JP2011121072A - Equipment for guaranteeing material of steel plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide equipment for guaranteeing the material of a steel plate, with which operation control for improving material uniformity in the plate thickness direction and in the plane of the steel plate is possible. <P>SOLUTION: In a steel plate manufacturing line which is provided with a finishing mill and an accelerated cooling system installed on a steel plate conveying line on the downstream side of the finishing mill, the equipment for guaranteeing the material of the steel plate includes a temperature measuring tool for measuring the temperature of the steel plate and a temperature result analyzing means for analyzing the measured temperature of the steel plate. The temperature measuring tool is constituted of: a spot type radiation thermometer and a scan type radiation thermometer which are installed in respective positions at the front and rear of the finishing mill and at the front and rear of the accelerated cooling system above the side of the upper surface of the steel plate conveying line; an optical fiber radiation thermometer which is installed in the lower surface of the steel plate conveying line and in the position corresponding to the spot type radiation thermometer at the upper surface side, and a plurality of optical fiber radiation thermometers which are installed with optional intervals in the line width direction in the position corresponding to the scanning direction of the scan type radiation thermometer. The temperature result analyzing means is constituted of a means for determining temperature distribution of the whole steel plate from the temperature of the steel plate measured by each temperature measuring tool. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steel sheet quality assurance facility in a thick steel plate production line, and more particularly to a material suitable for guaranteeing the quality of the entire surface of a steel sheet that is subjected to controlled rolling or accelerated cooling.

  Thermo-Mechanical Control Process (hereinafter referred to as TMCP) that improves the strength and toughness of the steel sheet with a microstructure having a crystal grain size of about 1 μm, and a steel sheet with less deformation such as warpage by controlling internal stress Therefore, it is necessary to strictly control the start temperature, end temperature of controlled rolling, cooling start temperature of accelerated cooling, and cooling stop temperature. Various cooling facilities that have been devised in arrangement have been proposed.

  Patent Document 1 relates to a cooling control device for hot-rolled steel plates. In order to prevent shape defects due to warpage in the plate width direction during cooling, the steel plate temperature is measured, and each nozzle disposed above and below the cooling device. The amount of cooling water and the start and end of cooling are strictly controlled, and optical fiber radiation thermometers are arranged on the rear surface of the finishing mill, on the front and rear surfaces of the cooling device, and inside.

  Patent Document 2 relates to a method for controlling the shape of a controlled cooling steel plate, estimating the shape after cooling at normal temperature of the accelerated cooling steel plate from the shape immediately after cooling and the temperature history of the steel plate, ensuring the shape of the next material, and the inside of the accelerated cooling device Describes that a steel plate surface temperature distribution meter (thermotracer) and a steel plate surface thermometer are arranged immediately after the steel plate front and back surface temperature measuring thermometer and the accelerated cooling device.

  Patent Document 3 relates to a method for cooling a thick steel plate, and in order to improve the flatness of the steel plate shape and to make the material uniform, after finish rolling, the thickness of the scale thickness is controlled to 10 μm or less by descaling or surface film coating. And disposing a radiation thermometer as a steel plate surface thermometer in front of the control cooling device.

Japanese Patent Publication No. 7-41303 Japanese Patent Laid-Open No. 10-5868 Japanese Patent Laid-Open No. 2001-300627

  In recent years, high-Ni steel, which has high material sensitivity to fluctuations in manufacturing conditions, has been manufactured by direct quenching, and TMCP has been applied to increase the rationalization of the product, so that users are required to guarantee the quality of the product's entire surface. Has increased.

  Thick steel plates tend to have non-uniform temperature distribution in the plate thickness direction and in the steel plate surface due to a continuous heating furnace, descaling device, cooling equipment, etc., and as a result, the material tends to be non-uniform.

  As a countermeasure, for example, measure the temperature of the steel sheet with a radiation thermometer attached above the transfer line, and if the measured temperature is within the control temperature range, the quality judgment is passed. Refusing was done.

  However, quality judgment using the temperature measurement result by the radiation thermometer measures the temperature at the center in the width direction of the steel sheet with the radiation thermometer attached to the upper surface at the center in the conveyance line width direction. Since the temperature range is contrasted and the quality judgment is performed only at the temperature in the center part in the width direction of the steel sheet, the material guarantee other than in the center part in the width direction of the steel sheet is insufficient.

  In addition, the method of performing various material tests on test pieces taken from the top, middle, and end positions of the large plate in the rolling direction requires several days after rolling and shearing the steel plate. When manufacturing in large quantities under the same manufacturing conditions, when the results of material testing are known after a few days, it is already after mass production has been completed, optimization of the conditions is not in time, and mass nonconformities may occur. obtain.

  Therefore, the present invention is a steel plate that can be operated and managed to improve material uniformity in the thickness direction of the steel plate and in the steel plate surface by appropriately arranging a thermometer that measures the temperature of the steel plate in the production line of the steel plate. The purpose is to provide material guarantee equipment.

  In addition, the upper hand of the sheet passing direction (FIG. 1) of the steel sheet is referred to as the front surface, and the lower hand is referred to as the rear surface.

  In order to solve the above problems, the present invention has the following features.

  1st invention is a steel plate manufacturing line provided with the finishing rolling mill and the accelerated cooling apparatus installed on the steel plate conveyance line of the downstream of a finishing rolling mill, in the steel plate manufacturing line, the temperature measuring means which measures steel plate temperature, and the measured steel plate A temperature record analyzing means for analyzing the temperature, and the temperature measuring means is a spot type installed at the respective positions of the front and rear surfaces of the finish rolling mill and the front and rear surfaces of the accelerated cooling device above the upper surface side of the steel sheet conveying line. A radiation thermometer, a scanning radiation thermometer, an optical fiber radiation thermometer installed at a position corresponding to the spot radiation thermometer on the upper surface side on the lower surface side of the steel sheet conveyance line, and the scanning radiation thermometer It consists of a plurality of optical fiber radiation thermometers installed at arbitrary intervals in the line width direction at positions corresponding to the scanning direction, and the temperature performance analysis means is a steel measured by each temperature measurement means Which is the material guarantee facilities of the steel sheet, characterized in that it comprises means for determining the temperature distribution of the entire steel sheet temperature.

  In a second aspect of the present invention, a plurality of spot type radiation thermometers are installed on the front and rear surfaces of the finish rolling mill, a spot type radiation thermometer and a scanning radiation thermometer are installed on the front surface of the accelerated cooling device, and the acceleration A plurality of spot type radiation thermometers and scanning type radiation thermometers are respectively installed on the rear surface of the cooling device, and each of the spot type radiation thermometer and the scanning radiation thermometer installed on the rear surface of the accelerated cooling device has a high temperature. The steel sheet quality assurance equipment according to the first aspect of the invention is characterized in that there are a plurality of units for measuring a region and for measuring a low temperature region.

  A third aspect of the invention is a spot-type radiation thermometer and a scanning radiation thermometer installed on the rear surface of the accelerated cooling device, respectively, a high temperature range measurement thermometer for measuring a temperature range of 200 ° C. or more and 700 ° C. or less, The steel sheet quality assurance facility according to the second aspect of the invention, comprising a plurality of low temperature range measuring thermometers for measuring a temperature range of 50 ° C. or higher and 300 ° C. or lower.

  According to the present invention, after finish rolling, it is possible to guarantee the material and shape of the steel sheet to be accelerated and cooled or directly quenched. In addition, since it is possible to determine whether or not the temperature of the entire surface of the steel sheet is right after rolling, it is possible to prevent the occurrence of mass nonconformity by controlling the temperature of the subsequent steel sheet, which is extremely useful industrially.

It is a figure which shows one Embodiment of the outline | summary of the quality assurance equipment of the steel plate which concerns on this invention. It is a figure explaining the transmission flow of the temperature information which concerns on this invention. It is a figure explaining the transmission flow of the upper and lower surface temperature information which concerns on this invention.

  The steel sheet quality assurance facility according to the present invention includes temperature measuring means and temperature performance analyzing means. Since it is technically difficult to measure the temperature of the entire surface of the steel sheet in the steel sheet production line, the temperature measuring means is a thermometer in the present invention, and a spot-type radiation thermometer and a scanning radiation above the upper surface of the steel sheet conveying line. A thermometer is a spot type radiation thermometer (hereinafter referred to as an optical fiber radiation thermometer) using an optical fiber on its lower surface, and a process computer (hereinafter referred to as a PC) is used to collect temperatures measured by a plurality of thermometers. ) Is used.

  In the present invention, the above-mentioned thermometer is appropriately combined, and the minimum temperature measurement position required for ensuring the temperature history of the entire surface of the steel sheet on the steel sheet transport line is 1. 1. Front and rear faces of finish rolling mill and Thermometers will be installed as front and back surfaces of the accelerated cooling device. When the temperature difference between the upper and lower surfaces of the steel plate is significant, the material properties of the upper and lower surfaces of the steel plate are considered to be different.

  In the present invention, the installation of thermometers on the front and rear surfaces of the finish rolling mill means that the thermometers are installed at positions closer to the finishing mill than other equipment, in front of and behind the finishing mill. The same applies to the acceleration cooling device.

  The spot-type radiation thermometers are arranged on the front and rear surfaces of the finish rolling mill and the front and rear surfaces of the acceleration cooling device above the upper surface side of the transport line.

  By installing a plurality of spot type radiation thermometers (6a, 6b) installed on the front and rear surfaces of the finishing mill, it is possible to perform mutual check of thermometer abnormality detection, which is more preferable. Compared to the case of a single thermometer, it can prevent the mill from stopping when the thermometer is abnormal, and can improve the reliability of the measured temperature when manufacturing mass-produced line pipe materials. It is. The installation positions of the plurality of thermometers are not particularly defined, but they are preferably arranged in the transport direction.

  Also, in finish rolling, if the thermometer is on both the front and rear faces of the finish rolling mill, the control rolling start temperature and rolling finish temperature can be measured on either side, so the control rolling start pass and rolling finish pass Is not limited to the rear side of the finishing mill, and the degree of freedom in setting the rolling pass schedule is expanded.

  That is, controlled rolling is not necessarily started from the first pass of finish rolling, and is often performed after performing multiple passes. In that case, using either the front or rear thermometer of the finishing mill, it is possible to determine whether or not the temperature has reached an appropriate temperature for the controlled rolling. Also, the rolling finishing temperature at the end of rolling can be measured.

  In addition, the finishing mill may be passed through an empty pass, and if the thermometer is on either of the front and rear surfaces of the rolling mill, the control rolling start path is not limited to the plate direction of the production line. The rolling pass at the beginning of rolling can be started from any thermometer installation direction, the controlled rolling start temperature can be measured, and the rolling finishing temperature can be measured even if the final pass is finished at either the front or rear side. It is.

  The spot type radiation thermometers (6c, 6d, 6e) and the scanning type radiation thermometers (7c, 7d, 7e) installed on the front and rear surfaces of the acceleration cooling device are respectively a single front surface of the acceleration cooling device and the rear surface of the acceleration cooling device. It is preferable to use a plurality of units with two specifications, a thermometer for high temperature range measurement and a thermometer for low temperature range measurement.

  In the accelerated cooling system, the cooling stop temperature fluctuates in a wide range from low to high, such as accelerated cooling with a cooling stop temperature of around 600 ° C and direct quenching where the cooling stop temperature is close to room temperature. Become.

  However, since it is difficult to keep the resolution of the thermometer within ± 5 ° C in a wide range of temperature measurement from low temperature to high temperature (about 50-700 ° C), the high temperature range thermometer (6d, 7d) is the minimum. It is necessary to install two types of thermometers (6e, 7e). The high temperature range measurement thermometers (6d, 7d) and the low temperature range measurement thermometers (6e, 7e) may be installed in this order from the machine side of the acceleration cooling device toward the downstream side of the transfer line.

  In addition, the thermometer for high temperature range measurement (6d, 7d) which measures the temperature range of 200 degreeC or more and 700 degrees C or less, and the low temperature range measurement thermometer which measures the temperature range of 50 degreeC or more and 300 degrees C or less (6e, By using 7e), a resolution of ± 5 ° C. can be ensured and temperature measurement with high accuracy becomes possible.

  In addition, the controlled rolling start temperature / rolling finishing temperature measured on the front and back surfaces of the finishing mill and the steel plate temperature measured on the front and back surfaces of the accelerated cooling device have a large effect on the material, so the temperature also extends in the width direction of the steel plate. It is necessary to perform measurement and guarantee material uniformity by temperature uniformity of the entire steel sheet.

Therefore, the scanning radiation thermometer is located above the upper surface side of the transport line, on the front and rear surfaces (7a, 7b) of the finish rolling mill, and on the front and rear surfaces (7c, 7d, 7e) of the accelerated cooling device. Set up to scan. This is because by installing the width direction scanning type, the temperature of the entire surface of the steel sheet can be measured by moving the steel sheet in the longitudinal direction. In addition, it is preferable to install in the vicinity of the spot type radiation thermometer. Thereby, mutual check of the thermometer abnormality detection is possible, and the reliability of the measured temperature can be improved.
As the scanning thermometer, an existing thermometer such as a rotating mirror type or a linear ray type may be appropriately selected according to the temperature measurement location.

  The optical fiber radiation thermometer is installed on the lower side of the transport line. The lower surface side of the transfer line is in an environment filled with various cooling water, water vapor, etc., and if a CR shower is installed on the downstream side closest to the finishing mill, the temperature measurement environment on the rear surface of the finishing mill is It will get worse. Therefore, even if a normal spot type radiation thermometer or scanning type radiation thermometer is installed in the vicinity of the rolling mill and in the vicinity of the lower surface side of the hot steel plate, it is difficult to accurately measure the temperature for a long time. On the other hand, the optical fiber radiation thermometer is hardly affected by various cooling water and water vapor, and can be placed in a narrow space. Therefore, an optical fiber radiation thermometer is used on the lower surface side of the transport line.

  The optical fiber radiation thermometer is installed on the lower surface side of the corresponding conveyance line with the installation position of the spot type radiation thermometer located on the front and back surfaces of the finishing mill and the front and rear surfaces of the accelerated cooling device on the upper surface side of the conveyance line. Install.

  In addition, the scanning radiation thermometer scans the position of the scanning radiation thermometer located on the front and rear faces of the finishing mill and the front and rear faces of the acceleration cooling device and the position on the lower surface side of the corresponding transportation line across the transportation line. Install multiple optical fiber thermometers along the direction.

  As the number of installed fiber optic thermometers increases, the temperature distribution in the width direction can be grasped accurately and quantitatively. However, from the viewpoint of cost and maintenance, the 1-point / m interval is the maximum and should be narrower than this. Is good. When the optical fiber radiation thermometer is arranged at a position on the lower surface side of the transport line corresponding to the installation position of the spot type radiation thermometer on the upper surface side of the transport line, a plurality of units may be installed in the width direction of the transport line.

FIG. 1 shows an embodiment of an outline of a steel sheet quality assurance facility according to the present invention provided with the above-described steel plate temperature measuring means, and FIG. 2 shows a partial example of the structure of the temperature measuring means according to the present invention. .
The steel plate production line includes a heating furnace 1, a finishing mill 2, a CR shower 4 and an accelerated cooling device 5, and FIG. 1 shows a state where the steel plate 3 is located between the finishing mill 2 and the CR shower 4. Show.

  6a to 6e are spot type radiation thermometers, 7a to 7e are scanning type radiation thermometers, 6a and 6b measure the temperature distribution in the length direction of the upper surface of the steel plate during finish rolling, and 7a and 7b are during finish rolling. The temperature distribution in the width direction and length direction of the upper surface of the steel plate is measured, and the data is sent to the control rolling start temperature / finishing temperature collection PC11 as shown in FIG. 6c and 7c are installed on the inlet side of the accelerated cooling device, 7c measures the temperature distribution in the width direction and length direction of the upper surface of the steel plate immediately before accelerated cooling, and 6c similarly measures the temperature distribution in the length direction. Is sent to the cooling start temperature collection PC 12. 6d, 6e, 7d, and 7e are installed on the exit side of the acceleration cooling device, 6d and 7d are thermometers for high temperature range measurement, 6e and 7e are thermometers for low temperature range measurement, and 7d and 7e are accelerated cooling. The temperature distribution in the width direction and the length direction on the upper surface of the steel sheet immediately after the measurement is the same as that in 6d and 6e, and the temperature distribution in the length direction is measured, and the data is sent to the cooling stop temperature collection PC13. 6d and 7d are used for temperature control of the accelerated coolant, and 6e and 7e are used for direct temperature control of the quenching material, respectively.

  8a to 8e are optical fiber radiation thermometers, 8a and 8b measure the temperature distribution in the width direction and the length direction of the lower surface of the steel plate during finish rolling, and the data is sent to the control rolling start temperature / finishing temperature collection PC11. 8c is installed on the entrance side of the acceleration cooling device, measures the temperature distribution in the width direction and the length direction of the lower surface of the steel plate immediately before the acceleration cooling, and the data is sent to the cooling start temperature collection PC12. 8d and 8e are installed on the exit side of the accelerated cooling device, 8d is a thermometer for high temperature region measurement, and 8e is a thermometer for low temperature region measurement, both of which are the width direction and length of the lower surface of the steel plate immediately after accelerated cooling. The temperature distribution in the direction is measured, and the data is sent to the cooling stop temperature collection PC 13. 8d may be used for temperature control of the accelerated coolant and 8e for direct quenching.

  Next, steps in which the steel plate temperature information measured by each thermometer is sent to each PC will be described with reference to FIGS. 11 is a control rolling start temperature / finishing temperature collection PC, 12 is a cooling start temperature collection PC, 13 is a cooling stop temperature collection PC, and 14 is a temperature performance analysis PC.

  Steel plate upper surface temperature information measured by spot-type radiation thermometers 6a and 6b and scanning radiation thermometers 7a and 7b installed on the front and rear surfaces of the finishing mill, and steel plate lower surface temperature measured by optical fiber radiation thermometers 8a and 8b The information is sent to the control rolling start temperature / finishing temperature collecting PC11 via the upper surface temperature collecting PC 15a (front / rear surface) or the lower surface temperature collecting PC 16a (front surface / rear surface), and the rolling starts on the front and rear surfaces of the finishing mill. Roll temperature management such as temperature and rolling end temperature, and steel plate width and length direction temperature distribution are managed.

  The steel plate upper surface temperature information measured by the spot-type radiation thermometer 6c and the scanning radiation thermometer 7c installed on the front surface of the accelerated cooling device 5 and the steel plate lower surface temperature information measured by the optical fiber radiation thermometer 8c are the upper surface, respectively. It is sent to the cooling start temperature collection PC 12 via the temperature collection PC 15b or the lower surface temperature collection PC 16b, and the steel plate temperature management before the start of accelerated cooling, the management of the steel plate width, and the temperature distribution in the length direction are performed.

  Steel plate upper surface temperature information measured by spot-type radiation thermometers 6d and 6e and scanning radiation thermometers 7d and 7e installed on the rear surface of acceleration cooling device 5, and steel plate lower surface temperature measured by optical fiber radiation thermometers 8d and 8e. The information is sent to the cooling stop temperature collection PC 13 via the upper surface temperature collection PC 15c or the lower surface temperature collection PC 16c, respectively, and the accelerated cooling stop temperature management, the steel plate width, and the temperature distribution in the length direction are managed.

  The control rolling start temperature / finishing temperature collection PC11, the cooling start temperature collection PC12, and the cooling stop temperature collection PC13 are as shown in FIG. 3, and the control rolling start temperature / finishing temperature collection PC11 is an upper surface temperature collection PC15a (front surface / rear surface) and a lower surface. The temperature collection PC 16a (front / rear surface) is configured, the cooling start temperature collection PC 12 is configured by the upper surface temperature collection PC 15b and the lower surface temperature collection PC 16b, and the cooling stop temperature collection PC 13 is formed by the upper surface temperature collection PC 15c and the lower surface temperature collection PC 16c. The steel plate temperatures collected in the upper and lower surface temperature collection PCs are taken into the temperature performance analysis PC 14 via the control rolling start temperature / finishing temperature collection PC 11, the cooling start temperature collection PC 12, and the cooling stop temperature collection PC 13, respectively. It is.

  In actual machine production, by comparing the operation management temperature (controlled rolling start temperature, steel plate finishing temperature, cooling start temperature, cooling stop temperature) range with the temperature measurement results taken in the temperature performance analysis PC 14, the quality judgment is carried out. The material of the entire surface of the steel plate can be guaranteed.

  In addition, in the temperature performance analysis PC14, the entire temperature of the finish rolling mill entry / exit side and the accelerated cooling device entry / exit side is grasped, the material is determined from a specific threshold value, temperature tolerance, and material model, and desired from the large plate. Outputs information about the cutout part that can secure the material.

  Moreover, the upper and lower surface temperature of the slab in the heating furnace after the next material is adjusted from the temperature difference between the upper and lower surfaces, and the water amount of the accelerated cooling equipment is controlled in the width direction and the longitudinal direction from the temperature distribution in the steel plate width direction and the longitudinal direction. Thereby, the defect of a steel plate shape can be reduced.

  According to the present invention, the material test failure rate has been reduced by about 30% compared to the prior art, the warpage correction time of the steel sheet has been reduced by about 20%, and the defective shape of the steel sheet has been reduced by about 10%. .

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Finishing rolling mill 3 Steel plate 4 CR shower 5 Accelerated cooling device 6a, 6b, 6c, 6d, 6e Spot type radiation thermometer 7a, 7b, 7c, 7d, 7e Scan type radiation thermometer 8a, 8b, 8c, 8d, 8e Optical fiber radiation thermometer 11 Control rolling start temperature / finishing temperature collection PC
12 Cooling start temperature collection PC
13 Cooling stop temperature collection PC
14 Temperature performance analysis PC
15a, 15b, 15c Upper surface temperature collection PC
16a, 16b, 16c Bottom surface temperature collection PC

Claims (3)

  In the steel sheet production line equipped with a finishing mill and an accelerated cooling device installed on the steel sheet conveyance line downstream of the finishing mill, temperature measurement means for measuring the steel sheet temperature and temperature results for analyzing the measured steel sheet temperature Analyzing means, and the temperature measuring means is a spot-type radiation thermometer and scanning type installed at respective positions on the front and rear surfaces of the finishing rolling mill and the front and rear surfaces of the accelerated cooling device above the upper surface side of the steel sheet conveying line. A radiation thermometer, an optical fiber radiation thermometer installed at a position corresponding to the upper surface side spot-type radiation thermometer on the lower surface side of the steel sheet conveying line, and a position corresponding to the scanning direction of the scanning radiation thermometer A plurality of optical fiber radiation thermometers installed at arbitrary intervals in the line width direction, and the temperature performance analysis means is a steel plate from the steel plate temperature measured by each temperature measurement means Material guarantee facilities of the steel sheet, characterized in that it comprises means for determining the temperature distribution in the body.   A plurality of spot-type radiation thermometers are installed on the front and rear surfaces of the finish rolling mill, a spot-type radiation thermometer and a scanning radiation thermometer are installed on the front surface of the accelerated cooling device, and a rear surface of the accelerated cooling device is installed on the rear surface of the accelerated cooling device. A plurality of spot-type radiation thermometers and scanning-type radiation thermometers are installed, and the spot-type radiation thermometer and the scanning radiation thermometer installed on the rear surface of the accelerated cooling device are respectively used for high temperature measurement and low temperature. The steel sheet material assurance equipment according to claim 1, wherein there are a plurality of units for area measurement.   A spot-type radiation thermometer and a scanning radiation thermometer installed on the rear surface of the accelerated cooling device are a high-temperature range measurement thermometer for measuring a temperature range of 200 ° C. or more and 700 ° C. or less, and a temperature of 50 ° C. or more and 300 ° C. or less, respectively. The material assurance equipment for a steel sheet according to claim 2, comprising a plurality of low temperature range measuring thermometers for measuring the temperature range of the steel sheet.

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