System and method for testing cooling heat transfer coefficient of steel plate
By designing a steel plate cooling heat transfer coefficient test system and using the thermal equilibrium relationship to determine the convection heat transfer coefficient, the temperature control problem during the cooling process of hot-rolled thin steel plates is solved, and accurate cooling and tissue performance forecast of steel plates with a thickness of ≤3mm are achieved.
Patent Information
- Application Number
- CN202411259772.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-01-03
AI Technical Summary
The prior art is difficult to achieve accurate temperature control during the cooling process of hot-rolled thin steel plates, especially steel plates with a thickness of ≤3mm, which makes it difficult to accurately predict and control the tissue performance.
A steel plate cooling heat transfer coefficient test system is designed to simulate the hot rolling process through a movable cooling device, and the convection heat transfer coefficient is measured in combination with the thermal equilibrium relationship to guide the setting of cooling model parameters.
Accurate temperature control and tissue performance forecast of the cooling process of hot-rolled thin steel plate with a thickness of ≤3mm are achieved, and the accuracy and reliability of the cooling model are improved.
Smart Images
Figure CN119246601A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of hot-rolled steel cooling treatment, and in particular relates to a steel plate cooling heat transfer coefficient testing system and method. Background Art
[0002] The post-rolling cooling technology of hot-rolled strip can make the grains of the strip orderly refined, strengthen the organization and mechanical properties. At present, the cooling methods of hot-rolled strip include spray cooling, pressure jet cooling, laminar cooling, water curtain cooling, atomization cooling and ultra-density impact jet cooling. There are many forms of heat exchange between cooling water and strip, mainly including heat transfer such as convection heat exchange between strip and cooling water, latent heat generated by heat conduction and phase change inside the strip, and radiation heat dissipation of the strip itself. The complexity of the heat transfer mechanism of the cooling process, the variability of strip product specifications (thickness, width) and steel quality, and the time-varying nature of strip parameters during cooling, and mid-to-high-end products such as high-grade pipeline steel and high-strength engineering machinery steel require the post-rolling cooling model to have precise temperature control accuracy. At present, the relevant fields at home and abroad have not yet achieved temperature control of the cooling process and accurate prediction of product organization and performance. Due to the complex cooling water flow field, the ability of convective heat transfer is related to the physical properties of water and the flow pattern of water on the strip, and different steel materials have different heat transfer characteristics. Therefore, multiple factors make it difficult to accurately control the temperature of the strip during the cooling process, especially for hot-rolled thin steel plates with a thickness of ≤3mm. It is difficult to directly measure the temperature change of the strip during the cooling process by the "buried couple" method, and it is also difficult to accurately cool the strip by controlling the temperature, which ultimately leads to the inability to accurately control and predict the organizational properties of cold-rolled steel. Summary of the invention
[0003] The purpose of the present invention is to address the shortcomings of the prior art that it is difficult to accurately control the temperature of hot-rolled thin steel plates with a thickness of ≤3mm during the cooling process, and thus propose a steel plate cooling heat transfer coefficient testing system and method. The system is provided with a movable cooling device to cool the steel plate to be cooled to simulate the cooling process of hot steel after rolling, and the convective heat transfer coefficient of the hot-rolled thin steel plate with a thickness of ≤3mm during cooling is calculated by measuring the convective heat transfer coefficient of the movable cooling device of the steel plate to be cooled, and according to the heat balance relationship and the physical properties of the steel plate to be cooled and the related cooling materials. The system described in the present invention has a simple structure, is easy to operate, and has accurate measurement data. The convective heat transfer coefficient finally calculated can be used to guide the relevant process parameters of the cooling model for the hot-rolled thin steel plate.
[0004] A first aspect of the present invention proposes a steel plate cooling heat transfer coefficient testing system, the system comprising a cooling device and a temperature measuring device; the cooling device moves along the surface of the steel plate to be cooled, and during the movement, the cooling water in the cooling device cools the surface of the steel plate to be cooled, and the temperature measuring device measures the temperature of the opposite side surface of the steel plate to be cooled.
[0005] Preferably, the system also includes a guide rail, a guide wheel group and a driving mechanism, the guide rail is arranged parallel to the steel plate to be cooled, the guide wheel group is installed on the guide rail, the cooling device is installed on the guide wheel group, and the driving mechanism is used to drive the guide wheel group to drive the cooling device to move along the guide rail toward the length direction of the steel plate to be cooled; the distance and angle between the cooling device and the surface of the steel plate to be cooled can be adjusted.
[0006] More preferably, the system is symmetrically provided with guide rails on the upper and lower sides of the steel plate to be cooled, and the guide rails on the upper and lower sides are both equipped with guide wheel groups, and cooling devices are both equipped on the guide wheel groups; when measuring the convective heat transfer coefficient of the upper surface of the steel plate to be cooled, the temperature measuring device is installed on the lower surface of the steel plate to be cooled, and the cooling device on the upper side of the steel plate to be cooled moves along the length direction of the upper surface of the steel plate to be cooled, and cools the upper surface of the steel plate to be cooled; when measuring the convective heat transfer coefficient of the lower surface of the steel plate to be cooled, the temperature measuring device is installed on the upper surface of the steel plate to be cooled, and the cooling device on the lower side of the steel plate to be cooled moves along the length direction of the lower surface of the steel plate to be cooled, and cools the lower surface of the steel plate to be cooled.
[0007] Preferably, the system also includes a pressure wheel group and a tension adjuster, the pressure wheel group is connected to the guide wheel group through a connecting rod, the pressure wheel group is in contact with the surface of the steel plate to be cooled, the tension adjuster is installed on the connecting rod, and the tension adjuster applies pressure to the surface of the steel plate to be cooled through the pressure wheel group.
[0008] Preferably, the system also includes a pump group, a water tank, a flow control valve, a flow meter and a water thermometer; the pump group is used to transport the cooling water in the water tank to the cooling device; the flow control valve is used to control the flow of cooling water entering the cooling device; the flow meter is used to measure the flow of cooling water entering the cooling device; the water thermometer is used to measure the temperature of the cooling water entering the cooling device.
[0009] Preferably, the system further comprises a limiting plate, wherein the limiting plate is used to fix the steel plate to be cooled, and the limiting plate is in a fixed state.
[0010] The second aspect of the present invention proposes a method for testing the cooling heat transfer coefficient of a steel plate implemented in the above-mentioned system, the method comprising: a cooling device moves along the surface of the steel plate to be cooled, and uses cooling water in the cooling device to cool the surface of the steel plate to be cooled during the movement, a temperature measuring device measures the temperature of the opposite side surface of the steel plate to be cooled, obtains the temperature of the steel plate to be cooled before and after cooling, and calculates the convective heat transfer coefficient of the cooling surface of the steel plate to be cooled based on a heat balance relationship.
[0011] Preferably, the calculation formula of the convective heat transfer coefficient of the cooling surface of the steel plate to be cooled is calculated according to the heat balance relationship as follows:
[0012]
[0013] In the formula, K b is the convective heat transfer coefficient of the cooling surface of the steel plate to be cooled, C p is the heat capacity of the steel plate to be cooled, ρ is the density of the steel plate to be cooled, h is the thickness of the steel plate to be cooled, v is the moving speed of the cooling device, t is the temperature of the steel plate to be cooled before cooling, t 0b is the temperature of the cooling surface of the steel plate to be cooled after cooling, b is the width of the steel plate to be cooled, t f is the temperature of cooling water.
[0014] More preferably, when the thickness of the steel plate to be cooled is 2h, the other side surface of the steel plate to be cooled is cooled by cooling water in the cooling device, the temperature of the steel plate to be cooled before and after cooling is measured, and the convective heat transfer coefficient K of the cooling surface on the other side of the steel plate to be cooled is calculated according to the heat balance relationship. t , convection heat transfer coefficient K t The calculation formula is as follows:
[0015]
[0016] In the formula, K t is the convective heat transfer coefficient of the cooling surface on the other side of the steel plate to be cooled, C p is the heat capacity of the steel plate to be cooled, ρ is the density of the steel plate to be cooled, h is the thickness of the steel plate to be cooled, v is the moving speed of the cooling device, t is the temperature of the steel plate to be cooled before cooling, t 0t is the temperature of the cooling surface on the other side of the steel plate to be cooled after cooling, b is the width of the steel plate to be cooled, t f is the temperature of the cooling water; then the convective heat transfer coefficient of the steel plate to be cooled is K = K b +K t .
[0017] Preferably, the thickness of the steel plate to be cooled is 0.6 mm ≤ 2h ≤ 3.0 mm.
[0018] The steel plate cooling heat transfer coefficient testing system and method described in the present invention have the following beneficial effects: the present invention combines radiation cooling and cooling water cooling into an equivalent cooling system, mainly considering the temperature drop caused by convective heat transfer, and simulates the cooling process of hot strip steel after rolling by fixing the steel plate to be cooled and cooling the steel plate to be cooled by a mobile cooling device. According to the heat balance relationship and related physical parameters, the convective heat transfer coefficient of the cooling device on the upper and lower surfaces of the thin-gauge steel plate is measured respectively, and the relationship between the flow state of cooling water on the upper and lower surfaces of the strip and the heat transfer coefficient is analyzed. The convective heat transfer coefficient of a certain gauge thickness steel plate when the upper and lower surfaces are cooled simultaneously is flexibly calculated to guide the setting of cooling model parameters. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a schematic diagram of the cooling heat transfer coefficient test on the upper surface of the steel plate to be cooled in the present invention;
[0020] Figure 2 It is a schematic diagram of the cooling heat transfer coefficient test of the lower surface of the steel plate to be cooled in the present invention;
[0021] Figure 3 It is a top view of the steel plate cooling heat transfer coefficient testing system of the present invention;
[0022] Figure 4 It is a schematic diagram of the water supply structure of the cooling device in the present invention. DETAILED DESCRIPTION
[0023] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.
[0024] The first aspect of the present invention proposes a steel plate cooling heat transfer coefficient testing system, which includes a cooling device 1 and a temperature measuring device 2; the cooling device 1 moves along the surface of the steel plate 3 to be cooled, and during the movement, the cooling water in the cooling device 1 cools the surface of the steel plate 3 to be cooled, and the temperature measuring device 2 measures the temperature of the opposite side surface of the steel plate 3 to be cooled.
[0025] In a specific embodiment of the system described in the present invention, the cooling device 1 is a nozzle. Specifically, different types of nozzles can be selected according to needs, and the shape of the nozzle matches the cooling nozzles such as spray cooling, pressure jet cooling, laminar cooling, water curtain cooling, atomization cooling, and ultra-density impact jet of the hot rolled strip post-rolling cooling device, which are respectively used to simulate the nozzle cooling process of the post-rolled strip.
[0026] In a specific embodiment of the system of the present invention, the temperature measuring device 2 is a thermocouple group, which is welded to the upper surface or lower surface of the steel plate 3 to be cooled. During the specific operation process, the thermocouple group is connected to the temperature detection system to record the temperature value of the steel plate 3 to be cooled during the entire process from entering the heating furnace to being cooled by the nozzle.
[0027] In a specific embodiment of the system of the present invention, the system further comprises a heating furnace 16, wherein the heating furnace 16 is used to heat and keep the test plate warm, simulate the temperature of the strip steel after rolling, and obtain the steel plate 3 to be cooled.
[0028] In a specific embodiment of the system of the present invention, Figure 3 As shown, the system also includes a guide rail 4, a guide wheel group 5 and a driving mechanism 6, the guide rail 4 is arranged parallel to the steel plate 3 to be cooled, the guide wheel group 5 is installed on the guide rail 4, the cooling device 1 is installed on the guide wheel group 5, and the driving mechanism 6 is used to drive the guide wheel group 5 to move along the guide rail 4 toward the length direction of the steel plate 3 to be cooled; the distance and angle between the cooling device 1 and the surface of the steel plate 3 to be cooled can be adjusted.
[0029] In a preferred embodiment of the system of the present invention, Figure 1-2 As shown, the system is symmetrically provided with guide rails 4 on the upper and lower sides of the steel plate 3 to be cooled, and the guide rails 4 on the upper and lower sides are both installed with guide wheel groups 5; when measuring the convective heat transfer coefficient of the upper surface of the steel plate 3 to be cooled, the cooling device 1 on the upper side of the steel plate 3 to be cooled is fixed below the axis between the guide wheel groups 5, and the temperature measuring device 2 is installed on the lower surface of the steel plate 3 to be cooled, and the cooling device 1 moves along the length direction of the upper surface of the steel plate 3 to be cooled, and cools the upper surface of the steel plate 3 to be cooled; when measuring the convective heat transfer coefficient of the lower surface of the steel plate 3 to be cooled, the cooling device 1 on the lower side of the steel plate 3 to be cooled is fixed above the axis between the guide wheel groups 5, and the temperature measuring device 2 is installed on the upper surface of the steel plate 3 to be cooled, and the cooling device 1 moves along the length direction of the lower surface of the steel plate 3 to be cooled, and cools the lower surface of the steel plate 3 to be cooled.
[0030] In a preferred embodiment of the system of the present invention, Figure 1-2 As shown, the system also includes a clamping wheel group 7 and a tension regulator 8. The clamping wheel group 7 is connected to the guide wheel group 5 through a connecting rod 9. The clamping wheel group 7 is in contact with the surface of the steel plate 3 to be cooled. The tension regulator 8 is installed on the connecting rod 9. The tension regulator 8 is used to apply pressure to the surface of the steel plate 3 to be cooled through the clamping wheel group 7, so that the steel plate 3 to be cooled maintains a stable state when subjected to the impact force of the water spray from the nozzle, so as to ensure the reliability and stability of the test data related to the heat transfer coefficient.
[0031] In a specific embodiment of the system of the present invention, the system also includes a limit plate 15, which is used to fix the steel plate 3 to be cooled; specifically, the limit plate 15 is a fixing device, and a square hole slot matching the shape of the steel plate 3 to be cooled is opened in the middle of the limit plate 15, and the steel plate 3 to be cooled can be fixed in the square hole slot of the limit plate 15.
[0032] In a specific embodiment of the system of the present invention, Figure 4 As shown, the system also includes a pump group 10, a water tank 11, a flow control valve 12, a flow meter 13 and a water thermometer 14; the water tank 11, the pump group 10 and the cooling device 1 are connected in sequence, and the flow meter 13 and the water thermometer 14 are arranged in sequence in the connecting pipes of the pump group 10 and the cooling device 1; the pump group 10 is used to transport the cooling water of a certain pressure in the water tank 11 to the cooling device 1; the flow control valve 12 is used to control the flow of cooling water entering the cooling device 1; the flow meter 13 is used to measure the flow of cooling water entering the cooling device 1; the water thermometer 14 is used to measure the temperature of cooling water entering the cooling device 1. In this article, the water tank 11 can provide a water source for the system, and can cool the return water of the steel plate cooling heat transfer coefficient test system of the present invention.
[0033] In the actual operation of the system of the present invention, when measuring the convective heat transfer coefficient of the upper surface of the steel plate 3 to be cooled, as shown in FIG. Figure 1 As shown, after the temperature measuring device 2 is spot-welded on the lower surface of the steel plate 3 to be cooled, the temperature measuring device 2 and the steel plate 3 to be cooled are placed in a heating furnace 16 and heated to a certain temperature. Then, the steel plate 3 to be cooled is quickly fixed in the square hole slot of the limit plate 15. The temperature measuring device 2 is connected to the temperature detection system to keep a dynamic record of the temperature state. The driving mechanism 6 is started to drive the guide wheel group 5 on the upper side of the steel plate 3 to be cooled and drive the cooling device 1 to move along the guide rail 4 at a certain speed in the length direction of the steel plate 3 to be cooled. The tension regulator 8 is used to apply pressure to the surface of the steel plate 3 to be cooled through the clamping wheel group 7; during the movement, the pump group 10 is synchronously started to a certain pressure through the control system, and the flow control valve 12 controls the cooling device 1 on the upper side of the steel plate 3 to be cooled to spray the upper surface of the steel plate 3 to be cooled according to a certain proportional flow rate. The flow meter 13 and the water temperature meter 14 respectively measure the flow rate and temperature of the cooling water of the jet. During the movement of the cooling device 1, the temperature measuring device 2 records the temperature of the steel plate 3 to be cooled before and after jet cooling;
[0034] When measuring the convective heat transfer coefficient of the lower surface of the steel plate 3 to be cooled, Figure 2As shown, after the temperature measuring device 2 is spot-welded on the upper surface of the steel plate 3 to be cooled, the temperature measuring device 2 and the steel plate 3 to be cooled are placed in a heating furnace 16 and heated to a certain temperature. Then, the steel plate 3 to be cooled is quickly fixed in the square hole slot of the limit plate 15. The temperature measuring device 2 is connected to the temperature detection system to keep a dynamic record of the temperature state. The driving mechanism 6 is started to drive the guide wheel group 5 on the lower side of the steel plate 3 to be cooled and drive the cooling device 1 to move along the guide rail 4 at a certain speed in the length direction of the steel plate 3 to be cooled. The tension regulator 8 is used to apply pressure to the surface of the steel plate 3 to be cooled through the clamping wheel group 7; during the movement, the pump group 10 is synchronously started to a certain pressure through the control system, and the flow control valve 12 controls the cooling device 1 on the lower side of the steel plate 3 to be cooled to jet the lower surface of the steel plate 3 to be cooled according to a certain proportional flow rate. The flow meter 13 and the water thermometer 14 respectively measure the flow rate and temperature of the cooling water of the jet. During the movement of the cooling device 1, the temperature measuring device 2 records the temperature of the steel plate 3 to be cooled before and after jet cooling.
[0035] The second aspect of the present invention proposes a steel plate cooling heat transfer coefficient testing method implemented in the above-mentioned system, the method comprising: a cooling device 1 moves along the surface of a steel plate 3 to be cooled, and uses cooling water in the cooling device 1 to cool the surface of the steel plate 3 to be cooled during the movement, a temperature measuring device 2 measures the temperature of the opposite side surface of the steel plate 3 to be cooled, obtains the temperature of the steel plate 3 to be cooled before and after cooling, and calculates the convective heat transfer coefficient of the cooling surface of the steel plate 3 to be cooled according to a heat balance relationship.
[0036] The convection heat transfer coefficient K is related to the temperature t of the steel plate 3 to be cooled, the physical parameters of the steel plate 3 to be cooled (heat capacity C p , density ρ, thickness h), cooling water temperature t f , flow rate q, pressure P, and the flow state of the cooling water after the cooling water is sprayed on the upper and lower surfaces of the steel plate 3 to be cooled. Before the test, the cooling water in the upper and lower cooling devices 1 was set to a fixed pressure P, and the flow rate was set to q t ,q b The temperature before cooling is generally the set value t, and a certain steel type with a thickness of h of 0.8 mm is selected, and the steel plate 3 to be cooled is cut into a shape of L and a width of b, which matches the square hole slot in the middle of the limit plate 15. During the cooling process of the thin plate, the cooling speed of the steel plate 3 to be cooled is fast, and the radiation cooling and water spray cooling are combined into an equivalent cooling system, mainly considering the temperature drop caused by convective heat transfer.
[0037] In a specific embodiment of the system of the present invention, the cooling device 1 moves along the lower surface of the steel plate 3 to be cooled, and uses the cooling water in the cooling device 1 to cool the lower surface of the steel plate 3 to be cooled during the movement. The temperature measuring device 2 measures the temperature of the upper surface of the steel plate 3 to be cooled to obtain the temperature of the steel plate 3 to be cooled before and after cooling. The calculation formula of the convective heat transfer coefficient of the lower surface of the steel plate 3 to be cooled is calculated according to the heat balance relationship as follows:
[0038]
[0039] In the formula, K b is the convective heat transfer coefficient of the cooling surface (lower surface) of the steel plate to be cooled, C p is the heat capacity of the steel plate to be cooled, ρ is the density of the steel plate to be cooled, h is the thickness of the steel plate to be cooled, v is the moving speed of the cooling device, t is the temperature of the steel plate to be cooled before cooling, t 0b is the temperature of the cooling surface (lower surface) of the steel plate to be cooled after cooling, b is the width of the steel plate to be cooled, t f is the temperature of cooling water.
[0040] In a preferred embodiment of the system of the present invention, when the thickness of the steel plate 3 to be cooled is 2h, the cooling water in the cooling device 1 is used to cool the other side surface of the steel plate 3 to be cooled (i.e., the upper surface of the steel plate 3 to be cooled), and the temperature of the steel plate 3 to be cooled before and after cooling is measured, and the convective heat transfer coefficient K of the cooling surface (upper surface) of the other side of the steel plate 3 to be cooled is calculated according to the heat balance relationship. t , convection heat transfer coefficient K t The calculation formula is as follows:
[0041]
[0042] In the formula, K t is the convective heat transfer coefficient of the other cooling surface (upper surface) of the steel plate to be cooled, C p is the heat capacity of the steel plate to be cooled, ρ is the density of the steel plate to be cooled, h is the thickness of the steel plate to be cooled, v is the moving speed of the cooling device, t is the temperature of the steel plate to be cooled before cooling, t 0t is the temperature of the other cooling surface (upper surface) of the steel plate to be cooled after cooling, b is the width of the steel plate to be cooled, t f is the temperature of the cooling water; then the convective heat transfer coefficient of the steel plate to be cooled is K = K b +K t .
[0043] In a preferred embodiment of the system of the present invention, the thickness of the steel plate 3 to be cooled is 0.6 mm≤2h≤3.0 mm.
[0044] The experimental methods or test methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified.
[0045] Example 1
[0046] A steel plate cooling heat transfer coefficient test system, such as Figure 1-4 As shown, the system includes a cooling device 1, a temperature measuring device 2, a limit plate 15, a steel plate to be cooled 3, a pump group 10, a water tank 11, a flow control valve 12, a flow meter 13 and a water temperature meter 14. The steel plate to be cooled 3 with a thickness h of 0.8 mm is selected, and the limit plate 15 is in a fixed state. Two guide rails 4 are fixed in parallel on the upper and lower sides of the limit plate 15, and each guide rail 4 is installed with a guide wheel group 5. A cooling device 1 is fixed below the shaft between the upper guide wheel groups 5, and another cooling device 1 is fixed above the shaft between the lower guide wheel groups 5. Each cooling device 1 is connected to the steel plate to be cooled. The distance and angle of the surface of the cooling steel plate 3 are both adjustable; the guide wheel groups 5 on the upper and lower sides are connected to the clamping wheel group 7 through the connecting rod 9, the clamping wheel group 7 is in contact with the surface of the steel plate 3 to be cooled, and the tension regulator 8 is installed on the connecting rod 9. The tension regulator 8 is used to apply pressure to the surface of the steel plate 3 to be cooled through the clamping wheel group 7, and the temperature measuring device 2 is welded on the surface of the steel plate 3 to be cooled; the water tank 11, the pump group 10 and the cooling device 1 are connected in sequence, and the flow meter 13 and the water temperature meter 14 are arranged in sequence in the connecting pipeline between the pump group 10 and the cooling device 1.
[0047] A method for testing the heat transfer coefficient of steel plate cooling implemented by the system described in Example 1, the method comprising: when measuring the convective heat transfer coefficient of the upper surface of the steel plate 3 to be cooled, after spot welding the temperature measuring device 2 on the lower surface of the steel plate 3 to be cooled, the steel plate 3 to be cooled is placed in a heating furnace 16 together with the temperature measuring device 2 and heated to a temperature of 890°C, and then the steel plate 3 to be cooled is quickly fixed in the square hole slot of the limit plate 15, and the temperature measuring device 2 is connected to the temperature detection system to keep a dynamic record of the temperature state; the driving mechanism 6 is started to drive the guide wheel group 5 on the upper side of the steel plate 3 to be cooled and drive the cooling device 1 along the guide rail 4 to the steel plate 3 to be cooled. It moves at a speed v of 7m / min in the length direction. During the movement, the tension regulator 8 is used to apply pressure to the surface of the steel plate 3 to be cooled through the clamping wheel group 7; during the movement, the pump group 10 is synchronously started to deliver cooling water with a pressure of 0.8MPa to the cooling device 1 through the control system, and the flow control valve 12 controls the cooling device 1 on the upper side of the steel plate 3 to be cooled to spray the upper surface of the steel plate 3 to be cooled according to a certain proportional flow rate. The flow meter 13 and the water temperature meter 14 respectively measure the flow rate and temperature of the cooling water of the spray. During the movement of the cooling device 1, the temperature of the steel plate 3 to be cooled after the spray cooling is recorded by the temperature measuring device 2;
[0048] When measuring the convective heat transfer coefficient of the lower surface of the steel plate 3 to be cooled, the temperature measuring device 2 is spot-welded on the upper surface of the steel plate 3 to be cooled, and the temperature measuring device 2 and the steel plate 3 to be cooled are placed in a heating furnace 16 and heated to a temperature of 890°C. The steel plate 3 to be cooled is quickly fixed in the square hole slot of the limit plate 15, and the temperature measuring device 2 is connected to the temperature detection system to keep a dynamic record of the temperature state; the driving mechanism 6 is started to drive the guide wheel group 5 on the lower side of the steel plate 3 to be cooled and drive the cooling device 1 to move along the guide rail 4 in the length direction of the steel plate 3 to be cooled at a speed v of 7m / min During the movement, the tension regulator 8 is used to apply pressure to the surface of the steel plate 3 to be cooled through the clamping wheel group 7; during the movement, the pump group 10 is synchronously started to deliver cooling water with a pressure of 0.8MPa to the cooling device 1 through the control system, and the flow control valve 12 controls the cooling device 1 on the lower side of the steel plate 3 to be cooled to spray the lower surface of the steel plate 3 to be cooled according to a certain proportional flow rate. The flow meter 13 and the water temperature meter 14 respectively measure the flow rate and temperature of the cooling water of the jet. During the movement of the cooling device 1, the temperature of the steel plate 3 to be cooled after jet cooling is recorded by the temperature measuring device 2;
[0049] The water flow states of the cooling devices 1 on the upper and lower sides after jetting on the upper and lower surfaces of the steel plate 3 to be cooled are different, which will affect the heat transfer coefficient. The flow setting can be fine-tuned according to the water flow state and the steel type of the steel plate 3 to be cooled. The relevant test parameters are shown in Table 1.
[0050] Table 1 Test parameters
[0051]
[0052] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.
Claims
1. A steel plate cooling heat transfer coefficient test system, characterized in that: The system comprises a cooling device (1) and a temperature measuring device (2); the cooling device (1) moves along the surface of a steel plate (3) to be cooled, and during the movement, cooling water in the cooling device (1) cools the surface of the steel plate (3) to be cooled, and the temperature measuring device (2) measures the temperature of the opposite side surface of the steel plate (3) to be cooled.
2. The steel plate cooling heat transfer coefficient testing system according to claim 1, characterized in that: The system further comprises a guide rail (4), a guide wheel group (5) and a driving mechanism (6); the guide rail (4) is arranged in parallel with the steel plate (3) to be cooled; the guide wheel group (5) is mounted on the guide rail (4); the cooling device (1) is mounted on the guide wheel group (5); and the driving mechanism (6) is used to drive the guide wheel group (5) to drive the cooling device (1) to move along the guide rail (4) in the length direction of the steel plate (3) to be cooled; The distance and angle between the cooling device (1) and the surface of the steel plate (3) to be cooled are adjustable.
3. The steel plate cooling heat transfer coefficient testing system according to claim 2, characterized in that: The system comprises guide rails (4) symmetrically arranged on the upper and lower sides of the steel plate (3) to be cooled, and the guide rails (4) on the upper and lower sides are both equipped with guide wheel groups (5), and the guide wheel groups (5) are both equipped with cooling devices (1); When measuring the convective heat transfer coefficient of the upper surface of the steel plate (3) to be cooled, the temperature measuring device (2) is installed on the lower surface of the steel plate (3) to be cooled, and the cooling device (1) on the upper side of the steel plate (3) to be cooled moves along the length direction of the upper surface of the steel plate (3) to be cooled, and cools the upper surface of the steel plate (3) to be cooled; When measuring the convective heat transfer coefficient of the lower surface of the steel plate (3) to be cooled, the temperature measuring device (2) is installed on the upper surface of the steel plate (3) to be cooled, and the cooling device (1) on the lower side of the steel plate (3) to be cooled moves along the length direction of the lower surface of the steel plate (3) to be cooled, and cools the lower surface of the steel plate (3) to be cooled.
4. The steel plate cooling heat transfer coefficient testing system according to claim 3, characterized in that: The system also includes a clamping wheel group (7) and a tension regulator (8), wherein the clamping wheel group (7) is connected to the guide wheel group (5) via a connecting rod (9), the clamping wheel group (7) is in contact with the surface of the steel plate (3) to be cooled, and the tension regulator (8) is mounted on the connecting rod (9), and the tension regulator (8) applies pressure to the surface of the steel plate (3) to be cooled through the clamping wheel group (7).
5. The steel plate cooling heat transfer coefficient testing system according to claim 4, characterized in that: The system also includes a pump group (10), a water tank (11), a flow control valve (12), a flow meter (13) and a water temperature meter (14); The pump group (10) is used to transport the cooling water in the water tank (11) to the cooling device (1); The flow control valve (12) is used to control the flow of cooling water entering the cooling device (1); The flow meter (13) is used to measure the flow rate of cooling water entering the cooling device (1); The water temperature meter (14) is used to measure the temperature of cooling water entering the cooling device (1).
6. The steel plate cooling heat transfer coefficient testing system according to claim 1, characterized in that: The system further comprises a limiting plate (15), wherein the limiting plate (15) is used to fix the steel plate (3) to be cooled, and the limiting plate (15) is in a fixed state.
7. A method for testing the heat transfer coefficient of steel plate cooling implemented in the system according to any one of claims 1 to 6, characterized in that: The method comprises: a cooling device (1) moves along the surface of a steel plate (3) to be cooled, and during the movement, cooling water in the cooling device (1) is used to cool the surface of the steel plate (3) to be cooled; a temperature measuring device (2) measures the temperature of the opposite side surface of the steel plate (3) to be cooled, obtains the temperature of the steel plate (3) to be cooled before and after cooling, and calculates the convective heat transfer coefficient of the cooling surface of the steel plate (3) to be cooled according to a heat balance relationship.
8. The steel plate cooling heat transfer coefficient testing method according to claim 7, characterized in that: The calculation formula of the convective heat transfer coefficient of the cooling surface of the steel plate (3) to be cooled is calculated according to the heat balance relationship as follows: In the formula, K b is the convective heat transfer coefficient of the cooling surface of the steel plate to be cooled, C p is the heat capacity of the steel plate to be cooled, ρ is the density of the steel plate to be cooled, h is the thickness of the steel plate to be cooled, v is the moving speed of the cooling device, t is the temperature of the steel plate to be cooled before cooling, t 0b is the temperature of the cooling surface of the steel plate to be cooled after cooling, b is the width of the steel plate to be cooled, t f is the temperature of cooling water.
9. The steel plate cooling heat transfer coefficient testing method according to claim 8, characterized in that: When the thickness of the steel plate (3) to be cooled is 2h, the other side surface of the steel plate (3) to be cooled is cooled by using cooling water in the cooling device (1), the temperature of the steel plate (3) to be cooled before and after cooling is measured, and the convection heat transfer coefficient K of the cooling surface on the other side of the steel plate (3) to be cooled is calculated according to the heat balance relationship. t , convection heat transfer coefficient K t The calculation formula is as follows: In the formula, K t is the convective heat transfer coefficient of the cooling surface on the other side of the steel plate to be cooled, C p is the heat capacity of the steel plate to be cooled, ρ is the density of the steel plate to be cooled, h is the thickness of the steel plate to be cooled, v is the moving speed of the cooling device, t is the temperature of the steel plate to be cooled before cooling, t 0t is the temperature of the cooling surface on the other side of the steel plate to be cooled after cooling, b is the width of the steel plate to be cooled, t f is the temperature of cooling water; Then the convective heat transfer coefficient of the steel plate to be cooled K = K b +K t .
10. The steel plate cooling heat transfer coefficient testing method according to claim 9, characterized in that: The thickness of the steel plate (3) to be cooled is 0.6 mm ≤ 2h ≤ 3.0 mm.