JP5915617B2 - Different thickness plate removal method - Google Patents

Description

  The present invention relates to a method for obtaining different thickness plate products for obtaining thick plate products having different thicknesses, and more particularly from a single accelerated cooling thick plate steel plate whose thickness changes stepwise and is accelerated by an accelerated cooling facility. This is suitable for obtaining accelerated cooling thick plate products having different plate thicknesses.

  In the steel plate manufacturing process at steelworks, an accelerated cooling facility is installed on the exit side of the rolling process, and the rolled steel plate is passed through the accelerated cooling facility to perform accelerated cooling, thereby mechanically TMCP (Thermo-Mechanical Control Process) for controlling characteristics is performed. In such an accelerated cooling facility, as a method of accelerating cooling a rolled steel sheet whose thickness changes in one thick steel sheet, there are those described in Patent Document 1 and Patent Document 2, for example. Among these, the cooling method described in the following Patent Document 1 is for a thick steel plate whose thickness changes continuously in the longitudinal direction. Measure the temperature, find the optimum cooling condition for each location based on the measured value, and correct the plate speed during cooling according to the plate thickness of the plate to be passed through to make the plate steel plate uniform It is to be cooled. Moreover, the cooling method described in the following Patent Document 2 arranges a plurality of cooling nozzles above and below the thick steel plate to be passed, and arranges an upper draining roll and a lower table roll facing each other on the outlet side of each cooling nozzle. In addition, a thick steel plate having a different thickness in the longitudinal direction is passed through and cooling water is injected from the upper and lower cooling nozzles, and the upper draining roll is adjusted in the vertical direction according to the thickness of the thick steel plate to be passed. Thus, the thick steel plate is cooled uniformly.

JP-A-62-166013 JP 2006-262274 A

  By the way, in order to acquire a plurality of products from a single steel plate, assigning a plurality of products to a single steel plate is referred to as plate removing. When chamfering, while ensuring product delivery, consideration is given to, for example, minimizing allocation gaps to reduce yield loss, and maximizing allocation weight to the manufacturing limit to improve manufacturing efficiency. The The same applies to the accelerated cooling thick steel plate, and the plate cutting is performed in consideration of how efficiently the accelerated cooling thick plate product can be cut. In general, not only the components of the accelerated cooling thick plate product, but also the plate thickness, the accelerated cooling thick plate product having the same thickness is cut into one accelerated cooling thick plate steel plate. However, in actual plate cutting, accelerated cooling plate products having different plate thickness may remain. In such a case, an accelerated cooling thick steel plate having a different thickness is manufactured by the number of remaining accelerated cooling thick plate products having different thicknesses, and the accelerated cooling thicknesses having different thicknesses from the accelerated cooling thick steel plates. We have acquired board products. Therefore, the production efficiency of accelerated cooling thick plate products may not be good.

  The present invention has been made paying attention to the above problems, and it is possible to obtain accelerated cooling thick plate products having different plate thicknesses from one accelerated cooling thick steel plate with a calculation function. It is an object of the present invention to provide a method for removing different thickness thick plates that can improve the production efficiency of accelerated cooling thick plate products having different thicknesses.

  In order to solve the above-mentioned problem, the plate thickness removal method of the present invention is different in plate thickness from one accelerated cooling thick plate steel plate that is stepwise changed and accelerated cooled by an accelerated cooling facility. A different thickness thick plate cutting method executed by a computer having a calculation function to obtain an accelerated cooling thick plate product, and among the required accelerated cooling thick plate products, the components are the same and the thicknesses are different from each other. In order to select an accelerated cooling plate product whose thickness difference is within a preset allowable range, and to set a specific accelerated cooling plate product among the selected accelerated cooling plate products to the cooling stop temperature of the product The calculated passing plate speed is calculated in the accelerated cooling plate products other than the specific accelerated cooling plate product among the selected accelerated cooling plate products. And the cooling stop of the product by performing accelerated cooling with the cooling length It is determined whether or not there is an accelerated cooling plate product that can be set to a temperature, and if there is an accelerated cooling plate product that can be set to the cooling stop temperature, the existing accelerated cooling plate product is present And the specific accelerated cooling thick plate product is detected as an accelerated cooling thick plate product having different plate thicknesses obtained from a single accelerated cooling thick plate steel plate whose thickness changes stepwise. is there.

  Further, when determining whether there is an accelerated cooling plate product that can be set to the cooling stop temperature, other than the specific accelerated cooling plate product among the selected accelerated cooling plate products Calculate the cooling start temperature of the accelerated cooling thick plate product, and other than the specific accelerated cooling thick plate product among the selected accelerated cooling thick plate products by accelerated cooling at the calculated plate passing speed and cooling length It is characterized by determining whether or not the accelerated cooling thick plate product can be set to the cooling stop temperature of the product from the cooling start temperature of the product.

  In addition, when there is no accelerated cooling plate product that can reach the cooling stop temperature, the specific accelerated cooling plate product is excluded from the selected accelerated cooling plate product, and the selected accelerated cooling thickness is selected. A different accelerated cooling thick plate product among the plate products is designated as the specific accelerated cooling thick plate product, and the determination and the detection are repeated.

  Thus, according to the different thickness plate removing method of the present invention, accelerated cooling with different plate thicknesses from a single accelerated cooling thick plate steel plate whose thickness changes stepwise and is accelerated by the accelerated cooling equipment. When executed by a computer having a calculation function to obtain a thick plate product, among the required accelerated cooling thick plate products, the components are equal, the plate thicknesses are different, and the plate thickness difference is set in advance. Select an accelerated cooling plate product within the range. Next, a plate passing speed and a cooling length for setting a specific accelerated cooling thick plate product among the selected accelerated cooling thick plate products to the cooling stop temperature of the product are calculated. Next, the accelerated cooling plate products other than the specific accelerated cooling plate product among the selected accelerated cooling plate products are subjected to accelerated cooling at the calculated plate passing speed and cooling length. It is determined whether there is an accelerated cooling plank product that can be brought to the product cooling stop temperature. When there is an accelerated cooling plank product that can be set to the cooling stop temperature, the existing accelerated cooling plank product and the specific accelerated cooling plank product are changed in a stepwise manner. Detected as an accelerated cooling thick plate product with different plate thickness obtained from the accelerated cooling thick plate steel plate. Therefore, by passing the same cooling length in the accelerated cooling equipment through the accelerated cooling thick steel plate with the plate thickness changing stepwise at a constant plate speed, the properties of the accelerated cooling thick plate product, especially the strength characteristics of the product Therefore, it is possible to stably achieve the cooling stop temperature that is important in ensuring the thickness of each plate thickness portion of the steel plate, thereby enabling the accelerated cooling thick plate product having different thickness to be obtained. It is possible to plan the board. And it becomes possible to improve the manufacture efficiency of the accelerated cooling thick board product from which board thickness differs by this.

  Further, when determining whether there is an accelerated cooling plate product that can be set to the cooling stop temperature, the accelerated cooling thickness other than the specific accelerated cooling plate product among the selected accelerated cooling plate products Calculate the cooling start temperature of the plate product. Then, the accelerated cooling thick plate product other than the specific accelerated cooling thick plate product among the accelerated cooling thick plate products selected by the accelerated cooling at the calculated plate passing speed and cooling length is determined from the cooling start temperature of the product. It is determined whether or not the product can be cooled to the cooling stop temperature. As a result, the strength of accelerated cooling thick plate products other than a specific accelerated cooling thick plate product can be secured, and as a result, the production efficiency of accelerated cooling thick plate products with different plate thicknesses can be further improved. Become.

  In addition, if there is no accelerated cooling plate product that can reach the cooling stop temperature, the specific accelerated cooling plate product is excluded from the selected accelerated cooling plate product, and the selected accelerated cooling plate product A different accelerated cooling plank product is designated as a specific accelerated cooling plank product, and the determination and the detection are repeated. As a result, it becomes possible to accurately and efficiently detect accelerated cooling thick plate products having different plate thicknesses that can be taken from one accelerated cooling thick steel plate whose thickness changes stepwise. Thus, it is possible to further improve the production efficiency of the accelerated cooling thick plate products having different values.

It is a schematic block diagram of the thick plate manufacturing process to which the different thickness thick plate cutting method of the present invention is applied. It is a flowchart which shows the arithmetic processing of the different thickness thick plate cutting method performed with the process computer of FIG. It is explanatory drawing of the effect | action of the arithmetic processing of FIG. It is explanatory drawing of an effect | action when the plate passing speed is changed with the conventional different thickness plate removing method.

  Next, an embodiment of the method for removing a thick plate according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a thick plate manufacturing process to which the different thickness thick plate cutting method of the present embodiment is applied. The left side of the figure is the entry side of the process, the right side of the figure is the exit side of the process, for example, there is a rolling process on the left side of the figure, and there is also a cutting process with a shear on the right side of the figure. To do. Reference numeral 1 in the figure denotes a finish rolling mill. The thick steel plate S is transported from the finish rolling mill 1 in the order of the entrance side transport device 2, the accelerated cooling equipment 3, and the exit side transport device 4 to become the accelerated cooling thick steel plate S. The accelerated cooling thick steel plate S is cut by a shear to become an accelerated cooling thick plate product. In place of the entrance side transport device 2 and the exit side transport device 4, it is possible to arrange other devices and equipment.

  This thick plate manufacturing process is controlled by a process computer (computer) 5 having a calculation function. The process computer 5 includes, for example, the rolling state of the finish rolling mill 1, the entrance-side transport device 2, the accelerated cooling facility 3, the transport speed of the thick steel plate S by the exit-side transport device 4, and the cooling of the thick steel plate S by the accelerated cooling facility 3. Control the state. Moreover, the accelerated cooling equipment 3 of this embodiment cools the thick steel plate S by injecting cooling water onto the upper and lower surfaces of the thick steel plate S. The accelerated cooling equipment 3 is configured by connecting a plurality of cooling stations in the conveying direction of the thick steel plate S, and the cooling length, that is, accelerated cooling, is prevented by not injecting cooling water for each cooling station from the outlet side. It is possible to shorten the length in the carrying direction for performing the above. When the cooling length is increased, the cooling water is jetted from the inlet side for each cooling station that is not jetting the cooling water. The cooling state of the thick steel plate S by the accelerated cooling facility 3 is controlled by the transport speed of the thick steel plate S and the cooling length in the accelerated cooling facility 3, and the plate thickness and transport speed of the thick steel plate S. Is constant, the temperature drop amount of the thick steel plate S per unit cooling length is assumed to be constant. Therefore, the amount of temperature decrease per unit cooling length decreases as the transport speed increases, and the amount of temperature decrease per unit cooling length increases as the transport speed decreases.

  Next, a method for cutting off the thick plate manufactured in the thick plate manufacturing process of FIG. 1 will be described with reference to the flowchart of FIG. The different thickness thick plate cutting method is a method of acquiring (plate cutting) accelerated cooling thick plate products having different plate thicknesses from one accelerated cooling thick plate steel sheet S. For that purpose, it is necessary to manufacture the accelerated cooling thick steel plate S whose thickness changes stepwise. Thus, the accelerated cooling thick steel plate S in which the plate thickness changes stepwise may be changed, for example, by changing the number of rolling passes of the finish rolling mill 1 in the middle of the conveying direction of the single thick steel plate S. Theoretically, it is possible to manufacture an accelerated cooling thick steel plate S whose thickness changes in three or more stages, but actually manufactures an accelerated cooling thick steel plate S whose thickness changes in two stages. Most of them. Further, the plate thicknesses of the accelerated cooling thick steel plates S that are different in stages are set in accordance with the plate thickness of the accelerated cooling thick plate product that can be picked up and detected by this arithmetic processing.

  In this calculation process, information on required accelerated cooling plate products, such as product components, specifications, strength, and delivery date, is input, and an accelerated cooling thick plate steel sheet S for obtaining those products is manufactured. This is performed by a host computer (computer) not shown in FIG. In this calculation process, first, in step S1, an accelerated cooling thick plate product having the same component, different thickness, and a difference in thickness within a preset allowable range is selected from the required accelerated cooling thick plate products. elect. The reason why the products having the same components are selected is because it is intended to roll from the same slab to thick steel plates including thick plate products having different thicknesses. Moreover, what is necessary is just to set the plate | board thickness difference which can be provided with the finish rolling mill 1 about the tolerance | permissible_range of a plate | board thickness difference.

Next, the process proceeds to step S2, and any one of the accelerated cooling thick plate products selected in step S1 is designated as a specific product.
Next, the process proceeds to step S3, and the plate passing speed and the cooling length for setting the specific accelerated cooling thick plate product among the accelerated cooling thick plate products selected in step S1 to the cooling stop temperature of the product are set. calculate. For the calculation of the sheet feeding speed and the cooling length, for example, when a specific accelerated cooling thick plate product is obtained from the accelerated cooling thick plate steel plate, the rolling end temperature of the thick plate steel plate after finish rolling is the same type as before. Since it is obtained in advance from the rolling results of thick steel plates, cooling starts when the thick steel plate of the specific accelerated cooling thick plate product reaches the accelerated cooling equipment from the finishing mill at a certain plate speed. The cooling length required to obtain the cooling start temperature of the specific accelerated cooling thick plate product as the cooling stop temperature is determined as the temperature. In addition, when the strength of the accelerated cooling plank product is given, the cooling stop temperature at which the accelerated cooling plank product is discharged from the accelerated cooling facility is determined in order to acquire the accelerated cooling plank product.

Next, it transfers to step S4 and calculates the cooling start temperature of acceleration cooling board products other than the specific acceleration cooling board product among the selected acceleration cooling board products. The cooling start temperature can be calculated using the rolling end temperature obtained in advance for each of the accelerated cooling thick plate products and the sheet passing speed calculated in step S3.
Next, the process proceeds to step S5, where the acceleration cooling plate products other than the specific acceleration cooling plate product among the selected accelerated cooling plate products are subjected to the step S3 from the cooling start temperature calculated in the step S4. It is determined whether or not there is an accelerated cooled rolled product that becomes the cooling stop temperature of the product by performing cooling at the plate passing speed and the cooling length calculated in step 1, and such an accelerated cooled rolled product exists. If so, the process proceeds to step S6. If not, the process proceeds to step S7.

In step S7, since there is no accelerated cooling plate product that can reach the cooling stop temperature in the determination in step S5, the specific accelerated cooling plate product used in steps S3 to S5 is selected. After the designated accelerated cooling thick plate product is designated as the specific accelerated cooling thick plate product, the process proceeds to step S8.
In the step S8, it is determined whether or not there is no other specific product remaining in the selected product. If there is no other specific product remaining in the selected product, the process is terminated. If so, the process proceeds to step S3.

On the other hand, in step S6, there is an accelerated cooling plate product that can reach the cooling stop temperature in the determination in step S5. Therefore, the existing accelerated cooling plate product and the specific accelerated cooling plate product are present. Are detected from one accelerated cooling thick steel plate whose thickness changes stepwise, that is, it is detected as an accelerated cooling thick plate product having a different plate thickness that can be removed, and the process proceeds to step S9.
In step S9, according to the individual arithmetic processing, other conditions such as rolling conditions are examined, and then the process ends.
According to this arithmetic processing, among the required accelerated cooling thick plate products, accelerated cooling thick plate products having the same components, different plate thicknesses, and difference in plate thickness within an allowable range are extracted. These are accelerated cooling thick plate product groups that can be obtained from one accelerated cooling thick steel plate whose thickness changes stepwise if the cooling conditions are the same. Then, one of these accelerated cooling thick plate product groups is set as a specific accelerated cooling thick plate product, and a plate passing speed and a cooling length for setting the specific accelerated cooling thick plate product to the cooling stop temperature are calculated. To do.

  In this embodiment, as will be described later, the plate passing speed and the cooling length are fixed, and other accelerated cooling thick plate products that can achieve the cooling stop temperature by the accelerated cooling by the plate passing speed and the cooling length are searched for, If there is another accelerated cooling plate product such as this, obtain that accelerated cooling plate product and a specific accelerated cooling plate product from a single accelerated cooling plate steel plate whose thickness changes in stages. Can be detected, that is, detected as a combination that can be removed.

  For example, FIG. 3 is an explanatory diagram of the temperature distribution of the accelerated cooling thick steel plate that has been cut by the different thickness plate cutting method of the present embodiment. In this example, the thickness of the right half is large and the thickness of the left half is small in one accelerated cooling thick steel plate. Moreover, in this example, the cooling start temperature when this accelerated cooling thick steel plate is charged into the accelerated cooling equipment from the finish rolling mill is uniform over the entire length regardless of the plate thickness. Further, the target cooling stop temperature of the accelerated cooling thick steel plate is large in the right half portion where the plate thickness is large and small in the left half portion where the plate thickness is small. As is well known, if the plate passing speed is the same and the cooling length is the same, the cooling stop temperature is high at the portion where the plate thickness is large, and the cooling stop temperature is low at the portion where the plate thickness is small. In the present embodiment, the specific accelerated cooling thick plate product and the specific accelerated cooling thick plate product that are cooled from the cooling start temperature to the cooling stop temperature with the same plate passing speed and cooling length are the plate thicknesses. Since the plate is taken in combination with different accelerated cooling thick plate products, the actual cooling stop temperature of each plate thickness portion of the accelerated cooling thick plate steel plate can be matched or substantially matched with the target cooling stop temperature. .

  On the other hand, FIG. 4 is explanatory drawing of the temperature distribution of the accelerated cooling thick steel plate when it plate-cuts by the conventional plate-cutting method and the plate passing speed is adjusted. In this example, as in FIG. 3, an accelerated cooling thick plate product having the same target cooling stop temperature is obtained from one accelerated cooling thick steel plate having a large right half plate thickness and a small left half plate thickness. I'm trying to take a plank. Further, similarly to FIG. 3, the accelerated cooling thick steel plate has a uniform cooling start temperature over the entire length regardless of the plate thickness when it is charged into the accelerated cooling equipment from the finish rolling mill. Thus, in order to achieve the target cooling stop temperature in the accelerated cooling thick steel plate whose thickness changes stepwise, the cooling start temperature and the target cooling stop temperature are equal, for example, the right half of the figure When passing thick steel plates in the order of the left half of the figure, the plate passing speed must be increased at the transition of the plate thickness (or vice versa in the reverse case). At this time, since the plate passing speed does not change instantaneously, the actual cooling stop temperature deviates from the target cooling stop temperature in the vicinity of the transition of the plate thickness. When the actual cooling stop temperature deviates from the target cooling stop temperature in this way, the strength of the accelerated cooling thick plate product having different plate thicknesses deviates from the specification. It can be seen that such a difference in cooling stop temperature also occurs when the cooling length is changed at the transition of the thickness of the accelerated cooling thick steel plate, for example.

  Paying attention to the problems of these conventional thick plate removal methods, even for accelerated cooling thick plate steel plates whose thickness changes stepwise, the plate passing speed and cooling length are kept constant. And a cooling stop temperature achievable by the cooling length, more precisely, an accelerated cooling plate product that is cooled from the cooling start temperature to the cooling stop temperature is detected, and the accelerated cooling plate product is detected as one accelerated cooling thickness. If the plate is made of sheet steel, the actual cooling stop temperature can be matched or substantially matched with the target cooling stop temperature. Table 1 below shows examples of accelerated cooling thick plate products having different plate thicknesses, which were performed by the different thickness plate removing method of the present embodiment.

  As described above, in the different thickness plate removing method of the present embodiment, the plate thickness changes stepwise and the accelerated cooling with different plate thickness from one accelerated cooling thick plate steel plate S that is accelerated and cooled by the accelerated cooling equipment 3. When the calculation for obtaining a thick plate product is executed by a computer, first, among the required accelerated cooling thick plate products, the components are the same, the plate thicknesses are different, and the plate thickness difference is within a preset allowable range. Accelerated cooling plate products are selected. Next, a plate passing speed and a cooling length for setting a specific accelerated cooling thick plate product among the selected accelerated cooling thick plate products to the cooling stop temperature of the product are calculated. Next, the accelerated cooling plate products other than the specific accelerated cooling plate product among the selected accelerated cooling plate products are subjected to accelerated cooling at the calculated plate passing speed and cooling length. It is determined whether there is an accelerated cooling plank product that can be brought to the product cooling stop temperature. When there is an accelerated cooling plank product that can be set to the cooling stop temperature, the existing accelerated cooling plank product and the specific accelerated cooling plank product are changed in a stepwise manner. Detected as an accelerated cooling thick plate product with different plate thickness obtained from the accelerated cooling thick plate steel plate. Therefore, by passing the same cooling length in the accelerated cooling equipment 3 through the accelerated cooling thick steel plate whose thickness changes stepwise at a constant plate speed, the properties, especially strength, of the accelerated cooling thick plate product are secured. Therefore, it is possible to stably achieve an important cooling stop temperature in each plate thickness portion of the steel plate, and thereby to obtain an accelerated cooling plate product having a different plate thickness in each plate thickness portion of the accelerated cooling plate steel plate. It becomes possible to take. And it becomes possible to improve the manufacture efficiency of the accelerated cooling thick board product from which board thickness differs by this.

  Further, when determining whether there is an accelerated cooling plate product that can be set to the cooling stop temperature, the accelerated cooling thickness other than the specific accelerated cooling plate product among the selected accelerated cooling plate products Calculate the cooling start temperature of the plate product. Then, the accelerated cooling thick plate product other than the specific accelerated cooling thick plate product among the accelerated cooling thick plate products selected by the accelerated cooling at the calculated plate passing speed and cooling length is determined from the cooling start temperature of the product. It is determined whether or not the product can be cooled to the cooling stop temperature. As a result, the strength of accelerated cooling thick plate products other than a specific accelerated cooling thick plate product can be secured, and as a result, the production efficiency of accelerated cooling thick plate products with different plate thicknesses can be further improved. Become.

  In addition, if there is no accelerated cooling plate product that can reach the cooling stop temperature, the specific accelerated cooling plate product is excluded from the selected accelerated cooling plate product, and the selected accelerated cooling plate product The different accelerated cooling plate products are designated as specific accelerated cooling plate products, and the determination and detection are repeated. As a result, it becomes possible to accurately and efficiently detect accelerated cooling thick plate products having different plate thicknesses that can be taken from one accelerated cooling thick steel plate whose thickness changes stepwise. Thus, it is possible to further improve the production efficiency of the accelerated cooling thick plate products having different values.

DESCRIPTION OF SYMBOLS 1 Finish rolling mill 2 Entry side conveyance apparatus 3 Accelerated cooling equipment 4 Delivery side conveyance apparatus 5 Process computer (computer)
S Thick steel plate (accelerated cooling thick steel plate)

Claims (3)

Different thicknesses executed by a computer with a calculation function to obtain accelerated cooled thick plate products with different plate thicknesses from one accelerated cooled thick steel plate that is gradually cooled and accelerated by an accelerated cooling facility. A plank removal method,
Among the required accelerated cooling plate products, select the accelerated cooling plate products whose components are the same, the plate thicknesses are different, and the plate thickness difference is within a preset allowable range,
Of the selected accelerated cooling plate products, calculate the plate speed and cooling length to make the specific accelerated cooling plate product the cooling stop temperature of the product,
By performing accelerated cooling at the calculated plate passing speed and cooling length in the accelerated cooling thick plate products other than the specific accelerated cooling thick plate product among the selected accelerated cooling thick plate products. Determine whether there is an accelerated cooling plank product that can be the cooling stop temperature of the product,
When there is an accelerated cooling plank product that can be set to the cooling stop temperature, the existing accelerated cooling plank product and the specific accelerated cooling plank product change in a stepwise manner. Detecting as an accelerated cooling thick plate product having a different thickness obtained from the accelerated cooling thick plate steel plate of the present invention.   When determining whether there is an accelerated cooling plate product that can be set to the cooling stop temperature, accelerated cooling other than the specific accelerated cooling plate product among the selected accelerated cooling plate products Calculating the cooling start temperature of the thick plate product, and accelerating other than the specific accelerated cooling thick plate product among the selected accelerated cooling thick plate products by accelerated cooling at the calculated plate passing speed and cooling length 2. The method for removing a thick plate according to claim 1, wherein it is determined whether or not the cooling plate product can be changed from a cooling start temperature of the product to a cooling stop temperature of the product.   If there is no accelerated cooling plate product that can be brought to the cooling stop temperature, the specific accelerated cooling plate product is excluded from the selected accelerated cooling plate product, and the selected accelerated cooling plate product The different thickness thick plate product according to claim 1, wherein the different accelerated cooling thick plate product is designated as the specific accelerated cooling thick plate product, and the determination and detection are repeated.

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