CN-116426742-B - Strip steel oxidation color difference control method

Abstract

The invention discloses a strip steel oxidation color difference control method, which relates to the technical field of strip steel oxidation color difference control and comprises the following operation steps of S1, instrument installation, S2, presetting of an oxygen content limit value, S3, limiting of fan rotating speed power, S4, image assistance, S5, fan power adjustment, S6, wind turbine oxygen inhalation setting, S7 and limited warning. The strip steel oxidation color difference control method solves the problem of the oxidation color defect caused by leakage of the most common slow cooling fan and the fast cooling fan, can solve the problem of the traditional oxidation color defect, can also solve the problem of the oxidation color difference defect along the width direction of the strip steel caused by micro leakage of the fans, achieves automatic control of the oxidation color difference defect, greatly improves the automation level of a unit, can lock the problem in time, alarms the abnormality of the fan to remind operators of timely disposing the abnormality of the unit, and can shorten the time for checking leakage points and effectively reduce the occurrence quantity of the oxidation color difference defect.

Inventors

• ZHANG LIYANG
• WANG JUNFEI
• WU JIATONG

Assignees

• 宝钢湛江钢铁有限公司

Dates

Publication Date

20260512

Application Date

20230329

Claims (6)

1. 1. The strip steel oxidation color difference control method is characterized by comprising the following operation steps of: S1, instrument installation: a set of ppm-level oxygen content measuring instrument is arranged in each of the slow cooling section hearth and the air duct, the fast cooling section hearth and the air duct and is used for fixed point real-time online circulation detection of the oxygen content of each air duct of the slow cooling section hearth and each air duct of the fast cooling section fan, and each air duct of the fast cooling section hearth and the fast cooling section fan; S2, presetting an oxygen content limit value: The slow cooling fan control PLC and the fast cooling fan control PLC are respectively preset with an air duct oxygen content limit value, and the slow cooling section furnace and the fast cooling section furnace fan rotating speed power limit value corresponding to the slow cooling fan control PLC and the fast cooling fan control PLC are determined according to fan leakage test results; s3, limiting the rotating speed power of the fan: Comparing the measured results of the air duct oxygen content of the slow cooling section and the fast cooling section with preset air duct oxygen content limiting values, limiting the rotating speed power of fans of the slow cooling section and the fast cooling section, and avoiding oxygen inhalation and oxidation of strip steel caused by too fast rotating speed of the fans; s4, image assistance: An oxidation color difference detector is arranged at an outlet of the annealing furnace, a plurality of high-speed cameras are arranged on the upper surface and the lower surface of the strip steel along the width direction of the strip steel, and the degree of the oxidation color difference is represented by photographing to obtain the gray scale difference of the strip steel surface along the width direction of the strip steel; S5, fan power adjustment: The method comprises the steps that a slow cooling fan control PLC and a fast cooling fan control PLC select a fan with the smallest difference value to perform fixed point detection on an air duct where the fan with the smallest difference value is located according to the average gray Y value of the upper surface and the lower surface of strip steel detected by an online oxidation color meter and the difference value of the preset limiting value of the oxygen content of each air duct, and perform limiting feedback control on the fan power of an area where the fan with the smallest difference value is located; Similarly, the slow cooling fan control PLC and the fast cooling fan control PLC are also preset with gray level difference delta Y limiting values at different positions along the width direction of the strip steel, the gray level difference delta Y is related to the oxygen content of the fan, the difference between the measured air duct oxygen content value and the air duct oxygen content limiting value is used for judging which fan the gray level difference delta Y exceeds the limiting value and is related to, the slow cooling fan control PLC and the fast cooling fan control PLC select the fan with the air duct oxygen content closest to the air duct oxygen content limiting value, lock the oxygen content detection on the area where the fan closest to the air duct oxygen content limiting value is located, and perform feedback control on the rotating speed power of the fan, when the difference between the measured air duct oxygen content value and the preset air duct oxygen content limiting value is not the smallest, the fan with the smallest new difference is automatically replaced to perform oxygen content fixed point detection on the air duct where the new gray level difference is located, and perform limiting feedback control on the fan power of the area where the new fan with the smallest difference is located until the oxidized color delta Y value meets the release standard; S6, oxygen inhalation setting of a wind prevention machine: During production, the glow heater is put into to consume residual oxygen in the furnace, and the shafts of the fans of the slow cooling section and the fast cooling section are sealed by high-pressure nitrogen with the pressure of more than or equal to 3kg besides adopting carbon sealing, so that the oxygen inhalation risk of the fans is reduced; S7, limited warning: and when the oxygen content of the slow cooling section hearth and the fast cooling section hearth exceeds the air duct oxygen content limit value, the picture character alarm and the sound alarm are also carried out.
2. 2. The method of claim 1, wherein in step S2, the oxygen content limit value is determined according to an actual oxygen content value corresponding to the strip steel oxidation limit template.
3. 3. The method for controlling strip steel oxidation color difference according to claim 1, wherein in the step S2, the specific mode of fan leakage test is as follows: Making corresponding curves of the rotational speed power and the oxygen content of different fans, determining corresponding rotational speed power values of the fans according to oxygen content limiting values on the curves, and determining the rotational speed power values of the fans as rotational speed power initial limiting values of the fans; And the characteristic parameters of curves corresponding to different fan rotational speed powers and oxygen contents are arranged in the slow cooling fan control PLC and the fast cooling fan control PLC, and the slow cooling fan control PLC can be dynamically maintained, and the fan rotational speed power corresponding to the oxygen contents is modified according to the real-time state of the unit.
4. 4. The method for controlling strip steel oxidation color difference according to claim 1, wherein in the step S3, the measured results of the air channel oxygen content of the slow cooling section and the fast cooling section are obtained by a ppm level oxygen content measuring instrument.
5. 5. The method for controlling the oxidation color difference of the strip steel according to claim 1, wherein in the step S4, the average gray scale in the degree of representing the oxidation color difference by photographing the gray scale difference of the strip steel surface along the width direction of the strip steel is represented by Y, the gray scale difference at different positions along the width direction of the strip steel is represented by DeltaY, namely, the average gray scale Y can be used for representing the oxidation color defect in the traditional sense and also can be used for measuring the oxidation color difference defect along the width direction of the strip steel, the larger the gray scale difference DeltaY is, the more serious the color difference of the same plate surface along the width direction is represented, and the slow cooling fan control PLC and the fast cooling fan control PLC carry out limit control on the rotating speed power of the slow cooling section and the fast cooling section according to the difference of the measured oxygen content and the limit oxygen content of each section and the gray scale difference DeltaY.
6. 6. The method for controlling strip steel oxidation color difference according to claim 1, wherein in the step S6, the furnace dew points of the slow cooling section and the fast cooling section are controlled below-40 ℃ to reduce strip steel oxidation risks.

Description

Strip steel oxidation color difference control method Technical Field The invention relates to the technical field of strip steel oxidation color difference control, in particular to a strip steel oxidation color difference control method. Background In the continuous annealing process of the strip steel, if the atmosphere in the furnace is controlled improperly, the strip steel is easy to generate oxidation color defects, especially for a continuous annealing machine set for producing the ultra-high strength steel, as a large number of reinforced alloy elements such as Si, mn and the like are added in a substrate of the ultra-high strength steel, the alloy elements can diffuse and enrich to the surface layer of the strip steel and oxidize during annealing, so that the ultra-high strength steel is easier to generate surface oxidation than the carbon steel with common strength level, especially the ultra-low carbon steel, and the surface of the strip steel is yellow or even blue after the surface oxidation, so that a plurality of users are unwilling to accept the strip steel, and therefore, the oxidation color defects on the surface of the strip steel need to be controlled during the continuous annealing process of the strip steel. The application number CN201611013306.6 discloses a method for eliminating the oxidation color of strip steel, which comprises the steps of controlling the heating temperature to 770-800 ℃, the slow cooling temperature to 630-680 ℃, the quick cooling temperature to 250-310 ℃, and the overaging temperature to 240-300 ℃ in the production process, controlling the furnace area speed of the strip steel to be less than 200m/min, the fluctuation to +/-10 m/min, and controlling the temperature of leakage points in a control furnace to be minus 55 ℃ to minus 45 ℃; the method for eliminating the oxidation color of the strip steel has the following defects: the application of the method has obvious limitation, the characteristics of different steel types are different, the required heating temperature ranges of the strip steel are also different, and the production process has strict process system, and the method is not limited in a certain range, so the method is inconvenient to widely use. Accordingly, in view of the above, research and improvement are made to the existing structure and defects, and a strip steel oxidation color difference control method is proposed. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a strip steel oxidation color difference control method, which solves the problems in the background art. The technical scheme of the invention is that the strip steel oxidation color difference control method comprises the following steps: S1, instrument installation: a set of ppm-level oxygen content measuring instrument is arranged in each of the slow cooling section hearth and the air duct, the fast cooling section hearth and the air duct and is used for fixed point real-time online circulation detection of the oxygen content of each air duct of the slow cooling section hearth and each air duct of the fast cooling section fan, and each air duct of the fast cooling section hearth and the fast cooling section fan; S2, presetting an oxygen content limit value: The slow cooling fan control PLC and the fast cooling fan control PLC are respectively preset with an air duct oxygen content limit value, and the slow cooling section furnace and the fast cooling section furnace fan rotating speed power limit value corresponding to the slow cooling fan control PLC and the fast cooling fan control PLC are determined according to fan leakage test results; s3, limiting the rotating speed power of the fan: Comparing the measured results of the air duct oxygen content of the slow cooling section and the fast cooling section with preset air duct oxygen content limiting values, limiting the rotating speed power of fans of the slow cooling section and the fast cooling section, and avoiding oxygen inhalation and oxidation of strip steel caused by too fast rotating speed of the fans; s4, image assistance: An oxidation color difference detector is arranged at an outlet of the annealing furnace, a plurality of high-speed cameras are arranged on the upper surface and the lower surface of the strip steel along the width direction of the strip steel, and the degree of the oxidation color difference is represented by photographing to obtain the gray scale difference of the strip steel surface along the width direction of the strip steel; S5, fan power adjustment: the method comprises the steps that a slow cooling fan control PLC and a fast cooling fan control PLC select a fan with the smallest difference value to perform fixed point detection on the fan according to the average gray Y value of the upper surface and the lower surface of the strip steel detected by an online oxidation color meter and the difference value of the measured oxygen content value of each f