the calculated laminar cooling temperature value reaches the target temperature of laminar cooling. Then, the upper and lower valves that are finally opened and the cooling water volume of the upper and lower valves are determined.

[0038] Specifically, when the valves used for cooling water spraying that are reduced belong to valves 01# to 24# in the strong cooling zone, the cooling water flow rate is gradually reduced from the current cooling water flow rate to 1% of the maximum water flow rate in increments of 0.1% of the maximum water flow rate, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when the flow rate is reduced to 1% of the maximum water flow rate or a value before 1% of the maximum water flow rate reaches the laminar cooling target temperature, then the currently determined valves used for cooling water spraying and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves. If the laminar cooling temperature value calculated when the flow rate is reduced to 1% of the maximum water flow rate does not reach the laminar cooling target temperature, then the process of gradually reducing the valves used for cooling water spraying and calculating the corresponding laminar cooling temperature value continues in reverse order until the calculated laminar cooling temperature value reaches the laminar cooling target temperature. In this case, the currently determined valves used for cooling water spraying and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves.

[0039] Furthermore, in some optional embodiments, the valve opening rule of the jet valves also includes: controlling the last four jet valves to remain open.

[0040] The main advantages of the technical solution of this invention are as follows:

[0041] The laminar flow cooling control method for stainless steel of the present invention controls the laminar flow cooling of stainless steel in the manner described above, which can avoid the appearance of laminar flow cooling watermarks on stainless steel, improve the shape of stainless steel sheet after cooling, significantly reduce the double-sided wave height of stainless steel, and improve the cold rolling stability of stainless steel. Attached Figure Description

[0042] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and constitute a part of this invention, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0043] Figure 1 This is a schematic diagram of the equipment layout for an existing 1549mm hot strip rolling production line.

[0044] Figure 2 for Figure 1 Schematic diagram of the layout of the mid-laminar flow cooling equipment. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] The technical solutions provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] For a 1549mm hot strip rolling production line, laminar flow cooling water mark refers to the mark formed on the surface of the strip after the cooling water remains on the surface of the strip after passing through the laminar flow cooling zone and turns into steam. Due to the high surface requirements of stainless steel itself, this mark will affect the user's use.

[0048] Analysis revealed that during laminar flow water spraying, the lower the surface temperature of the strip steel, the easier it is for watermarks to form; conversely, the higher the surface temperature of the strip steel, the less likely watermarks are to form. To ensure that the produced stainless steel meets quality requirements and is supplied to users, it is necessary to eliminate laminar flow cooling watermarks.

[0049] For the 1549mm hot strip rolling production line, the double-sided waves of stainless steel are not obvious during the laminar cooling process. The double-sided waves mainly occur after the strip has been completely cooled to room temperature. They are very serious in the cold rolling process and have the following characteristics: the double-sided waves are most serious at the head, with a wave height of more than 60mm. They gradually decrease thereafter, and by the tail end, the wave height drops to less than 40mm.

[0050] Analysis and research revealed the following reasons for the formation of double-sided waves in stainless steel:

[0051] 1) The intensive laminar flow cooling method results in uneven longitudinal cooling of the strip steel. Depending on the steel plate temperature, there are three different boiling cooling methods: film boiling at high temperatures (where a vapor film exists between the steel plate and the cooling water); nucleus boiling at low temperatures (where no vapor film exists between the steel plate and the water, and heat exchange occurs directly); and a transitional boiling stage between film boiling and nucleus boiling. In this transitional boiling stage, different parts of the steel plate surface can experience both boiling cooling methods with different cooling rates. In this transitional boiling stage, some parts of the plate are in film boiling with a lower cooling rate, while others are in nucleus boiling with a higher cooling rate. Because different parts of the steel plate are in different cooling states, extremely uneven cooling occurs, easily causing warping and forming apparent or potential shape defects. In intensive cooling, due to the large volume of water used for cooling, the process quickly enters the transitional boiling stage where nucleus boiling and film boiling coexist, resulting in an unstable cooling process. Furthermore, cooling water that falls onto the steel plate and remains on its surface can cause secondary cooling over a wide area. This secondary cooling caused by stagnant water can easily lead to an unstable transitional boiling state. Under these unstable conditions, as cooling progresses, temperature deviations will continuously increase, becoming a major cause of uneven cooling and also deteriorating the quality of the steel plate. Therefore, avoiding transitional boiling is extremely important for ensuring uniform cooling.

[0052] 2) During the cooling process, the cooling conditions and cooling rates differ between the edges and the center. Specifically, the temperature in the center is higher than that at the edges. When cooled to room temperature, the edges and center will experience different amounts of cooling contraction, with the edges contracting less and the center contracting more, resulting in edge waviness or warping. If the cooling intensity is low, this non-uniformity will not be obvious.

[0053] 3) Uneven cooling between the upper and lower surfaces, with high cooling efficiency on the upper surface and low cooling efficiency on the lower surface.

[0054] Based on the above analysis and research, this invention provides a laminar flow cooling control method for stainless steel, which can avoid laminar flow cooling watermarks on stainless steel, improve the shape of the cooled stainless steel sheet, significantly reduce the double-sided wave height of stainless steel, and improve the cold rolling stability of stainless steel. The method specifically includes the following steps:

[0055] Step 1: Determine the type and thickness of the stainless steel to be subjected to laminar flow cooling, as well as the target temperature for laminar flow cooling;

[0056] Step 2: Based on the preset valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures, and the preset maximum cooling water volume of the valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel, calculate the upper and lower valves that need to be opened to reach the determined laminar flow cooling target temperature, as well as the cooling water volume of the upper and lower valves; wherein, based on the laminar flow cooling target temperature of stainless steel, and the preset non-cooling valves that do not produce watermarks corresponding to different laminar flow cooling target temperatures, the valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures is preset according to the principle of sparse first and dense later, and the upper valve cooling is stronger than the lower valve cooling.

[0057] Step 3: During the actual rolling process, based on the calculated upper and lower valves required to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves, and according to the difference between the actual laminar cooling temperature and the laminar cooling target temperature, the valves and their cooling water volume are dynamically increased or decreased in sequence according to the preset upper and lower valve opening cooling sequence and the preset maximum cooling water volume of the valves in the strong cooling zone. Based on the finally opened upper and lower valves, the corresponding blow valves are opened according to the preset blow valve opening rules. The blow valve opening rules include: for each upper valve opened, the blow valve adjacent to the current upper valve is opened, and the two blow valves adjacent to the current upper valve are opened.

[0058] The laminar flow cooling control method for stainless steel provided in this invention controls the laminar flow cooling of stainless steel in the manner described above, which can avoid the appearance of laminar flow cooling watermarks on stainless steel, improve the shape of the stainless steel sheet after cooling, significantly reduce the double-sided wave height of stainless steel, and improve the cold rolling stability of stainless steel.

[0059] Analysis and research revealed that the problem of watermarks during laminar cooling can be solved by adopting a non-cooling method in the later stage. Since the generation of watermarks is related to the target temperature of laminar cooling of stainless steel, in this embodiment of the invention, the non-cooling valves that do not generate watermarks corresponding to different target temperatures of laminar cooling are shown in Table 1 below.

[0060] Table 1. Non-cooling valves that do not produce watermarks corresponding to different laminar flow cooling target temperatures.

[0061] Laminar flow cooling target temperature (°C) non-cooling valve <650 [38#，48#] 650～680 [41#，48#] 680～710 [43#，48#] ≥710 [45#，48#]

[0062] In Table 1, when the laminar cooling target temperature is a range value, the value includes the lower boundary value but does not include the upper boundary value. That is, "650~680" means "650℃≤Laminar cooling target temperature<680℃". The non-cooling valves include all valves, including the first and last valves in the given range, and include the upper and lower valves. That is, "[38#,48#]" means "the non-cooling valves are the upper and lower valves of 38#-48#".

[0063] In this embodiment of the invention, stainless steel is controlled by using non-cooling valves that do not produce watermarks corresponding to different laminar cooling target temperatures. That is, specific upper and lower valves in the laminar cooling equipment are not used for different laminar cooling target temperatures, which can ensure that stainless steel does not produce watermarks after laminar cooling.

[0064] Furthermore, in this embodiment of the invention, in order to improve the shape of the cooled stainless steel plate and significantly reduce the double-sided wave height of the stainless steel while eliminating the watermark of the stainless steel, the opening and cooling sequence of the upper and lower valves corresponding to different laminar cooling target temperatures is pre-set according to the laminar cooling target temperature of the stainless steel and the non-cooling valves that do not produce watermarks corresponding to different laminar cooling target temperatures, following the principle of sparse first and dense later, and the upper valve cooling being stronger than the lower valve cooling.

[0065] Specifically, in this embodiment of the invention, in order to eliminate the watermark on the stainless steel while maximally improving the shape of the cooled stainless steel plate, the upper valves 01# to 48# are numbered 1 to 48 in sequence, and the lower valves 01# to 48# are numbered 101 to 148 in sequence. Based on the above numbering, the valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures is shown in Table 2 below.

[0066] Table 2. Valve opening sequence for different laminar flow cooling target temperatures.

[0067]

[0068] In Table 2, when the target temperature for laminar cooling is a range value, the target temperature for laminar cooling includes the lower boundary value but does not include the upper boundary value. That is, "650~680" means "650℃≤Laminar cooling target temperature<680℃".

[0069] Furthermore, since the water volume of the valve located in the strong cooling zone in the laminar flow cooling equipment can be arbitrarily adjusted within the maximum water volume, in order to improve the phenomenon of stainless steel plate deterioration caused by uneven cooling, in this embodiment of the invention, the maximum cooling water volume of the valve in the strong cooling zone corresponding to different types and thicknesses of stainless steel is preset for different types and thicknesses of stainless steel.

[0070] Specifically, in this embodiment of the invention, in order to maximize the improvement of the stainless steel plate shape deterioration caused by the uneven cooling in the strong cooling zone, the maximum cooling water volume of the valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel is shown in Table 3 below.

[0071] Table 3. Maximum cooling water volume of valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel.

[0072]

[0073]

[0074] In Table 3, when the thickness value is a range value, the thickness value includes the lower boundary value but does not include the upper boundary value. That is, "3.0~5.0" means "3.0mm≤thickness<5.0mm". The maximum cooling water volume of the valve is expressed as a percentage of the maximum water volume of the valve. When the maximum cooling water volume is a range value, the maximum cooling water volume value includes the lower boundary value but does not include the upper boundary value. That is, "50~60" means "50% maximum water volume≤maximum cooling water volume<60% maximum water volume".

[0075] Furthermore, in this embodiment of the invention, based on the preset valve opening and cooling sequence corresponding to different laminar cooling target temperatures, and the preset maximum cooling water volume of the valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel, the calculation of the upper and lower valves that need to be opened to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves, includes the following steps:

[0076] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, according to the preset upper and lower valve opening cooling sequence and the preset maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially and the corresponding laminar cooling temperature values ​​are calculated until the calculated laminar cooling temperature reaches the laminar cooling target temperature. Then, the currently determined valves used for cooling water spray and the cooling water volume of the valves are used as the upper and lower valves that need to be opened to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves.

[0077] Specifically, when adding valves for cooling water spray that belong to the strong cooling zone (valve #01 to #24), the cooling water flow rate is increased sequentially from 1% of the maximum flow rate in increments of 0.1% of the maximum flow rate, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate or a value before the maximum cooling water flow rate reaches the laminar cooling target temperature, then the currently determined valves for cooling water spray and their cooling water flow rates are considered as the valves that need to be opened to reach the determined laminar cooling target temperature. The cooling water volume of the upper and lower valves, and the cooling water volume of the upper and lower valves; if the calculated laminar cooling temperature value when the maximum cooling water volume is increased does not reach the laminar cooling target temperature, then continue to sequentially increase the valves used for cooling water spray and calculate the corresponding laminar cooling temperature value until the calculated laminar cooling temperature value reaches the laminar cooling target temperature. The currently determined valves used for cooling water spray and the cooling water volume of the valves are used as the upper and lower valves, and the cooling water volume of the upper and lower valves, that need to be opened to reach the determined laminar cooling target temperature.

[0078] Furthermore, in this embodiment of the invention, based on the difference between the actual laminar cooling temperature and the target laminar cooling temperature, and according to a preset valve opening and cooling sequence and the maximum cooling water volume of the valves in the preset strong cooling zone, the valves opened and their cooling water volume are dynamically increased or decreased in reverse order, including the following steps:

[0079] If the actual temperature of laminar cooling is higher than the target temperature of laminar cooling, the valves used for cooling water spray are added sequentially according to the preset valve opening and cooling sequence of the upper and lower valves and the maximum cooling water volume of the valves in the preset strong cooling zone, and the corresponding laminar cooling temperature value is calculated until the calculated laminar cooling temperature value reaches the target temperature of laminar cooling. Then, the upper and lower valves that are finally opened and the cooling water volume of the upper and lower valves are determined.

[0080] If the actual temperature of laminar cooling is lower than the target temperature of laminar cooling, the valves used for cooling water spray are reduced in reverse order according to the preset valve opening sequence of the upper and lower valves and the maximum cooling water volume of the valves in the preset strong cooling zone, and the corresponding laminar cooling temperature value is calculated until the calculated laminar cooling temperature value reaches the target temperature of laminar cooling. Then, the upper and lower valves that are finally opened and the cooling water volume of the upper and lower valves are determined.

[0081] Specifically, when adding valves for cooling water spray that belong to valves 01# to 24# in the strong cooling zone, the cooling water flow rate is increased sequentially from 1% of the maximum flow rate in increments of 0.1% of the maximum flow rate until the maximum cooling water flow rate is reached, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when the flow rate is increased to the maximum cooling water flow rate or a value before the maximum cooling water flow rate reaches the laminar cooling target temperature, then the currently determined valves for cooling water spray and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves. If the laminar cooling temperature value calculated when the flow rate is increased to the maximum cooling water flow rate does not reach the laminar cooling target temperature, then the process of sequentially adding valves for cooling water spray and calculating the corresponding laminar cooling temperature value continues until the calculated laminar cooling temperature value reaches the laminar cooling target temperature, and the currently determined valves for cooling water spray and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves.

[0082] Specifically, when the valves used for cooling water spraying that are reduced belong to valves 01# to 24# in the strong cooling zone, the cooling water flow rate is gradually reduced from the current cooling water flow rate to 1% of the maximum water flow rate in increments of 0.1% of the maximum water flow rate, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when the flow rate is reduced to 1% of the maximum water flow rate or a value before 1% of the maximum water flow rate reaches the laminar cooling target temperature, then the currently determined valves used for cooling water spraying and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves. If the laminar cooling temperature value calculated when the flow rate is reduced to 1% of the maximum water flow rate does not reach the laminar cooling target temperature, then the process of gradually reducing the valves used for cooling water spraying and calculating the corresponding laminar cooling temperature value continues in reverse order until the calculated laminar cooling temperature value reaches the laminar cooling target temperature. In this case, the currently determined valves used for cooling water spraying and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves.

[0083] In this embodiment of the invention, by determining the upper and lower valves for cooling water spray and the cooling water volume of the upper and lower valves in the above manner, it is possible to avoid laminar cooling water marks on stainless steel while ensuring that the actual temperature of laminar cooling is basically consistent with the target temperature of laminar cooling, and to improve the shape of stainless steel sheet after cooling to the greatest extent, significantly reduce the double-sided wave height of stainless steel, and improve the cold rolling stability of stainless steel.

[0084] In this embodiment of the invention, the valve opening rules of the blow valve include: for each upper valve opened, the blow valve adjacent to the current upper valve is opened, and the two blow valves adjacent to the current upper valve are opened.

[0085] In this embodiment of the invention, by controlling the opening rule of the blow valve as described above, the excessive boiling and secondary cooling can be minimized, thereby improving the shape of the cooled stainless steel plate.

[0086] Furthermore, in this embodiment of the invention, the valve opening rule of the blow valve also includes: controlling the last 4 blow valves to remain open.

[0087] Specifically, in the actual rolling process, keeping the last four blow valves open ensures that the stainless steel surface is cleaned before temperature detection, thus guaranteeing the accuracy and reliability of the temperature detection results.

[0088] To make the above technical solutions of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0089] Example 1

[0090] This embodiment rolls 430 stainless steel, steel grade: SUS430; steel coil number: 954912201, with a target finished thickness of 2.85mm, a target finished width of 1040mm, a target finishing mill exit temperature of 930℃, and a target laminar flow cooling temperature of 680℃.

[0091] According to Table 2, the target temperature for laminar flow cooling is 680℃. The valve opening sequence for cooling is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 142, 104, 25, 108, 112, 29, 116, 120, 33, 124, 128, 37, 132, 136, 41, 140, 144, 3, 101, 103, 7, 105, 1 07,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,39,137,139,43,141,143,4,8,12,16,20,24,28,32,36,40,44,2,6,10,14,18,22,26,30,34,38,42.

[0092] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 55% of the maximum water flow rate.

[0093] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0094] valve 1 102 106 5 110 114 9 118 122 13 Water volume (%) 55 55 55 55 55 55 55 55 55 55 water spray valve 126 130 17 134 138 21 142 104 25 Water volume (%) 100 100 55 100 100 55 100 55 26.3

[0095] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 15# and valves 22# to 25#.

[0096] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0097] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 134 Water volume (%) 55 55 55 55 55 55 55 55 55 55 100 100 55 100 valve 138 21 142 104 25 108 112 29 116 120 33 124 128 37 Water volume (%) 100 55 100 55 100 55 55 100 55 55 100 55 100 100

[0098] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 20# and valves 22# to 25#.

[0099] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0100] valve 1 102 106 5 110 114 9 118 122 13 Water volume (%) 55 55 55 55 55 55 55 55 55 55 valve 126 130 17 134 138 21 Water volume (%) 100 100 55 100 100 42.8

[0101] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0102] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 22mm, which met the quality and control requirements of stainless steel.

[0103] Example 2

[0104] This embodiment rolls 430 stainless steel, grade: SUS430E; coil number: 955759701, with a target finished thickness of 4.38 mm, a target finished width of 1257 mm, a target finishing mill exit temperature of 940°C, and a target laminar flow cooling temperature of 730°C.

[0105] According to Table 2, the target temperature for laminar flow cooling is 680℃. The valve opening sequence for cooling is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 142, 104, 25, 108, 112, 29, 116, 120, 33, 124, 128, 37, 132, 136, 41, 140, 101, 3, 103, 105. 7,107,109,11,111,113,15,115,117,19,119,121,23,123,125,27,127,129,31,131,133,35,135,137,39,139,141,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38,42.

[0106] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 65% of the maximum water flow rate.

[0107] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0108]

[0109]

[0110] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 11# and valves 22# to 25#.

[0111] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0112] valve 1 102 106 5 110 114 9 118 122 13 126 130 Water volume (%) 65 65 65 65 65 65 65 65 65 65 100 100 valve 17 134 138 21 142 104 25 108 112 29 116 Water volume (%) 65 100 100 65 100 65 100 65 65 100 57.8

[0113] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 17# and valves 22# to 25#.

[0114] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0115] valve 1 102 106 5 110 114 9 118 122 13 Water volume (%) 65 65 65 65 65 65 65 65 65 65 valve 126 130 17 134 138 Water volume (%) 100 100 65 100 100

[0116] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 11# and valves 22# to 25#.

[0117] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 25mm, which met the quality and control requirements of stainless steel.

[0118] Example 3

[0119] This embodiment rolls 430 stainless steel, steel grade: 430R; steel coil number: 951771101, with a target finished thickness of 6.07mm, a target finished width of 1290mm, a target finishing mill exit temperature of 930℃, and a target laminar flow cooling temperature of 650℃.

[0120] According to Table 2, the target temperature for laminar flow cooling is 650℃. The valve opening sequence for the upper and lower valves is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 104, 108, 25, 112, 116, 29, 120, 124, 33, 128, 132, 37, 136, 140, 3, 101, 103, 7, 10 5,107,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,39,137,139,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38.

[0121] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 79% of the maximum water flow rate.

[0122] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0123] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 79 79 79 79 79 79 79 79 79 79 100 100 79 valve 134 138 21 104 108 25 112 116 29 120 Water volume (%) 100 100 79 79 79 100 79 79 100 71.3

[0124] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 16# and valves 22# to 25#.

[0125] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0126] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 79 79 79 79 79 79 79 79 79 79 100 100 79 valve 134 138 21 104 108 25 112 116 29 120 124 33 128 Water volume (%) 100 100 79 79 79 100 79 79 100 79 79 100 100 valve 132 37 136 140 3 101 103 7 Water volume (%) 100 100 100 100 79 79 79 35.6

[0127] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 20# and valves 22# to 25#.

[0128] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0129] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 79 79 79 79 79 79 79 79 79 79 100 100 79 valve 134 138 21 104 108 25 112 116 29 120 Water volume (%) 100 100 79 79 79 100 79 79 100 71.3

[0130] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 16# and valves 22# to 25#.

[0131] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 27mm, which met the quality and control requirements of stainless steel.

[0132] Example 4

[0133] This embodiment rolls 430 stainless steel, steel grade: 430R; steel coil number: 952710301, with a target finished thickness of 7.9mm, a target finished width of 1290mm, a target finishing mill exit temperature of 930℃, and a target laminar flow cooling temperature of 650℃.

[0134] According to Table 2, the target temperature for laminar flow cooling is 650℃. The valve opening sequence for the upper and lower valves is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 104, 108, 25, 112, 116, 29, 120, 124, 33, 128, 132, 37, 136, 140, 3, 101, 103, 7, 10 5,107,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,39,137,139,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38.

[0135] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 89% of the maximum water flow rate.

[0136] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0137] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 89 89 89 89 89 89 89 89 89 89 100 100 89 valve 134 138 21 104 108 25 112 116 29 120 124 33 Water volume (%) 100 100 89 89 89 100 89 89 100 89 89 100

[0138] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 18# and valves 22# to 25#.

[0139] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0140] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 89 89 89 89 89 89 89 89 89 89 100 100 89 valve 134 138 21 104 108 25 112 116 29 120 124 33 128 Water volume (%) 100 100 89 89 89 100 89 89 100 89 89 100 100 valve 132 37 136 140 3 101 103 7 105 107 11 Water volume (%) 100 100 100 100 89 89 89 89 89 89 88

[0141] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 20# and valves 22# to 25#.

[0142] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0143] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 89 89 89 89 89 89 89 89 89 89 100 100 89 valve 134 138 21 104 108 25 112 116 29 120 Water volume (%) 100 100 89 89 89 100 89 89 100 87.2

[0144] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 16# and valves 22# to 25#.

[0145] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 27mm, which met the quality and control requirements of stainless steel.

[0146] Example 5

[0147] This embodiment rolls 409 stainless steel, steel grade: SUH409L; steel coil number: 94C674001, finished product thickness target 5.43mm, finished product width target 1258mm, finishing mill exit target temperature 830℃, laminar flow cooling target temperature 650℃.

[0148] According to Table 2, the target temperature for laminar flow cooling is 650℃. The valve opening sequence for the upper and lower valves is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 104, 108, 25, 112, 116, 29, 120, 124, 33, 128, 132, 37, 136, 140, 3, 101, 103, 7, 10 5,107,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,39,137,139,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38.

[0149] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 81% of the maximum water flow rate.

[0150] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0151] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 81 81 81 81 81 81 81 81 81 81 100 100 81 valve 134 138 Water volume (%) 100 100

[0152] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 11# and valves 22# to 25#.

[0153] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0154] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 81 81 81 81 81 81 81 81 81 81 100 100 81 valve 134 138 21 104 108 25 112 116 29 120 Water volume (%) 100 100 81 81 81 100 81 81 100 78.4

[0155] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 16# and valves 22# to 25#.

[0156] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0157] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 81 81 81 81 81 81 81 81 81 81 100 100 81 valve 134 Water volume (%) 100

[0158] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 11# and valves 22# to 25#.

[0159] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 21mm, which met the quality and control requirements of stainless steel.

[0160] Example 6

[0161] This embodiment rolls 409 stainless steel, grade: 1.4512; coil number: 951726701, with a target finished product thickness of 3.98 mm, a target finished product width of 1023 mm, a target finishing mill exit temperature of 810°C, and a target laminar flow cooling temperature of 600°C.

[0162] According to Table 2, the target temperature for laminar flow cooling is 600℃. The valve opening sequence for cooling is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 104, 21, 108, 112, 25, 116, 120, 29, 124, 128, 33, 132, 136, 37, 3, 101, 103, 7 ,105,107,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,4,137,8,12,16,20,24,28,32,36,2,6,10,14,18,22,26,30,34.

[0163] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 70% of the maximum water flow rate.

[0164] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0165] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 70 70 70 70 70 70 70 70 70 70 100 100 70 valve 134 104 21 108 112 Water volume (%) 100 70 70 70 23.9

[0166] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0167] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0168] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 70 70 70 70 70 70 70 70 70 70 100 100 70 valve 134 104 21 108 112 25 116 120 29 124 128 33 Water volume (%) 100 70 70 70 70 100 70 70 100 70 100 100

[0169] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 18# and valves 22# to 25#.

[0170] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0171]

[0172]

[0173] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0174] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 21mm, which met the quality and control requirements of stainless steel.

[0175] Example 7

[0176] This embodiment describes the rolling of ultrapure ferritic stainless steel, grade 439M, coil number 952E02101, with a target finished thickness of 3.95mm, a target finished width of 1268mm, a target finishing mill exit temperature of 880℃, and a target laminar flow cooling temperature of 680℃.

[0177] According to Table 2, the target temperature for laminar flow cooling is 680℃. The valve opening sequence for cooling is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 142, 104, 25, 108, 112, 29, 116, 120, 33, 124, 128, 37, 132, 136, 41, 140, 101, 3, 103, 105. 7,107,109,11,111,113,15,115,117,19,119,121,23,123,125,27,127,129,31,131,133,35,135,137,39,139,141,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38,42.

[0178] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 65% of the maximum water flow rate.

[0179] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0180] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 65 65 65 65 65 65 65 65 65 65 100 100 65 valve 134 138 21 142 104 Water volume (%) 100 100 65 100 62.9

[0181] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0182] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0183] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 65 65 65 65 65 65 65 65 65 65 100 100 65 valve 134 138 21 142 104 25 108 112 29 116 120 33 124 Water volume (%) 100 100 65 100 65 100 65 65 100 65 65 100 61.1

[0184] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 18# and valves 22# to 25#.

[0185] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0186] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 65 65 65 65 65 65 65 65 65 65 100 100 65 valve 134 138 21 142 Water volume (%) 100 100 65 100

[0187] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0188] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 22mm, which met the quality and control requirements of stainless steel.

[0189] Example 8

[0190] This embodiment rolls 304 stainless steel, steel grade: SUS304; steel coil number: 952E12001, finished product thickness target 2.85mm, finished product width target 1034mm, finishing mill exit target temperature 1000℃, laminar flow cooling target temperature 670℃.

[0191] According to Table 2, the target temperature for laminar flow cooling is 670℃. The valve opening sequence for the upper and lower valves is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 104, 108, 25, 112, 116, 29, 120, 124, 33, 128, 132, 37, 136, 140, 3, 101, 103, 7, 10 5,107,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,39,137,139,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38.

[0192] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 61% of the maximum water flow rate.

[0193] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0194] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 61 61 61 61 61 61 61 61 61 61 100 100 61 valve 134 138 21 104 108 25 112 116 29 120 124 33 128 Water volume (%) 100 100 61 61 61 100 61 61 100 61 61 100 100

[0195] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 18# and valves 22# to 25#.

[0196] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0197]

[0198]

[0199] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 20# and valves 22# to 25#.

[0200] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0201] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 61 61 61 61 61 61 61 61 61 61 100 100 61 valve 134 138 21 104 108 25 112 116 29 120 124 Water volume (%) 100 100 61 61 61 100 61 61 100 61 59.5

[0202] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 16# and valves 22# to 25#.

[0203] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 27mm, which met the quality and control requirements of stainless steel.

[0204] Example 9

[0205] This embodiment rolls other stainless steels, steel grade: CTSZB; coil number: 951658101, finished product thickness target 4.5mm, finished product width target 1080mm, finishing mill exit target temperature 890℃, laminar flow cooling target temperature 650℃.

[0206] According to Table 2, the target temperature for laminar flow cooling is 650℃. The valve opening sequence for the upper and lower valves is as follows: 1, 102, 106, 5, 110, 114, 9, 118, 122, 13, 126, 130, 17, 134, 138, 21, 104, 108, 25, 112, 116, 29, 120, 124, 33, 128, 132, 37, 136, 140, 3, 101, 103, 7, 10 5,107,11,109,111,15,113,115,19,117,119,23,121,123,27,125,127,31,129,131,35,133,135,39,137,139,4,8,12,16,20,24,28,32,36,40,2,6,10,14,18,22,26,30,34,38.

[0207] According to Table 3, the maximum cooling water flow rate of the valve in the strong cooling zone is taken as 72% of the maximum water flow rate.

[0208] Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, and following the valve opening sequence and maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially, and the corresponding laminar cooling temperature values ​​are calculated, until the calculated laminar cooling temperature reaches the laminar cooling target temperature. The final calculated valves and their cooling water volumes are shown in the table below:

[0209] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 72 72 72 72 72 72 72 72 72 72 100 100 72 valve 134 138 21 104 Water volume (%) 100 100 72 68.5

[0210] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0211] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The table below shows the situation with the most valves opened:

[0212] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 72 72 72 72 72 72 72 72 72 72 100 100 72 valve 134 138 21 104 108 25 112 116 29 120 124 Water volume (%) 100 100 72 72 72 100 72 72 100 72 70.3

[0213] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 16# and valves 22# to 25#.

[0214] In the actual rolling process, during the laminar flow cooling dynamic control stage, based on the difference between the actual laminar flow cooling temperature and the target laminar flow cooling temperature, and according to the valve opening and cooling sequence of the upper and lower valves, as well as the maximum cooling water volume of the valves in the strong cooling zone, the number of valves opened and the cooling water volume of the valves are dynamically increased or decreased in reverse order. The result is shown in the table below, which shows the case with the fewest valves opened.

[0215] valve 1 102 106 5 110 114 9 118 122 13 126 130 17 Water volume (%) 72 72 72 72 72 72 72 72 72 72 100 100 72 valve 134 138 21 Water volume (%) 100 100 23.6

[0216] According to the valve opening rules of the blow valve, the side blow valves that are opened are: valves 1# to 13# and valves 22# to 25#.

[0217] Laminar flow cooling control was performed using the parameters determined above. The cooled stainless steel had no surface watermark defects, and the maximum wave height on both sides was 21mm, which met the quality and control requirements of stainless steel.

[0218] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the terms "front," "back," "left," "right," "upper," and "lower" in this document refer to the placement shown in the accompanying drawings.

[0219] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laminar flow cooling control method for stainless steel cooling, characterized in that, The method is used in a 1549mm hot strip rolling production line and includes: Determine the type and thickness of the stainless steel to be subjected to laminar flow cooling, as well as the target temperature for laminar flow cooling; Based on the preset valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures, and the preset maximum cooling water volume of the valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel, the upper and lower valves that need to be opened to reach the determined laminar flow cooling target temperature, as well as the cooling water volume of the upper and lower valves, are calculated. Among them, based on the laminar flow cooling target temperature of stainless steel, and the preset non-cooling valves that do not produce watermarks corresponding to different laminar flow cooling target temperatures, the valve opening and cooling sequence of the upper and lower valves corresponding to different laminar flow cooling target temperatures is preset according to the principle of sparse first and dense later, and the upper valve cooling is stronger than the lower valve cooling. In the actual rolling process, based on the calculated upper and lower valves required to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves, and according to the difference between the actual laminar cooling temperature and the laminar cooling target temperature, the valves and their cooling water volume are dynamically increased or decreased in sequence according to the preset upper and lower valve opening cooling sequence and the preset maximum cooling water volume of the valves in the strong cooling zone. Based on the finally opened upper and lower valves, the corresponding blow valves are opened according to the preset blow valve opening rules. The blow valve opening rules include: for each upper valve opened, the blow valve adjacent to the current upper valve is opened, and the two blow valves adjacent to the current upper valve are opened. The non-cooling valves that do not produce watermarks for different laminar flow cooling target temperatures are listed in the table below: ； To take control; When the laminar cooling target temperature is a range value, the laminar cooling target temperature includes the lower boundary value but does not include the upper boundary value. The non-cooled valves include all valves, including the first and last valves in the given range, and include the upper valve and the lower valve. The upper valves 01#~48# are numbered sequentially from 1 to 48, and the lower valves 01#~48# are numbered sequentially from 101 to 148. Based on the above numbering, the valve opening sequence for different laminar flow cooling target temperatures is as follows: ； To take control; When the target temperature for laminar flow cooling is a range value, the target temperature for laminar flow cooling includes the lower boundary value but does not include the upper boundary value. The calculation of the upper and lower valves required to open to reach the determined laminar cooling target temperature, and the cooling water volume of the upper and lower valves, based on the preset valve opening and cooling sequence corresponding to different laminar cooling target temperatures and the preset maximum cooling water volume of the valves in the strong cooling zone corresponding to different stainless steel types and thicknesses, includes: Based on the stainless steel finishing mill exit temperature, thickness, width, laminar cooling target temperature, and cooling water temperature, according to the preset upper and lower valve opening cooling sequence and the preset maximum cooling water volume of the valves in the strong cooling zone, the valves used for cooling water spray are added sequentially and the corresponding laminar cooling temperature values ​​are calculated until the calculated laminar cooling temperature reaches the laminar cooling target temperature. Then, the currently determined valves used for cooling water spray and the cooling water volume of the valves are used as the upper and lower valves that need to be opened to reach the determined laminar cooling target temperature, as well as the cooling water volume of the upper and lower valves. Specifically, when adding valves for cooling water spray that belong to the strong cooling zone (valve #01 to #24), the cooling water flow rate is increased sequentially from 1% of the maximum flow rate in increments of 0.1% of the maximum flow rate, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate or a value before the maximum cooling water flow rate reaches the laminar cooling target temperature, then the currently determined valves for cooling water spray and their cooling water flow rates are considered as the valves that need to be opened to reach the determined laminar cooling target temperature. The cooling water volume of the upper and lower valves, and the cooling water volume of the upper and lower valves; if the calculated laminar cooling temperature value when the maximum cooling water volume is increased does not reach the laminar cooling target temperature, then continue to sequentially increase the valves used for cooling water spray and calculate the corresponding laminar cooling temperature value until the calculated laminar cooling temperature value reaches the laminar cooling target temperature. The currently determined valves used for cooling water spray and the cooling water volume of the valves are used as the upper and lower valves, and the cooling water volume of the upper and lower valves, that need to be opened to reach the determined laminar cooling target temperature.

2. The laminar flow cooling control method for stainless steel cooling according to claim 1, characterized in that, The maximum cooling water flow rate for valves in the strong cooling zone corresponding to different types and thicknesses of stainless steel is shown in the table below: ； To take control; When the thickness is a range value, the thickness value includes the lower boundary value but does not include the upper boundary value. The maximum cooling water volume of the valve is expressed as a percentage of the maximum water volume of the valve. When the maximum cooling water volume is a range value, the maximum cooling water volume value includes the lower boundary value but does not include the upper boundary value.

3. The laminar flow cooling control method for stainless steel cooling according to claim 1, characterized in that, The method of dynamically increasing or decreasing the number of valves opened and their cooling water volume in sequence, according to a preset valve opening sequence and the maximum cooling water volume of valves in the preset strong cooling zone, based on the difference between the actual temperature and the target temperature of laminar flow cooling, includes: When the actual temperature of laminar cooling is higher than the target temperature of laminar cooling, the valves used for cooling water spray are added sequentially according to the preset valve opening sequence of the upper and lower valves and the maximum cooling water volume of the valves in the preset strong cooling zone, and the corresponding laminar cooling temperature value is calculated until the calculated laminar cooling temperature value reaches the target temperature of laminar cooling. Then, the upper and lower valves that are finally opened, as well as the cooling water volume of the upper and lower valves, are determined. Specifically, when adding valves for cooling water spray that belong to valves 01# to 24# in the strong cooling zone, the cooling water flow rate is increased sequentially from 1% of the maximum flow rate in increments of 0.1% of the maximum flow rate until the maximum cooling water flow rate is reached, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate or a value before the maximum cooling water flow rate reaches the laminar cooling target temperature, then the currently determined valves for cooling water spray and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves. If the laminar cooling temperature value calculated when increasing to the maximum cooling water flow rate does not reach the laminar cooling target temperature, then the process of sequentially adding valves for cooling water spray and calculating the corresponding laminar cooling temperature value continues until the calculated laminar cooling temperature value reaches the laminar cooling target temperature, and the currently determined valves for cooling water spray and their cooling water flow rates are used as the final opened upper and lower valves, as well as the cooling water flow rates of the upper and lower valves.

4. The laminar flow cooling control method for stainless steel cooling according to claim 3, characterized in that, The method of dynamically increasing or decreasing the number of valves opened and their cooling water volume in sequence or in reverse sequence, based on the difference between the actual temperature and the target temperature of laminar flow cooling, according to a preset valve opening and cooling sequence and the maximum cooling water volume of valves in the preset strong cooling zone, further includes: If the actual temperature of laminar cooling is lower than the target temperature of laminar cooling, the valves used for cooling water spray are reduced in reverse order according to the preset valve opening sequence of the upper and lower valves and the maximum cooling water volume of the valves in the preset strong cooling zone, and the corresponding laminar cooling temperature value is calculated until the calculated laminar cooling temperature value reaches the target temperature of laminar cooling. Then, the upper and lower valves that are finally opened and the cooling water volume of the upper and lower valves are determined. Specifically, when the valves used for cooling water spraying that are reduced belong to valves 01# to 24# in the strong cooling zone, the cooling water volume is gradually reduced from the current cooling water volume to 1% of the maximum water volume in increments of 0.1% of the maximum water volume, and the laminar cooling temperature value corresponding to each step is calculated. If the laminar cooling temperature value calculated when the volume is reduced to 1% of the maximum water volume or a value before 1% of the maximum water volume reaches the laminar cooling target temperature, then the currently determined valves used for cooling water spraying and their cooling water volume are used as the final opened upper and lower valves, as well as the cooling water volume of the upper and lower valves. If the laminar cooling temperature value calculated when the volume is reduced to 1% of the maximum water volume does not reach the laminar cooling target temperature, then the process of gradually reducing the valves used for cooling water spraying in reverse order and calculating the corresponding laminar cooling temperature value continues until the calculated laminar cooling temperature value reaches the laminar cooling target temperature. Then, the currently determined valves used for cooling water spraying and their cooling water volume are used as the final opened upper and lower valves, as well as the cooling water volume of the upper and lower valves.

5. The laminar flow cooling control method for stainless steel cooling according to claim 1, characterized in that, The valve opening rules also include: keeping the last 4 valves open.

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