JP5589260B2 - Thick steel plate quality assurance system - Google Patents

Description

  The present invention relates to a material guarantee system for a thick steel plate, and more particularly to a suitable material guarantee material for the entire surface of a thick steel plate to be subjected to controlled rolling or accelerated cooling.

  In order to produce 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, the control rolling start temperature, Since it is necessary to strictly control the end temperature, the cooling start temperature of accelerated cooling, and the cooling stop temperature, a measurement method that accurately measures the steel sheet temperature and a cooling facility that devises the placement of the thermometer It is adopted as equipment.

  For example, Patent Literature 1 relates to a cooling control device for hot-rolled steel plates, and measures the steel plate temperature to prevent shape defects due to warpage in the plate width direction during cooling, and is arranged above and below the cooling device. It is described that the amount of cooling water from the nozzle and the start and end of cooling are strictly controlled and optical fiber thermometers are arranged on the rear surface of the finish rolling mill, on the front and rear surfaces of the cooling device, and inside.

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

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 make the material uniform, after finishing rolling, the thickness of the scale thickness is 10 μm or less by deske or surface film coating, and controlled cooling, and It is described that a radiation thermometer is arranged 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

  Recently, with regard to heat-treated materials (especially high-Ni steels with high material sensitivity to fluctuations in manufacturing conditions), it is possible to manufacture products by direct quenching or expanding the scope of application of TMCP for rationalization. There is an increasing demand for quality assurance on the entire surface.

  In addition, there is a need to guarantee the strength deviation within the line pipe original plate, ship building material plate, etc. below a certain threshold.

  In the thick steel plate, the temperature distribution due to the continuous heating furnace, deske device, cooling equipment, etc. tends to be non-uniform in the thickness direction or in the plate surface, 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, the quality determination using the temperature measurement result by the radiation thermometer is to measure a specific location (for example, the temperature in the center in the width direction of the steel sheet) with a radiation thermometer attached to the upper surface in the center in the conveyance line width direction. Since the measured temperature is compared with each control temperature range, and the quality judgment is performed only at a specific temperature, the material guarantee of the full length (entire surface) 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. In the case of mass production under the same production conditions, mass incompatibility may occur.

  Therefore, the present invention is a quality assurance system for a thick steel plate that accurately measures the steel plate temperature on the production line, predicts the material in the plate surface of the thick steel plate from the obtained temperature distribution, and evaluates the material uniformity. The purpose is to provide.

The object of the present invention can be achieved by the following means.
1. A steel plate quality assurance system for measuring steel plate temperature and guaranteeing material quality in a steel plate production line equipped with a finish rolling mill and a cooling device disposed downstream of the finish rolling mill,
The material assurance system includes a temperature measurement unit, a temperature analysis unit, and a material determination unit,
Said temperature measuring means, a pre-Symbol finishing mill spot type radiation thermometer on the front of, the front and rear surfaces of the rear surface and the cooling device of the finishing mill wherein a spot type radiation thermometer and a scanning radiation thermometer A spot type fiber thermometer is arranged above the transport line, and a spot type fiber thermometer is arranged below the transport line at a position opposite to the spot radiation thermometer and the scanning radiation thermometer across the transport line. The spot-type fiber thermometers disposed at positions facing the scanning radiation thermometers are arranged at a suitable interval in the scanning direction of the scanning radiation thermometer , and further, the temperature A temperature collecting means for collecting the temperature measured by the meter,
The temperature analysis means creates a steel sheet overall surface temperature MAP from the temperature collected by the temperature collection means, and the material judgment means estimates pass / fail judgment by estimating the material properties of the steel sheet overall surface from the temperature MAP . A material guarantee system for thick steel plates.
2 . Wherein when estimating the material properties of the steel sheet over the entire surface from the temperature MAP, 1 Symbol placement thick steel material assurance system of which comprises using a DB-type material prediction model.

  According to the present invention, it is possible to guarantee the material and shape of the thick steel plate that is subjected to accelerated cooling or directly quenched after finish rolling. Moreover, since it is possible to determine whether or not the temperature of the entire surface is right after rolling, it is possible to prevent the occurrence of mass nonconformity by controlling the temperature of the subsequent steel plates, which is extremely useful in the industry.

  The material assurance system according to the present invention includes a temperature measuring unit, a temperature analyzing unit, and a material determining unit. The temperature analyzing unit creates a steel plate full surface temperature MAP from the steel plate temperature measured by the temperature measuring unit, and Based on the temperature MAP, the material judgment means evaluates the material on the entire surface of the steel plate.

  FIG. 1 is a flowchart showing an outline of a material guarantee system according to the present invention. First, it is determined whether or not a rolled steel sheet to be manufactured is a material subject to overall material guarantee (S1). Examples of the material subject to guarantee of the entire surface include DQ materials such as line pipe original plate, shipbuilding 50K steel, and DQ type 9% Ni steel, which are highly sensitive to manufacturing conditions.

  In the case of the entire surface material guarantee material, the entire surface temperature of the rolled steel sheet is measured using temperature measuring means and temperature analyzing means (S2). In the material assurance system according to the present invention, the temperature measurement means and the temperature analysis means are not particularly defined, but those having the configurations described below are appropriate.

  Since it is technically difficult to measure the temperature of the entire surface of a thick steel plate in the production line, the temperature measuring means is a thermometer, and a spot-type radiation thermometer and a scanning radiation thermometer are placed below the carrier line, Uses a spot-type radiation thermometer using an optical fiber (hereinafter referred to as an optical fiber radiation thermometer) and collects temperatures measured by a plurality of thermometers, and therefore uses a PC as a temperature collecting means.

  In the temperature measurement means, the above-mentioned thermometers are appropriately combined, and the minimum temperature measurement position necessary for guaranteeing the temperature history of the entire surface on the production line is 1. 1. Front and rear faces of finish rolling mill and Thermometers are arranged as front and rear surfaces of the cooling device. When the temperature difference between the upper and lower surfaces of the steel sheet is significant, the material properties of the upper and lower surfaces may be different. Therefore, the temperature is measured on the upper and lower surfaces.

  In the description, the installation of a thermometer on the front (rear) surface of the finish rolling mill means that the thermometer is placed near the front of the finish mill (rear) and closer to the finish mill than other equipment. means. The same applies to the 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 cooling device above the transport line.

  Multiple spot-type radiation thermometers are arranged on the front and rear faces of the finish rolling mill. When one unit is used, it prevents the mill from stopping when a thermometer malfunctions, or when manufacturing line pipe materials that are produced in large quantities. Improve the reliability of measurement temperature. The arrangement position of the plurality of units is not particularly defined, but it is desirable to arrange them in the transport direction.

  The spot type radiation thermometer to be arranged on the front and rear surfaces of the cooling device has a single front surface and a rear surface of a plurality of units with two specifications for high temperature measurement and low temperature measurement.

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

  In a wide range of temperature measurement from low temperature to high temperature (about 50 to 700 ° C.), the resolution of the thermometer (± 5 ° C.) cannot be secured. Therefore, as a minimum, it is necessary to install two specification thermometers for high temperature measurement and low temperature measurement. A high temperature measurement is arranged on the side close to the cooling device, and a low temperature measurement is arranged on the remote side.

  A scanning radiation thermometer arranges the width direction of a conveyance line as a scanning direction so that the width direction of a steel plate may be scanned above the conveyance line on the rear surface of the finish rolling mill and the front and rear surfaces of the cooling device. Preferably, it is arranged close to the spot type radiation thermometer.

Since the rolling finishing temperature measured on the rear surface of the finish rolling mill and the steel plate temperature measured on the front and rear surfaces of the cooling device have a great influence on the material, it is measured in the width direction of the steel plate to ensure material uniformity.
An infrared thermography apparatus may be used as an alternative to the scanning radiation thermometer.

  The optical fiber radiation thermometer is disposed below the transport line. The environment is bad due to water, water vapor, etc., and a scanning radiation thermometer that measures the temperature of the entire surface cannot be installed. In particular, when the CR shower is installed immediately downstream of the finish rolling mill, the temperature measurement environment deteriorates on the rear surface of the finish rolling mill.

  Therefore, a spot type radiation thermometer using an optical fiber (hereinafter referred to as an optical fiber radiation thermometer) is disposed below the transport line.

  The optical fiber radiation thermometer is arranged at a position opposite to the spot type radiation thermometer arranged on the front and rear surfaces of the finish rolling mill and the front and rear surfaces of the cooling device with the conveyance line interposed therebetween.

  In addition, along the scanning direction of the scanning radiation thermometer, at the opposite position across the transportation line, below the transportation line of the scanning radiation thermometer arranged on the rear surface of the finishing mill and on the front and rear surfaces of the cooling device Arrange multiple units.

  As the number of optical fiber radiation thermometers increases, the temperature distribution in the width direction can be quantitatively grasped. However, from the viewpoint of cost and maintenance, the interval of 1 place / m is the minimum. In addition, when arrange | positioning an optical fiber radiation thermometer facing a spot type | mold radiation thermometer, you may arrange | position several units | sets in the width direction of a conveyance line.

  FIG. 6 shows an outline of a temperature measurement system provided with the above-described temperature measurement means, and FIG. 7 shows a part of the configuration of the temperature measurement means. In these figures, 1 is a heating furnace, 2 is a finish rolling mill, 3 is a steel plate, 4 is a CR shower, 5 is a cooling device, 6, 6a, 6b, 6c, and 6d are scanning radiation thermometers, and 6c is a high temperature. For measurement, 6d for low temperature measurement, 7, 7a, 7b, 7c, 7d for optical fiber radiation thermometer, 7c for high temperature measurement, 7d for low temperature measurement, 8 for controlled rolling start temperature, finishing temperature collection PC, 9 for The cooling start temperature collection PC, 10 is a cooling stop temperature collection PC, 11 and 11a are temperature performance analysis PCs, 12 is a back surface temperature collection PC, and 13 is a surface temperature collection PC. However, the spot type radiation thermometer is omitted in the figure.

  The thick steel plate production line includes a heating furnace 1, a finish rolling mill 2, a CR shower 4 and a cooling device 5, and the figure shows a state in which the steel plate 3 is located between the finishing mill 2 and the CR shower 4. .

  It was measured by a spot-type radiation thermometer (not shown) arranged on the front and rear surfaces of the finish rolling mill, and a steel plate temperature measuring means composed of a scanning radiation thermometer 6a and an optical fiber radiation thermometer 7a arranged on the rear surface. The temperature is taken into the control rolling start temperature and the finishing temperature collection PC8.

  The temperatures measured by the spot type radiation thermometer (not shown), the scanning radiation thermometer 6b, and the optical fiber radiation thermometer 7b arranged in front of the cooling device 5 are taken into the cooling start temperature collection PC9.

  The temperature measured by a temperature measuring means comprising a spot type radiation thermometer (not shown in the figure), scanning type radiation thermometers 6c and 6d and optical fiber radiation thermometers 7c and 7d arranged on the rear surface of the cooling device 5 is Then, it is taken into the cooling stop temperature collection PC 10.

  The temperature collecting means is composed of a finish temperature collecting PC8, a cooling start temperature collecting PC9 and a cooling stop temperature collecting PC10, each of which is composed of a surface temperature collecting PC13 and a back surface temperature collecting PC12, and each of the steel plate surface temperature and the back surface temperature is a temperature. It is taken into the temperature performance analysis PC 11a which is an analysis means.

  In the actual temperature analysis PC11a, the actual temperatures captured by the finishing temperature collection PC8, the cooling start temperature collection PC9, and the cooling stop temperature collection PC10 are converted into operation management temperatures (control rolling start temperature, steel plate finishing temperature, cooling start temperature, cooling stop temperature). (S3), if it is within the range, product measurement is performed (S4), and if it is outside the range, the material of the region is determined (S5).

  2 and 3 show a PC display screen for supporting a temperature determination operation for determining a product shipment by comparing the operation management temperature and the temperature measurement result taken in the temperature result analysis PC 11a (FIG. 3). This will be described as a creation procedure (FIG. 2).

  First, the temperature of the entire surface is measured by the above-described temperature measuring means (S11), and the temperature MAP of the entire surface of the steel sheet and the large plate 14 is created by the temperature analyzing means (S12).

  Then, based on the results of shearing, as shown in FIG. 3, the sample 15 from the top of the large plate 14, the sample 16 from the middle, the sample 17 from the bottom, and the product (small plates 18, 19, 20, 21). (S13).

  Moreover, the accuracy of the quality design and the material prediction model can be improved by calculating the temperature of the sample position from the temperature MAP and correlating the material test results.

  The region where the actual temperature deviates from the operation management temperature, the temperature determination NG portion is surrounded by thick frames 22 and 23 (S14), the mesh representative temperature is obtained (S15), and displayed on the screen (S16). The mesh representative temperature is an average temperature in the mesh, and the mesh is appropriately selected depending on the use, but a size of 50 to 1000 mm is preferable.

  Here, the mesh refers to one small region when the entire surface of the steel plate is divided into small regions in order to create the steel plate entire surface temperature MAP.

  FIG. 4 is a flowchart for explaining a processing method of the temperature determination NG portion when the portion is generated on the small plate. Steps S21 to S24 are similar to steps S11 to S14 of FIG.

  If the temperature judgment NG part is included in the small plate, it is determined as NG hold (S25), the quality of the material is determined by the DB type (database type) material prediction model (S26), and if it is acceptable, the hold is released and the plate is released. Take.

  FIG. 5 shows an example of a PC display screen when the NG portions 22 and 23 in the small plates 20 and 21 are determined according to the flowchart of FIG.

  On the other hand, when the temperature determination NG portion is included in the large plate, the NG process is performed, and the plate cutting is corrected so as to collect the product within the high quality range (S7), and the product is collected (S8).

  As described above, the material assurance system according to the present invention predicts the material based on the temperature distribution of the whole surface of the steel plate measured with high accuracy and the actual value, and uses the DB type material prediction model with high prediction accuracy. It is possible to ship a product whose material is guaranteed (S9). In addition, the shape can be guaranteed over the entire surface.

  3 and 5 are examples of a PC display screen obtained by one procedure of the material assurance system according to the present invention. The purpose is to assist an engineer to intervene in the system. It is also possible to use a system that performs automatic control and does not involve engineers.

  According to the present invention, the material test failure rate is reduced from 0.08% to 0.06%, the warp correction time is reduced by 20%, and the effect of suppressing the shape failure of the steel sheet by 10% is obtained. .

The figure which shows the flowchart of the material guarantee system of this invention. The figure which shows the procedure of the intensity | strength determination of this invention. The figure which shows the example of the PC display screen which supports the temperature determination business of this invention. The figure which shows the flowchart of a process when the temperature determination NG part arises. The figure which shows the example of a PC display screen when the NG part is a pass in the flowchart shown in FIG. The figure which shows the outline | summary of the temperature measurement system which concerns on this invention. The figure explaining the structure of the temperature measurement system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Finish rolling mill 3 Steel plate 4 CR shower 5 Cooling device 6, 6a, 6b, 6c, 6d Scan type radiation thermometer 7, 7a, 7b, 7c, 7d Optical fiber radiation thermometer 8 Control rolling start temperature, finish temperature Collection PC
9 Cooling start temperature collection PC
10 Cooling stop temperature collection PC
11, 11a Temperature performance analysis PC
12 Backside temperature collection PC
13 Surface temperature collection PC
14 Large plate 15, 16, 17 Sample 18, 19, 20, 21 Small plate 22, 23 Thick frame

Claims (2)

A steel plate quality assurance system for measuring steel plate temperature and guaranteeing material quality in a steel plate production line equipped with a finish rolling mill and a cooling device disposed downstream of the finish rolling mill,
The material assurance system includes a temperature measurement unit, a temperature analysis unit, and a material determination unit,
The temperature measuring means transports a spot-type radiation thermometer on the front surface of the finishing mill, and a spot-type radiation thermometer and a scanning radiation thermometer on the rear surface of the finishing mill and on the front and rear surfaces of the cooling device. The spot type fiber thermometer is arranged above the line, and the spot type thermometer and the scanning type radiation thermometer are arranged opposite to each other across the carrier line. The spot type fiber thermometer arranged at a position facing the scanning radiation thermometer is configured by arranging a plurality of spots at appropriate intervals in the scanning direction of the scanning radiation thermometer , and further, the thermometer Temperature collecting means for collecting the temperature measured in
The temperature analysis means creates a steel sheet overall surface temperature MAP from the temperature collected by the temperature collection means, and the material judgment means estimates pass / fail judgment by estimating the material properties of the steel sheet overall surface from the temperature MAP . A material guarantee system for thick steel plates. When estimating the material properties of the steel sheet over the entire surface from the temperature MAP, claim 1 Symbol placement thick steel material assurance system of which comprises using a DB-type material prediction model.

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