JP2015123477A - Rolling operation design method of steel sheet pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling operation design method of a steel sheet pile, capable of manufacturing a large-sized product by reducing a minimum diameter of a roll compared to those of prior products while securing quality of the product.SOLUTION: The rolling operation design method of the steel sheet pile comprises: a first step of designing a hole type roll shape on the basis of a shape of a steel sheet pile product to be manufactured; a second step of setting a temporary effective diameter using a minimum roll diameter of a hole type roll based on an actual value; a third step of designing a pass schedule for securing a mechanical property of the steel sheet pile product to be manufactured with the temporary effective diameter of the hole type roll; a temperature evaluation step of evaluating the finish rolling temperature of a rolled material in the pass schedule; and a load evaluation step of evaluating a rolling load and/or rolling torque to the hole type roll with the temporary effective diameter having been set in the pass schedule.

Description

  The present invention relates to a rolling operation design method for steel sheet piles such as hat-shaped steel sheet piles, U-shaped steel sheet piles, and Z-shaped steel sheet piles.

  It is known that the manufacture of steel sheet piles is generally performed by a perforated rolling method. Specifically, as a general process of the hole-type rolling method, first, a raw material (such as a slab) heated to a predetermined temperature in a heating furnace is subjected to a roughing mill, an intermediate rolling mill and a finish rolling mill equipped with a hole mold. It is known to roll in order.

  When manufacturing steel products including steel sheet piles, generally the rolling equipment and rolling conditions for operation are evaluated comprehensively in consideration of the desired product quality, operation efficiency, cost, etc. The order of items to be prioritized is determined and set. For example, Patent Document 1 discloses a technique for maximizing the rolling efficiency under a predetermined condition in rolling H-section steel. Further, for example, Patent Document 2 discloses a technique for suppressing wrinkles generated in a material to be rolled in rolling H-section steel and greatly improving the rolling efficiency.

  As in Patent Documents 1 and 2, various techniques have been devised for improving the rolling efficiency when manufacturing steel products. Here, in particular, the manufacture of the steel sheet pile product is performed by the perforated rolling method in the rolling equipment equipped with the perforated roll, and therefore the design of the perforated roll greatly affects the rolling efficiency. Specifically, when forming the hole-type roll, if the minimum roll diameter of the hole-type roll is not equal to or greater than a predetermined value, roll strength is insufficient, roll breakage or the like occurs, and roll cost becomes excessive. That is, the minimum roll diameter of the hole-type roll is restricted, and the operation is performed while limiting the rolling load applied to the portion of the minimum roll diameter.

  However, in recent years, there has been a demand for efficient cost reduction in placing steel sheet piles, and steel sheet piles having appropriate cross-sectional performance according to the placement location are manufactured, that is, a plurality of types of steel having different cross-sectional performances. There is a need to efficiently manufacture sheet piles. In particular, a large product with a high steel sheet pile height is desired, and when manufacturing such a large product, it is required to optimize rolling conditions such as a roll diameter while ensuring quality. .

Japanese Patent No. 3293393 JP-A-9-108704

  Conventionally, in optimizing rolling conditions when rolling a steel material, a roll shape is determined, and then an effective roll diameter that is acceptable for operation is set. And while confirming the guarantee of quality, the reaction force concerning the roll at the time of rolling is evaluated, evaluation which determines the frequency | count of a pass is repeated, and rolling conditions are finally optimized. That is, in the prior art, after determining a predetermined roll effective diameter, a method of ensuring the product quality and reducing the number of passes so that the rolling efficiency is maximized has been adopted. In addition, the guarantee of the quality of the product here satisfies the mechanical properties (impact test value / elongation) defined by the JIS standard of the product when the finished temperature of the product is within a predetermined range. That means.

  However, when manufacturing a large product, it is possible to increase the size of the product by reducing the effective roll diameter as much as possible. Therefore, it is possible to ensure the product quality and reduce the minimum roll diameter as much as possible. Desired. That is, in the above prior art, the roll minimum diameter is determined so as to maximize the rolling efficiency under operational constraints, but a sufficiently large product cannot be manufactured with the roll minimum diameter thus determined. There is a problem.

  Therefore, an object of the present invention is to ensure the quality of the product and to design a rolling operation of a steel sheet pile capable of producing a large product by reducing the minimum diameter of the roll as compared with the conventional one while maintaining the roll strength. It is to provide a method.

  In order to achieve the above object, according to the present invention, there is provided a method for designing a rolling operation of a steel sheet pile, the first step of designing a hole roll shape based on the shape of a steel sheet pile product to be manufactured, and the actual value. The second step of setting the temporary effective diameter using the minimum roll diameter of the base hole roll, and the pass schedule that ensures the mechanical properties of the steel sheet pile products manufactured with the temporary effective diameter of the hole roll are designed. A third step, a temperature evaluation step for evaluating a finished rolling temperature of the material to be rolled in the pass schedule, and an evaluation of a rolling load and / or a rolling torque with respect to the perforated roll in which the temporary effective diameter is set in the pass schedule A method for designing the rolling operation of a steel sheet pile, comprising:

  In addition, the temperature evaluation step includes a fourth step of evaluating whether or not the finished rolling temperature of the material to be rolled in the pass schedule is below a lower limit value of a predetermined temperature range, and the finish of the material to be rolled in the pass schedule. It may consist of a fifth step for evaluating whether the rolling temperature exceeds the upper limit of the predetermined temperature range.

  In the load evaluation step, a rolling load and / or a rolling torque for the hole roll whose temporary effective diameter is set in the pass schedule is less than a predetermined amount of the allowable load and / or the allowable torque of the hole roll. The sixth step of evaluating whether or not the rolling load and / or the rolling torque for the punch roll whose temporary effective diameter is set in the pass schedule exceeds the allowable load and / or the allowable torque of the punch roll. It may consist of a seventh step for evaluating whether or not.

  In the rolling operation design method of the steel sheet pile, the second step to the fifth step are repeated until the finish temperature of the material to be rolled falls within a predetermined temperature range in the fourth step and the fifth step. The second step to the seventh step may be repeated until the rolling load and / or the rolling torque with respect to the perforated roll having the provisional effective diameter set falls within a predetermined range.

  Moreover, the said steel sheet pile is a hat-shaped steel sheet pile, and 720 degreeC or more and 800 degrees C or less may be sufficient as the predetermined temperature range in the said 4th step and 5th step.

  The steel sheet piles may be manufactured using a material heated to 1200 ° C. or higher in a heating furnace.

  ADVANTAGE OF THE INVENTION According to this invention, while ensuring the quality of a product, it becomes possible to manufacture a large sized product by making the minimum diameter of a roll small compared with the past, maintaining roll strength.

It is a schematic explanatory drawing of the rolling line concerning embodiment of this invention. It is a schematic explanatory drawing about the hole shape of a 1st hole type. It is a schematic explanatory drawing about the hole shape of a 2nd hole type. It is a schematic explanatory drawing about the hole shape of a 3rd hole type. It is a schematic explanatory drawing about the hole shape of a 4th hole type. It is a schematic explanatory drawing about the hole shape of a 5th hole type. It is a flowchart which shows the rolling operation design method in the conventional manufacturing method. It is a flowchart which shows the rolling operation design method which concerns on this invention. It is the schematic of the hole-type roll which manufactures a hat-shaped steel sheet pile.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted. In the present embodiment, a case where a hat-shaped steel sheet pile is manufactured as a steel product will be described as an example.

  Moreover, in this Embodiment, when manufacturing a hat-shaped steel sheet pile, the steel materials passed on the rolling line L are named generically as a material to be rolled A, and each part of the material A to be rolled is described below. It shall be described with a different name. Here, the material A to be rolled includes a web corresponding portion 3 corresponding to the web of the hat-shaped steel sheet pile product, flange corresponding portions 4 and 5 connected to both ends of the web corresponding portion 3, and flange corresponding portions 4 and 5 respectively. The arm corresponding portions 6 and 7 formed at the respective distal ends and the joint corresponding portions 8 and 9 formed at the distal ends of the arm corresponding portions 6 and 7. Further, claw corresponding portions 8a and 9a are formed at the tips of the joint corresponding portions 8 and 9, respectively.

  FIG. 1 is an explanatory diagram of a rolling line L for manufacturing a hat-shaped steel sheet pile according to an embodiment of the present invention and a rolling mill provided in the rolling line L. As shown in FIG. 1, in the rolling line L, a rough rolling mill (BD) 10, an intermediate rolling mill (R1) 13, and a finishing rolling mill (F) 19 are arranged in this order. The rolling line L is composed of a plurality of lines L1 to L3. The line L1 and the line L2 are adjacent to each other, and the line L2 and the line L3 are adjacent to each other. Each of the lines L1 to L3 is connected in series so that a part of each line overlaps, and the material A to be rolled is moved in parallel in the width direction from L1 to L2 or from L2 to L3. It is the structure which advances L.

Moreover, as shown in FIG. 1, the roughing mill 10 is arrange | positioned at the line L1, the intermediate rolling mill 13 is arrange | positioned at the line L2, and the finishing mill 19 is arrange | positioned at the line L3. Each of the lines L1 to L3 can be rolled with another material A to be rolled, and a plurality of materials A can be simultaneously rolled on the rolling line L in parallel. It has a configuration.

  In the rolling line L shown in FIG. 1, a rectangular material (rolled material A) heated to, for example, 1200 ° C. or higher in a heating furnace (not shown) is sequentially rolled in a roughing mill 10 to a finishing mill 19 to be a final product. It becomes a hat-shaped steel sheet pile. That is, the final product is manufactured by performing the rough rolling process, the intermediate rolling process, and the finish rolling process in this order on the material A to be rolled.

  Below, the hole type | mold stamped by the rough rolling mill 10 arrange | positioned at the rolling line L, the intermediate rolling mill 13, and the finishing mill 19 (Hereafter, it abbreviates as the rough rolling mill 10-the finishing mill 19 suitably.) This configuration will be briefly described with reference to the drawings sequentially from the upstream of the rolling line L. Note that the rough rolling mill 10, the intermediate rolling mill 13, and the finish rolling mill 19 are general facilities that have been conventionally used. Therefore, in the following description in the present specification, attention is paid to the description of the hole-type configuration. A description of the equipment configuration is omitted.

  However, the configuration of the hole mold (the first hole mold to the fifth hole mold shown below) according to the present embodiment described below is not limited to the illustrated form, for example, the arrangement order of the hole molds, The increasing / decreasing arrangement of the modified hole types of various hole types can be changed as appropriate according to conditions such as equipment conditions and product dimensions. Further, depending on the type of material, a configuration in which a preformed hole mold used for a rough modeling process from the material is separately provided is also conceivable.

Moreover, although the hole mold | type demonstrated below with reference to FIGS. 2-6 is engraved in each rolling mill of the rough rolling mill 10-finishing mill 19, each hole mold demonstrated below is shown. Which rolling mill is engraved can be changed as appropriate according to conditions such as equipment conditions and product dimensions. Therefore, in the present embodiment, these hole types are referred to as a first hole type to a fifth hole type, and each hole type will be described as long as it is formed in order from the upstream side of the rolling line L. In FIGS. 2 to 6, the shape of the material A to be rolled that is reduced and shaped in each hole mold is shown by a one-dot chain line for reference.

  FIG. 2 is a schematic explanatory diagram of the hole shape of the first hole mold 30. As shown in FIG. 2, the first hole mold 30 includes an upper hole mold roll 30 a and a lower hole mold roll 30 b, and the thickness reduction is performed on the entire material A to be rolled by the first hole mold 30.

  FIG. 3 is a schematic explanatory diagram of the hole shape of the second hole mold 40. As shown in FIG. 3, the second hole mold 40 is composed of an upper hole mold roll 40 a and a lower hole mold roll 40 b, and the thickness reduction is performed on the entire material to be rolled A by the second hole mold 40. At the same time, molding is performed so that the heights of the nail corresponding portions 8a and 9a are made equal to a desired height.

  FIG. 4 is a schematic explanatory view of the hole shape of the third hole mold 50. As shown in FIG. 4, the 3rd hole type | mold 50 is comprised from the upper hole type | mold roll 50a and the lower hole type | mold roll 50b, and thickness reduction is performed with respect to the to-be-rolled material A whole by this 3rd hole type | mold 50. As shown in FIG.

  FIG. 5 is a schematic explanatory diagram of the hole shape of the fourth hole mold 60. As shown in FIG. 5, the 4th hole type | mold 60 is comprised from the upper hole type | mold roll 60a and the lower hole type | mold roll 60b, and this nail | claw corresponding | compatible part 8a of the to-be-rolled material A of the to-be-rolled material A in this 4th hole type | mold 60b. 9a is preferentially performed. Specifically, the reduction is performed such that the nail heights of the nail corresponding portions 8a and 9a are aligned to a desired height.

  FIG. 6 is a schematic explanatory diagram of the hole shape of the fifth hole mold 70. As shown in FIG. 6, the 5th hole type | mold 70 is comprised from the upper hole type | mold roll 70a and the lower hole type | mold roll 70b, In this 5th hole type | mold 70, the bending forming of the joint corresponding parts 8 and 9 of the to-be-rolled material A is carried out. Alternatively, the entire material A to be rolled is shaped by light rolling. Specifically, joint molding is performed in which the joint corresponding portions 8 and 9 including the claw corresponding portions 8a and 9a are bent so as to have a shape close to the joint shape of the product. Thereby, in the 5th hole type | mold 70, the to-be-rolled material A will be shape | molded to the shape very close to a hat-shaped steel sheet pile product. In particular, in the fifth hole mold 70, the shape of the joint corresponding portions 8 and 9 of the material A to be rolled is made to be a shape close to the product shape.

  The hole shape of the first hole mold 30 to the fifth hole mold 70 has been described above with reference to FIGS. As described above, the hole rolling method includes a rough rolling process, an intermediate rolling process, and a finish rolling process. For example, the rough rolling process and the intermediate rolling process are sequentially performed in the hole molds of the first hole mold 30 to the fourth hole mold 60. The rolling in the fifth hole mold 70 is performed as a finish rolling process. The hole shapes of the first hole mold 30 to the fifth hole mold 70 are all substantially hat-shaped, but are engraved in a shape that is closer to the product shape toward the hole mold in the subsequent stage. That is, the hole shape of the fifth hole mold 70 in which the final process is performed is substantially a hat-shaped steel sheet pile product shape.

  In the present embodiment, it is assumed that the roughing mill 10 to the finishing mill 19 are arranged in the rolling line L. However, the first hole mold 30 to the fifth hole mold 70 have arbitrary configurations in each rolling mill. Scattered and engraved. As an example, the first hole mold 30 is engraved in the roughing mill 10, the second hole mold 40 and the third hole mold 50 are engraved in the intermediate rolling mill 13, and the fourth hole mold 60 is formed in the finishing mill 19. And the structure that the 5th hole type | mold 70 is engraved is mentioned. However, the hole configuration in the present invention is not limited to such a configuration.

Further, in addition to the first to fifth hole molds described above, a hole mold for further forming the joint corresponding portions 8 and 9 (that is, a joint molding step) may be provided. The hole mold for performing the joint forming step is provided in the roughing mill 10, for example. By providing such a hole mold, it becomes possible to form the joint portion and the claw portion of the steel sheet pile product with higher accuracy.
Furthermore, it is good also as a structure which provided the hole type which adds the thickness reduction of the to-be-rolled material A whole in addition to the said 1st-5th hole type | mold. Such a hole mold is provided, for example, in the intermediate rolling mill 13, and the thickness reduction of the steel sheet pile product can be performed with higher accuracy.

  When setting the roll diameter of the hole-type roll which comprises the said 1st-5th hole type | mold (when setting rolling conditions), the present inventors set the minimum diameter of a roll, ensuring the quality of a product. We have intensively studied how to make it smaller. Conventionally, after determining the effective roll diameter, the product quality is ensured, the number of passes is reduced so that the rolling efficiency is maximized, and the rolling reaction force is evaluated to determine the final rolling conditions. The method of deciding was adopted. Here, it has been found that by increasing the number of passes during rolling, the rolling load per pass can be reduced and the minimum diameter of the roll to be used can be made smaller. In addition, although the setting method of the rolling conditions based on this knowledge is applicable to any of the said 1st-5th hole type | mold, when manufacturing the product of the same shape normally, it is 1st-5th. The shape of the hole shape is linked, and it is desirable to select a hole shape that preferentially revises the rolling conditions from the degree of influence of roll cost, the degree of processing of the material to be rolled, and the like. In general, it is effective to preferentially apply to a roll having a third hole type function that determines the actual product thickness. Furthermore, it is also possible to apply to all hole types on the rolling line L.

  Below, the rolling operation design in the conventional manufacturing method and the rolling operation design in the manufacturing method based on the said knowledge based on the said knowledge are each demonstrated with reference to a flowchart. Note that the rolling operation design described below is carried out by measurement and simulation using an actual machine.

  FIG. 7 is a flowchart showing a rolling operation design method in a conventional manufacturing method, and steps 1 to 8 are denoted as S1 to S8, respectively. As shown in FIG. 7, first, a roll shape (hole shape) is designed as S1. The design of the roll shape is uniquely determined according to the product shape, and differs depending on the shape of the product to be manufactured.

  Next, after the roll shape is determined, a roll diameter range (hereinafter also referred to as an effective diameter) that is acceptable in operation is set as S2. The effective diameter set here refers to a range of roll diameters that can be allowed in operation in a state where quality is confirmed (that is, a difference between the maximum roll diameter and the minimum roll diameter). The range of roll diameter that is acceptable for operation is determined by, for example, calculating the life of a roll evaluated based on the amount of roll wear.

  Subsequently, on the premise of the effective diameter defined in S2, a pass schedule design (operation design) is performed for ensuring that the product after rolling has a predetermined quality (mechanical property) as S3.

  Next, as S4, it is evaluated whether the temperature of the product after rolling (finished rolling temperature) is below a predetermined value. Here, the finished rolling temperature must be within a certain temperature range in order for the product to maintain a predetermined quality. However, in S2, the minimum roll diameter that is acceptable for operation is set after ensuring the quality of the product, and the pass schedule is designed in S3 based on that, so the finished rolling temperature is usually below a predetermined value. There is nothing.

  Next, in S5, it is evaluated whether or not the temperature of the product after rolling (finished rolling temperature) exceeds a predetermined value. Here, the finished rolling temperature must be within a certain temperature range in order for the product to maintain a predetermined quality. That is, in S5, it is determined whether or not the finished rolling temperature exceeds the upper limit value in the temperature range. Here, when the finished rolling temperature is not within the predetermined temperature range, the process returns to S3 again, and the operation conditions including the number of passes are reset. In this resetting of operating conditions, in addition to the number of passes, the rolling speed and steel weight are also examined.

In addition, as a general steel sheet pile product, the predetermined temperature range of the finished rolling temperature that guarantees the quality of the product is, for example, 720 ° C. when a hat-shaped steel sheet pile product is manufactured using a material of 1200 ° C. ~ 800 ° C. The temperature of the material to be rolled is non-patent document 1 (bar wire / shape / tube rolling world leading rolling technology (plastic working technology series 8), edited by Japan Society for Plastic Working, Corona, August 20, 1991). No. 87, etc. is calculated by the unsteady heat conduction equation.

  And evaluation about a rolling reaction force is performed as S6 and S7. Specifically, with respect to the roll having the smallest diameter within the range of the effective diameter of the roll set in S1, the degree of load or rolling torque actually applied to the roll is calculated, and the allowable load is calculated. -Whether the load and torque applied to the roll compared to the permissible torque are not significantly lower than the permissible load / permissible torque (S6), or whether the permissible load / permissible torque is not exceeded (S7). Determine. Here, assuming that the allowable load of the roll is P allowable and the load applied to the roll derived by simulation or actual measurement is the P actual, in S6 and S7, for example, the P actual is about 90% to 95% of the P allowable. Is the preferred condition. When the P performance is significantly lower than the P tolerance (P performance << P tolerance in S6) or when the P performance exceeds the P tolerance (P achievement P> S tolerance in S7), the process returns to S3 again. The operation conditions are reset.

  Here, the calculation of rolling load and rolling torque is, for example, Non-Patent Document 1 (Rolling wire / shape / tube rolling world leading rolling technology (plastic working technology series 8), Japan Plastic Working Society, edited by Corona, 1991. (August 20), which is performed by the rectangular conversion method described on pages 85 to 88 and the like.

In addition, about evaluation of rolling load, rolling torque, and finishing rolling temperature, it can also be performed based on the data obtained by test rolling or actual operation, and the above-described evaluation can be corrected based on these data. Is possible.

  Then, it is repeatedly verified for S1 to S7, and when the product satisfies the predetermined quality, if it is recognized that the load applied to the roll having the smallest diameter within the range of the effective diameter of the roll satisfies the preferable condition, as S8 Operation setting is completed.

  As mentioned above, S1-S7 demonstrated with reference to the flowchart shown in FIG. 7 is repeated, and the rolling operation design method in the conventional manufacturing method is performed. The feature of the conventional rolling operation design method shown in FIG. 7 is that, after the roll shape design is performed as S1, the effective diameter range of the roll that is allowable in operation is determined in S2. As a result, under the set operating conditions, the maximum rolling efficiency is directed within the range of the determined effective diameter.

  FIG. 8 is a flowchart showing a rolling operation design method according to the present invention, and steps 1 to 8 are denoted as M1 to M8, respectively. As shown in FIG. 8, first, a roll shape (hole shape) is designed as M1. The design of the roll shape is uniquely determined according to the product shape in the same manner as the conventional method described above, and differs depending on the shape of the product to be manufactured.

  Next, as M2, the minimum diameter of the roll to be used is temporarily set with a very small value. The value of the roll minimum diameter that is temporarily set is appropriately determined with reference to the actual value such as the minimum diameter of the roll used in a product manufactured in the past. Specifically, for example, based on the effective diameter of a roll in rolling of a VL type steel sheet pile having an effective width of 500 mm, an IIW type steel sheet pile having an effective width of 600 mm, and a 10H type steel sheet pile having an effective width of 900 mm, which are representative products of each effective width. Is set. This is a product with a low product height selected from products of each effective width, and consideration is given to reducing the minimum diameter. Hereinafter, a diameter range (a difference between the set maximum roll diameter and minimum roll diameter) set using the temporarily set minimum roll diameter is referred to as a temporary effective diameter.

  Subsequently, on the premise of the provisional effective diameter defined in M2, as M3, a pass schedule design (operation design) for ensuring a predetermined quality (mechanical property) of the rolled product is performed.

  Next, as M4, it is evaluated whether or not the temperature of the product after rolling (finished rolling temperature) is below a predetermined value. Here, the finished rolling temperature must be within a certain temperature range in order for the product to maintain a predetermined quality. When the finished rolling temperature falls below a predetermined value, the process returns to M2, and the provisional effective diameter value is reduced. That is, in order to reduce the number of rolling passes, the roll minimum diameter is slightly increased to increase the allowable rolling load. In the method according to the present invention, the roll minimum diameter is temporarily set as an extremely small value, and the evaluation of the rolling reaction force in M7, which will be described later, increases the number of passes for reduction. become. As the number of passes increases, the finished rolling temperature decreases, and therefore, the evaluation of the finished rolling temperature at M4 is important. Then, the provisional effective diameter value set based on the evaluation in M4 can be reduced, and conditions can be obtained such that the finished rolling temperature does not fall below a predetermined value as the number of passes decreases.

  Next, as M5, it is evaluated whether the temperature of the product after rolling (finished rolling temperature) exceeds a predetermined value. Here, the finished rolling temperature must be within a certain temperature range in order for the product to maintain a predetermined quality. That is, in M5, it is determined whether or not the finished rolling temperature exceeds the upper limit value in the temperature range. However, in the method according to the present invention, as described above, it is assumed that the roll minimum diameter is set as small as possible and the rolling is performed with a relatively large number of passes. If the upper limit of the predetermined temperature range is not exceeded, but the finished rolling temperature is not within the predetermined temperature range at M5, the process returns to M3 again, and the operation conditions including the number of passes are reset. Is done.

  And evaluation about a rolling reaction force is performed as M6 and M7. Specifically, for a roll having a temporary effective diameter set under the conditions set in the above M1 to M5, it is calculated how much the load is actually applied to the roll, and the allowable load / allowable torque is calculated. It is determined whether or not the load / torque applied to the roll is significantly lower than the allowable load / allowable torque (M6) or whether it exceeds the allowable load / allowable torque (M7). To do. However, M6 evaluates whether or not the load / torque applied to the roll for which the temporary effective diameter is set is significantly lower than the allowable load / allowable torque of the roll. As described above, since the minimum roll diameter is set as small as possible, it is unlikely that the load / torque applied to the roll is significantly lower than the allowable load / allowable torque.

Further, assuming that the allowable load of the roll is P allowable and the load applied to the roll derived by simulation or actual measurement is the P actual, in M7, for example, it is preferable that the P actual is about 90% to 95% of the P allowable. It is. This suitable condition (P performance is about 90% to 95% of P tolerance) is considered in consideration of variations in rolling operation. The variation in rolling operation is due to various factors such as the elapsed time since the rolling load of the roll was extracted, the difference in conditions such as whether the operation is performed automatically or manually, and material variations. It is based. That is, in the rolling process in a specific predetermined facility, an evaluation test can be performed in advance in the facility to evaluate the degree of variation in rolling operation, and the above-described preferable conditions can be determined. In M7, when the P performance exceeds the P tolerance (P performance> P tolerance), the process returns to the above M3 again, and the operation conditions are reset.

  Then, M1 to M7 are repeatedly verified, and after the product satisfies a predetermined quality, operation is performed with a temporarily set roll diameter, and when it is recognized that the load applied to the roll satisfies a suitable condition, as M8 Operation setting is completed. Note that the temperature of the material to be rolled at M4 and M5 shown in FIG. 8 is calculated by the unsteady heat conduction equation as in the conventional case. Further, the calculation of the rolling load and rolling torque in M6 and M7 is also performed by the rectangular conversion method as in the conventional case.

  As described above, the rolling operation design method according to the present invention is performed by repeating M1 to M7 described with reference to the flowchart shown in FIG. The feature of the rolling operation design method according to the present invention shown in FIG. 8 is that, after roll shape design is performed as M1, the minimum diameter of the roll used in M2 is an extremely small value based on the past actual product values and the like. Thus, provisional setting is performed, and the provisionally set temporary effective diameter is gradually reduced according to the verification in M3 to M7. Thereby, the minimum diameter of the roll in the set operation condition can be set as small as possible in the operation on the premise of ensuring the quality of the product.

  Referring to FIGS. 7 and 8, the conventional operation design method and the operation design method according to the present invention are compared. In the conventional operation design method, the product quality is ensured and the effective diameter is within the determined range. However, in the operation design method according to the present invention, it is possible to set the minimum roll diameter that can be operated on the facility as well as ensuring the product quality.

  Here, considering the manufacture of the hat-shaped steel sheet pile manufactured by the hole molds shown in the first to fifth hole molds, a product having a higher height can be manufactured as the minimum roll diameter of the hole roll used is smaller. 9 (a) and 9 (b) are schematic views of a perforated roll for producing a hat-shaped steel sheet pile, and show a case where two types of products having the same width and different heights are produced.

  Here, the minimum roll diameter of the perforated roll shown in FIG. 9A is R1, and the minimum roll diameter of the perforated roll shown in FIG. 9B is R2 (R1> R2) smaller than R1. Compared with the hat-shaped steel sheet pile product manufactured by the hole mold shown in FIG. 9 (a), the hat-shaped steel sheet pile product manufactured by the hole mold shown in FIG. 9 (b) has a long flange part and a high height. It becomes. As can be seen by comparing FIG. 9 (a) and FIG. 9 (b), it is possible to manufacture a hat-shaped steel sheet pile product having a higher height as the roll minimum diameter of the hole-type roll is smaller.

  Therefore, by using the operation design method (see FIG. 8) according to the present invention, which can set the roll diameter smaller than the conventional operation design method (see FIG. 7) as the minimum diameter of the perforated roll, the product quality is improved. It is possible to manufacture a hat-shaped steel sheet pile product having a height higher than that of conventional products. Further, in this case, it is not necessary to increase the equipment such as increasing the size of the perforated roll itself or to newly provide a rolling stand, so that it is possible to manufacture a large product while suppressing an increase in equipment cost. Become.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the form of illustration. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  For example, in the above embodiment, the case where a hat-shaped steel sheet pile is manufactured as a steel sheet pile product is illustrated and described as an example, but the scope of application of the present invention is not limited to this, and a U-shaped steel sheet pile It is possible to apply to various steel sheet pile products such as Z-shaped steel sheet piles. That is, when a steel product is manufactured by a perforated rolling method using a perforated roll, it is possible to manufacture products that are enlarged for various products by setting the minimum roll diameter by the method according to the present invention. It becomes possible.

  The present invention can be applied to a manufacturing method for steel sheet piles such as hat-shaped steel sheet piles, U-shaped steel sheet piles, and Z-shaped steel sheet piles.

DESCRIPTION OF SYMBOLS 3 ... Web corresponding part 4, 5 ... Flange corresponding part 6, 7 ... Arm corresponding part 8, 9 ... Joint corresponding part 8a, 9a ... Nail corresponding part 10 ... Rough rolling mill 13 ... Intermediate rolling mill 19 ... Finishing rolling mill 30, 40, 50, 60, 70 ... 1st to 5th hole type L (L1 to L3) ... Rolling line A ... Rolled material

Claims (6)

A rolling operation design method for steel sheet piles,
A first step of designing a perforated roll shape based on the shape of the steel sheet pile product to be manufactured;
A second step of setting the temporary effective diameter using the minimum roll diameter of the hole roll based on the actual value;
A third step of designing a pass schedule that ensures the mechanical properties of the steel sheet pile product manufactured with the temporary effective diameter of the perforated roll;
A temperature evaluation step for evaluating the finished rolling temperature of the material to be rolled in the pass schedule;
A load evaluation step of evaluating a rolling load and / or a rolling torque for the perforated roll in which the temporary effective diameter is set in the pass schedule, and a rolling operation design method for a steel sheet pile. The temperature evaluation step includes
A fourth step of evaluating whether the finished rolling temperature of the material to be rolled in the pass schedule is below a lower limit value of a predetermined temperature range;
The steel sheet pile rolling operation design method according to claim 1, comprising a fifth step of evaluating whether a finished rolling temperature of the material to be rolled in the pass schedule exceeds an upper limit value of a predetermined temperature range. The load evaluation step includes
A sixth evaluation is made as to whether or not the rolling load and / or the rolling torque with respect to the perforated roll for which the provisional effective diameter is set in the pass schedule is lower than the permissible load and / or the permissible torque of the perforated roll by a predetermined amount or more. Steps,
From the seventh step of evaluating whether or not the rolling load and / or rolling torque for the hole roll whose temporary effective diameter is set in the pass schedule exceeds the allowable load and / or allowable torque of the hole roll. The rolling operation design method of the steel sheet pile according to claim 1 or 2. Until the finish temperature of the material to be rolled falls within a predetermined temperature range in the fourth step and the fifth step, the second step to the fifth step are repeatedly performed,
Furthermore, the rolling of the steel sheet pile according to claim 3, wherein the second step to the seventh step are repeated until a rolling load and / or a rolling torque with respect to the perforated roll having the provisional effective diameter set fall within a predetermined range. Operation design method. The steel sheet pile is a hat-shaped steel sheet pile, and the predetermined temperature range in the fourth step and the fifth step is 720 ° C or higher and 800 ° C or lower, and the steel sheet pile according to any one of claims 2 to 4. Rolling operation design method. The manufacturing method of the steel sheet pile according to any one of claims 1 to 5, wherein the steel sheet pile is manufactured using a material heated to 1200 ° C or higher in a heating furnace.

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