A method for controlling black spot defects on the surface of pickled plates

Abstract

The present application relates to a method for controlling black spot defects on the surface of a pickled plate, the method comprising: controlling the steel passageway before the strip enters the pickling tank to reach a set standard, so that no impurities adhere to the surface of the strip after the strip passes through the steel passageway; controlling the feeding temperature of the strip to be not higher than a first set temperature; and / or controlling the weld temperature of the strip to be not higher than a second set temperature; and controlling the cleanliness of the acid solution. The method for controlling black spot defects on the surface of a pickled plate can effectively reduce the number of pickled products with black spot defects and reduce the degradation rate of black spot defects on the surface of the pickled plate.

Description

Technical Field

[0001] The present application relates to the field of pickling plate production, and in particular to a method for controlling black spot defects on the surface of pickling plates. Background Art

[0002] Hot-rolled pickled plate is an intermediate product made of high-quality hot-rolled thin plate. After the oxide layer is removed, the edges are trimmed and the plate is finished by the pickling unit, the surface quality and use requirements are between hot-rolled plate and cold-rolled plate. Due to its high cost performance and good economic benefits, the application range of hot-rolled pickled plate is becoming more and more extensive.

[0003] Pickling black spot defect is a common surface quality defect of the pickling line, which seriously affects the surface quality of the pickled plate and the subsequent process products; on the other hand, after the black spot defect occurs, it is difficult to eliminate it by secondary rewashing, and the defect can only be downgraded or removed, resulting in huge quality losses. The existing control method for the black spot defect on the surface of the pickled plate cannot completely eliminate the pickling black spot defect. The downgrade rate of the pickling black spot defect has reached more than 0.5%, causing serious quality losses. Summary of the invention

[0004] The present application provides a method for controlling black spot defects on the surface of a pickling plate, so as to solve the technical problem that the existing method for controlling black spot defects on the surface of a pickling plate has poor effect in eliminating the black spot defects of the pickling plate.

[0005] In a first aspect, the present application provides a method for controlling black spot defects on the surface of a pickled plate, the method comprising:

[0006] Controlling the steel passageway before the strip enters the pickling tank to reach a set standard so that no impurities adhere to the surface of the strip after the strip passes through the steel passageway;

[0007] Controlling the feeding temperature of the strip steel to be not higher than a first set temperature;

[0008] Controlling the weld temperature of the strip steel to be no higher than a second set temperature;

[0009] Control the cleanliness of the acid.

[0010] Furthermore, the controlling of the steel passage of the strip before entering the pickling tank to reach a set standard comprises:

[0011] Check whether the steel passage reaches the set standard, and adjust the steel passage to make it reach the set standard; and / or

[0012] The rubber-coated rollers of the steel passage are replaced regularly.

[0013] Furthermore, the set standard includes: all nylon linings of the steel passage are intact and not missing; and / or

[0014] The fixing screws of the steel passage have no protrusions and are at a lower elevation than the steel passage; and / or

[0015] The rubber coating on all roller surfaces of the steel passage is intact, without any missing parts or foreign matter falling off.

[0016] Furthermore, the method for measuring the feeding temperature includes: measuring the temperature at three points with a circumferential interval of 120 degrees at a position of 1 / 3 of the inner ring height of the steel coil of the strip, and taking the highest value to obtain the feeding temperature.

[0017] Furthermore, the first set temperature is 60°C.

[0018] Further, the controlling the weld temperature of the steel strip to be no higher than a second set temperature comprises:

[0019] A purge air duct is arranged at the outlet of the welding machine to cool down the weld of the strip steel.

[0020] Furthermore, the method for measuring the weld temperature includes: measuring the weld temperature of the steel strip at the end point of welding of the steel strip.

[0021] Furthermore, the second set temperature is 60°C.

[0022] Furthermore, the cleanliness of the acid solution is controlled, including:

[0023] An acid pump filter is installed at the outlet of the acid circulation pump in the acid supply system.

[0024] Furthermore, the acid pump filter has a mesh size of 10-20 meshes.

[0025] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0026] The control method of the black spot defect on the surface of the pickling plate provided in the embodiment of the present application controls the steel passage to reach the set standard, so that no impurities adhere to the surface of the strip after the strip passes through the steel passage, thereby preventing impurities from being brought into the pickling tank to cause the pickling black spot defect; by controlling the feeding temperature of the strip, it can be avoided that the strip temperature is too high, thereby scalding the nylon cover plate, guide roller, etc. in the steel passage, thereby causing nylon debris, etc. to adhere to the surface of the strip, thereby causing black spot defects during the pickling process; by controlling the weld temperature of the strip, it can be avoided that the strip weld temperature is too high to scald the nylon liner plate or rubber-wrapped roller in the steel passage, thereby bringing impurities into the pickling tank to cause the pickling black spot defect; by controlling the cleanliness of the acid solution, it can be prevented that impurities such as block or large particles of iron mud in the acid solution cause black spot defects on the surface of the strip during the pickling process. Therefore, this method can effectively avoid the formation of black spot defects on the surface of the pickling plate, and can solve the technical problem that the control method of the black spot defect on the surface of the pickling plate is not effective in eliminating the pickling black spot defect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0029] Figure 1 A black spot defect image on the surface of a strip obtained by a method for controlling black spot defects on the surface of a pickled plate provided in an embodiment of the present application;

[0030] Figure 2 This is the black spot defect diagram on the existing strip steel surface;

[0031] Figure 3 A schematic flow chart of a method for controlling black spot defects on the surface of a pickling plate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0033] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0034] Hot-rolled pickled plate is an intermediate product made of high-quality hot-rolled thin plate. After the oxide layer is removed, the edges are trimmed and the plate is finished by the pickling unit, the surface quality and use requirements are between hot-rolled plate and cold-rolled plate. Due to its high cost performance and good economic benefits, the application range of hot-rolled pickled plate is becoming more and more extensive.

[0035] Pickling black spot defect is a common surface quality defect of the pickling line, which seriously affects the surface quality of the pickled plate and the subsequent process products; on the other hand, after the black spot defect occurs, it is difficult to eliminate it by secondary rewashing, and the defect can only be downgraded or removed, resulting in huge quality losses. The existing control method for the black spot defect on the surface of the pickled plate cannot completely eliminate the pickling black spot defect. The downgrade rate of the pickling black spot defect has reached more than 0.5%, causing serious quality losses.

[0036] The technical solution provided by the embodiment of the present invention is to solve the above technical problems, and the overall idea is as follows:

[0037] The present application embodiment provides a method for controlling black spot defects on the surface of a pickling plate, such as Figure 3 As shown, the method includes:

[0038] Controlling the steel passageway before the strip enters the pickling tank to reach a set standard so that no impurities adhere to the surface of the strip after the strip passes through the steel passageway;

[0039] Controlling the feeding temperature of the strip steel to be not higher than a first set temperature;

[0040] Controlling the weld temperature of the strip steel to be no higher than a second set temperature;

[0041] Control the cleanliness of the acid.

[0042] The control method of the black spot defect on the surface of the pickling plate provided in the embodiment of the present application controls the steel passage to reach the set standard, so that no impurities adhere to the surface of the strip after the strip passes through the steel passage, thereby preventing impurities from being brought into the pickling tank to cause the pickling black spot defect; by controlling the feeding temperature of the strip, it can be avoided that the strip temperature is too high, thereby scalding the nylon cover plate, guide roller, etc. in the steel passage, thereby causing nylon debris, etc. to adhere to the surface of the strip, thereby causing black spot defects during the pickling process; by controlling the weld temperature of the strip, it can be avoided that the strip weld temperature is too high to scald the nylon liner plate or rubber-wrapped roller in the steel passage, thereby bringing impurities into the pickling tank to cause the pickling black spot defect; by controlling the cleanliness of the acid solution, it can be prevented that impurities such as block or large particles of iron mud in the acid solution cause black spot defects on the surface of the strip during the pickling process. Therefore, this method can effectively avoid the formation of black spot defects on the surface of the pickling plate, and can solve the technical problem that the control method of the black spot defect on the surface of the pickling plate is not effective in eliminating the pickling black spot defect.

[0043] As an implementation method of the embodiment of the present invention, the control of the steel passageway before the strip enters the pickling tank to reach a set standard includes:

[0044] Check whether the steel passage reaches the set standard, and adjust the steel passage to make it reach the set standard; and / or

[0045] The rubber-coated rollers of the steel passage are replaced regularly.

[0046] In this application, in order to ensure the surface and plate quality of the strip, foreign matter must not adhere to the strip before entering the pickling tank. Therefore, it is necessary to focus on checking the pickling unit entrance equipment and the supporting scale breaking and straightening unit or leveling unit and other steel passages to prevent impurities from adhering to the surface of the strip after the strip passes through the steel passage, and then being brought into the pickling tank to form black spot defects. The guide rollers, supporting rollers, pinch rollers and tensioning rollers of the steel passage are coated with rubber. As time goes by, the elasticity of the rubber layer will gradually be lost, the hardness will gradually increase, and it will show different degrees of aging. Therefore, it is necessary to replace it regularly according to the use time and service cycle to prevent abnormal conditions such as the rubber particles of the rubber-coated rollers falling off.

[0047] As an implementation method of the embodiment of the present invention, the set standard includes: all nylon linings of the steel passage are intact and not missing; and / or

[0048] The fixing screws of the steel passage have no protrusions and are at a lower elevation than the steel passage; and / or

[0049] The rubber coating on all roller surfaces of the steel passage is intact, without any missing parts or foreign matter falling off.

[0050] In this application, it is required that all nylon linings in the steel channel are intact and without any missing parts, the fixing screws have no protrusions, and the elevation is lower than the steel channel; the rubber coating on the roller surfaces of all guide rollers, supporting rollers, pinch rollers and tensioning rollers in the steel channel is intact and without any missing parts, and no foreign matter falls off, so as to prevent residual nylon debris from being brought into the pickling tank and causing pickling black spot defects.

[0051] As an implementation of an embodiment of the present invention, the method for measuring the feeding temperature includes: measuring the temperature at three points 120 degrees apart along the circumferential direction at a position 1 / 3 of the height of the inner ring of the steel coil of the strip, and taking the highest value to obtain the feeding temperature.

[0052] In the present application, the temperature of a specific position of the steel strip is measured, thereby ensuring the accuracy of measuring the temperature of the steel strip on the machine.

[0053] As an implementation manner of the embodiment of the present invention, the first set temperature is 60°C.

[0054] In this application, the strip feeding temperature is controlled not to be higher than 60°C, which can prevent the strip from scalding the nylon cover plate, guide rollers, etc. of the steel passage, thereby causing nylon debris to adhere to the strip surface, and further causing black spot defects during the pickling process.

[0055] As an implementation manner of the embodiment of the present invention, the step of controlling the weld temperature of the steel strip to be no higher than a second set temperature includes:

[0056] A purge air duct is arranged at the outlet of the welding machine to cool down the weld of the strip steel.

[0057] In this application, in order to enhance the cooling effect of the weld, a purge air duct is provided at the outlet of the welding machine.

[0058] As an implementation manner of an embodiment of the present invention, the method for measuring the weld temperature includes: measuring the weld temperature of the steel strip at the end point of welding of the steel strip.

[0059] In this application, the temperatures of three points on the weld of the steel strip can be measured at the end point of the steel strip welding, and the highest value can be taken.

[0060] As an implementation manner of the embodiment of the present invention, the second set temperature is 60°C.

[0061] In the present application, the temperature of the weld is controlled not to be higher than 60°C, thereby preventing the weld temperature from being too high and scalding the nylon lining plate or rubber-coated roller of the steel channel.

[0062] As an implementation method of an embodiment of the present invention, controlling the cleanliness of the acid solution includes:

[0063] An acid pump filter is installed at the outlet of the acid circulation pump in the acid supply system.

[0064] In the present application, there is a strong correspondence between the control of black spots during the pickling process and the cleanliness of the acid solution. By setting an acid pump filter at the outlet of the acid circulation pump, impurities such as block or large particles of iron mud remaining in the acid solution can be filtered out, thereby blocking large impurities from entering the acid solution, thereby causing the hidden danger of black spot quality defects.

[0065] As an implementation method of the embodiment of the present invention, the mesh number of the acid pump filter is 10-20 meshes.

[0066] In this application, the mesh size of the acid pump filter is set to 10-20 meshes, and all acid pump filter screens are cleaned during weekly maintenance time. At the same time, each acid circulation tank is cleaned during annual maintenance, which can greatly reduce the black spot defects caused by the acid supply system.

[0067] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0068] Example 1

[0069] A method for controlling black spot defects on the surface of a pickled plate, the flow diagram of which is as follows Figure 3As shown, specifically: this embodiment is a push-pull and continuous pickling line for hot rolling at Qiangang;

[0070] (1) Before the pickling process and the pre-pickling process (offline straightening and offline leveling), the steel passage is inspected, abnormal points are processed, and the rollers with damaged surfaces are replaced;

[0071] (2) At the position of 1 / 3 of the inner ring height of the steel coil, the temperature is measured at three points with an interval of 120 degrees along the circumference, and the highest value is taken, and the feeding temperature is 53°C;

[0072] (3) A purge duct was set at the outlet of the welding machine to cool the weld of the strip steel. The weld temperature at the end point of the strip steel welding was measured to be 55°C.

[0073] (4) Install a 20-mesh acid pump filter at the outlet of the first acid circulation pump in the acid supply system.

[0074] Example 2

[0075] A method for controlling black spot defects on the surface of a pickled plate, the flow diagram of which is as follows Figure 3 As shown, specifically: this embodiment is a push-pull and continuous pickling line for hot rolling at Qiangang;

[0076] (1) Before the pickling process and the pre-pickling process (offline straightening and offline leveling), the steel passage is inspected, abnormal points are processed, and the rollers with damaged surfaces are replaced;

[0077] (2) At the position of 1 / 3 of the inner ring height of the steel coil, measure the temperature at three points with an interval of 120 degrees along the circumference, and take the highest value, and the feeding temperature is 60°C;

[0078] (3) A purge duct is set at the outlet of the welding machine to cool the weld of the strip steel. The weld temperature at the end point of the strip steel welding is measured to be 60°C;

[0079] (4) Install a 10-mesh acid pump filter at the outlet of the first acid circulation pump in the acid supply system.

[0080] Example 3

[0081] A method for controlling black spot defects on the surface of a pickled plate, the flow diagram of which is as follows Figure 3 As shown, specifically: this embodiment is a push-pull and continuous pickling line for hot rolling at Qiangang;

[0082] (1) Before the pickling process and the pre-pickling process (offline straightening and offline leveling), the steel passage is inspected, abnormal points are processed, and the rollers with damaged surfaces are replaced;

[0083] (2) At the position of 1 / 3 of the inner ring height of the steel coil, the temperature is measured at three points with an interval of 120 degrees along the circumference, and the highest value is taken, and the feeding temperature is 54°C;

[0084] (3) A purge duct was set at the outlet of the welding machine to cool the weld of the strip steel. The weld temperature at the end point of the strip steel welding was measured to be 57°C.

[0085] (4) Install a 10-mesh acid pump filter at the outlet of the first acid circulation pump in the acid supply system.

[0086] Example 4

[0087] A method for controlling black spot defects on the surface of a pickled plate, the flow diagram of which is as follows Figure 3 As shown, specifically: this embodiment is a push-pull and continuous pickling line for hot rolling at Qiangang;

[0088] (1) Before the pickling process and the pre-pickling process (offline straightening and offline leveling), the steel passage is inspected, abnormal points are processed, and the rollers with damaged surfaces are replaced;

[0089] (2) At the position of 1 / 3 of the inner ring height of the steel coil, the temperature is measured at three points with an interval of 120 degrees along the circumference, and the highest value is taken, and the feeding temperature is 54°C;

[0090] (3) A purge duct was set at the outlet of the welding machine to cool the weld of the strip steel. The weld temperature at the end point of the strip steel welding was measured to be 58°C.

[0091] (4) Install a 10-mesh acid pump filter at the outlet of the first acid circulation pump in the acid supply system.

[0092] Example 5

[0093] A method for controlling black spot defects on the surface of a pickled plate, the flow diagram of which is as follows Figure 3 As shown, specifically: this embodiment is a push-pull and continuous pickling line for hot rolling at Qiangang;

[0094] (1) Before the pickling process and the pre-pickling process (offline straightening and offline leveling), the steel passage is inspected, abnormal points are processed, and the rollers with damaged surfaces are replaced;

[0095] (2) At the position of 1 / 3 of the inner ring height of the steel coil, the temperature is measured at three points with a circumferential interval of 120 degrees, and the highest value is taken, and the feeding temperature is 56°C;

[0096] (3) A purge duct was set at the outlet of the welding machine to cool the weld of the strip steel. The weld temperature at the end point of the strip steel welding was measured to be 59°C.

[0097] (4) Install a 10-mesh acid pump filter at the outlet of the first acid circulation pump in the acid supply system.

[0098] Comparative Example 1

[0099] The step (1) in Example 1 is eliminated, and the rest is the same as Example 1.

[0100] Comparative Example 2

[0101] The step (2) in Example 1 is eliminated, and the rest is the same as Example 1.

[0102] Comparative Example 3

[0103] The step (3) in Example 1 is eliminated, and the rest is the same as Example 1.

[0104] Comparative Example 4

[0105] The step (4) in Example 1 is eliminated, and the rest is the same as Example 1.

[0106] After testing, the degradation rate of black spot defects on the surface of the pickled plate obtained in the embodiment of the present application was reduced to less than 0.1%, while the degradation rate of black spot defects on the surface of the pickled plate in the comparison example and the prior art was above 0.5%. It can be seen that the control method of black spot defects on the surface of the pickled plate of the present application can effectively reduce the number of pickled products with black spot defects.

[0107] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0108] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc or abc, where a, b, c can be single or plural, respectively.

[0109] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for controlling black spot defects on the surface of a pickled plate, characterized in that: The method comprises: Controlling the steel passageway before the strip enters the pickling tank to reach a set standard so that no impurities adhere to the surface of the strip after the strip passes through the steel passageway; Controlling the feeding temperature of the strip steel to be no higher than 60°C; A purge air duct is provided at the outlet of the welding machine to cool the weld of the strip steel and control the weld temperature of the strip steel to be no higher than 60°C; An acid pump filter with a mesh size of 10-20 is installed at the outlet of the first acid circulation pump in the acid supply system to control the cleanliness of the acid solution; The setting standards include: all nylon linings of the steel passage are intact and not missing; the fixing screws of the steel passage have no protrusions and the elevation is lower than the steel passage; all the rubber coatings of the rollers of the steel passage are intact and not missing, and no foreign matter falls off; The method for measuring the feeding temperature includes: measuring the temperature at three points with a circumferential interval of 120 degrees at a position of 1 / 3 of the inner ring height of the steel coil of the strip, and taking the highest value to obtain the feeding temperature.

2. The method for controlling black spot defects on the surface of pickled plates according to claim 1, characterized in that: The control of the steel passageway before the strip enters the pickling tank to meet the set standard includes: Check whether the steel passage reaches the set standard, and adjust the steel passage to make it reach the set standard; and / or The rubber-coated rollers of the steel passage are replaced regularly.

3. The method for controlling black spot defects on the surface of pickled plates according to claim 1, characterized in that: The method for measuring the weld temperature comprises: measuring the weld temperature of the steel strip at the end point of the steel strip welding.

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