JP5146062B2 - Steel plate rolling method and equipment - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a steel plate cooling method and its equipment in steel plate rolling, and more particularly to a steel plate rolling method and equipment for uniforming the temperature distribution in the width direction of the steel sheet and making the material uniform, and suppressing and preventing plate shape deformation during and after cooling.

FIG. 6 schematically shows a layout of main apparatuses constituting a conventional general hot-rolled steel sheet rolling facility. The hot-rolled steel sheet rolling equipment 4 is mainly composed of a heating furnace 10, a rough rolling mill 12, a finishing mill 14, a rough rolling mill entry side cooling device 21, a rough rolling mill inter-stand cooling device 22, a finishing rolling mill entrance cooling device 24, and a finishing. It consists of a rolling mill inter-stand cooling device 25, an ROT cooling device 54 and a winder 50.

  The rough rolling mill 12 consists of 5 stands 12a to 12e, and the finish rolling mill 14 consists of 7 stands 14a to 14g. In the rolling mill entry side cooling device 24 and the inter-stand cooling device 25, a plurality of nozzles (none of which are not shown) are attached to a header extending in the plate width direction along the plate width direction. A meandering detector 40 for detecting the plate width direction position of the steel plate and a plate temperature detector 41 for detecting the plate width direction temperature distribution are arranged on the exit side of the rough rolling mill 12 and the finish rolling mill 16, respectively.

  In the hot-rolled steel sheet rolling equipment 4 configured as described above, the slab SL is heated to a predetermined temperature in the heating furnace 10, and the heated slab SL is rolled into a rough bar RB having a predetermined thickness by the roughing mill 12. The Next, the coarse bar RB is finish-rolled to a strip ST having a predetermined thickness by the finish rolling mill 14. The side guide (not shown) is moved according to the position in the plate width direction of the steel plate detected by the meandering detector 40 to guide the slab SL, coarse bar RB and strip ST to the rolling line center. Based on the temperature distribution in the plate width direction, for example, the edge portion of the coarse bar RB is heated by an edge heater (not shown) to make the temperature distribution in the plate width direction uniform.

  At the end in the width direction of the hot-rolled steel plate and the thick steel plate, there is heat radiation from the side surface outside the upper and lower surfaces, and therefore the temperature is lower than that at the center portion. When significant overcooling occurs at the edge of the plate, it becomes difficult to produce a product that is uniform in the width direction, which hinders quality. Also, in high-tensile steel sheets, etc., the end part breakage, called ear cracking, is caused by the temperature difference between the center part and the end part in the width direction during cooling (refers to the case where the end part is lower, hereinafter referred to as “end part overcooling”) There is also a problem that the yield of the product is reduced. Furthermore, if the temperature distribution after run-out table (hereinafter referred to as “ROT”) cooling or control cooling after rolling is not uniform, the plate wave shape deteriorates in a cold state. As a method of solving these problems, there is a method of inductively heating the end of the rough bar with an edge heater before finish rolling (see, for example, Patent Document 1).

  If the technique of patent document 1 is used, finish rolling can be started in a state in which end supercooling is relatively small. However, since end supercooling occurs again in the middle of finish rolling, a means for preventing the metal plate end supercooling is necessary in the subsequent processes.

  As a method for solving the above problem, in a cooling method for a high temperature metal plate, cooling water is supplied from a plurality of nozzles arranged in the plate width direction of the high temperature metal plate traveling on the ROT, and the upper surface or the lower surface of the metal plate is cooled. , A plurality of means for shielding the cooling water directly supplied to the end portion in the plate width direction of the high-temperature metal plate are arranged in the running direction in the cooling zone, and the range for shielding the cooling water is individually expanded and reduced in the plate width direction, There is a cooling method for controlling the cooling capacity in the plate width direction (see, for example, Patent Document 2).

  FIG. 6 shows the ROT cooling device 54 arranged on the exit side of the finishing mill. The ROT cooling device 54 is provided with a ROT masking device 55. The strip ST rolled by the finish rolling mill 14 is cooled by the ROT cooling device 54 based on the plate temperature detected by the plate temperature detector 41. When the strip is cooled, the ROT masking device 55 blocks the cooling water applied to the edge portion by the blocking plate, thereby preventing the side edge portions of the strip from being overcooled. As a result, the temperature distribution in the plate width direction becomes uniform, and plate shape defects such as the middle extension and end extension of the strip ST are prevented.

However, the cooling by the ROT has a problem in terms of cost because it is necessary to install an edge mask over the entire length of the ROT cooling device. In addition, since it cannot follow due to disturbance due to meandering or lateral bending of the plate, the position of the edge mask and the target range do not match, which promotes a non-uniform temperature distribution.
JP-A-3-248709 JP-A-8-71630

  It is an object of the present invention to provide a steel plate rolling method that follows a meandering and bending of a plate and has a uniform temperature in the plate width direction after cooling at a low cost and its equipment.

  According to the investigations and studies by the inventors, in the state where the edge mask is not used in the finishing mill 14, as shown in FIG. 3A, the sheet is wound through the temperature distribution (b) in the sheet width direction immediately after finish rolling and ROT cooling. It has been found that although the average temperature in the plate width direction is different from the temperature distribution (b) in the plate width direction immediately before winding by the take-up machine 50, it has a similar trapezoid. This suggests that the masking device 55 is not necessary in the ROT cooling device 54 if the temperature distribution in the plate width direction is almost uniform immediately after finish rolling, that is, before ROT cooling. Therefore, in the present invention, as shown in FIG. 1, the cooling device 25 is arranged between the stands of the finishing mill 14, and the edge mask device 36 is installed corresponding to the cooling device 25. In this respect, the continuous hot rolling method and apparatus of the present invention is greatly different from the conventional method and apparatus. The present invention has been made based on this finding.

The present invention has been made in order to achieve the above-mentioned problems, and the steel plate rolling method and its equipment of the present invention include:
(1) In the steel plate rolling method in which the rolling step includes a rough rolling step and a finish rolling step, and the steel plate is cooled in the rolling step,
Between the rolling passes, the steel plate is cooled between the pass between the final rolling final pass and the last pass of the last pass, and between the passes other than the pass is cooled without cooling by a cooling device ,
Between the rolling passes, the steel plate is cooled between the passes between the last stage of the final rolling final pass and the last two passes of the final pass, and the passes other than the pass are cooled without cooling by a cooling device , or rolled. Among the passes, the steel sheet is cooled between the final rolling final pass and the final pass one previous pass, and the pass between the final pass one previous pass and the final pass two previous passes, and between passes other than those passes Then, cool without cooling by the cooling device ,
Masking the steel plate edge to block the cooling water directly applied to the edge so that the temperature distribution in the sheet width direction on the exit side of the finish rolling final pass is uniform.
A hot-rolling method for steel sheets, characterized in that:
(2) In a hot-rolled steel sheet rolling method for cooling a steel sheet in a rough rolling process and a finish rolling process of a hot-rolled steel sheet,
Between the rolling passes, the steel plate is cooled between the final rolling pass between the final rolling pass and the last pass, and the cooling passes between the passes other than the pass without cooling by a cooling device ,
Between the rolling passes, the steel plate is cooled between the passes between the last stage of the final rolling final pass and the last two passes of the final pass, and the passes other than the pass are cooled without cooling by a cooling device , or rolled. Among the passes, the steel sheet is cooled between the final rolling final pass and the final pass one previous pass, and the pass between the final pass one previous pass and the final pass two previous passes, and between passes other than those passes Then, cool without cooling by the cooling device ,
Masking the steel plate edge to block the cooling water directly applied to the edge so that the temperature distribution in the sheet width direction on the exit side of the finish rolling final pass is uniform.
A hot-rolling method for steel sheets, characterized in that:
(3) In the thick steel plate rolling method for cooling the thick steel plate in the rough rolling and finish rolling steps of the thick steel plate,
Between the rolling passes, the steel plate is cooled between the pass between the final rolling final pass and the last pass of the last pass, and between the passes other than the pass is cooled without cooling by a cooling device ,
Between the rolling passes, the steel plate is cooled between the passes between the last stage of the final rolling final pass and the last two passes of the final pass, and the passes other than the pass are cooled without cooling by a cooling device , or rolled. Among the passes, the steel sheet is cooled between the final rolling final pass and the final pass one previous pass, and the pass between the final pass one previous pass and the final pass two previous passes, and between passes other than those passes Then, cooling without cooling by a cooling device and masking the cooling water directly applied to the edge part by masking the steel sheet edge part so as to make the temperature distribution in the sheet width direction on the finish rolling final pass exit side uniform.
A hot-rolling method for steel sheets, characterized in that:
(4) The hot-rolled steel sheet rolling method according to any one of (1) to (3), wherein the sheet temperature immediately after the finish rolling mill exit side is 900 ° C. or higher.
(5) The hot-rolled steel sheet rolling method according to any one of (1) to (4), wherein the steel type of the hot-rolled sheet is medium carbon steel.
(6) The hot-rolled steel plate rolling method according to any one of (1) to (5), wherein the entire steel plate is uniformly heated on the entrance side of the finish rolling mill.
(7) The steel plate edge is masked so that the steel plate is cooled between the previous pass and the final pass of the rough rolling final pass, and the temperature distribution in the plate width direction on the exit side of the rough rolling final pass is made uniform. The hot steel sheet rolling method according to any one of (1) to (6), wherein the cooling water directly applied to the edge portion is cut off.
(8) The plate width direction position and the plate width direction temperature distribution of the steel plate are detected on the exit side of the rough rolling final stand, and the first stage of the rough rolling final pass based on the detected plate width direction position and plate width direction temperature distribution of the steel plate. The steel sheet rolling method according to (7), characterized in that the masking amount is controlled between the pass and the final pass or between the pass of the last pass and the pass of the last pass.
(9) The plate width direction position and the plate width direction temperature distribution of the steel plate are detected at the finish rolling final stand exit side, and the first stage of the final rolling final pass based on the detected plate width direction position and plate width direction temperature distribution of the steel plate The steel sheet according to any one of (1) to (8), wherein a masking amount is controlled between a pass and a final pass or between a pass before and after the final pass. Rolling method.
(10) A steel plate rolling facility for carrying out the steel plate rolling method according to any one of (1) to (9) above, between the last pass of the final rolling final pass and the final pass. The cooling device that cools the steel plate between the first and second stages of the above includes a slit laminar nozzle, and the masking device that masks the steel plate edge portion does not directly apply the cooling water from the nozzle to the steel plate edge portion. A steel plate rolling facility comprising a blocking plate for blocking cooling water as described above.
(11) The steel plate rolling facility according to (10), wherein the blocking plate is provided in a side guide on a stand entry side that is movable in a plate width direction.
(12) Finishing rolling final based on the meandering detector and the temperature detector installed on the finish rolling final stand outlet side, the plate width direction position of the steel plate from the meandering detector and the plate width direction temperature distribution from the temperature detector. And a finish rolling masking amount control device for controlling the masking amount between the pass between the previous pass and the final pass of the pass or between the pass before and after the last pass of the final pass (10). ) Or (11) steel plate rolling equipment.
(13) The steel plate rolling facility according to any one of (10) to (12), wherein a steel plate heating device that uniformly heats the entire steel plate is provided on the entrance side of the finishing mill.
(14) A steel plate rolling facility for performing the steel plate rolling method according to (7) or (8) above, between a pass between the preceding pass and the final pass of the rough rolling final pass, or one step before the final pass, The cooling device that cools the steel plate between the two previous passes is equipped with a slit laminar nozzle, and the masking device that masks the steel plate edge portion supplies the cooling water so that the cooling water from the nozzle is not directly applied to the steel plate edge portion. A steel sheet rolling facility comprising a blocking plate for blocking.
(15) The steel plate rolling facility according to (14), wherein the blocking plate is provided on a side guide on the stand entrance side that is movable in the plate width direction.
(16) Based on the meandering detector and the temperature detector installed on the exit side of the rough rolling final stand, the plate width direction position of the steel plate from the meander detector and the temperature distribution in the plate width direction from the temperature detector. And a rough rolling masking amount control device for controlling a masking amount between the pass between the preceding pass and the final pass of the pass or between the pass before and after the last pass of the final pass (14). ) Or (15) steel plate rolling equipment.

According to the present invention, the following special effects can be obtained.
(1) Cooling that suppresses the temperature drop of the edge portion is possible without installing a ROT cooling device and a masking device on the exit side of the finishing mill.
(2) Therefore, the cost of the steel sheet cooling device can be greatly reduced.
(3) When the masking amount can be changed at any time, it is possible to follow the change in the amount of heat released from the side end portion, so that it is possible to compensate for thermal rundown and processing heat fluctuations that change depending on the rolling speed.

The best mode for carrying out the present invention will be described mainly with reference to FIGS. FIG. 1 schematically shows a layout of main apparatuses constituting the hot-rolled steel sheet rolling facility of the present invention. 2 is an enlarged view of the finish rolling stand 14 of the hot-rolled steel sheet rolling apparatus shown in FIG. 1, FIG. 2 (a) is a side view, and FIG. 2 (b) is a view taken along the line bb in FIG. 2 (a). It is.
The hot-rolled steel sheet rolling equipment 1 mainly includes a heating furnace 10, a roughing mill 12, a finishing mill 14, a roughing mill entry side cooling device 21, a rough rolling stand cooling device 22, a rough rolling masking device 33, and a finishing rolling mill entrance side. It comprises a cooling device 24, a finish rolling stand cooling device 25, a finish rolling masking device 36, an ROT cooling device 54 and a winder 58. A steel plate heating device 30 for heating the coarse bar RB is disposed on the entry side of the finish rolling mill 14. The steel plate heating device 30 is, for example, an induction heating type bar heater.

  The rough rolling mill 12 includes five rough rolling stands 12a to 12e, and the finishing mill 14 includes seven finishing rolling stands 14a to 14g. In the rough rolling mill 12, the cooling device 22 between the rough rolling stands is arranged between the stands together with the rough rolling masking device 33. Similarly, the finish rolling mill 14 is disposed between the stands together with the finish rolling stand cooling device 25 and the finish rolling masking device 36. In the rough rolling cooling devices 21 and 22 and the finish rolling cooling devices 24 and 25, a nozzle 28 is attached to a header 27 extending in the plate width direction along the plate width direction.

  Cooling devices 21, 22, 24, 25 between the rolling mill entrance side and the stand of the rough rolling mill 12 and the finishing rolling mill 14 suppress the temperature rise of the steel sheet due to processing heat generated by rolling. As a cooling method of these cooling apparatuses, there are generally cases where both the upper and lower parts using a laminar nozzle and a spray nozzle, only the upper part, or only the lower part. Although the spray nozzle also has a masking effect, depending on the situation, the impact pressure unevenness that contributes most to the cooling capacity is likely to occur in the width direction at the nozzle pitch, and the masking width may deviate from the target masking width. Therefore, the nozzle is preferably a slit laminar nozzle to which cooling water is supplied uniformly in the plate width direction. The slit laminar nozzle has a uniform collision pressure, eliminates uneven cooling at each nozzle pitch, and can control the edge mask amount in the width direction without any variation.

On the other hand, the rough rolling masking device 33 and the finish rolling masking device 36 are attached to the side guide 17. Side guide 17, typically, there is provided in the roughing mill 12 and the finishing mill 14, the steel sheet is guided to allow straight through plate along the pass line with respect to bending meandering or horizontal. The side guides 17 on both sides are individually moved in the plate width direction by a retractor (not shown). On the upper and lower ends of the side guide 17, the shielding plate moving device 19 and the shielding plate 37 of the finish rolling masking device 36 are respectively attached. The blocking plate moving device 19 includes, for example, a hydraulic cylinder or a motor as a drive source, and moves the blocking plate 37 so as to have an appropriate masking amount. When the side guide 17 is fixed, only the blocking plate 37 is moved by the blocking plate moving device 19. The rough rolling masking device 33 of the rough rolling mill 12 is configured in the same manner as that of the finishing rolling mill 14.

A plate temperature detector 41 for detecting the temperature distribution in the plate width direction and a meandering detector 40 for detecting the position in the plate width direction are arranged on the exit side of the roughing mill 12. The plate temperature detector 41 and the meandering detector 40 are connected to a rough rolling masking amount control device 43. Similarly, a meandering detector 40 and a plate temperature detector 41 are arranged on the exit side of the finish rolling mill 14, and are connected to the finish rolling masking amount control device 48. In the masking amount control devices 43 and 48, the relationship between the position in the plate width direction and the temperature distribution in the plate width direction and the required masking amount, which are obtained in advance through operation results, experiments, etc., are stored in a table format, for example.

Plate temperature detector 4 1, it is desirable to install the rough rolling mill outlet, and finishing mill outlet to increase the responsiveness of the temperature distribution uniformity and control of the rolling mill outlet, for example, within 10 m. The plate width direction temperature distribution detected by the plate temperature detector may not be a distribution continuous in the plate width direction. If the plate width direction temperature distribution is not continuous, the plate width direction pitch of the temperature detecting point may not be equal pitch, the pitch of the plate lateral edge closer may be finer pitch than the pitch of the plate width central portion. For example, it may be a temperature distribution consisting of five points of 25 mm and 50 mm from the left end of the plate, the center of the plate width, 25 mm and 50 mm from the right end of the plate, or a temperature distribution consisting of about 256 detection points. Good. The number of temperature detection points in the temperature distribution is determined by the plate width and the type and size of the shape defect that occurs due to the uneven temperature distribution.

  In the hot-rolled steel sheet rolling equipment configured as described above, the slab is heated to a predetermined temperature in the heating furnace 10. The heated slab SL is rolled into a rough bar RB having a predetermined thickness by the roughing mill 12.

During rough rolling, on the exit side of the rough rolling mill 12, the plate width direction position of the slab SL detected by the meandering detector 40 and the plate width direction temperature distribution detected by the plate temperature detector 41 are the masking amount control device. 43. The masking amount control device 43 obtains the amount of movement of the shielding plate from the data stored in the table format based on the detected position in the plate width direction of the steel plate, and outputs an operation signal to the shielding plate moving device 19 of the masking device 33. To do. Thereby, the blocking plate 37 of the masking device 33 is moved, and the cooling water supplied to the thick steel plate edge is blocked. Thereby, it is prevented that the both-sides edge part of slab SL is overcooled. Further, based on the detected value of the plate width direction position and the plate width direction temperature distribution, it is possible to change the masking amount needed, conformal edge Masking effect is obtained in the rolling direction. The cause of the temperature decrease at the edge of the steel plate at the finish rolling mill is originally generated in the coarse bar RB. As described above, the coarse mill 12 also performs inter-stand cooling and edge masking, so that there is more temperature deviation. Get smaller.

Following the rough rolling, the coarse bar RB is heated by the steel plate heating device 30 on the entry side of the finishing mill 14. The effect of heating the coarse bar RB with the steel plate heating device 30 is as follows. A change in rolling speed, thermal run-down and work-induced heat to fluctuate along the steel plate longitudinal direction. For this reason, the effect of an edge mask sufficient to make the product plate shape the target plate shape may not be obtained. In such a case, the fluctuation amount of the thermal rundown and the processing heat generation is anticipated in advance, the entire coarse bar RB is uniformly heated by the steel plate heating device 30, and the heat is compensated for each position in the longitudinal direction of the steel plate, so that a sufficient edge mask effect is obtained. Can be obtained.

  The uniformly heated coarse bar RB is finish-rolled to a hot-rolled steel sheet SL having a predetermined thickness by a finish rolling mill 14. During finish rolling, the hot rolled steel sheet ST is cooled by all of the finish rolling mill entry side cooling device 24 and the finish rolling stand cooling device 25. During cooling, the masking device blocks the cooling water applied to the edge portion by the blocking plate. As in the case of rough rolling, the amount of masking is controlled so that the temperature distribution in the sheet width direction on the exit side of the finishing mill becomes uniform by the finish rolling masking amount control device 48 based on the detected values of the position in the sheet width direction and the temperature distribution in the sheet width direction. Controlled. Thereby, the supercooling of the both-sides edge part of hot-rolled steel plate ST is prevented, and the product of the favorable plate shape without board shape defects, such as middle extension and edge extension, is obtained.

  In finish rolling, since the inter-stand cooling device 25 is disposed between the stands, the steel sheet is cooled while being restrained by a rolling roll. For this reason, in the conventional continuous hot rolling equipment, the fluttering of the leading end of the steel plate, which becomes a disturbance during ROT cooling, is eliminated, so that the entire length of the steel plate can be effectively masked.

  In rough rolling and finish rolling, the masking devices 33 and 36 are attached to the movable side guide 17, so that the masking amount can be set by adjusting the position of the side guide 17 according to the manufacturing plate width. There is no need to use a large retracting device. Therefore, the hot-rolled steel sheet rolling equipment cost can be reduced. Further, since it is possible to set a fine masking amount, the temperature deviation of the temperature distribution in the plate width direction can be remarkably reduced.

  The effect of the temperature distribution in the sheet width direction on the exit side of the finishing mill depending on whether or not the present invention was applied was investigated. FIG. 3 schematically shows an example of the temperature distribution (b) in the sheet width direction immediately after the finishing mill exit side and the temperature distribution (b) in the sheet width direction immediately before the winder. FIG. 3 (a) shows a case where rolling is performed without edge masking between the stands by the conventional hot-rolled steel sheet rolling device 4 shown in FIG. 6, and FIG. 3 (b) is rolling with edge masking between the stands in the rolling device of the present invention. The masking amount was 100 mm. The steel type of the hot rolled sheet is medium carbon steel, the sheet width is 1200 mm, and the sheet thickness is 3 mm. The plate temperature immediately after the finishing mill exit side is 900 ° C., and the plate temperature just before the winder is 600 ° C. As apparent from FIG. 3, in the conventional case, the edge width at which the temperature drop occurs is 75 mm, the edge temperature drop immediately after the finishing mill exit side is 30 ° C., and the edge temperature drop immediately before the winder is reduced. 100 ° C. On the other hand, in the case of the present invention, the edge width at which the temperature drop occurs is 7 mm, the edge temperature drop immediately after the finishing mill exit side is 5 ° C., and the edge temperature drop immediately before the winder is 15 ° C. The temperature distribution in the plate width direction has been greatly improved. As a result, in the present invention, it is possible to obtain a plate shape that is much superior to the conventional one.

The present invention is not limited to the above best mode depending on the steel type, thickness, width, rolling condition (rolling load, rolling speed, unit tension, rolling end temperature, etc.) and product quality of the steel plate. As another aspect of the present invention, it is not necessary to perform inter-stand cooling and masking of the present invention on all the stands in rough rolling and finish rolling. For example, in rough rolling, when the plate thickness is thick, in order to increase the effect, a cooling capacity is required as it is, and it is impossible in terms of cost. Therefore, it is practical to perform the final pass and the 2nd and 3rd passes before the final pass. In the finish rolling, the inter-stand cooling and masking of the present invention may be performed at least between the preceding pass and the final pass of the finish rolling final pass . Also, the uniform heating of the entire steel sheet by finish rolling mill entry side, may be omitted. Furthermore, as another aspect of the present invention, masking amount control may be omitted. Further, the masking amount control may be performed based on any one of the plate width direction position and the plate width direction temperature distribution of the steel plate.

  Next, thick steel plate rolling will be described. In the following description, the same devices and members as those shown in FIG. 1 are given the same reference numerals, and detailed descriptions thereof are omitted.

  First, conventional thick steel plate rolling will be described. FIG. 7 schematically shows a layout of main apparatuses constituting the conventional thick steel plate rolling apparatus 5. The thick steel plate rolling device 5 mainly comprises a heating furnace 10, a descaling device 52, a thick steel plate rolling mill 60, a cooling device 66, a meandering detector 40, and a cooling bed 78.

  The date scaling device 52 generally removes the scale by spraying high pressure water of 15 MPa or more on the slab at the rolling mill biting side. In general, descaling is not performed on the side of the rolling mill bite. The steel plate rolling machine 60 is a single stand / reverse mill. The cooling device 66 is provided on the biting side, and a nozzle 68 is attached to a header 67 extending in the plate width direction along the plate width direction.

  In the thick steel plate rolling equipment 5 configured as described above, the slab is heated to a predetermined temperature in the heating furnace 10, and the heated slab undergoes rough rolling, tenter rolling and finish rolling in the thick steel plate rolling mill 60, It is rolled into a thick steel plate having a predetermined thickness. The thick steel plate having a predetermined thickness is conveyed to the cooling floor 78 and cooled to room temperature to become a product.

  Even in thick steel plates, the temperature distribution in the sheet width direction on the exit side of the normal finish rolling mill is trapezoidal, and the temperature distribution in the sheet width direction just before the cooling bed is also trapezoidal although the average temperature in the sheet width direction is different. As with the continuous hot-rolled steel sheet. Therefore, the finish-rolled thick steel plate has a problem that the temperature distribution in the plate width direction is not uniform, and a medium wave, an ear wave, etc. are generated, and good flatness cannot be obtained.

In the thick steel plate rolling of the present invention, a cooling device and a masking device are installed on the bite side to improve the flatness of the thick steel plate. FIG. 4 schematically shows a layout of main apparatuses constituting the thick steel plate rolling equipment 2 of the present invention. The thick steel plate rolling equipment 2 mainly comprises a heating furnace 10, a descaling device 52, a thick steel plate rolling mill 60, a cooling device 66, a masking device 70, a meandering detector 40, a masking amount control device 74 , and a cooling bed 78. In FIG. 4, the cooling device 66 and the masking device are provided only on the biting side, but may be provided on the biting side.

In the thick steel plate rolling equipment 2 configured as described above, the slab is heated to a predetermined temperature in the heating furnace 10, and the heated slab undergoes rough rolling, tenter rolling and finish rolling in the thick steel plate rolling mill 60, It is rolled into a thick steel plate having a predetermined thickness. The plate width direction position of the steel plate is detected by the meandering detector 40 on the biting side of the thick steel plate rolling mill 60, and the detected plate width direction position is sent to the masking amount control device 74. The masking amount control device 74 obtains the movement amount of the shielding plate according to the detected position in the plate width direction of the steel plate and outputs an operation signal to the masking device 70. The blocking plate of the masking device 70 is moved, and the cooling water supplied to the thick steel plate edge is blocked. As a result, the plate width direction temperature distribution of the finish-rolled thick steel plate becomes uniform, and good flatness can be obtained.

  FIG. 8 is another example of a conventional thick steel plate rolling apparatus, and schematically shows a layout of main devices constituting the thick steel plate rolling apparatus 6. The thick steel plate rolling device 6 mainly comprises a heating furnace 10, a rough rolling mill 62, a finish rolling mill 63, a cooling device 66, a control cooling device 76, and a cooling bed 78. The rough rolling mill 62 and the finish rolling mill 63 are single stand / reverse mills. A meandering detector 40 for detecting the position in the plate width direction of the steel sheet is disposed on the biting side of the roughing mill 62 and the finishing mill 63, respectively. The controlled cooling device 76 improves the strength and toughness of the thick steel plate by controlled cooling.

  In the conventional thick steel plate rolling device 6 configured as described above, the slab is heated to a predetermined temperature in the heating furnace 10, and the heated slab is roughly rolled by the roughing mill 62 and finish-rolled by the finishing mill 63. And rolled into a thick steel plate having a predetermined thickness. However, as described above, the finish-rolled thick steel plate has a problem that the temperature distribution in the plate width direction is not uniform, and a medium wave, an ear wave, etc. are generated, and good flatness cannot be obtained.

In the thick steel plate rolling of the present invention, a cooling device and an edge mask are installed on the biting side to improve the flatness of the thick steel plate. FIG. 5 schematically shows a layout of main apparatuses constituting the thick steel plate rolling equipment 3 of the present invention. The thick steel plate rolling device 3 mainly comprises a heating furnace 10, a descaling device 52, a roughing mill 62, a finishing mill 63, a cooling device 66, a masking device 70, a control cooling device 76, and a cooling bed 78. The rough rolling mill 62 and the finish rolling mill 63 are single stand / reverse mills. The blocking plate of the masking device 70 is movable in the plate width direction. A meandering detector 40 and a masking amount control device 74 are arranged on the biting side of the rough rolling mill 62 and the finishing rolling mill 63, respectively.

  In the thick steel plate rolling device 3 configured as described above, the slab is heated to a predetermined temperature in the heating furnace 10, and the heated slab is roughly rolled by a roughing mill 62 and finish-rolled by a finishing mill 63, It is rolled into a thick steel plate. The shielding plate of the masking device 70 is moved according to the position in the plate width direction of the steel plate detected by the meandering detector 40. As a result, the cooling water supplied to the thick steel plate edge is blocked, and overcooling of the thick steel plate edge is prevented. As a result, the plate width direction temperature distribution of the finish-rolled thick steel plate becomes uniform, and good flatness can be obtained.

  In the thick steel plate rolling facilities 2 and 3, in addition to the meandering detector, a thick steel plate having no temperature variation in the rolling direction is manufactured by controlling the masking amount based on a temperature detector installed on the delivery side of the rolling mill. It becomes possible. As a result, a thick steel plate having a better shape can be obtained.

It is a layout figure of the main apparatuses which comprise the hot rolled sheet steel rolling apparatus of this invention. It is an enlarged view of the finishing rolling stand of the hot-rolled steel plate rolling apparatus shown in FIG. 1, FIG. 2 (a) is a side view, FIG.2 (b) is a bb arrow line view of Fig.2 (a). FIG. 3 is a diagram schematically showing the temperature distribution in the sheet width direction immediately after the final pass of finish rolling and immediately before the winder in continuous hot rolling, and FIG. 3 (a) is a diagram showing a conventional hot-rolled steel sheet rolling apparatus shown in FIG. FIG. 3B shows a case where rolling is performed without edge masking, and FIG. 3B shows a case where rolling is performed with edge masking between stands by the rolling apparatus of the present invention. It is a layout figure of the main apparatuses which constitute the thick steel plate rolling apparatus of the present invention. It is a layout figure of the main apparatuses which comprise the other thick steel plate rolling apparatus of this invention. It is a layout figure of the main apparatuses which comprise the conventional hot-rolled steel plate rolling apparatus. It is a layout figure of the main apparatuses which comprise the conventional thick steel plate rolling apparatus. It is a layout diagram of main apparatuses constituting another conventional thick steel plate rolling apparatus.

Explanation of symbols

1-3 Steel plate rolling equipment of the present invention 4-6 Conventional steel plate rolling installation 10 Heating furnace 12, 62 Rough rolling 14, 63 Finishing mill 17 Side guide 19 Shutter moving device 21, 24 Rolling mill entry side cooling device 22, 25 Inter-stand cooling device 30 Steel plate heating device 33, 36 Masking device 37 Blocking plate 40 Meander detector 41 Temperature detector 43, 48, 74 Masking amount control device 52 Descaling device 54 ROT cooling device 55 ROT masking device 58 Winder 60 Thick Steel Plate Roller 62 Thick Steel Plate Coarse Roller 63 Thick Steel Plate Finish Roller 66 Cooling Device 70 Masking Device 76 Control Cooling Device 78 Cooling Bed

Claims (16)

In the steel sheet rolling method in which the rolling process includes a rough rolling process and a finish rolling process, and the steel sheet is cooled in the rolling process,
Between the rolling passes, the steel plate is cooled between the pass between the final rolling final pass and the last pass of the last pass, and between the passes other than the pass is cooled without cooling by a cooling device ,
Between the rolling passes, the steel plate is cooled between the passes between the last stage of the final rolling final pass and the last two passes of the final pass, and the passes other than the pass are cooled without cooling by a cooling device , or rolled. Among the passes, the steel sheet is cooled between the final rolling final pass and the final pass one previous pass, and the pass between the final pass one previous pass and the final pass two previous passes, and between passes other than those passes Then, cool without cooling by the cooling device ,
Masking the steel plate edge to block the cooling water directly applied to the edge so that the temperature distribution in the sheet width direction on the exit side of the finish rolling final pass is uniform.
A hot-rolling method for steel sheets, characterized in that: In the hot-rolled steel sheet rolling method for cooling the steel sheet in the rough rolling process and the finish rolling process of the hot-rolled steel sheet,
Between the rolling passes, the steel plate is cooled between the pass between the final rolling final pass and the last pass of the last pass, and between the passes other than the pass is cooled without cooling by a cooling device ,
Between the rolling passes, the steel plate is cooled between the passes between the last stage of the final rolling final pass and the last two passes of the final pass, and the passes other than the pass are cooled without cooling by a cooling device , or rolled. Among the passes, the steel sheet is cooled between the final rolling final pass and the final pass one previous pass, and the pass between the final pass one previous pass and the final pass two previous passes, and between passes other than those passes Then, cool without cooling by the cooling device ,
Masking the steel plate edge to block the cooling water directly applied to the edge so that the temperature distribution in the sheet width direction on the exit side of the finish rolling final pass is uniform.
A hot-rolling method for steel sheets, characterized in that: In the thick steel plate rolling method for cooling the thick steel plate in the rough rolling and finish rolling steps of the thick steel plate,
The steel plate between the path between the out finish rolling final pass and the final pass one preceding path between rolling passes was cooled, and the inter-path other than between the paths is cooled without cooling by the cooling device,
Between the rolling passes, the steel plate is cooled between the passes between the last stage of the final rolling final pass and the last two passes of the final pass, and the passes other than the pass are cooled without cooling by a cooling device , or rolled. Among the passes, the steel sheet is cooled between the final rolling final pass and the final pass one previous pass, and the pass between the final pass one previous pass and the final pass two previous passes, and between passes other than those passes Then, cool without cooling by the cooling device ,
Masking the steel plate edge to block the cooling water directly applied to the edge so that the temperature distribution in the sheet width direction on the exit side of the finish rolling final pass is uniform.
A hot-rolling method for steel sheets, characterized in that: The hot strip rolling method according to any one of claims 1 to 3, wherein the plate temperature immediately after the finish rolling mill exit side is 900 ° C or higher. The hot-rolled steel sheet rolling method according to any one of claims 1 to 4, wherein the steel type of the hot-rolled sheet is medium carbon steel. The hot steel plate rolling method according to any one of claims 1 to 5, wherein the entire steel plate is uniformly heated at the finishing mill entry side. The edge of the steel plate is masked so that the steel plate is cooled between the preceding pass and the final pass of the rough rolling final pass, and the temperature distribution in the plate width direction on the exit side of the rough rolling final pass is made uniform. The method for rolling a hot steel sheet according to any one of claims 1 to 6, wherein the cooling water directly applied to the water is cut off. The plate width direction position and the plate width direction temperature distribution of the steel plate are detected on the final rolling rolling stand delivery side, and the preceding and final passes of the rough rolling final pass are determined based on the detected plate width direction position and plate width direction temperature distribution of the steel plate. The steel plate rolling method according to claim 7, wherein a masking amount is controlled between passes with the pass or between passes between the first step and the second step before the final pass. The sheet width direction position and the sheet width direction temperature distribution of the steel sheet are detected at the finish rolling final stand outlet side, and based on the detected sheet width direction position and the sheet width direction temperature distribution of the steel sheet, the first pass and the final path of the final rolling final pass The steel sheet rolling method according to any one of claims 1 to 8, wherein a masking amount is controlled between passes with a pass or between passes in the last step and two passes in the final pass. It is a steel plate rolling equipment which implements the steel plate rolling method according to any one of claims 1 to 9, and is between the pass of the last pass of the final rolling final pass and the pass of the final pass, or 1 step before the final pass and 2 The cooling device that cools the steel plate between the pass with the previous stage is equipped with a slit laminar nozzle, and the masking device that masks the edge of the steel plate blocks the cooling water so that the cooling water from the nozzle does not directly hit the steel plate edge. A steel plate rolling facility characterized by comprising a blocking plate. The steel plate rolling equipment according to claim 10, wherein the blocking plate is provided on a side guide on a stand entry side movable in a plate width direction. The first stage of the final rolling final pass based on the meandering detector and temperature detector installed on the exit side of the finish rolling final stand, and the plate width direction position of the steel plate from the meander detector and the temperature distribution in the plate width direction from the temperature detector 12. A finishing rolling masking amount control device for controlling a masking amount between a pass and a final pass or between a pass between the first pass and the last pass of the final pass is provided. The steel plate rolling equipment described in 1. The steel plate rolling facility according to any one of claims 10 to 12, further comprising a steel plate heating device that uniformly heats the entire steel plate on the entry side of the finishing mill. A steel plate rolling facility for performing the steel plate rolling method according to claim 7 or claim 8, wherein the rough rolling final pass is preceded by a pass between the previous pass and the final pass, or one step before and two steps before the final pass. The cooling device for cooling the steel plate between the passes is provided with a slit laminar nozzle, and the masking device for masking the steel plate edge portion blocks the cooling water so that the cooling water from the nozzle is not directly applied to the steel plate edge portion. A steel plate rolling facility comprising: The steel plate rolling equipment according to claim 14, wherein the blocking plate is provided on a side guide on a stand entry side movable in a plate width direction. The first stage of the rough rolling final pass based on the meandering detector and the temperature detector installed on the outlet side of the rough rolling final stand, the plate width direction position of the steel plate from the meander detector and the temperature distribution in the plate width direction from the temperature detector. 16. A rough rolling masking amount control device for controlling a masking amount between a pass and a final pass or between a pass before and after the final pass is provided. The steel plate rolling equipment described in 1.

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