JP5577583B2 - Online quality assurance system for thick steel plates - Google Patents

Description

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

  For TMCP technology to improve the strength and toughness of thick steel plates by refining the crystal grain size in the material structure, strictly control the inlet side temperature, outlet side temperature, inlet side temperature of accelerated cooling, and outlet side temperature for controlled rolling. Is important, and a method of accurately measuring the temperature of the thick steel plate and a manufacturing facility with a devised arrangement of thermometers are adopted, and the material judgment is performed by these.

  For example, in Patent Document 1, the temperature distribution in the rolling direction and the width direction on only the final finish rolling delivery side is measured, a temperature difference with a required value is obtained, and this is used as an index to exclude a portion that deviates from this temperature difference index. The method of discarding is described.

However, the material of a thick steel plate changes depending on conditions such as controlled rolling and accelerated cooling, and the material changes due to a significant change in the structure. In particular, it is known that the temperature of the steel plate greatly affects the material. In the conventional method described in Patent Document 1, even if the temperature history experienced by the thick steel plate during rolling changes, only the temperature at the final finish rolling exit side is evaluated. Judging by the temperature difference on the side, there were many cases where the product partially collected from the large plate of thick steel plate was out of the material that should be guaranteed, so it was a big problem because sufficient material guarantee could not be done . Further, as described in the example of Patent Document 1, since the temperature of either the upper surface or the lower surface is measured, it is not possible to evaluate the difference between the upper surface temperature and the lower surface temperature in the thick steel plate having a large plate thickness. In some cases, there was a strong demand for material guarantee in the thickness direction.
JP 52-117857 A

  In recent years, thick steel plates whose materials change sensitively even if the manufacturing conditions such as heat treatment materials fluctuate slightly are manufactured by the direct quenching method from the viewpoint of efficiency improvement, and TMCP technology is applied and expanded for rationalization. Conventionally, the material of the thick steel plate has been passed if it guarantees a part such as the central portion in the width direction. However, the demand for guaranteeing the entire surface of the steel plate has been issued by customers, and the severity has been increasing year by year. In line pipe original plates, ship building materials, etc., there is an unprecedented requirement to guarantee the strength deviation within a thick steel plate to a specific value or less.

  On the other hand, in the manufacturing process, a thick steel plate is passed through a continuous heating furnace, roughing mill, finish rolling mill, descaling device, accelerated cooling device, etc., so that the temperature distribution in the plate surface and thickness direction. Tends to be non-uniform, and as a result, the material tends to be non-uniform. Therefore, conventionally, for example, by using a radiation thermometer attached above the conveyance line, the temperature at the central part in the plate width direction of the thick steel plate is continuously measured in the rolling direction, and the measured temperature only at the central part falls within the allowable temperature range. If it is, the quality judgment of the entire thick steel plate is accepted, and if it is off, the quality judgment is rejected.

  However, this method cannot guarantee the material of the full width (that is, the entire surface) even on the surface where the temperature is measured, and the material guarantee is insufficient.

  In addition, since thick steel plates are manufactured in large quantities under the same manufacturing conditions, the conventional method for judging various materials using test pieces taken from the tip, center and tail positions in the rolling direction is to use test pieces of thick steel plates. In some cases, it may take several days after collection, and in the unlikely event that the judgment is impossible, all the thick steel plates manufactured during that period may be rejected and a large amount of defective materials may be generated.

  The present invention has been made in order to solve the above-described problems in guaranteeing the material, and accurately and promptly determines and guarantees the material of the steel plate that has been finish-rolled and accelerated and cooled. It is an object of the present invention to provide an on-line material quality assurance system for thick steel plates.

  In order to solve the above-mentioned problems, the present invention measures and analyzes the temperature distribution of the entire surface of the thick steel plate on the thick steel plate production line, and uses the temperature measurement / analysis result and a separately prepared material prediction model. The material in the thick steel plate is predicted and the material uniformity is judged and evaluated.

  That is, in order to solve the above problems, the present invention has the following features.

[1] In a thick steel plate production line equipped with a finish rolling mill and an accelerated cooling device disposed on the downstream side of the finish rolling mill, the temperature of the entire upper surface or the entire lower surface of the thick steel plate is measured and analyzed. An online material guarantee system for thick steel plates that guarantees the quality of thick steel plates,
The material assurance system includes a temperature measurement unit and a temperature analysis unit,
The temperature measuring means includes a thermometer arranged in the vicinity of the finish rolling mill and in the vicinity of the accelerated cooling device, and a temperature collecting means for collecting the temperature measured by the thermometer,
The temperature analysis means includes a material prediction model for predicting the material according to the temperature of the thick steel plate, and the temperature MAP on the entire upper surface of the thick steel plate or the entire lower surface is measured using the temperature measurement values collected by the temperature collecting means. An on-line material assurance system for a thick steel plate, wherein the temperature MAP of the thick steel plate is created, and the pass / fail judgment of the material of the thick steel plate is performed from the temperature MAP and a prediction result by the material prediction model.

[2] In a thick steel plate production line equipped with a finish rolling mill and an accelerated cooling device arranged on the downstream side of the finish rolling mill, the temperature of the entire upper surface of the thick steel plate and the temperature of the entire lower surface are measured and analyzed. An online material guarantee system for thick steel plates that guarantees the quality of thick steel plates,
The material assurance system includes a temperature measurement unit and a temperature analysis unit,
The temperature measuring means includes a thermometer arranged in the vicinity of the finish rolling mill and in the vicinity of the accelerated cooling device, and a temperature collecting means for collecting the temperature measured by the thermometer,
The temperature analyzing means includes a material prediction model for predicting the material according to the temperature of the thick steel plate, and using the temperature measurement values collected by the temperature collecting means, the temperature MAP of the entire upper surface of the thick steel plate and the lower surface A thickness characterized in that a temperature MAP on the entire surface and a temperature MAP at a predetermined position in the plate thickness direction are created, and pass / fail judgment of the material of the thick steel plate is performed from the temperature MAP and a prediction result by the material prediction model. Online quality assurance system for steel sheets.

  ADVANTAGE OF THE INVENTION According to this invention, the material of the thick steel plate which was finish-rolled and accelerated-cooled can be determined and guaranteed accurately and rapidly. That is, in the present invention, since the material of the thick steel plate is determined based on the temperature distribution over the entire surface of the thick steel plate, it is possible to guarantee the material over the entire surface of the thick steel plate. In addition, immediately after finish rolling / accelerated cooling, it can be determined whether the temperature of the entire surface of the thick steel plate is within the allowable range, so the temperature of the subsequent thick steel plate can be controlled with reference to this temperature. It also has a secondary effect, can prevent the generation of a large amount of defective materials, can produce a thick steel plate efficiently and with good yield, and is extremely useful industrially.

  As described above, since the thick steel plate passes through a continuous heating furnace, rough rolling mill, finish rolling mill, descaling device, accelerated cooling device, etc., the temperature distribution in the plate surface and thickness direction tends to be non-uniform. . Since the material of the thick steel plate is greatly influenced by the temperature, the material is likely to be non-uniform due to the temperature history in the passing process.

  Therefore, in order to guarantee the material of the thick steel plate, it is necessary to measure the temperature over the entire surface of the plate, and it is important to evaluate and judge the temperature over the entire upper surface or the entire lower surface.

  In addition, it is preferable to measure and analyze the entire plate temperature for each passing position (each equipment entry side or exit side) to make a judgment. However, in the examination by the present inventors, in particular, the material of the thick steel plate is affected. Since it is understood that the large passing process is after the entrance to the finishing mill, in the present invention, the temperature in the vicinity of the finishing mill and in the vicinity of the accelerated cooling device is measured and analyzed on the entire upper surface or the lower surface of the thick steel plate. I made it.

  Since these temperature measurement and analysis results have a large amount of data, they can be easily determined by converting them to MAP (temperature distribution chart), and can be quickly converted to MAP by using a computer. Can be done.

  That is, the material guarantee system according to the present invention measures and analyzes the temperature of the entire upper surface of the thick steel plate and / or the temperature of the entire lower surface in the vicinity of the finish rolling mill and in the vicinity of the accelerated cooling device, and temperature measuring means therefor And a temperature analysis means, a steel plate full surface temperature MAP is created by the temperature analysis means from the steel plate temperature measured by the temperature measurement means, and the steel plate full surface temperature MAP and the temperature analysis means are provided. By using the material prediction model, the pass / fail judgment of the material of the thick steel plate is performed.

  Details of the present invention will be described below.

  First, it is determined whether or not the rolled steel sheet to be manufactured is a material for which the entire surface is guaranteed. The target materials for which material guarantee is required over the entire surface are, for example, line pipe original plate, high-strength steel (for shipbuilding, DQ materials, tank materials, penstock, for industrial machinery, for building bridges, etc.) It is a steel plate whose material is easily affected by

  In the case of the entire surface material guarantee material, the surface temperature is measured / analyzed using means (temperature measuring means and temperature analyzing means) for measuring and analyzing the temperature over the entire upper surface and / or the entire lower surface of the thick steel plate.

  At that time, the actual temperature data measured by the temperature measuring means is taken into the process computer, and the entire upper surface or / and the entire lower surface is determined by the actual temperature data and the analyzed temperature data analyzed and calculated based on the actual temperature data. MAP of the temperature distribution. Thereby, the temperature of the whole thick steel plate in the entrance side and / or exit side of each apparatus (finish rolling mill and accelerated cooling device) can be grasped at a glance.

  And when determining the material using this MAP-formed temperature distribution, the material prediction model that predicts the material based on the temperature of the thick steel plate is utilized, and the pass / fail judgment of the material on the entire surface of the thick steel plate is performed. The portion of the steel sheet that falls within the allowable range can be determined as a non-defective product, and can be cut and shipped.

  For example, the temperature distribution is converted to MAP for the finish rolling mill entry side, finish rolling mill exit side, accelerated cooling device entrance side, and accelerated cooling device exit side, and the MAP and material prediction model according to the material requirement level for each product of thick steel plate It is better to make a pass / fail decision using the prediction result in and collect the corresponding product.

  In addition, for extremely thick steel plates with heavy plate thickness and steel plates with severe materials, the temperature distribution in the plate thickness direction is unknown in the temperature measurement / analysis of only the entire upper surface or the entire lower surface, which may prevent the material from being determined. . In this case, the temperature over the entire upper surface and lower surface of the thick steel plate is measured and analyzed, and the temperature distribution in the plate thickness direction, plate width direction, and plate longitudinal direction of the thick steel plate is measured on the entry side and the exit side of each device. In this case, it is preferable to make a MAP, make a pass / fail judgment using the MAP and a material prediction model, and make a material judgment in all of the plate thickness direction, the plate width direction, and the plate longitudinal direction.

  In addition, as the material determination, first, regarding the temperature at either the entry side or the exit side of each device, an individual temperature threshold value selected from each thermometer setting position at that position (hereinafter, temperature threshold value). The material may be subjected to primary determination based on the temperature threshold, and the material may be subjected to secondary determination using the temperature MAP and the material prediction model.

  One embodiment of the present invention as described above will be described below with reference to the drawings.

  FIG. 5 shows an outline of a material assurance system provided with a temperature measuring means (thermometer and temperature collecting means) and a temperature analyzing means in this embodiment, and FIG. 6 shows an example of the configuration of the temperature measuring means. Indicates the part. In these figures, 1 is a heating furnace, 2 is a finish rolling mill, 3 is a thick steel plate, 4 is a cooling device between rolling passes (cooling device for controlled rolling), 5 is an accelerated cooling device, 6, 6a, 6b, 6c. , 6d is a scanning radiation thermometer, 6c is for high temperature measurement, 6d is for low temperature measurement, 7, 7a, 7b, 7c, 7d are optical fiber radiation thermometers, 7c is for high temperature measurement, 7d is for low temperature measurement, 8 Is a controlled rolling start temperature / finishing temperature collection process computer, 9 is a cooling start temperature collection process computer, 10 is a cooling stop temperature collection process computer, 11 is a temperature performance analysis process computer, 12 is a bottom surface temperature collection process computer, and 13 is a top surface temperature. Figure 2 shows a collection process computer. However, in the figure, the roughing mill and the spot type radiation thermometer are omitted.

  Measured with a steel plate temperature measuring means composed of a spot type radiation thermometer (not shown) arranged on the front and back surfaces of the finish rolling mill 2, and a scanning type radiation thermometer 6a and an optical fiber radiation thermometer 7a arranged on the rear surface. The obtained temperature is taken into the control rolling start temperature / finishing temperature collection process computer 8.

  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 accelerated cooling device 5 are taken into the cooling start temperature collection process computer 9. .

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

  The temperature collecting means is composed of a finishing temperature collecting process computer 8, a cooling start temperature collecting process computer 9 and a cooling stop temperature collecting process computer 10, each comprising an upper surface temperature collecting process computer 13 and a lower surface temperature collecting process computer 12. Each of the collected thick steel plate upper surface temperature and lower surface temperature is taken into the temperature performance analysis process computer 11 which is a temperature analysis means.

  The actual temperature analysis process computer 11 performs analysis / calculation based on the measured temperature data captured by the finishing temperature collection process computer 8, the cooling start temperature collection process computer 9 and the cooling stop temperature collection process computer 10, and the measured temperature data. Based on the analysis temperature data, the temperature distribution on the entire upper surface and / or the entire lower surface is converted to MAP, and when the desired material is obtained by material prediction using the material prediction model for the temperature MAP, the temperature range (allowable temperature range) If it is within the allowable temperature range, the product is measured from the large plate of the thick steel plate.

  In FIG. 1, an example of the processing flow of the quality assurance system of the thick steel plate which concerns on this embodiment is shown. Here, the suitability of product shipment is determined based on the temperature measurement / analysis result (temperature MAP) taken in and analyzed by the temperature performance analysis process computer 11 and the material prediction based on the material prediction model. . FIG. 4 is a process computer screen for visually displaying the process.

  First, the above-described temperature measuring means and temperature analyzing means measure and analyze the entire upper surface temperature or lower surface temperature of the thick steel plate (S1), and the temperature analyzing means measures the upper surface entire surface temperature MAP or the entire lower surface temperature of the thick steel plate (large plate 14). A temperature MAP is created (S2). Here, the size of the mesh of the temperature MAP is appropriately selected depending on the application, but preferably in the range of 50 to 1000 mm. Incidentally, the mesh of the temperature MAP refers to one small region when the entire surface of the steel plate is divided into small regions in order to create the entire surface temperature MAP of the steel plate.

  When a temperature distribution in the plate thickness direction is required, such as a very thick steel plate having a large plate thickness, in (S2) above, the upper surface whole surface temperature MAP, the lower surface whole surface temperature MAP, and the temperature at a specific position in the plate thickness direction. Create a MAP. At that time, in (S1), the upper surface temperature and the lower surface temperature of the thick steel plate are measured and analyzed.

  Next, as shown in FIG. 4, with respect to the large plate 14, a material test tip sampling material 15, a material test center sampling material 16, a material test tail sampling material 17, a product (small plate 18, 19, 20, 21) is assigned (S3).

  Next, using the material prediction model for the created temperature MAP, it is determined whether or not the temperature is in a temperature range (allowable temperature range) where it is predicted that a desired material can be obtained. A region outside the range is surrounded by thick frames 22 and 23 (S4).

  Note that the thick frame portion outside the allowable temperature range may be reassigned by changing the sampling position according to the product if it can be diverted to another less demanding product (S5).

  Then, a product whose temperature is within the allowable temperature range is collected as a product (S6).

  In FIG. 2, the other example of the processing flow of the quality assurance system of the thick steel plate which concerns on this embodiment is shown.

  Here, as shown in FIG. 2, overall temperature measurement / analysis (S1), temperature MAP creation (S2), product position and test piece position assignment (S3) are performed in the same manner as in FIG. For the temperature at a specific position on the entry side or exit side of each device, set the temperature threshold value (primary allowable temperature range) and perform material determination, and thicken the area outside the primary temperature allowable range determined by the temperature threshold value. A frame is displayed (S7). Thereafter, a secondary allowable temperature range at least partially wider than the primary allowable temperature range is set as a secondary determination for the thick frame portion, and the secondary allowable temperature range is set using the temperature MAP and the material prediction model. The product collection position is determined (S8), and diversion to a less demanding product is possible.

  Then, a small plate within the allowable temperature range (within the primary allowable temperature range and the secondary allowable temperature range) is collected as a product (S9).

  FIG. 3 shows another example of the processing flow of the material assurance system for thick steel plates according to this embodiment.

  Here, as shown in FIG. 3, the entire surface temperature measurement / analysis (S1), temperature MAP creation (S2), product position and test piece position assignment (S3) are performed in the same manner as in FIG. Then, the temperature at a specific position on the entry side or the exit side of each device is determined by using the temperature MAP and the material prediction model, and a region outside the allowable temperature range (primary allowable temperature range) is displayed with a thick frame. (S10). Thereafter, a secondary allowable temperature range (temperature threshold), at least a part of which is wider than the primary allowable temperature range, is set as a secondary determination for the thick frame portion, a pass / fail determination is made, and a product collection position is determined (S11). ), Diversion to less demanding products is possible.

  Then, a small plate that is within the allowable temperature range (within the primary allowable temperature range and the secondary allowable temperature range) is collected as a product (S12).

  In this way, the steel plate material assurance system according to this embodiment uses the temperature distribution of the entire surface of the thick steel plate, which has been accurately measured and analyzed, as a MAP, and based on the actual temperature value (actual temperature measurement value). Therefore, it is possible to ship a product whose entire surface is guaranteed. Also, the shape (flatness etc.) can be guaranteed over the entire surface.

  In the conventional material judgment / guarantee method, material defects are mixed to some extent (for example, about 0.8%) in the product collected from the large plate, and the product must be recreated from the large plate, and the product is collected again. However, according to this embodiment, the material failure portion in the material determination is almost zero. It is possible to guarantee the quality of the product that has been significantly reduced and that has been collected.

The figure which shows an example of the processing flow of one Embodiment of this invention. The figure which shows the other example of the processing flow of one Embodiment of this invention. The figure which shows the other example of the processing flow of one Embodiment of this invention. The figure which shows the process computer screen in one Embodiment of this invention. The figure which shows the outline | summary of the material guarantee system which concerns on one Embodiment of this invention. The figure explaining a part of material guarantee system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Finishing rolling mill 3 Steel plate 4 Rolling pass cooling device 5 Acceleration cooling device 6, 6a, 6b, 6c, 6d Width direction scanning type radiation thermometer 7, 7a, 7b, 7c, 7d Optical fiber radiation thermometer 8 Control Rolling start temperature / finishing temperature collection process computer 9 Cooling start temperature collection process computer 10 Cooling stop temperature collection process computer 11 Temperature performance analysis process computer 12 Lower surface temperature collection process computer 13 Upper surface temperature collection process computer 14 Large plate 15, 16, 17 Material Sampling material for test 18, 19, 20, 21 Small plate 22, 23 Plate part outside allowable temperature range (thick frame display)

Claims (1)

In a thick steel plate production line equipped with a finish rolling mill and an accelerated cooling device arranged on the downstream side of the finish rolling mill, the temperature of the entire upper surface of the thick steel plate and the temperature of the entire lower surface are measured and analyzed. An online quality assurance system for thick steel plates that guarantees the quality of materials.
The material assurance system includes a temperature measurement unit and a temperature analysis unit,
The temperature measuring means includes a thermometer arranged in the vicinity of the finish rolling mill and in the vicinity of the accelerated cooling device, and a temperature collecting means for collecting the temperature measured by the thermometer,
The temperature analyzing means includes a material prediction model for predicting the material according to the temperature of the thick steel plate, and using the temperature measurement values collected by the temperature collecting means, the temperature MAP of the entire upper surface of the thick steel plate and the lower surface A thickness characterized in that a temperature MAP on the entire surface and a temperature MAP at a predetermined position in the plate thickness direction are created, and pass / fail judgment of the material of the thick steel plate is performed from the temperature MAP and a prediction result by the material prediction model. Online quality assurance system for steel sheets.

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