Strip steel surface quality control system

Abstract

The invention discloses a strip steel surface quality control system, and relates to the technical field of strip steel production, the control system comprises a continuous annealing furnace, one end of the continuous annealing furnace is provided with a strip steel inlet, a plurality of furnace rollers are arranged in the continuous annealing furnace, and the inner wall of the continuous annealing furnace is provided with an in-furnace protective gas pipeline; one end of the furnace nose is communicated with the other end of the continuous annealing furnace, and a furnace nose protective gas pipeline is arranged on the inner wall of the furnace nose; the sinking roller is arranged in the zinc pot, and the other end of the furnace nose is arranged at the upper end of the sinking roller; the strip steel enters a continuous annealing furnace and is conveyed to a sink roller through a plurality of furnace rollers; the humidity in the continuous annealing furnace is adjusted to control the dew point in the continuous annealing furnace; the data set affecting the dew point in the furnace nose is adjusted to control the dew point in the furnace nose. By adjusting the dew point in the continuous annealing furnace and the dew point of the furnace nose and controlling the atmosphere diffusion of the furnace nose, the Mn element is prevented from being separated out to the surface of the strip steel, and a series of influences of alloy element separation and zinc liquid level oxidation on the surface quality of the strip steel are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of strip steel production, and in particular to a control system for strip steel surface quality. Background Art

[0002] Due to the different application parts of automotive steel, the required physical properties are quite different. For the exterior covering parts of automobile bodies, materials with better stamping deformation performance are required to meet their complex shape requirements, so interstitial atomic steel with lower yield strength and higher elongation is often used. However, for parts with large forming areas such as engine hoods, a certain strength is required to maintain their anti-sag performance, so bake-hardened steel or high-strength interstitial atomic steel materials are often used. For high-strength interstitial atomic steel, different amounts of alloying elements such as Mn and Si need to be added to meet its strength requirements. As annealing proceeds, alloying elements will diffuse from the inside of the steel plate to the surface, enrich on the surface of the steel plate to form oxides covering the surface of the steel plate. These alloying elements enriched on the surface will cause problems such as nodules on the furnace rollers and reduce the wettability of the strip to the zinc liquid. In addition, the zinc ash in the furnace nose is easy to fall onto the surface of the strip, all of which affect the surface quality of the strip.

[0003] The Mn element inside high Mn content interstitial-free steel is more likely to form tiny nodule particles on the surface of the furnace roller than conventional interstitial-free steel, causing relative friction displacement between the strip surface and the furnace roller to form point scratches. At the same time, the residual Mn oxides on the surface will reduce the wettability of the strip surface to the zinc liquid, making the oxides on the surface of the zinc liquid more likely to adhere to the strip surface to form film-like zinc ash defects. Summary of the invention

[0004] The object of the present invention is to provide a control system for the surface quality of strip steel, which can hinder the further precipitation of Mn elements to the surface of the strip steel by adjusting the dew point in the continuous annealing furnace and the dew point in the furnace nose, thereby reducing the series of effects of the precipitation of alloy elements on the surface quality of the strip steel.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] According to one aspect of an embodiment of the present invention, a control system for the surface quality of a steel strip is provided, the control system comprising: a continuous annealing furnace, wherein a steel strip inlet is provided at one end of the continuous annealing furnace, a plurality of furnace rollers are provided in the continuous annealing furnace, the plurality of furnace rollers are staggered in two rows, a furnace protective gas pipeline is provided on the inner wall of the continuous annealing furnace; a furnace nose, wherein one end of the furnace nose is connected with the other end of the continuous annealing furnace, and a furnace nose protective gas pipeline connected with the furnace protective gas pipeline is provided on the inner wall of the furnace nose; a zinc pot and a sinking roller, the sinking roller is provided in the zinc pot, and the other end of the furnace nose is provided at the upper end of the sinking roller; the steel strip enters the continuous annealing furnace through the steel strip inlet, and is transmitted to the sinking roller through a plurality of furnace rollers; the humidity in the continuous annealing furnace is adjusted to control the dew point in the continuous annealing furnace to reach a first preset range value; and a data set affecting the dew point in the furnace nose is adjusted to control the dew point in the furnace nose to reach a second preset range value.

[0007] In some embodiments, a protective gas is injected into the protective gas pipeline in the furnace, and the proportion of nitrogen in the protective gas is a first proportion value, and the proportion of hydrogen in the protective gas is a second proportion value; the first proportion value is 95%, and the second proportion value is 5%; the furnace pressure in the protective gas pipeline in the furnace is controlled within a set pressure range value; the set pressure range value is 100 to 300 Pa.

[0008] In some embodiments, the dew points of the heating section and the soaking section in the continuous annealing furnace are controlled within a first preset range of values, and the first preset range of values ​​is -25°C to 0°C.

[0009] In some embodiments, the multiple furnace rollers include a first type of convex roller, the roughness Ra of the middle part of the first type of convex roller is 4μm~5μm, the roughness Rz of the middle part of the first type of convex roller is Rz≤5×Ra, the roughness Ra and Rz at both ends of the first type of convex roller are both less than 1μm; the roughness gradient width from the middle to the two ends of the first type of convex roller is 50mm.

[0010] In some embodiments, the plurality of furnace rollers also include a first type flat roller, the roughness Ra of the middle part of the first type flat roller is 4 μm to 5 μm, the roughness Rz of the middle part of the first type flat roller is Rz≤5×Ra, and the roughness Ra and Rz at both ends of the first type flat roller are both less than 1 μm.

[0011] In some embodiments, the plurality of furnace rollers further include a second type of flat roller, the roughness Ra of the second type of flat roller is 5 μm to 6 μm, and the roughness Rz of the second type of flat roller is Rz≤5×Ra.

[0012] In some embodiments, vent pipes are provided on both sides of the furnace nose, and the vent flow rates of the vent pipes are recorded; and the second preset range value is less than -5°C.

[0013] In some embodiments, a target training model based on machine learning is established in the control system, and the target training model is used to adjust the data set, and the data set includes intake pressure, wet nitrogen flow, heating power, strip width, strip thickness, production speed and discharge flow. The target training model based on machine learning includes: step 101, adjusting the data value of each data in the data set, when the dew point in the furnace nose reaches a second preset range value, recording the data value of each data to obtain a data value combination; step 102, repeating step 101 to record multiple groups of data value combinations; step 103, using the dew point of the second preset range value as the input data of the training model, using the multiple groups of data value combinations as the output data of the training model, repeating the training and testing to obtain a target training model that has completed the training.

[0014] In some embodiments, the furnace nose is connected to a furnace nose air intake structure, and the furnace nose air intake structure includes a protective gas main pipeline, a dry protective gas pipeline, a first valve, a first pressure gauge, a first flow valve, a humidifying gas pipeline, a second valve, a humidifier, a second pressure gauge and a second flow valve, the protective gas main pipeline is respectively connected to the dry protective gas pipeline and the humidifying gas pipeline, the dry protective gas pipeline is sequentially provided with the first valve, the first pressure gauge and the first flow valve, the humidifying gas pipeline is sequentially provided with the second valve, the humidifier, the second pressure gauge and the second flow valve, the dry protective gas pipeline and the humidifying gas pipeline are both connected to the furnace nose protective gas pipeline; the protective gas main pipeline inputs nitrogen, the dry protective gas pipeline outputs dry nitrogen, the humidifying gas pipeline outputs wet nitrogen, the dry nitrogen and the wet nitrogen are mixed and input into the furnace nose protective gas pipeline, and the dew point is controlled by adjusting the flow rate of the wet nitrogen.

[0015] In some embodiments, the control system also includes a humidification pipeline and a furnace main pipeline, the heating section, soaking section and cooling section of the continuous annealing furnace are all connected to the furnace main pipeline, and a heating section air intake structure, a soaking section air intake structure and a cooling section air intake structure are connected between the furnace main pipeline and the humidification pipeline; the heating section air intake structure includes a first humidification gas inlet and a second humidification gas inlet respectively connected to the furnace main pipeline and the humidification pipeline, the first humidification gas inlet is sequentially provided with a first pressure reducing valve, a first pressure pump, a third valve and a first flow meter, and the second humidification gas inlet is sequentially provided with a second pressure reducing valve, a second pressure pump, a fourth valve and a second flow meter; the soaking section air intake structure includes a first pressure reducing valve, a first pressure pump, a third valve and a first flow meter respectively connected to the furnace main pipeline and the humidification pipeline The third humidified gas inlet and the fourth humidified gas inlet are connected to the furnace main pipeline and the humidification pipeline, and the third humidified gas inlet is sequentially provided with a third pressure reducing valve, a third pressure pump, a fifth valve and a third flow meter, and the fourth humidified gas inlet is sequentially provided with a fourth pressure reducing valve, a fourth pressure pump, a sixth valve and a fourth flow meter; the cooling section air intake structure includes a fifth humidified gas inlet and a sixth humidified gas inlet respectively connected to the furnace main pipeline and the humidification pipeline, and the fifth humidified gas inlet is sequentially provided with a fifth pressure reducing valve, a fifth pressure pump, a seventh valve and a fifth flow meter, and the sixth humidified gas inlet is sequentially provided with a sixth pressure reducing valve, a sixth pressure pump, an eighth valve and a sixth flow meter.

[0016] A control system for the surface quality of a steel strip according to an embodiment of the present invention has at least the following beneficial effects: the present application further adjusts the dew point in the continuous annealing furnace by adjusting the humidity in the continuous annealing furnace, so that the dew point in the continuous annealing furnace reaches a first preset range value, so as to ensure that an internal oxidizing atmosphere is formed in the steel strip during the annealing heat treatment process, so that Mn and Fe elements form an oxide layer on the shallow surface layer of the steel strip to hinder the further precipitation of Mn element to the surface of the steel strip; the dew point in the furnace nose is further adjusted by adjusting the air intake pressure, wet nitrogen flow, heating power, strip width, strip thickness, production speed and discharge flow in the furnace nose, so that the dew point in the furnace nose reaches a second preset range value, thereby reducing the thickness of the oxide film on the surface of the zinc liquid; discharge pipes are added on both sides of the furnace nose, and while adjusting the humidification amount and dew point of the furnace nose, a small amount of zinc vapor is discharged through the atmosphere discharge function of the furnace nose discharge pipe, so as to avoid a small amount of zinc vapor caused by too low dew point adhering to and contaminating the inner wall of the furnace nose, thereby causing zinc ash to fall onto the surface of the steel strip and affect the quality of the surface of the steel strip.

[0017] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of a strip steel production structure according to an embodiment;

[0020] Figure 2 is a schematic diagram of a furnace nose air intake structure according to an embodiment;

[0021] Figure 3 It is a structural schematic diagram of a continuous annealing furnace humidification according to an embodiment;

[0022] Figure 4 is a schematic diagram of the structure of a crowning roller according to an embodiment;

[0023] Figure 5 Schematic diagram of the flat roller structure according to an embodiment.

[0024] The accompanying drawings are marked as follows: 1. annealing furnace; 2. protective gas pipeline in the furnace; 3. strip steel; 4. furnace roller; 5. furnace nose; 6. furnace nose protective gas pipeline; 7. sinking roller; 8. zinc pot; 9. vent pipe; 10. protective gas main pipeline; 11. dry protective gas pipeline; 12. first valve; 13. first pressure gauge; 14. first flow valve; 15. humidifying gas pipeline; 16. second valve; 17. humidifier; 18. second pressure gauge; 19. second flow valve; 20. humidifying pipeline; 21. furnace main pipeline; 100. heating section; 200. soaking section; 300. cooling section; 22. first humidifying gas inlet; 23. second humidifying gas inlet; 24. first pressure reducing valve; 25. first pressure reducing valve; 26. second pressure reducing valve; 27. first pressure reducing valve; 28. first pressure reducing valve; 29. ​​first pressure reducing valve; 30. first pressure reducing valve; 31. first pressure reducing valve; 32. first pressure reducing valve; 33. first pressure reducing valve; 34. first pressure reducing valve; 35. first pressure reducing valve; 36. first pressure reducing valve; 37. first pressure reducing valve; 38. first pressure reducing valve; 39. first pressure reducing valve; 40. first pressure reducing valve; 41. first pressure reducing valve; 42. first pressure reducing valve; 43. first pressure reducing valve; 44. first pressure reducing valve; 45. first pressure reducing valve; 46. first pressure reducing valve; 47. first pressure reducing valve; 48. first pressure reducing valve; 49. first pressure reducing valve; 50. first pressure reducing valve; 51. first pressure reducing valve; 52. first pressure reducing valve; 53. first pressure reducing valve; 54. first pressure reducing valve; 55. first pump; 26, the third valve; 27, the first flow meter; 28, the second pressure reducing valve; 29, the second booster pump; 30, the fourth valve; 31, the second flow meter; 32, the third humidification gas inlet; 33, the fourth humidification gas inlet; 34, the third pressure reducing valve; 35, the third booster pump; 36, the fifth valve; 37, the third flow meter; 38, the fourth pressure reducing valve; 39, the fourth booster pump; 40, the sixth valve; 41, the fourth flow meter; 42, the fifth humidification gas inlet; 43, the sixth humidification gas inlet; 44, the fifth pressure reducing valve; 45, the fifth booster pump; 46, the seventh valve; 47, the fifth flow meter; 48, the sixth pressure reducing valve; 49, the sixth booster pump; 50, the eighth valve; 51, the sixth flow meter. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0027] The terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that the description of the present disclosure will be more comprehensive and complete and the concepts of the example embodiments will be fully conveyed to those skilled in the art. The accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0030] The technical solution of the embodiment of the present application is briefly described below:

[0031] According to some embodiments, Figure 1As shown, the present application provides a control system for the surface quality of a strip steel, the control system comprising:

[0032] A continuous annealing furnace 1, wherein a strip steel inlet 3 is provided at one end of the continuous annealing furnace 1, a plurality of furnace rollers 4 are provided in the continuous annealing furnace 1, and the plurality of furnace rollers 4 are staggered and arranged in two rows, and a furnace protection gas pipeline 2 is provided on the inner wall of the continuous annealing furnace 1;

[0033] A furnace nose 5, one end of which is connected to the other end of the continuous annealing furnace 1, and an inner wall of the furnace nose 5 is provided with a furnace nose protective gas pipeline 6 connected to the protective gas pipeline 2 in the furnace;

[0034] A zinc pot 8 and a sinking roller 7, wherein the sinking roller 7 is arranged in the zinc pot 8, and the other end of the furnace nose 5 is arranged on the upper end of the sinking roller 7;

[0035] The steel strip 3 enters the continuous annealing furnace 1 through the steel strip 3 inlet and is transferred to the sinking roller 7 through a plurality of furnace rollers 4 .

[0036] The process based on the above embodiment is that after the strip steel 3 enters the furnace protective gas pipeline 2 in the continuous annealing furnace 1, it is transmitted to the furnace nose 5 through multiple furnace rollers 4, and then passes through the sinking roller 7 in the zinc pot 8 to perform the hot-dip galvanizing production process on its surface.

[0037] The present application adjusts the humidity in the continuous annealing furnace 1 to control the dew point in the continuous annealing furnace 1 to reach a first preset range value, and adjusts the data set affecting the dew point in the furnace nose 5 to control the dew point in the furnace nose 5 to reach a second preset range value. Finally, the Mn element is prevented from further precipitating on the surface of the steel strip 3, and the series of effects of the precipitation of alloy elements on the surface quality of the steel strip 3 are reduced.

[0038] The following is combined with the appendix of this manual Figures 1 to 5 , the preferred implementation modes of the present disclosure are further elaborated in detail.

[0039] According to some embodiments, a protective gas is injected into the protective gas pipeline 2 in the furnace, and the proportion of nitrogen in the protective gas is a first proportion value, and the proportion of hydrogen in the protective gas is a second proportion value. The first proportion value and the second proportion value can be set according to actual needs. In some embodiments, the first proportion value is set to 95%, and the second proportion value is set to 5%.

[0040] Furthermore, the furnace pressure in the protective gas pipeline 2 in the furnace is controlled within a set pressure range. The set pressure range can be set according to actual needs. In some embodiments, the set pressure range is set to 100-300 Pa.

[0041] Furthermore, the dew points of the heating section 100 and the soaking section 200 in the continuous annealing furnace 1 are controlled within a first preset range. The first preset range can be set according to actual needs. In some embodiments, the first preset range is set to -25°C to 0°C.

[0042] Based on the above embodiment, in order to prevent the steel strip 3 from being oxidized during the heat treatment process in the continuous annealing furnace 1, nitrogen and hydrogen (N2, H2, with 5% H2 content) protective gas is continuously injected into the furnace, and the continuous annealing furnace 1 ensures that the furnace pressure is between 100 and 300 Pa by controlling the furnace pressure control system. In the continuous annealing furnace 1, the dew point temperature represents the strength of the oxidizing property. The dew point temperature refers to the temperature at which the air is cooled to water vapor saturation under the condition that the water vapor content and air pressure do not change. That is, the temperature at which the water vapor in the air turns into dewdrops is the dew point temperature. The higher the dew point temperature, the greater the water vapor content in the furnace atmosphere.

[0043] The dew point of the original nitrogen and hydrogen gas is -60℃, and the dew point of the atmosphere in each section of the furnace during operation is generally -60℃~-40℃. In this dew point range, the Mn alloy in the matrix of the strip steel 3 will precipitate to the surface of the strip steel 3, and then form Mn oxides that adhere to the surface of the furnace roller 4, affecting the surface quality. In order to ensure that the strip steel 3 forms an internal oxidizing atmosphere during the annealing heat treatment process so that the Mn and Fe elements form an oxide layer on the shallow surface of the strip steel 3 to hinder the further precipitation of the Mn element on the surface of the strip steel 3, and at the same time ensure the uniformity of the humidification dew point to avoid excessive local dew point, so as to ensure that the surface of the strip steel 3 is not oxidized, the dew point of each part in the continuous annealing furnace 1 is uniformly controlled by the humidified protective gas, so that the dew point of the heating section 100 and the soaking section 200 in the annealing furnace is maintained at -25℃~0℃.

[0044] According to some embodiments, Figure 4 As shown, the plurality of furnace rollers 4 include a first type crown roller, the roughness Ra of the middle portion of the first type crown roller is 4 μm to 5 μm, the roughness Rz of the middle portion of the first type crown roller is Rz≤5×Ra, and the roughness Ra and Rz of both ends of the first type crown roller are less than 1 μm;

[0045] The width of the roughness gradient from the middle to both ends of the first type of crown roller is 50mm.

[0046] Further, such as Figure 5 As shown, the plurality of furnace rollers 4 also include a first type flat roller, the roughness Ra of the middle portion of the first type flat roller is 4 μm to 5 μm, the roughness Rz of the middle portion of the first type flat roller is Rz≤5×Ra, and the roughness Ra and Rz at both ends of the first type flat roller are both less than 1 μm.

[0047] Furthermore, the plurality of furnace rollers 4 further include a second type flat roller, the roughness Ra of the second type flat roller is 5 μm to 6 μm, and the roughness Rz of the second type flat roller is Rz≤5×Ra.

[0048] According to some embodiments, Figure 1 As shown, a vent pipe 9 is provided on both sides of the furnace nose 5, and the vent flow rate of the vent pipe 9 is recorded;

[0049] The second preset range value is less than -5°C.

[0050] Further, such as Figure 2 As shown, the furnace nose 5 is connected to the furnace nose air intake structure, and the furnace nose air intake structure includes a protective gas main pipeline 10, a dry protective gas pipeline 11, a first valve 12, a first pressure gauge 13, a first flow valve 14, a humidifying gas pipeline 15, a second valve 16, a humidifier 17, a second pressure gauge 18 and a second flow valve 19, the protective gas main pipeline 10 is respectively connected to the dry protective gas pipeline 11 and the humidifying gas pipeline 15, the dry protective gas pipeline 11 is sequentially provided with the first valve 12, the first pressure gauge 13 and the first flow valve 14, the humidifying gas pipeline 15 is sequentially provided with the second valve 16, the humidifier 17, the second pressure gauge 18 and the second flow valve 19, and the dry protective gas pipeline 11 and the humidifying gas pipeline 15 are both connected to the furnace nose protective gas pipeline 6;

[0051] The shielding gas main pipeline 10 inputs nitrogen, the dry shielding gas pipeline 11 outputs dry nitrogen, the humidifying gas pipeline 15 outputs wet nitrogen, and the dry nitrogen and wet nitrogen are mixed and input into the furnace nose shielding gas pipeline 6. The dew point is controlled by adjusting the flow rate of the wet nitrogen.

[0052] Based on the above embodiment, the water content in the furnace nose 5 is reflected by the dew point. The higher the dew point, the higher the water content and the oxidizing atmosphere. In principle, the dew point should not be too low to make it difficult to form a ZnO film, which will lose the function of inhibiting the evaporation of zinc vapor. Usually, the dew point in the furnace nose 5 is controlled above -5°C. However, for interstitial-free steel with a high Mn content, the zinc liquid surface oxide film is still relatively thick at this dew point state. Since the Mn alloy precipitates and forms MnO on the surface of the steel strip 3, it will deteriorate the wettability of the zinc liquid, making the zinc liquid surface oxide film more likely to adhere to the surface of the steel strip 3 and affect the quality.

[0053] Therefore, it is necessary to lower the dew point of the furnace nose 5 to less than -5°C to reduce the thickness of the oxide film on the surface of the zinc liquid. At the same time, the furnace nose 5 is improved to make the humidified gas evenly distributed on the zinc liquid surfaces adjacent to the upper and lower surfaces of the strip 3 to avoid local concentration of the humidified gas; vent pipes 9 are added on both sides of the furnace nose 5 to release a small amount of zinc vapor through the atmosphere release function of the furnace nose 5 vent pipe 9 while adjusting the humidification amount of the furnace nose 5 and the dew point of the furnace nose 5, so as to avoid a small amount of zinc vapor caused by the low dew point adhering to and contaminating the inner wall of the furnace nose 5, thereby causing zinc ash to fall onto the surface of the strip 3 and affect the surface quality of the strip 3.

[0054] Controlling the water content of the furnace nose 5 section can be solved by two methods: one is to increase the air intake; the other is to increase the temperature of the water in the humidifier 17. The air intake at the furnace nose 5 is injected into the furnace nose 5 chamber after mixing wet nitrogen containing water vapor with dry nitrogen. The dry nitrogen flow rate is generally unchanged, and the dew point adjustment is achieved by controlling the wet nitrogen flow rate. The method to increase the temperature of the water in the humidifier 17 is: wrap a heating belt of a certain power around the humidifier 17 tank and pipeline, and track the dew point changes after power is turned on for heating. The power is divided into three levels of 70kW, 90kW, and 110kW. In this way, the main factors that actually affect the dew point of the equipment are: air intake pressure, wet nitrogen flow regulating valve opening, and heating belt power. The main process factors are: strip 3 width, strip 3 thickness, production speed, and furnace nose 5 discharge flow.

[0055] According to some embodiments, a target training model based on machine learning is established in the control system, and the target training model is used to adjust the data set, and the data set includes intake pressure, wet nitrogen flow, heating power, strip steel 3 width, strip steel 3 thickness, production speed and discharge flow, and the target training model based on machine learning includes:

[0056] Step 101, adjusting the data value of each data in the data set, when the dew point in the furnace nose 5 reaches the second preset range value, then recording the data value of each data to obtain a data value combination;

[0057] Step 102, repeating step 101 to record multiple sets of data value combinations;

[0058] Step 103, using the dew point within the second preset range as input data for the training model, combining multiple groups of data values ​​as output data for the training model, and repeating training and testing to obtain a target training model that has completed training.

[0059] In some specific embodiments, data collection is first performed, including inlet pressure, wet nitrogen flow, heating power, dew point in furnace nose 5, strip steel 3 width, strip steel 3 thickness, production speed, and discharge flow. The dew point in furnace nose 5 is a "label" and other data are "characteristic values".

[0060] After collecting the data, the data is preprocessed, including removing blank values, invalid values, and singular values.

[0061] After data preprocessing, the sample space is established. The actual value of the dew point of the furnace nose 5 is used as the sample label, and the other data is used as the sample feature. The sample feature and the sample label constitute a sample, and all samples in a continuous production period constitute the sample space. 75% of the data in this sample space is used as model training data, and 25% is used as test data to train the model.

[0062] When the optimization system is running, the dew point set point of furnace nose 5 is given and set to N1.

[0063] Assume that the upper and lower limits of the main pipeline pressure value are (Pmax, Pmin). In the interval (Pmax, Pmin), M values ​​are evenly taken, recorded as (P1, P2, P3...PM).

[0064] The upper and lower limits of the opening degree of the wet nitrogen flow control valve are (Vmax, Vmin). In the interval (Vmax, Vmin), M values ​​are evenly taken, which are recorded as (V1, V2, V3...VM).

[0065] The heating zone temperature is divided into three levels, recorded as (T1, T2, T3).

[0066] Arrange and combine (P1, P2, P3...PM), (V1, V2, V3...VM), (T1, T2, T3) into the form of (Pi, Vj, Tn), where 1≤i≤M, 1≤j≤M, and n is 1, 2, 3. In this way, 3×M2 parameter vectors are constructed.

[0067] Traverse these 3×M2 parameter vectors and substitute them into the model calculation, so as to obtain 3×M2 dew point calculation values ​​of the furnace nose 5. Compare the difference between these dew point calculation values ​​and N1, and find the parameter vector (Pi′, Vj′, Tn′) corresponding to the minimum difference. If there are multiple, randomly select one from them.

[0068] The optimization system automatically changes the set value corresponding to the furnace nose 5 humidification system to (Pi′, Vj′, Tn′).

[0069] By humidifying the gas in the continuous annealing furnace 1 to control the dew point in the furnace, the processing accuracy of the furnace roller 4 is improved and nodules on the surface of the furnace roller 4 are avoided; a humidification system is added to the furnace nose 5, and a technical solution for optimizing the dew point control is implemented, which has achieved good results.

[0070] According to some embodiments, Figure 3 As shown, the control system further includes a humidifying pipeline 20 and a furnace main pipeline 21. The heating section 100, the soaking section 200 and the cooling section 300 of the continuous annealing furnace 1 are all connected to the furnace main pipeline 21. The heating section 100 air intake structure, the soaking section 200 air intake structure and the cooling section 300 air intake structure are connected between the furnace main pipeline 21 and the humidifying pipeline 20.

[0071] The air intake structure of the heating section 100 includes a first humidified gas inlet 22 and a second humidified gas inlet 23 respectively connected to the furnace main pipeline 21 and the humidified pipeline 20. The first humidified gas inlet 22 is sequentially provided with a first pressure reducing valve 24, a first pressure pump 25, a third valve 26 and a first flow meter 27. The second humidified gas inlet 23 is sequentially provided with a second pressure reducing valve 28, a second pressure pump 29, a fourth valve 30 and a second flow meter 31.

[0072] The air intake structure of the soaking section 200 includes a third humidified gas inlet 32 ​​and a fourth humidified gas inlet 33 respectively connected to the furnace main pipeline 21 and the humidification pipeline 20. The third humidified gas inlet 32 ​​is sequentially provided with a third pressure reducing valve 34, a third pressure pump 35, a fifth valve 36 and a third flow meter 37. The fourth humidified gas inlet 33 is sequentially provided with a fourth pressure reducing valve 38, a fourth pressure pump 39, a sixth valve 40 and a fourth flow meter 41.

[0073] The air intake structure of the cooling section 300 includes a fifth humidified gas inlet 42 and a sixth humidified gas inlet 43 respectively connected to the furnace main pipeline 21 and the humidification pipeline 20. The fifth humidified gas inlet 42 is sequentially provided with a fifth pressure reducing valve 44, a fifth pressure pump 45, a seventh valve 46 and a fifth flow meter 47. The sixth humidified gas inlet 43 is sequentially provided with a sixth pressure reducing valve 48, a sixth pressure pump 49, an eighth valve 50 and a sixth flow meter 51.

[0074] The process according to the above embodiment is to increase humidity in the continuous annealing furnace 1 and control the stability of its dew point. Figure 3As shown, the first humidified gas inlet 22 and the second humidified gas inlet 23 of the air inlet structure of the heating section 100 are respectively arranged at both ends of the heating section 100; the third humidified gas inlet 32 ​​and the fourth humidified gas inlet 33 of the air inlet structure of the soaking section 200 are respectively arranged at both ends of the soaking section 200; the fifth humidified gas inlet 42 and the sixth humidified gas inlet 43 of the air inlet structure of the cooling section 300 are respectively arranged at both ends of the cooling section 300. This structural design facilitates the uniform distribution of the protective gas in the continuous annealing furnace 1, so that the dew point of each part in the continuous annealing furnace 1 is stable. It prevents the strip steel 3 from being oxidized during the annealing heat treatment process. The gas in the humidification pipeline 20 enters the furnace main pipeline 21 through the first humidification gas inlet 22, the first pressure reducing valve 24, the first pressure pump 25, the third valve 26 and the first flow meter 27, and then enters the heating section 100; the gas in the humidification pipeline 20 enters the furnace main pipeline 21 through the second humidification gas inlet 23, the second pressure reducing valve 28, the second pressure pump 29, the fourth valve 30 and the second flow meter 31, and then enters the heating section 100. The gas in the humidification pipeline 20 enters the furnace main pipeline 21 through the third humidification gas inlet 32, the third pressure reducing valve 34, the third pressure pump 35, the fifth valve 36 and the third flow meter 37, and then enters the soaking section 200; the gas in the humidification pipeline 20 enters the furnace main pipeline 21 through the fourth humidification gas inlet 33, the fourth pressure reducing valve 38, the fourth pressure pump 39, the sixth valve 40 and the fourth flow meter 41, and then enters the soaking section 200. The gas in the humidification pipeline 20 enters the furnace main pipeline 21 through the fifth humidification gas inlet 42, the fifth pressure reducing valve 44, the fifth pressure pump 45, the seventh valve 46 and the fifth flow meter 47, and then enters the cooling section 300; the gas in the humidification pipeline 20 enters the furnace main pipeline 21 through the sixth humidification gas inlet 43, the sixth pressure reducing valve 48, the sixth pressure pump 49, the eighth valve 50 and the sixth flow meter 51, and then enters the cooling section 300.

[0075] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0076] Although the present disclosure has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present disclosure can be implemented in a variety of forms without departing from the spirit or essence of the present application, it should be understood that the above-mentioned embodiments are not limited to any of the foregoing details, but should be widely interpreted within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A control system for strip surface quality, characterized in that: The control system comprises: A continuous annealing furnace, wherein a strip steel inlet is arranged at one end of the continuous annealing furnace, a plurality of furnace rollers are arranged in two rows in a staggered manner, and a furnace protection gas pipeline is arranged on the inner wall of the continuous annealing furnace; A furnace nose, one end of which is connected to the other end of the continuous annealing furnace, and an inner wall of the furnace nose is provided with a furnace nose protective gas pipeline connected to a protective gas pipeline in the furnace; A zinc pot and a sinking roller, wherein the sinking roller is arranged in the zinc pot, and the other end of the furnace nose is arranged on the upper end of the sinking roller; The strip steel enters the continuous annealing furnace through the strip steel inlet and is transferred to the sinking roller through a plurality of furnace rollers; Adjusting the humidity in the continuous annealing furnace to control the dew point in the continuous annealing furnace to reach a first preset range value; The data set affecting the dew point in the furnace nose is adjusted to control the dew point in the furnace nose to reach a second preset range value.

2. The control system according to claim 1, characterized in that: Injecting a protective gas into the protective gas pipeline in the furnace, wherein the proportion of nitrogen in the protective gas is a first proportion value, and the proportion of hydrogen in the protective gas is a second proportion value; The first ratio value is 95%, and the second ratio value is 5%; Controlling the furnace pressure in the protective gas pipeline in the furnace within a set pressure range; The set pressure range is 100-300 Pa.

3. The control system according to claim 1, characterized in that: The dew points of the heating section and the soaking section in the continuous annealing furnace are controlled within a first preset range of values, wherein the first preset range of values ​​is -25°C to 0°C.

4. The control system according to claim 1, characterized in that: The plurality of furnace rollers include a first type crown roller, the roughness Ra of the middle part of the first type crown roller is 4 μm to 5 μm, the roughness Rz of the middle part of the first type crown roller is Rz≤5×Ra, and the roughness Ra and Rz of both ends of the first type crown roller are less than 1 μm; The width of the roughness gradient from the middle to both ends of the first type of crowned roller is 50 mm.

5. The control system according to claim 1, characterized in that: The plurality of furnace rollers also include a first type flat roller, the roughness Ra of the middle part of the first type flat roller is 4 μm to 5 μm, the roughness Rz of the middle part of the first type flat roller is Rz≤5×Ra, and the roughness Ra and Rz of both ends of the first type flat roller are less than 1 μm.

6. The control system according to claim 1, characterized in that: The plurality of furnace rollers further include a second type flat roller, the roughness Ra of the second type flat roller is 5 μm to 6 μm, and the roughness Rz of the second type flat roller is Rz≤5×Ra.

7. The control system according to claim 1, characterized in that: Discharge pipes are arranged on both sides of the furnace nose, and the discharge flow of the discharge pipes is recorded; The second preset range value is less than -5°C.

8. The control system according to claim 7, characterized in that: A target training model based on machine learning is established in the control system, and the target training model is used to adjust the data set, and the data set includes intake pressure, wet nitrogen flow, heating power, strip width, strip thickness, production speed and discharge flow, and the target training model based on machine learning includes: Step 101, adjusting the data value of each data in the data set, and when the dew point in the furnace nose reaches a second preset range value, recording the data value of each data to obtain a data value combination; Step 102, repeating step 101 to record multiple sets of data value combinations; Step 103, using the dew point of the second preset range value as input data of the training model, combining the multiple groups of data values ​​as output data of the training model, repeating training and testing to obtain a target training model that has completed training.

9. The control system according to claim 1, characterized in that: The furnace nose is connected to a furnace nose air intake structure, and the furnace nose air intake structure includes a protective gas main pipeline, a dry protective gas pipeline, a first valve, a first pressure gauge, a first flow valve, a humidifying gas pipeline, a second valve, a humidifier, a second pressure gauge and a second flow valve, the protective gas main pipeline is respectively connected to the dry protective gas pipeline and the humidifying gas pipeline, the dry protective gas pipeline is sequentially provided with the first valve, the first pressure gauge and the first flow valve, the humidifying gas pipeline is sequentially provided with the second valve, the humidifier, the second pressure gauge and the second flow valve, and the dry protective gas pipeline and the humidifying gas pipeline are both connected to the furnace nose protective gas pipeline; The shielding gas main pipeline inputs nitrogen, the dry shielding gas pipeline outputs dry nitrogen, the humidifying gas pipeline outputs wet nitrogen, the dry nitrogen and the wet nitrogen are mixed and input into the furnace nose shielding gas pipeline, and the dew point is controlled by adjusting the flow rate of the wet nitrogen.

10. The control system according to claim 1, characterized in that: The control system further comprises a humidifying pipeline and a furnace main pipeline, the heating section, soaking section and cooling section of the continuous annealing furnace are all connected to the furnace main pipeline, and the heating section air intake structure, soaking section air intake structure and cooling section air intake structure are connected between the furnace main pipeline and the humidifying pipeline; The heating section air intake structure comprises a first humidified gas inlet and a second humidified gas inlet respectively connected to the furnace main pipeline and the humidified pipeline, the first humidified gas inlet is sequentially provided with a first pressure reducing valve, a first pressure pump, a third valve and a first flow meter, and the second humidified gas inlet is sequentially provided with a second pressure reducing valve, a second pressure pump, a fourth valve and a second flow meter; The soaking section air intake structure comprises a third humidified gas inlet and a fourth humidified gas inlet respectively connected to the furnace main pipeline and the humidification pipeline, the third humidified gas inlet is sequentially provided with a third pressure reducing valve, a third pressure pump, a fifth valve and a third flow meter, and the fourth humidified gas inlet is sequentially provided with a fourth pressure reducing valve, a fourth pressure pump, a sixth valve and a fourth flow meter; The cooling section air intake structure includes a fifth humidification gas inlet and a sixth humidification gas inlet respectively connected to the furnace main pipeline and the humidification pipeline, the fifth humidification gas inlet is sequentially provided with a fifth pressure reducing valve, a fifth pressure pump, a seventh valve and a fifth flow meter, and the sixth humidification gas inlet is sequentially provided with a sixth pressure reducing valve, a sixth pressure pump, an eighth valve and a sixth flow meter.

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