TW565474B - Hot-rolling mill, method of manufacturing fine grain steel, and continuous hot rolling method - Google Patents

Abstract

A hot rolling mill in accordance with the present invention, comprising the mills disposed on a front stage and the mills of a plurality stands disposed on a rear stage, is comprised of roll mills of different diameters having a pair of work rolls of different diameters of less than 600 mm in equivalent roll diameter or the very small diameter roll mills having the pair of work rolls of less than 600 mm in diameter, and cooling means disposed on the outlet side of the millers of at least two stands on the rear stage, whereby a hot rolled fine grained steel plate can be manufactured smoothly.

Description

565474 A7 _B7 V. Description of the Invention (1) (Technical Field) The present invention relates to a hot rolling device (hot rolling device) and a hot rolling method, and particularly to heat for a steel plate having a fine structure with fine grained iron as a main body. Rolling device and hot rolling method. (Background Art) Generally, as a means for improving the mechanical properties of steel materials, it is known to take measures to refine the structure of steel materials. When the mechanical properties of steel become higher, many benefits such as weight reduction of steel structures can be achieved. Many methods for manufacturing microstructured steel, in other words, fine-grained steel, have been proposed until now. Among them, representative are ① high rolling reduction method and ② controlled rolling method. Among them, the rolling method with a large reduction ratio of ① is described in Japanese Patent Laid-Open No. 58-1 23823 or Japanese Patent No. 5-65564. In detail, the same law system promotes the strain induced by the strain from Vostian Iron (r) phase to the ferrous iron (^) phase by applying large rolling to the Vostian iron particles. Those who seek to refine the organization. In addition, the controlled rolling method of ② is that the composition contains Nb or T i, which not only achieves high tension easily by the precipitation strengthening effect of Nb or Ti, but also renews the Vostian iron particles of N b and T i Crystallization suppressing effect. When low-temperature rolling (rolling in the ferrous grain iron field) is performed, the strain from the r phase to the ^ phase can be induced to induce metamorphosis to achieve the refinement of the ferrous grain iron particles. According to the controlled rolling method, finishing rolling is performed in a low temperature range (below 800 ° C), so the deformation resistance of the rolled material is very large. Therefore, for (Please read the precautions on the back before filling this page ) Packing · • J— · Printed by the 8th Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The paper size is applicable to Chinese National Standard (CNS) A4 (210X297 mm) -4-565474 A7 ____ B7_ V. Description of the invention (2) Unfavorable situations with heavy rolling equipment. (Please read the precautions on the back before filling in this page) On the other hand, the rolling method of large reduction rate is as shown in the above-mentioned special fair No. 5-6 5 5 6 4 and cannot be used with ordinary hot-rolled slab rolling mills. (Hot Stdp Mill) industrial implementation requires the use of special rolling equipment. This is because, as shown in the above-mentioned publications, continuous rolling is performed on the basis of a High Rolling Reduction Ratio (for example, 40% or more) that cannot be achieved by a conventional rolling device. The industrial and commercial production of fine-grained steel by carrying out the above-mentioned high-reduction-ratio rolling method still has the following problems, in addition to the inability to use a rolling device formed by a conventional hot-strip rolling mill. i) In order to implement rolling, in other words to implement rolling with a high rolling ratio, it is easy to cause unfavorable conditions caused by rolling load. In other words, the rolling load may reach the limits inherent in the rolling device (the rolling rate and the power limit and the mechanical strength), and rolling may not be possible. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. Regarding rolled materials, a specified reduction rate cannot be achieved, or a large edge-drop may occur. The reason why the prescribed reduction rate cannot be obtained is because the thickness of the exit side of the rolling device is less than 2 mm and the reduction rate is more than 40%, etc., because not only the rolling load is large, but the deformation resistance is high. Because of this, the flatness of the rollers will become larger. At this time, as far as possible, the application of the shrinkage in order to implement the high-shrinking rolling can not increase the reduction rate. The reason why the edge of the plate becomes thinner (edge-drop) becomes larger because of the high load near the edge (wide end) of the rolled material. Unable to obtain good board contours. ϋ) The difficulty in maintaining the temperature of the rolled material is also a great problem. Use-5- This paper size applies Chinese National Standard (CNS) A4 specification (210X297mm) 565474 A7 B7 V. Description of the invention (3) (Please read the precautions on the back before filling this page) When rolling with a high reduction rate is performed, the temperature of the material to be rolled will increase significantly due to the heating of the process. It must be maintained at a temperature suitable for the large reduction rolling method (A r 3 abnormal point ~ A r 3 + 50 ° C range) is not easy. Since the rolled material is fed, the strain rate becomes higher as the transfer speed (feed speed) increases, which increases the processing heat, so it is more difficult to maintain the temperature. iii) The unsuitable situation related to the heat load of the roll is also easy to occur. When high-load rolling with high shrinkage is carried out, the processing heat of the material being rolled also becomes high, and the heat load of the roll of that weight also changes. high. As a result, a "thermal-crown" in which the diameter of the roll is enlarged at its central portion easily occurs. The degree of heat bulge, and sometimes there are cases that can not be resolved by the cooling roller. It is also possible that the shape of the rolled material is deteriorated, and the plate cannot be stably inserted (rolled through plate). Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs iv) The wear of the rolls is intense, and the shape of the rolled material (central bulge) is even worse. Because of high rolling reduction and high-load rolling, the heat load or mechanical load applied to the roller is high, so that the friction of the roller is easy to perform. The part of the roller that is in contact with the plate end of the material being rolled is particularly fast due to the high rolling load, which easily reduces the quality of the profile (shape) of the material being rolled. Moreover, the roller is easy to wear and tear, and the maintenance cost for honing or replacement of the roller is also significantly increased. It is therefore an object of the present invention to provide a solution to the above-mentioned problems concerning the manufacture of hot-rolled steel sheet of fine-grained steel. On the other hand, the above-mentioned hot-rolling device for a steel sheet and a method for manufacturing a fine-grained steel can be smoothly produced. In addition, the purpose of the present invention is to provide excellent cost-effectiveness. The paper size applies the Chinese National Standard (CNS) A4 (210X297 mm) -6-565474 A7 B7. 5. Description of the invention (4) is suitable for manufacturing Continuous hot rolling method of fine-grained steel hot-rolled steel sheet. Furthermore, an object of the present invention is to provide a continuous hot rolling method for smoothly manufacturing a thick plate using a hot rolling device capable of manufacturing a thin plate. (Disclosure of the invention) The present invention is mainly a hot rolling device for manufacturing steel plates by rolling rolled materials, and includes: a rolling mill arranged in a front stage, and a plurality of rolling mills arranged in a rear stage, and has Reduced-diameter rolling mills with equivalent diameters of one pair of different-diameter processing rolls less than 600 mm, or extremely-small-diameter processing mills with one diameter of each pair of processing rolls less than 600 mm It is characterized by a cooling mechanism for cooling the above-mentioned rolled material that is arranged on the exit side of the above-mentioned rolling mill and at least one of the rolling mills arranged in the latter stage. The so-called "equivalent roll diameter" in this example is About reducing rollers. The average of the diameters of the upper and lower pairs of different diameter processing rolls. Furthermore, the cooling mechanism is preferably a cimain wall type for cooling heat. According to the "curtain wall cooler", a large number of cooling water flows in a layered manner from above and below in a curtain-like stack and contacts the top and bottom of the rolled material. Speak. In addition, among the rolling mills arranged in the foregoing and subsequent stages, at least the rolling mills arranged in the preceding stage are a plurality of CVC rolling mills. According to the "c VC rolling mill", the outer diameter is continuous in the axial length direction. Changing rolls, including those that can be moved in the axial length direction (CVC light paper size applies Chinese National Standard (CNS) A4 specifications (210 × 297 mm) (Please read the precautions on the back before filling out this page)) • Installation · Order the printing machine printed by 565474 A7 B7 of the Intellectual Property Bureau of the Ministry of Economic Affairs, 565474 A7 B7 V. Invention Roller (5)). (Please read the precautions on the back before filling in this page) Also, it is better to use one of the above-mentioned different-diameter roll mills with the above-mentioned equivalent roll diameter of the different-diameter processing rolls or the above-mentioned extremely small-diameter roll mill with the above-mentioned processing roll The roll diameter is below 5 50 mm. Further, it is preferable that the processing roll of the different-diameter roll mill or the processing roll of the extremely small-diameter roll mill is provided with a C V C function and a bending function. The so-called "CVC function" in this case is a function of continuously changing the roll's outer diameter in the shaft length direction to move the roller in the shaft length direction in order to implement the change control of the roll gap shape. The so-called "bending function" is a function that applies a bending force (bending moment) to a roller to change the "roll gap shape". Furthermore, a lubricant mechanism for supplying a lubricant to the roll surface of the rolling mill provided in at least one of the rolling mills arranged in the preceding and subsequent rolling mills is provided. It is preferable that the above-mentioned lubricant supply mechanism supplies the lubricant containing fine solid lubricant to butter. The above-mentioned hot rolling device is printed by the employee's consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, which is preferably located on the exit side of the rolling mill at the last stage, and is further provided with a downstream side of the cooling mechanism arranged in the flow direction of the rolled material. A fluid jet sprayer that sprays fluid on the rolled material to remove cooling water existing in the rolled material. Further, the fluid jet sprayer includes, with respect to the material to be rolled, diagonally downward from above the material to be rolled toward an upstream side in a direction of flow of the material to be rolled, and is extended to the material to be rolled. Wide direction spray -8- This paper size is applicable to Chinese National Standard (CNS) A4 (210X297 mm) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 565474 A7 B7 V. Description of the invention (6) Plural nozzles. A method for manufacturing fine-grained steel, which is mainly used in a method for manufacturing fine-grained steel by rolling a rolled material, and is characterized in that: the heated rolled material is supplied to a rolling mill arranged at a front stage; And a rolling device arranged at the rear stage of the rolling mill, the rolling mill arranged at the rear stage of the rolling apparatus is provided with a processing roll having a diameter of 55 mm or less, and the rolling mill arranged at the rear stage of the rolling apparatus The material to be rolled is cooled before and after the flow direction, and the material to be rolled is applied to the person to be rolled while the energy of the accumulated strain is above 0 · 9. The so-called "strain" in this case is the thickness h of the material to be rolled on the entrance side of each rolling mill. The difference from the thickness h i on the exit side is the average thickness of the two. ε = (ho-hi) /! (h〇 + hi) / 2} Also, the cumulative strain (cumulative distortion ❖) will be in the rolling mills (for example, 3, 2 are also possible) of each rolling mill ( The influence of these rolling mills is smaller than those on the upstream side, so the strain is ignored. Those who have considered the intensity of the influence on the metal structure and accumulate the accumulators, such as the last stage, the front stage, and When the strain of the front stage is determined as ε η, ε η-i, ε n-2, respectively, ε can be represented by £ c = 8n-\-£ nl // 2i ~ ^^ n ~ 2 // 4. In terms of. The method for manufacturing fine-grained steel according to the present invention is to use one of the above-mentioned hot-rolling devices, and use the above-mentioned rolling device and the above-mentioned rolled material (please read the precautions on the back before filling this page)

This paper size applies the Chinese National Standard (CNS) A4 specification (210 × 297 mm) -9-565474 A7 B7 V. Description of the invention (7) It is characterized by rolling the above-mentioned rolled material with a cumulative strain of 0.9 or more. (Please read the precautions on the back before filling in this page.) Also, it is best to cool the rolled material from the last rolling mill straight above at a temperature drop rate of more than 20 ° C per second. 〇 The present invention is mainly a method for continuously manufacturing hot rolled rolled material to manufacture a steel sheet. The heated rolled material is supplied to a roll having a plurality of rolling mills arranged in series at the front stage and the rear stage. The rolling device uses the rolling device to roll the material to be rolled so that the accumulated strain of the rolled device becomes 0.6 or more, and the rolling device includes one or more of the rolling devices described later in the rolling device. The exit side cools the above-mentioned rolled material as its characteristic. It is also preferable that the rolling completion temperature of the material to be rolled is determined to be within a range of A r 3 transformation point-50 t or more, and A I * 3 transformation point + 50 ° C or less. Printed by the Intellectual Property of the Ministry of Economic Affairs / Employee Consumer Cooperatives The so-called "rolling completion temperature" in this example is set by the downstream side of the rolling device installed in the direction of flow of the rolled material In terms of the surface temperature of the rolled material measured by a thermometer on the downstream side of several meters. Further, it is preferable that the average grain size of the iron particles in the steel sheet obtained by rolling the material to be rolled is about 3 to 7 // m. The present invention mainly relates to a continuous hot rolling method in which a rolled material is rolled to produce a thick plate. The rolled material is rolled to form a thin plate, and the heated rolled material is supplied to a series configuration. Reply to the previous paragraph and the latter paragraph-10- This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7 V. Description of the invention (8) (Please read the precautions on the back before filling this page) Number The rolling device of the rolling mill of the Taiwan does not use at least a part of the plurality of rolling mills of the aforementioned _ rolling apparatus arranged in the above-mentioned later stage, but uses at least three rolling mills of the above-mentioned rolling apparatus on the incoming side. So that the cumulative strain of the above-mentioned rolled mill becomes 0 · 25 or lower, or the reduction rate of the above-mentioned rolling mill of the last stage of the above-mentioned rolling mill used is 12% or more. One side of the material is the exit side of the above-mentioned rolling mill in the last stage for use, and it is characterized by cooling the above-mentioned rolled material. The so-called "thin plate" in this case refers to a steel plate with a thickness of less than 6 mm. "Thick plate" means a steel plate with a thickness of 6 m m or more (less than 50 m m). In addition, it is preferable that the rolling completion (end) temperature of the rolled material does not exceed the A r 3 transformation point + 50 ° C. In this case, the "rolling completion temperature" refers to the downstream side of the rolling device provided by the flow direction (rolling progress direction) of the material being rolled (the downstream side of a few meters of the rolling mill in the last configuration). ) The surface temperature of the rolled material measured by a thermometer. The intellectual property of the Ministry of Economic Affairs and the employee's consumer cooperation are printed. It is best to roll the above-mentioned thick plate obtained by rolling the above-mentioned rolled material from the surface, and the average iron grain size of the inner side of its thickness is 1/4. 3 to 1 0 // rn degree. (Best Mode for Carrying Out the Invention) A hot rolling apparatus according to an embodiment of the present invention and a method for manufacturing a fine-grained steel using the same apparatus will be described below with reference to the drawings. The hot-rolling device according to this embodiment shown in Figure 1 is finished (manufactured-11-this paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 565474 printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs) A7 B7 V. Description of the invention (9) Product) Rolling device, on the upstream side (not shown) of the flow direction (rolling flow direction) of the material P to be rolled (not shown) is equipped with a heating furnace and a rough (processing) rolling mill On the downstream side (not shown), there is a Run-out-table, and a steel coil machine. This hot rolling device (hot rolling device) can be manufactured by continuously rolling the rolled material P which is coarsely rolled on the upstream side, and is a hot-rolled steel plate of fine-grained steel having a fine ferrous iron structure. It is structured as follows. First, three rolling mills before and after the hot rolling apparatus are configured, and so-called C V C rolling mills 1, 2, 3 are arranged in series. The CVC rolling mill 1 of the hot rolling device according to the position of the most entering side is configured as shown in FIG. 1 by the processing rolls 1 a, 1 b and the backing roll 1 as shown in FIG. 1. c, 1 d is a four-fold rolling mill, and the processing rolls 1 a, 1 b have crowns as shown in FIG. 2A (continuous change in diameter in CVC). The processing rollers la and lb can be moved simultaneously in opposite axial length directions as shown in FIG. 2B and FIG. 2C, so that the positional relationship between the rollers can be adjusted, that is, the roll gap can be adjusted. The diameters of the processing rolls 1 a and 1 b are set to 70 mm, and the maximum displacements are set to 100 mm respectively. The CVC roll mills 2 and 3 of the two sets and the CVC roll mills 1 are in this structure and There is no difference in performance. The reason why the C V C rolling mills 1, 2, and 3 configured as described above are disposed at the front stage is for the purpose of appropriately maintaining the shape of the (center) bulging state of the rolling mill P. The different-diameter roller mills 4, 5, and 6 (described below) in the rear section are easy to initiate thermal bulges due to the heat generated by the rolling process (thermal (please read the precautions on the back before filling this page). • Installation ·

This paper size applies to Chinese National Standard (CNS) A4 specification (210X297 mm) -12- 565474 A7 B7 V. Description of the invention (10)

Crown), etc. Therefore, by using the CVC roller car L machines 1, 2, and 3 in the front section, the ridges of the plates are corrected in advance to reduce the shrinkage of the rolled material P, etc. According to CVC rolling mills 1, 2, and 3, compared with the simple roll-bendig method, the roll gap shape has a greater ability to change, and the thickness of the material being rolled is thicker, and the It is easy to control the central part of the front part, so it is advantageous for implementing the adjustment of the bulge and the large post-constriction rear part to prevent the unstability of the through plate. In addition, according to the hot rolling device of this embodiment, the so-called different-roller rolling mills 4, 5 and 6 are arranged in series as three rolling mills which are continuous in the front and rear stages. The above-mentioned CVC rolling mills 1, 2 are included. The interval between the three stations is equal to 5.5 meters. It is equivalent to the fourth reduced-diameter rolling mill 4 starting from the CVC rolling mill 1. As shown in FIG. 1, it is composed of processing rolls 4a, 4b and backing rolls 4c, 4d. It is constituted by a four-roller rolling mill, and as the processing rolls 4a, 4b, a roll having a different diameter as shown in the figure is used. And among the processing rolls 4a and 4b, only the lower large-diameter roll 4b is rotationally driven using a motor or the like (not shown). The upper small-diameter roller 4 a is configured to rotate freely without giving a drive. Since a bending machine (not shown) is attached to the processing rolls 4a and 4b, bending can be applied to the processing rolls. In addition, each processing roller 4a, 4b also has a CVC function, which moves the two in a range of 10 Omm in both directions (please read the precautions on the back before filling this page). The paper size printed by the Ministry of Intellectual Property Bureau's Consumer Cooperatives applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -13- 565474 A7 B7____ V. Description of the invention (11) As mentioned above, for processing rollers 4 3 '4 b provides the bending function and c V c function, so it can improve the shape control performance of the rolled material, and can obtain a good profile (shape) of the steel plate. Processing roller 4 a diameter of 4 8 Omm 'processing light 4 b diameter 6 0 0 mm, which is the average equivalent light diameter of 5 4 0 mm ° About this kind of structure and function 'there are two different diameter lighter rollers in the rear and two different diameter rollers 5' 6 There is also no difference in the above-mentioned different diameter light dryer 4. In addition, the processing rate of the ‘reducing roller_Kun mill 4’ 5 ’6 is equivalent to a light diameter of Kun, although it may be less than 5 mm ′, but it is more than 400 mm or more from the viewpoint of strength. These three different-roller rolling mills 4, 5, 6 are printed by the Intellectual Property Bureau of the Intellectual Property Bureau of the Ministry of Economic Affairs because the equivalent roll diameter is a small diameter, and only one processing roll (4b, etc.) is driven. The _ rolling material P has a shearing force effect. Therefore, a relatively low rolling load can also be implemented with a high rolling reduction rate (for example, a rolling reduction rate of 50%). Therefore, rolling with a high rolling reduction ratio (for example, a rolling reduction ratio of 50%) can be performed with a small rolling load. Therefore, with a small rolling load, it is possible to carry out large-scale rolling and the like that require the formation of a fine ferrous iron structure in the material to be rolled P. And because the rolling load is small, it does not cause unfavorable situations that arise from light flatness and edge-drop. The line drawing X 3 in FIG. 6 indicates that the steel plate 6 with different diameters is provided with a thickness of 2.3 mm and a width of 7 30 mm (composition: C: 0-16%, Si: 〇-22%, Mn: 0.82%) When rolling is manufactured at the same reduction rate (48%), how will the rolling load change as the equivalent diameter of the processing roll changes? -14- The paper size is in accordance with Chinese National Standard (CNS) A4 specification (2⑴ × 297mm) 565474 A7 B7 V. Description of the invention (12) 〇 In addition, the line graph X 5 in Figure 7 is shown in a certain different diameter roller Rolling mills 5, 6 (the diameters of the processing rolls 5a, 6a are 480mm, 5b, 6b are 60mm, and the equivalent roll diameter of each rolling mill is 5400mm) When rolling the same steel sheet as in Figure 6 The occurrence of the thinning of the plate end. The line graph X 4 in Fig. 7 is shown for comparison. The processing lightness is not a different diameter roller but a same diameter (600 mm medium diameter) for rolling. The thinning of the plate ends that occurs when manufacturing the same steel plate. As a modification of this embodiment, as shown in FIG. 9, the rollers arranged in the rear stage are replaced by the reducer rolling mills 4, 5, and 6 and each of the diameters is less than 600 mm. It is also possible to process small-diameter roll mills 4 ', 5', 6 'such as the rolls 4a', 4b '. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Furthermore, in the hot rolling device according to this embodiment, a lubricant supply mechanism is provided for each of the processing rolls of the six rolling mills 1 to 6. The same mechanism is composed of the ejection port facing the surface of the power roller and the pushing pump for the lubricant there, as indicated by reference numerals 5e, 5f, 6e, and 6f in Fig. 3. As a modification, instead of applying lubricant directly to the surface of the processing roll, lubricant may be applied to the surface of the material P to be rolled and indirectly supplied to the surface of the roll. Furthermore, in the hot rolling apparatus according to this embodiment, the lubricant is used to prevent wear on the surface of the roll, not to reduce the coefficient of friction. As a lubricant, a solid lubricant containing fine particles of calcium phosphate, mica, calcium carbonate and the like in butter was used. The size of this paper is matched with these solid particles, and the paper size is in accordance with the Chinese National Standard (CNS) A4 (210X297 mm) -15- 565474 A7 B7 V. Description of the invention (13) Each processing roller and rolled The coefficient of friction between the materials P is about 0 · 2 8 or higher. If this degree of friction coefficient can be ensured, it is possible to appropriately prevent the roll of the rolled material P from slipping. When the lubricant is used as described above, the above-mentioned fine particles are interposed between the surface of the roll and the material to be rolled, which can prevent the roll. The direct contact between the material to be rolled can reduce the wear on the surface of the roll and be rolled. The shape of the material P can be maintained well for a long time, and the solid particles are not contained in the mineral oil, but are contained in the butter, so there is no risk of the precipitation of the particles in the lubricant storage container, and the solid particles The points of interest are often evenly distributed on the surface of the roll. Figure 8 shows the effect of reducing the friction of the roller caused by the use of a lubricant. Line graph X 6 shows a case where no lubricant is used, and line graph X 7 shows a case where a lubricant is used. The horizontal axis of Fig. 8 indicates the load of the processing roller, and the vertical axis indicates the friction amount of the processing roller. Furthermore, in the hot rolling apparatus of this embodiment, curtain-wall-type coolers are arranged on the exit sides of the three different-diameter rollers 4, 5, and 6 arranged in the subsequent stage. Take the cooler 7 B as an example, that is, as shown in FIG. 3, the cooler 7B is from the top 7B a, and the consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs prints 7 B b toward the rolled material P. The full-width surface will impact a large amount of room-temperature cooling water in a laminar flow and in a curtain-like shape (curtain-flow, thickness 10 mm or more, optimal thickness 16 mm) to cool the rollers aggressively. The amount of cooling water of the rolling material P ° is based on the unit width of the rolled material P, which can be adjusted within the range of 1 0 ~ 5 0 0 m3 / h per meter. It is caused by cooling. -16- This paper size applies to China National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7 V. Description of the invention (14) The temperature drop of the rolled material P becomes more than 20 ° c / se C. In the curtain wall type cooler, cooling water of 350 m3 / h per unit width is usually used. However, at this time, the temperature drop rate of the rolled material P is based on the product of plate thickness and speed of 12 Omm · mpm. It can reach 60 ~ 8 Ot / sec (including temperature rise due to processing heat and around 40 t: / sec). The structure and function of other coolers 7 A and 7 C are the same. In addition, in the hot rolling device of this embodiment, curtain wall type coolers are arranged on the exit side of each of the rolling mills 4, 5, and 6, but the number of set coolers is not limited to this example. The type of material can be changed as appropriate. By using such curtain wall type coolers 7 A, 7 B, 7 C, it is possible to suppress the temperature rise of the rolled material P caused by processing heat during rolling, and to maintain the rolled material P suitable for large rolling. The rolling method or controlling the temperature range of the rolling method can also suppress the growth of grains caused by the fine structure after rolling. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs and located on the transfer platform (not shown) on the downstream side of the hot rolling device in Fig. 1. The cooling water is also used at 10 ° C / sec to prevent grain growth. The material to be rolled P is cooled at the above speed. A water-jet sprayer 8 is arranged at a distance from the curtain wall-type cooler 7 C at a distance of several hundreds to 1 m from the exit side of the reducer roll milker 6 at the last stage of the hot rolling device in FIG. 1. This is for removing the cooling water placed on the rolled material P by the cooler 7C. As shown in Figure 3, 'this sprayer 8 is composed of a plurality of nozzles 8 a, and for the paper size of the rolled material P, the Chinese National Standard (CNS) A4 specification (210X297 mm)-_ 565474 A7 B7___ 5. Description of the invention (15) The surface is slanted downward from above the rolled material P toward the upstream side of the flow direction of the rolled material P so that the angle with the upper surface of the rolled material P becomes 65 ° ( Or within the range of 50 ~ 80 °), there are a plurality of nozzles 8a blown out at a pressure of 10 kg / cm2 before and after each 300 liters per minute. (This example is four). As shown in FIG. 3, the plurality of nozzles 8a are arranged at intervals in the longitudinal direction of the rolled material P and at intervals in the width direction thereof, and each of the nozzles 8a is located at the rolled material P. For those spouting water that expands in the width direction, the widening angle of the rolled material P in the wide direction is 15 to 30 °, and the widening angle of the longitudinal direction is 1 to 10 °. (The morphology of this embodiment is 21 ° and 3 °, respectively). When the above-mentioned water jet sprayer 8 is used, the cooling water placed on the rolled material P by the cooling mechanism 7 can be smoothly removed. Therefore, it can be appropriately determined by each measuring device provided on the downstream side thereof. The rolled material P after the rolling is measured, in other words, various measurement data on the manufactured steel sheet. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. The water system is better than gas, so it is easy to give transport functions. It is also easy to obtain, so it is suitable as a jet fluid. The pressurized water is sprayed obliquely downward toward the upstream side, so that the cooling water can be prevented from flowing to the downstream side (equipped with the measuring device side), and a nozzle widening in the width direction of the rolled material P The fact that cooling water can be removed at the full width of the rolled material P may be the reason to achieve its good effect. For the processing rolls of each rolling mill, as shown in Figure 3, the spray nozzles (for example, 5 i, 5 j '6 i, 6 j) are equipped with cooling water for the rolls, and the cooling water caused by it is removed. The water-removal plate (for example, No. -18- this paper size applies to the Chinese National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7 V. Description of the invention (16) 5g, 5h, 6g, 6h) also. (Please read the precautions on the back before filling out this page.) The following shows an example of implementing the hot car L using the above hot rolling device (Figure 1). For steels with chemical composition of: C: 0.16%, Si: 0.22%, Μη: 〇.82% (other components that do not contain any amount of interest), the thickness is 2.3 by the rolling device shown in Fig. 1 A steel plate with a width of 3 mm and a width of 73 mm was manufactured under three conditions (Examples 1 to 3). The following table 1-1 shows the through plate reservation table (rolling conditions) of Example 1, and Tables 1-2 show the through plate reservation table of Examples 2 and 3. Tables 1 to 3 are the use conditions of curtain wall type coolers 7A, 7B, and 7C in each of Examples 1 to 3. Table 1 to 4 are measured in each of Examples 1 to 3 after the last rolling mill 6 The finishing temperature of the rolled material P. "Rough rolling" in each table indicates a rough rolling device. "F 1" to "F 6" refer to each of the rolling mills 1 to 6 of the first to sixth stations. Regarding the rolling speed, there is no particular limitation, and the rolling speed (for example, 7 to 9 m / sec) commonly used in general hot strip rolling mills is adopted. Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs -19- This paper size applies to China National Standard (CNS) A4 (210X297 mm) 565474

7 B V. Description of the invention (17) [Table 1-1] Example 1 Through plate schedule (cumulative strain = 0 · 6 5) Rough rolling F1 F2 F3 F4 F5 F6 Sheet thickness Mm 40 22.82 12.55 7.53 4.89 3.33 2.33 Rolling Shrinkage% 43 45 40 35 32 30 Strain-0.55 0.58 0.50 0.42 0.38 0.35 Cumulative Strain — 0.65 [Table 1-2] Example 2, 3 Through Board Schedule Table (Cumulative Strain = 0 · 92) (Please read the back Note: Please fill in this page again)-Packing. Order printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs [Table 1-3] Cooling conditions (curtain wall type) Example F4 after F5 After F6 After 1 Not used Not used 2 Not used Not used 3 Used roughed F1 F2 F3 F4 F5 F6 Sheet thickness Mm 40 25.96 17.39 12.17 7.06 3.88 2.33 Rolling reduction% 35 33 30 42 45 40 Strain — 0.42 0.40 0.35 0.53 0.58 0.50 Cumulative strain 0.92 -20- This paper size applies to China National Standard (CNS) A4 (210X 297 mm) 565474

Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (18) [Tables 1-4] Temperature conditions Example Finishing temperature 1 800 ~ 850 2 800 ~ 850 3 750 ~ 780 Tables 1-5 indicate The ferrous iron particle size and mechanical properties of the hot-rolled steel sheets obtained in Examples 1 to 3. In Tables 1-5, "TS" is the tensile strength, "YP" is the drop point, and "EL" is the extension. Also in Tables 1 to 5, the main rolling conditions shown in Tables 1 to 1 to 3 are also noted. [Tables 1 to 5] Rolling bar f 戸 and mechanical properties Example Curtain wall type cumulative fertilizer grain iron particle size TS YP EL Cooling strain β m kg / mm2 kg / mm2% 1 F6 0.65 6 to 9 40 to 50 30 to 40 25 to 30 2 F6 0.92 4 to 4.5 55 to 65 45 to 55 25 to 30 3 F4, F5, F6 0.92 3.5 to 4 57 to 65 49 to 57 26 to 30 TS ·· Tensile strength, γρ: drop point, EL : The extension is shown in Tables 1-5, which is the embodiment 2 and 3 of which the cumulative strain (the above-mentioned weighted accumulation 値 ee) is set to 0-9. The particle size is the size of the paper and the Chinese national standard (CNS) is applied. ) A4 size (210X 297mm) (Please read the notes on the back before filling this page)

-21-565474 A7 B7 V. Description of the invention (19) (Please read the precautions on the back before filling in this page) 4 // Steel plate with excellent mechanical properties before and after the ferrite grain structure. The third example (F 4 to F 6) on the back side (rear side), and the curtain wall type cooler 7 A to 7 C was used in Example 3 to obtain a ferrous iron particle size of 4 // m or less. 'Mechanical Particularly excellent steel sheet. Fig. 4 is a graph showing the relationship between the grain size (grain diameter D (// m times-1/2)) and the yield point of the crystal grains of the ferrous iron structure for the steel plates obtained in Examples 1 to 3. As shown in the figure, when the cumulative strain of the three rolling mills in the latter stage is set to 0 · 65 (group X2 in the fourth figure), the particle size is 0.43 or less (particle size 5 · 4 // m or more ) And the drop point is not sufficient, but when the cumulative strain is set to 0.92, the particle size becomes about 0.5 (particle size 4 // m), and the drop point can be increased to more than 4 5 kg / m 2. Figures 5A, 5B, and 5C are diagrams showing the crystal structure of the steel plate obtained in Example 3 near the upper surface, near the center of the plate thickness, and near the lower surface, respectively. Any part is formed with a fine ferrous iron organizer with a particle size of 3 // m. The employee consumer cooperative of the Intellectual Property Bureau of the Ministry of Economics has printed it as described above. According to this embodiment, it can be smoothly produced. Fine ferrous iron structure. Including the balance of tensile strength, elongation, toughness and fatigue strength Excellent fine-grained steel hot-rolled steel sheet. Commercial (industrial) production of the same steel sheet is also possible. The reasons for this are summarized in the following 〇a , 6 or very small diameter roll mills 4 ', 5', 6 'is because the equivalent roll diameter or the processing rolls of both sides (a pair) are small, so it can be made with a low rolling load. -22- This paper size applies to China National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7 V. Description of the invention (20) (Please read the precautions on the back before filling this page) Implement large rolling, in other words, rolling with high rolling rate . The rolling load that achieves the same reduction ratio is because the smaller the diameter of the processing roller, the smaller the diameter is roughly proportional to the processing light diameter (see Figure 6). When the rolling load becomes smaller, the phenomenon that the roll cannot be rolled due to the flatness of the roll can be eliminated, and the thinning of the plate end due to the reduction of the flat deformation of the roll can also be reduced (see Figure 7 of P language) ). b) The curtain wall type coolers 7 A, 7 B, and 7 C installed in the rear section will suppress the cumulative strain of 0.9 or more caused by rolling with a high shrinkage rate caused by the roller L material P caused by processing heat Temperature rise. The same as the coolers 7A, 7 B, and 7 C, the rolled material P is strongly cooled with the flowing large amount of cooling water as described above, so the rolled material P can still be maintained at a suitable level when the rolled material P is accelerated. The temperature range in which the large reduction rolling method is implemented (for example, A r 3 abnormal point ~ A r 3 + 50 ° C). As described above, the material P to be rolled after the strong cooling roll is rolled can thereby stop the grain growth of the fine structure in the material to be rolled P. And the crystal grain size of the ferrous iron structure in the manufactured steel plate can be as fine as 4 // m or less. The employee consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs does not just print on the side of the rolling mill at the last stage, but The same side coolers 7 A, 7 B, and 7 C are arranged on the exit side of at least two rolling mills in the section, so the rolling of the last rolling mill 6 and the rolling mills of the preceding rolling mills can be effectively captured. The heat generated at that time maintains the most suitable temperature. It is also equipped with the same coolers 7 A, 7 B, and 7 C on the exit side of each rolling mill, so it can cool the rolled material P after rolling straight on each rolling mill to ensure that the fineness is stopped. The role of grain growth. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -23- 565474 A7 B7 V. Description of the invention (21) It is the same as the coolers 7A, 7B, 7C for the full width of the rolled material P The person who hits the cooling water can cool the rolled material P evenly in a wide direction without bias. As described above, according to this embodiment, the above-mentioned problems i), ϋ) of the large-scale rolling method can be solved, and a fine-grained steel plate using a general hot-strip rolling type rolling device is used. Smooth manufacturing becomes possible. The production of fine-grained steel plates is also possible. Furthermore, it is appropriate to use curtain wall type coolers 7A, 7B, and 7C to maintain the temperature range of the rolled material P at 7 0 ~ 80 0 ° C (temperature range), that is, steel containing Nb or Ti It is also possible to stably implement the above-mentioned controlled rolling method (for the production of fine-grained steel plates) for the rolled material P. It is also printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, and the carbon content of the rolling is 0.5%. In the following, when a rolled material with an alloy element content of 5% or less, a fine-grained steel plate of this composition is universal in terms of its mechanical properties (tensile strength or ductility), or It can be considered to be high because it has high weldability and is widely used, relatively inexpensive, easy to obtain, and also has reusability. Therefore, when there is a steel plate with this content, the social contribution is high, and the economic rationality will be accompanied by its production. Generally, when the amount of C (carbon) increases, the amount of iron in the fertile grains decreases and the steel becomes the main body of the boron body. Organizers with a main body of phytosomes can be obtained up to 5%. In addition, this embodiment does not consider alloys other than C in the rolled material P. This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 565474 Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Explanation of the invention (22) The presence or absence of the element can achieve the effect, but the temperature range of A r 3 ~ AI * 3 + 5 0 t: The temperature range is included in the optimal temperature of the thermal processing 7 〇 0 ~ 9 Ο Ο ° For the sake of C, it is appropriate to adjust the temperature of the abnormal point as the total amount of alloying elements. However, when the total content of alloying elements exceeds 5%, A r 3 is deformed, and it is difficult to obtain fine particles. Next, a hot rolling apparatus and a hot rolling method according to other embodiments of the present invention will be described. The hot rolling method according to the above-mentioned embodiment is to use a rolling mill in the subsequent stage as the center to strongly roll the rolled material (in other words, to implement a high rolling with a cumulative strain of 0.9 or more). At the same time, the material to be rolled is maintained at a suitable temperature to produce high-quality fine-grained steel steel plates with a grain size of less than 4 // m of the ferrous iron. In order to realize the above method, the hot rolling method shown in Fig. 1 adopts a structure in which the necessary rolling can be achieved with a relatively low rolling load while the rolled material can be cooled strongly. As a result, the material to be rolled is fully subjected to high shrinkage and strong cooling (temperature management), and it is possible to produce high-quality fine-grained steel hot-rolled steel sheet with a general tandem rolling device. However, the above-mentioned embodiment is to reduce the burden on the equipment or operation, and there is room for improvement in terms of the most efficient production of fine-grained steel hot-rolled steel sheets. In other words, by reviewing the degree of influence of the various elements of rolling and cooling on the metal structure of the material being rolled, etc., the reduction of quality (such as the particle size of fertilizer and iron) is greatly suppressed while Those who relax the manufacturing conditions and produce fine-grained steel hot-rolled steel sheets at low cost. As mentioned above, the rolling method is improved by the side of the cost to the effect, which is easy to manufacture, rich in practicality and a lower level of quality (particle size, etc.) (please read the precautions on the back before filling this page) -Installation · • Customized r-line This paper size is applicable to Chinese National Standard (CNS) A4 (210X297 mm) -25- 565474 A7 B7 V. Description of Invention (23) Commercial production of grain steel. (Please read the precautions on the back before filling in this page.) If the high level of high shrinkage described in the above embodiment is indispensable regardless of the quality of the steel plate, it is related to the rolling device or the roll. The consumption of rolls leads to an increase in production costs. It is also caused by the heating of the rolled material due to high rolling shrinkage, and the cooling mechanism also requires higher equipment costs and operating costs. The hot rolling apparatus and method according to this embodiment are those who solve this problem. The continuous hot rolling device of this embodiment shown in FIG. 10 is a so-called finishing rolling device of the rolled material P, and heating is provided on the upstream side (not shown) in the flow direction of the rolled material P. The furnace and the rough rolling device are provided with a transfer platform or a coiler on the downstream side (not shown). Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs This hot rolling device is a series of 6 to 10 rolling mills equipped with a total of 6 rolling rolls. The material to be rolled P, which is rough-rolled on the upstream side, is continuously rolled. Usually, hot-rolled steel plates with a thickness of 2 to 16 mm are manufactured. On the one hand, smooth rolling of steel plates with a general internal structure (average grain size of iron particles is greater than 10 // m) can be carried out smoothly, and fine-grained steel rolling can be performed by appropriately setting the operating conditions. In other words, for a hot-rolled steel sheet of fine grain steel that is manufactured and has a fine-grained iron structure, the rolling device shown in FIG. 10 is constructed as follows. First of all, three sets of so-called CVC rolling mills 10, 20, and 30 are arranged in series. As shown in FIG. 10, four are formed by processing rolls 101a, 101b and backing rolls 10lc and 10ld. It is composed of heavy rolling mill, and the processing rolls 1 0 1 a, 1 〇 1 b are provided with the ridges (CVC, that is, the continuous change of diameter) as shown in Figure 1 A, plus the paper size applies the Chinese national standard (CNS ) A4 specifications (210X297 mm) -26- 565474 A7 B7 V. Description of the invention (24) The work rolls 101a and 101b are as shown in Figure 11B and Figure 1C (please read the precautions on the back before filling this page) It can be moved (shifted) to the opposite axial length direction at the same time. Thus, the positional relationship between the rollers can be adjusted, in other words, the roller gap. The diameter of the processing rolls 101a and 10lb is set to 700mm, and the maximum displacement is set to 100mm in the forward and reverse directions. The other two CVC roll mills 20 and 30 have the same structure and function as the CVC roll mill 10. The reason why the CVC rolling mills 10, 20, and 30 are arranged in the front stage is to properly maintain the bulge (shape) of the rolled material P. Since the different-diameter roller rolling mills 40, 50, and 60 described later are susceptible to thermal crowns and the like caused by processing heat generated during the rolling of fine-grained steel, they are set in advance by The CVC rolling mill in the previous stage 10, 20, 30 is used to correct the plate bulge in order to reduce the rolling shrinkage of the rolled material P in the middle. Each of the CVC rolling mills '10, 20, and 30 processing rolls 101a' 1 〇1 b, etc. are connected to an AC motor with a variable speed control mechanism (not shown) via a speed reducer or a free connector (not shown), respectively. Show). Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. In the subsequent three stages, so-called reducer roll mills 40 ′ 50, 60 are also arranged in series. The interval between all six units including the above-mentioned CVC rolling mills 10, 20 '30 is equal to 5 · 5m. From the CVC rolling mill 10, the fourth reduced-diameter rolling mill 4 0 is, as shown in Fig. 10, composed of processing rolls 104a, 104b, and backing rolls 104c'1 04. The quadruple rolling mill formed by d is constituted. Processing_104a'104b used in this example is the one having different diameters. Only in Likougong _ 1 0 4 a, 1 〇 4 b The large diameter roller on the lower side. The paper size is applicable to China National Standard (CNS) A4 (210x297 mm) -27- 565474 A7 B7 V. Invention Explanation (25) (Please read the precautions on the back before filling out this page) 1 〇4b, variable speed control mechanism is connected to the motor (not shown) through the reducer and free joint (universal joint), etc. AC motor) to rotate. For the small-diameter roller 10 4 a on the upper side, even if it can rotate freely, no driving force is given. Since the bending rolls (not shown) are attached to the processing rolls 104a and 104b, bending may also be added to the processing rolls 104a and 104b. In addition, the CVC function is provided to each of the processing rollers 104a and 104b, and both of them can be moved in the axial length direction within a range of 100 mm in the forward and reverse directions. Since the diameter of the processing roll 10 4 a is set to 480 mm and the diameter of the processing roll 10 4 b is set to 600 mm, the average equivalent roll diameter of the two is a small diameter of 5 40 mm. Regarding the above-mentioned structure and function, the other two different-diameter roller mills 50 and 60 are the same as the aforementioned different-diameter roller 40. The Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs printed 3 sets of different-diameter roll mills 40, 50, and 60. Because the equivalent roll diameter is a small diameter, and only one processing roll 104b is driven, The rolling material P is subjected to a shearing force, so that a comparatively small rolling load can still be rolled with a high reduction ratio (for example, a reduction ratio of 50%). Therefore, under a small rolling load, rolling with a large reduction rate for fine-grained steel rolling is performed to an extreme degree, and at this time, because the rolling load is small, it lies in the thin plate before and after the thickness of 2 mm. "Under rolling" can still avoid the unfavorable situation caused by the flatness of the roll or the thinning of the end of the plate. In order to continuously implement the rolling of fine-grained steel, 'necessary cooling is required. The Chinese standard (CNS) A4 size (210X297 mm) is applied to this paper size. -28-565474 A7 B7 V. Description of the invention (26) (please first (Please read the notes on the reverse side and fill in this page.) It is necessary to keep the rolling material P in a suitable temperature range. Therefore, each of the rear and / or front portions of the rolling mills 40, 50, and 60 at the rear stage of the hot rolling device is equipped with a curtain wall type cooler 1 07 (No. 12) (No. 107A to 107H in the figure). Each cooler 107 is provided with a head located above or below toward the full width surface of the rolled material P, and a large amount of room temperature cooling water (such as the first 2 The reference number f) is a cooling mechanism. The thickness of the cooling water (curtain thickness) to flow into a curtain shape needs to be more than 10mm. A degree of 16mm is suitable because of the cooling effect. The amount of cooling water of each cooler 107 can be adjusted within the range of 100 ~ 500m3 / h per unit width (lm) of the rolled material P, so as to provide for the cooling of the rolled material P. It is appropriate that the temperature drop rate can reach more than 2CTC / S ec. If you want to strengthen rolling, use 350 m 3 / h of cooling water per unit width. At this time, the temperature drop rate of the rolled material P is 60 to 80 ° C / sec when the product of sheet thickness and speed is 1200mm * mpm (including the rise in temperature due to processing heat and 40 ° C / sec. around sec). Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The cooler 107 shown in FIG. 10 is provided with a plurality of tools above and below the rolled material P as shown in FIG. 12. The upper part is the rear part of the rolling mill 40 and the front part and the rear part of the rolling mill 50, and the front part and the rear part of the rolling mill 60 are provided with a cooler 1 〇 A '107B, 107D, 107E' 107G ° Rolling mill 4 0, 5 0, 6 0 respectively -29- This paper size applies Chinese National Standard (CNS) A4 (210X297 mm) 565474 A7 B7 V. Description of the invention (27) Coolers 107C, 107F , 107H. These coolers 10 7H are located behind the rolling mill 60 in the last stage and are mounted on the frame of the transfer platform T. Other coolers 1 0 7A to 10 7G are mounted on the casing of each unit. The curtain wall type cooler 7 configured as described above is used at each exit side of the rolling mills 40, 50, 60 and so on at the rear stage, so that it is implemented by using the hot rolling device according to this embodiment. In the case of a large heat rolling method or a controlled rolling method, it is still possible to suppress the increase in the temperature of each of the rolling mills 40, 50, and 60 to be maintained by the rolled material P in a suitable temperature range, and it can be suppressed. The grain growth is caused by the fine structure after rolling. It also lies on the transfer platform located on the downstream side of the hot rolling device as shown in Fig. 10. It also uses cooling water to cool the rolling mill to prevent grain growth. As shown in FIG. 10, the hot-rolling finishing rolling device is a curtain wall type cooler 1 0 (1 0 7 G, 1 〇7 Η) at the exit side of the rolling mill 60 at the final stage. A water jet sprayer 108 is arranged at a position on the downstream side of several hundred mm to 1 m. These are used to remove the cooling water placed on the surface of the rolled material P by the coolers 10 7G, 107H, and the nozzles (not shown) are arranged on the surface of the rolled material P by a plurality of nozzles (not shown). The person who blows the pressurized water from the upper side of the rolled material P toward the upstream side in the flow direction of the rolled material P so as to expand in the width direction of the rolled material P. When such a water jet sprayer 108 is used, the cooling water placed on the rolled material P can be smoothly removed by the cooler 107, so various measuring devices (thermometers) on the downstream side can be removed. (Not shown) to properly measure various kinds of rolled material P after rolling (light paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) (please read the precautions on the back first) (Fill in this page again)

Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs -30- 565474 A7 B7 V. Description of the invention (28) Rolling completion temperature, etc.) Due to the high accuracy of the measurement, the cooling completion can be accurately controlled by controlling the cooling water amount Rolling conditions such as temperature. The rolling completion temperature of the rolled material P was measured with a thermometer installed downstream of this water jet sprayer 108 and about 2 m downstream from the rolling mill 60 at the last stage. The calculation and operation mechanism (not shown) of the measurement results increase or decrease the cooling water amount of each curtain wall type cooler 1107 (especially the coolers 107E, 107G, 107H of the rolling mill 60). The feedback completion is used to control the rolling completion temperature 'so that it is maintained in a suitable range. The continuous hot-rolling device constructed as described above is capable of producing a fine-grained steel hot-rolled steel sheet of about 2 to 6 m in order to ensure sufficient productivity at a sufficient speed (for example, 7 to 9 m / s e c). Specifically, rolling can be carried out so that the cumulative strain (the above-mentioned accumulative accumulation 値 ε.) Can be greater than or equal to 0.6, and the rear side of each of the rolling mills 40, 50, and 60 is a curtain wall type cooler. 1 0 7 Gives strong cooling, so even though the steel with low carbon content and alloying element content is under the rolled material, it can still produce an average fertilizer grain iron particle size of 3 ~ 7 // m Fine grain steel plate. Although fine-grained steel may also have poor elongation, these shortcomings can be eliminated in this example. The possible reason for such good production is that the curtain wall type cooler 10 with high cooling capacity is used in the stage after the metal structure has a large influence, and the temperature of the rolled material P is maintained at a suitable level. Below the range, a small diameter reducer can be used on one side. _ Rolling mill 4 0, 5 0, 6 0 (Please read the precautions on the back before filling out this page.) • Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) -31-565474 Printed by A8 Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs A7 ___B7_ V. Description of Invention (29) Implementation can achieve the above cumulative strain Because of high rolling rate of rolling. In the rolling mills 40, 50, and 60, the "roll flatness" and "thinning of the plate end" can be avoided, and the "crowding" control can be implemented by the CVC function of each rolling mill 10 ~ 60, so the thickness Even after the thinning, the meandering or shape deterioration of the rolled material P can be suppressed. Therefore, in this embodiment, rolling of fine-grained steel can be smoothly performed with ample capacity, and the steel sheet can be made into a product with high shape accuracy. Regarding the fact that suitable fine-grained steel plates can be produced under the above-mentioned conditions, the inventors have changed the strength of the cooling of the rolled material P by using the hot rolling device shown in FIG. 10 (rolling completed) Temperature), and the degree of rolling (cumulative strain), and many experimental investigations are carried out to find out the verified ones. The results of this test and investigation, as well as information on an example of a suitable fine-grained steel plate, are disclosed below. Using the hot rolling apparatus of this embodiment, test rolling was performed by changing the pass schedule and the rolling completion temperature for the steel types (excluding other significant components) shown in Table 2-1. However, the sheet thickness on the exit side of the last-stage rolling mill 60 of any one is 2 to 3 mm, and the rolling speed is 8 to 9 m / s e c. [Table 2 — 1] (Please read the precautions on the back before filling out this page)

Chemical composition of steel 1% (% by weight) Metamorphic point (° C) C Si Μη Αγ3 Example 0.16 0.2 0.8 785 This paper size applies Chinese National Standard (CNS) A4 specification (21〇χ; 297 mm) -32- 565474 Printed by the Consumer Property Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of Invention (3Q) For various types of steel plates obtained by test rolling, the grain size of the ferrous iron was measured at the center of the thickness, and the rolling was investigated. The relationship between the cumulative strain at the time and the working temperature (rolling completion temperature). The horizontal axis is the cumulative strain 'and the vertical axis is fat iron, and the relationship between the two is shown in Fig. 13. In Fig. 13, the symbol • indicates the data in which the finishing temperature is within the range of A 3 transformation point ± 10 ° C. ▲ The symbol indicates that the same temperature is lower than A r 3 abnormal point -10 ° C. The symbol indicates that the same temperature exceeds A r 3 abnormal point + 1 〇 T: The data (the same is shown in Figures 13 to 17) ). According to Fig. 13, when the finishing temperature exceeds the AI * 3 abnormal point + 1 0 t, although it can be seen slightly, as the cumulative strain increases, the grain size of the iron particles decreases, but finishing When the temperature is outside this range, the iron grain size of the fertilizer grains will hardly decrease even if the cumulative strain is increased. Figure 14 shows the relationship between the horizontal axis and the diameter of the ferrous iron particles on the vertical axis to indicate the relationship between the two. From Figure 14 it can be seen that the lower the finishing temperature, the smaller the particle size of the iron particles significantly decreases. Situation. In addition, in the diagrams (Figures 15 to 17) where the mechanical properties of each manufactured steel plate are investigated, and the results are related to the diameter of the ferrite grains (Figures 15 to 17), the horizontal axis The particle size (// m) is multiplied by-1/2. Fig. 15 shows the relationship between the iron particle size of the fertile grains and the tensile strength (µ P a) '. Fig. 16 shows the relationship between the iron particle size of the fertile grains and the elongation (%). According to the results described above, the smaller the iron particle size of the fertile grains (the horizontal axis is to the right), the higher the tensile strength tends to be. However, when the finishing temperature is lower than the A 3 transformation point -10 ° C (▲ in the figure), it will extend with the refinement of the fertilizer iron I m Jn I —J—! 11-II j ill— T — —A—-(Please read the notes on the back before filling this page)

、 1T _ · ι The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) -33- Printed by the Intellectual Property Bureau Employee Consumer Cooperatives of the Ministry of Economic Affairs 565474 A7 B7 5. The invention description (31) has also been reduced trend. The product of tensile strength and elongation (MP ax%) can also be seen from Fig. 17 that when the A 3 abnormality point is less than 10 ° C, it will become smaller with miniaturization. Based on these results, we can understand The following facts. a) In order to obtain a fine-grained hot-rolled steel sheet with a small grain size of ferrous grains and iron in accordance with the rolling device according to this embodiment (figure 10), the measures of increasing the cumulative strain are compared with the setting of the finishing temperature When the temperature is lower, the effect of lower temperature is greater. b) However, when the finishing temperature is excessively lowered compared with the A 3 abnormal point, although fine graining will progress, the extensibility will be reduced, so the strength point is reduced. c) If you consider that when the high rolling shrinkage is implemented in order to increase the cumulative strain, the cost will increase due to the configuration of the rolling device and the consumption of the rolls, that is, do not increase the cumulative strain too much (for example, 0. 6 (preferably 0 · 65) or more, but less than 0.9, and the precise management of the finishing temperature is the most suitable point for the effect of the cost of manufacturing fine-grained steel plates. Keep the finishing temperature at Within the range of A r 3 abnormality point ± 50 ° C, fine-grained steel with a particle size of 4 ~ 6 // m and excellent mechanical strength balance can be produced. In order to obtain high tensile strength For steel plates, set the finishing temperature at, for example, A 3 transformation point-50 ° C to the same transformation point + 20 ° C, and when the extension point is also excellent, for example, set at A 3 transformation A point of 20 ° C ~ the same metamorphic point + 50 ° C is sufficient. However, from the point of each strength and the balance of these, to observe the finishing temperature of IIII batch ^ order II line (please read first Note on the back, please fill in this page) This paper size is applicable to China National Standard (CNS) A4 (210X297 mm) -34- 565474 a7 ___ B7 V. Description of the invention (32) The range of readings held at A 3 abnormality point ± 1 ° C is most appropriate. Table 2-2 ~ Table 2-1 and the first Figure 18 is an example of a good fine-grained steel plate manufactured based on the knowledge and experience gained from the above efforts. Also, "F 1 0" to "6 0" in A respectively represent the first One rolling mill 10 to the sixth rolling mill 60 each of the rolling mills 10 to 60. Table 2-2 shows the sheet thickness at the exit side of each rolling mill 10 to 60 ("rough rolling"). “Thickness” indicates the thickness of the plate at the exit side of the finishing roll mill), rolling reduction (%), strain, cumulative strain, and plate width. Tables 2-3 show the curtain walls at the rear of the rolling mill 40 to 60 Usage status and finishing temperature (rolling completion temperature) of the type cooler 7 〇 Tables 2 to 4 are steel plates obtained by implementing the conditions in Tables 2 to 1 to 2 to 3, showing the fat particles in the center of the plate thickness Iron particle size and mechanical properties: Figures 18A, 18B, and 18C are shown for steel plates printed by the Ministry of Economic Affairs ’Smart Money / $ ^ 7 Employee Consumption Cooperative Do not near the upper surface, and its thickness is 1/4 inside, the thickness of the central position of the crystalline structure of the figure. In any part of the formation of fertilizer grain iron particle size of 4 ~ 6 // m The organizer: In addition, the rolling in order to obtain the information in Figures 13 to 17 and the light rolling in order to obtain the light rolling in this embodiment are also light rolling devices according to this embodiment (refer to Figures 10 to 12). (Figure), but if you want to obtain rolling with a cumulative strain of 0.6 ~ 0 · 9 degree, it can be presumed to be the back stage and use the above-mentioned different-diameter roll rolling machine 40 ~ 60. In other words, as long as the paper size applies the Chinese National Standard (CNS) A4 specification (210X29 * 7 mm) -35- 565474 A7 B7 V. Description of the invention (33) The diameter of these rollers is about 6 0 0 ~ 7 0 Omm A rolling mill with processing rollers of the same diameter above and below is sufficient to achieve this. As long as these levels of accumulated strain are sufficient, even the thermal bulge caused by processing heat is not noticeable, so the necessity of imparting c V C function and bending function to the rolling mills 1 to 60 is also low. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs [Table 2-2] Example Rough rolling F10 F20 F30 F40 F50 F60 Plate width mm Plate thickness Mm 40 22.28 13.19 7.78 4.52 2.85 2.07 Rolling reduction% 44 41 41 42 37 28 670 Strain — 0.56 0.51 0.52 0.53 0.45 0.32 Cumulative strain — [Table 2 — 3] F 4 0 back F50 back F60 back finishing temperature ° c Example use use 782 -36- _ This paper is suitable for national standards of the country ( CNS) A4 specification (210X297 mm) 565474 A7 B7 V. Description of the invention (34) [Table 2-4] Mechanical characteristics; particle size of raw fertilizer grains β m TS Mpa YP Mpa EL% Example 4.5 519 43 1 34 TS: Tensile strength, YP: Drop point, EL: Extension (please read the precautions on the back before filling this page) In the continuous hot rolling method according to this embodiment, the manufacturing conditions can be relaxed and the cost can be reduced at a very low cost. It is possible to produce a fine-grained steel hot-rolled steel sheet having a sufficiently fine average grain size of ferrous iron and sufficiently high practical qualities such as mechanical properties. Printed by the Intellectual Property Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs in detail, a)-the use of multiple rolling mills to implement rolling with a cumulative strain of 0.6 or higher, and b) the number of The exit side of the rolling mill should strongly cool the rolled material P, so as to effectively capture the processing heat generated during rolling when the rolling mill before the last stage and the last stage is rolled to maintain a suitable temperature (for example, to complete the rolling The temperature is stored in the range of 50 ° C of the soil centered on the abnormal point of Ar 3, and the treatment to stop the grain growth of the fine structure can be made, so that the average iron grain size of the fertilized grains is less than 1 0 // m Fine-grained steel hot-rolled steel sheets are also available. The reason why fine-grained steel steel sheets can be obtained by this treatment is based on recent investigations conducted by the inventors. In other words, it was found that the high rolling shrinkage of the rolled material is high. Under the conditions of strong cooling conditions, the former conditions are slightly alleviated (in other words, the cumulative strain is not increased to 0.9), and the grains of the ferrous grains are not too coarse and high-quality fine grains. Gangsteel-37- This paper is of suitable size China National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7 V. Description of invention (35) (Please read the precautions on the back before filling this page) The fact of the board. Specifically, the carbon content is 0 · 5% or less, and the content of alloy elements is 5% or less of the thin plate, and the above-mentioned cumulative strain and cooling may make the average ferrous grain iron particle size of about 3 to 7 // m. If the cumulative strain is 0 · 6 When the above is sufficient, the rolling reduction necessary for each rolling mill, especially the rolling mill in the subsequent stage, becomes considerably lower (about 30%), and the costs necessary for equipment and operation can be greatly reduced. Therefore, it is not easy for the front end of the rolled material P to slip into one of the rolling mills to cleverly slip. In addition, the average grain size of the iron particles is less than 10 / m. Fine-grained steel plates are significantly more mechanical than ordinary (non-fine-grained) hot-rolled steel plates with a particle size of more than 10, and can be expected to have a wide range of uses. Employees, Bureau of Intellectual Property, Ministry of Economic Affairs Printed in detail by consumer cooperatives, with As mentioned above, the fine-grained steel plate with the chemical composition and the grain size of the ferrous iron is high in mechanical properties (tensile strength and extensibility, equal surface and general versatility), and also excellent in weldability, so it is widely used. ... and it is relatively cheap and easy to obtain. It is recyclable and therefore has high demand. Therefore, the rolling method according to this embodiment, which is used to manufacture this type of steel sheet, has high social contribution, and The production is accompanied by economic rationality. The hot rolling method according to another embodiment of the present invention will be described below. The hot rolling method according to this embodiment uses a hot rolling device according to the above embodiment as shown in FIG. 10. The method for manufacturing thick plates. In the hot rolling device according to the above embodiment shown in Fig. 10, the CVC rolling mills 10, 20, 30 and the reducer rolling mills 40, -38- This paper is applicable to China National Standard (CNS) A4 specification (210X297 mm) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 565474 A7 B7 V. Description of the invention (36) 5 0, 6 0 It is considered that the plate thickness will decrease as the rolling progresses While rolling The degree of increase will be lower, and the reduction ratio of the rolling mill in the later stage of the rolling mill will be lower, increasing the maximum number of rotations of the processing roll, and at the same time setting the maximum output torque to a low value. Moments are 1 2 5 · 0, 9 8.2. 61.4, 3 4.1. 22.7, 19.5 (the average unit is metric ton (tf) · m). In addition, using all the rolling mills 10 to 60 of the rolling apparatus according to the above embodiment shown in FIG. 10, the thickness can be produced at a speed (for example, 7 to 9 m / sec) that can ensure good productivity. Good fine-grained steel hot-rolled steel sheet of about 2 to 6 mm. Specifically, while the energy of the cumulative strain (the above-mentioned accumulative accumulated ε c) is 0.6 or more, rolling is applied, and at the rear of the rolling mills 40, 50, and 60 in the rear stage, the curtain wall cooling is used. The device 107 performs strong cooling, so that even if the steel with low carbon content and low alloy element content is used as the rolled material P, it can still produce an average fertilizer grain iron particle size of 4 ~ 6 / / m is a suitable fine-grained steel plate. In particular, when the cumulative strain is greater than or equal to 0 · 9, the average iron grain size of the fertile grains can be 4 // m or less due to the same steel type. Comparative Example A described later is an example of this (in the case of ε c 2 0.6). The possible reason for this kind of production is that the curtain wall type cooler 1 0 7 with high cooling capacity is used in Taichung, which has a strong influence on the metal structure, and the temperature of the rolled material P is kept in a suitable range. In the case, the reduction rolling with a high reduction ratio is carried out with a small-diameter different-roller rolling mill 40, 50, and 60. The reason is that in the rolling mills 40, 50, and 60, flatness or plate end can be avoided. Thin. This paper is also rolled in accordance with China National Standard (CNS) Α4 specifications (210 × 297 mm 1 7 ^ (Please read the precautions on the back before filling this page)

565474 A7 B7 V. Description of the invention (37) The CVC function of the machine 1 0 ~ 60 can be implemented to control the bulge, so it can suppress the meandering of the rolled material P or the deterioration of the shape, etc. after the thickness of the plate is reduced. This is also one of the reasons why rolling of such fine grain steel is possible. However, when the last stage rolling mill 60 is used instead of producing thin plates but produces fine-grained steel plates with a thickness of 6 mm or more, the last stage rolling mill 60 (or the preceding stage rolling mill) 50, etc.) There is a case where the output torque is insufficient to continue rolling (for example, the motor will stop). In the manufacture of thick plates, although the reduction rate is the same (or slightly smaller) than that of thin plates, the contact arc length becomes longer when the plates are thin, so a larger rolling torque is required. The rolling mill 60 in the last stage or the rolling mill 50 in the front stage is a case where the maximum allowable output torque is small as described above, and therefore the load cannot be continued as a result of the load being greater than the capacity. Such a case is shown in Comparative Example B described later. The reason why the latter rolling mill cannot exhibit sufficient rolling torque can be explained as follows. In the rolling mill in the latter stage, the drive system of the rolling roll is formed to perform rolling and becomes a high-speed specification as the rolling speed corresponding to the decrease in sheet thickness increases. In other words, it is higher than that in the preceding stage. The rotation speed is high (in other words, the reduction ratio is small) and the rolling torque is set lower. This is a common practice. In contrast, if you want to roll a thick plate, although the reduction rate is lower than that when rolling a thin plate, Since the contact arc length (contact length) on the entry side is long (the contact angle is large), the necessary torque becomes considerably larger than when the sheet is rolled. Therefore, although the rolling mill in the latter stage of low torque can smoothly roll the thin plate, due to the equipment capacity, the Chinese National Standard (CNS) A4 specification (210X297 mm) is applied to the paper size of the thick plate (please read first) Note on the back, please fill out this page again.) ·· ΊOrder printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economics-40- 565474 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economics A7 B7 V. Description of the invention (38) Necessary to impose It is difficult to produce a fine-grained steel sheet by rolling. In addition, as for the above-mentioned subject of the manufacture of thick-plate fine-grained steel steel plates in which a plurality of rolling mills are arranged in series, no document has been disclosed so far. The description in this description is described as the prior art in the above. The technology of the publication is only for the manufacture of fine-grained steel plates with a thickness of 3 mm to 5 mm or less, or for manufacturers using reflow-type rolling mills. Therefore, the present inventors, in order to use the continuous hot rolling device according to the above embodiment shown in FIG. 10, in other words, use a continuous hot rolling device that can manufacture thin-grained steel plates, and produce thick plates with a thickness of 6 mm or more For the production of fine-grained steel sheet, the rolling device is operated in the following a) to d). a) The last rolling mill 60 with a small output torque is not used, and the rolling mills 40 and 50 near it are also used if the required torque calculated from the plate thickness or rolling reduction rate, deformation resistance, etc. is greater than It is not used at the maximum allowable output torque. Therefore, among the rolling mills 60 at the last stage and the rolling mills 10 to 50 at the entrance side of the rolling device, three or more rolling torques can be satisfied, and they can be selected and used in accordance with the schedule of the plate. . b) The cumulative strain energy will be above 0.25 (preferably above 0.29), or among the three rolling mills used, the rolling reduction rate of the last roller L machine can be 12% Above (preferably 14%) set the through board schedule table. Since it is not implemented with a certain reduction ratio or more, it is difficult to minimize the particle size of the ferrous iron when rolling on a downstream rolling mill having a strong influence on the metal structure. (Please read the precautions on the back before filling out this page)-Installation · • Customized k This paper size is applicable to the Chinese National Standard (CNS) A4 specification (21 ×: 297 mm) -41-565474 Intellectual Property Bureau, Ministry of Economic Affairs Printed by employee consumer cooperative A7 B7 V. Invention description (39) c) Use curtain wall cooler 1 07 to cool the steel plate strongly (the temperature drop rate on the surface is about 40 ° C per second), cooler 1 0 7 It is at least the last one of the rolling mills in use, straight to the latter. It is preferable to use the cooler 107 (107A to 107H) including all the coolers in front of the rolling mill in the last stage. In order to make the grain size of the ferrous iron small, it is indispensable to sufficiently cool the rolled material P after rolling and keep it in a suitable temperature range, and to properly suppress the grain growth after rolling. d) By the cooling of c) above, the rolling completion temperature (the surface temperature of the rolled material P measured by a thermometer set at 60 m downstream of the last rolling mill) shall not exceed AI * 3 Abnormal point + 50 ° C (preferably below A 3 abnormal point). There should be a suitable lower limit, but the surface temperature drops a lot, which still does not hinder the production of fine-grained steel. This is because as long as the steel plate with a thickness of 6 mm or more is rolled at 2 to 3 m / sec, regardless of the surface temperature It is because the temperature near the center of the plate thickness of the rolled material P may be maintained at a temperature around the abnormal point of A r 3. As a result of rolling as described above, for a steel sheet having a carbon content of 0.5% or less and an alloy element content of 5%, the average ferrous grain iron particle size from the surface to the thickness of 1/4 inside can be produced. 1 0 // m thick hot-rolled steel plate with fine grain thickness. In the following, examples C and D are used to show such data on the production of thick steel plates. According to the above-mentioned continuous hot rolling equipment, the thin plate and thick plate of the fine-grained steel hot-rolled steel sheet are shown below with their respective rolling data. In each table, Comparative Example A is about the above-mentioned sheet (thickness i0 (please read the precautions on the back before filling this page) --- installed ) A4 size (210X29? Mm) -42- 565474 A7 __B7 V. Production description (4〇) 2.07mm) steel plate production. Comparative Example B is an example in which it is impossible to continue rolling by using a rolling mill 10 to 60 to produce a thick steel plate. Comparative Examples C and D are examples of smooth production of thick steel (thickness: 12 · 2 mm) fine-grained steel sheets using a rolling device. First, Table 3-1 shows the chemical composition of the steel plates of each of the Examples and Comparative Examples A to D (components that do not contain an intentional amount other than those indicated) and the temperatures at the A 3 abnormality points. Table 3-2 shows the rolling completion temperature (the temperature at the finish-out side) and the plate width of each steel plate. The use status of each curtain wall type cooler 107 in the rear of the rolling mill 40 ~ 60. Tables 3-3 show the sheet thickness on the exit side of each rolling mill from 10 to 60 ("rough rolling thickness" means the sheet thickness on the exit side of the rough rolling device), Tables 3-4, Tables 3-5, and Table 3 -6 represents the rolling reduction (%) of each roll 10 to 60 according to the through-board schedule in Table 3-3, and the rolling torque (metric ton · m) required for strain and cumulative strain. —! !! ♦ (Please read the notes on the back before filling in this page) -Installation · I order. • I line printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, Employees' Cooperatives. This paper is printed in accordance with China National Standard (CNS) A4 (210X297 mm). ) -43- 565474 B7 V. Description of the invention (41) [Table 3-1] Chemical composition (% by weight) of the steel Metamorphic point (please read the precautions on the back before filling this page) [Table 3-2] Through plate Schedule Table Example Finished Sheet Width Comparative Example Side Temperature [° C] [mm] F40 Back F50 Back F60 Back Comparative Example A 782 670 Use Usage Comparison Example B 757 660 Use Usage Use Example C 679 660 Use Usage Use Example D 676 660 Use the use of the intellectual property of the Ministry of Economics ¾ Printed by the Consumer Consumption Cooperative Example Comparative Example Component C Component Si Component M Ar Component [Arc] [° c] Comparative Example A 0.16 0.2 0.8 0.014 785 Comparative Example B 0.15 0.18 0.77 0.02 795 Example c 0.17 0.21 0.8 0.014 785 Example D 0.17 0.21 0.8 0.014 785 -44 The paper size applies to the Chinese National Standard (CNS) A4 specifications (210X297 mm) 565474

7 B V. Description of the invention (42) [Table 3-3] Example Thick rod F10 plate thickness F20 plate thickness F30 plate thickness F40 plate thickness F50 plate thickness F60 plate thickness Comparative example thickness [mm] [mm] [mm] [ mm] [mm] [mm] A 40.00 22.28 13.19 7.78 4.52 2.85 2.07 B 39.8 39.8 31.1 24.5 19.2 15.0 12.2 C 32.2 21.2 16.6 14.1 12.2 12.2 12.2 D 36.1 23.4 18.2 15.4 12.2 12.2 12.2 [Table 3 — 4] Example F10 F20 F30 F40 F50 F60 Comparative Example Rolling Rate Rolling Rate Rolling Rate Rolling Rate Rolling Rate Rolling Rate Rolling Rate [%] [%] [%] [%] [%] [%] Comparative Example A 44 41 41 42 37 28 Comparative example B 22 21 22 22 19 Example C 34 22 15 14 Example D 35 22 15 21! Ilr (Please read the precautions on the back before filling out this page) • Installation .. Printed by the Intellectual Property Bureau's Consumer Cooperatives [Table 3-5] Example F10 Strain F20 Strain F30 Strain F40 Strain F50 Strain F60 Strain Strain Comparative Example [-] [-] [-] [·] [-] [-] [-] A 0.56 0.51 0.52 0.53 0.45 0.32 0.68 B 0.25 0.24 0.24 0.24 0.20 0.39 C 0.41 0.24 0.16 0.15 0.29 D 0.43 0.25 0.17 0.23 0.38 paper The dimensions are applicable to Chinese National Standard (CNS) A4 specifications (210X 297 mm) -45- 565474 A7 B7 V. Description of the invention [Table 3 — 6 1 Example Comparative Example F10 Rolling Torque_ [t〇nm] F20 Roller Rolling torque [ton.m] F30 Rolling torque [ton-m] F40 Rolling torque [ton-m] F50 Rolling torque [torrm] F60 Rolling torque [torrm] Comparative example A __U2 59 48 31 19 16 Comparative Example B 38 36 25 23 23 Example C __1} 28 14 18 Example D 85 33 17 30 (Please read the precautions on the back before filling out this page) Installation. According to Table 3-6, you can know The torque required for the rolling mill 6 in the last stage of Comparative Example 1 B, which cannot continue rolling, is 2 3 t 〇n • m is greater than the allowable maximum torque of the rolling mill 6 〇 (19 · 5 t 〇η · χη). It can also be seen in Example d as shown in Table 3-5 'Implementing the cumulative strain system 0_ 3 8 of the stronger rolling and rolling, so the last stage of the rolling mill used in the rolling mill 40 needs to be as shown in the table 3-6 shows the fact that a large torque of 30 t ο η · ιη (in other words, the rolling mill 50 or 60 in the later stage will require a torque that it cannot exert). Tables 3 to 7 show the results of investigating the grain size and mechanical properties of the ferrous iron in the steel plates produced in the examples and comparative examples A to D. However, Comparative Example B only shows the data of the steel sheet obtained in a short period of time until it cannot be rolled. The particle diameters shown are those in which Comparative Example A is measured at the center of the thickness, Comparative Example B, and Examples C and D are measured at the inner position of the thickness of 1/4 on the surface. This paper size applies to Chinese National Standard (CNS) A4 (210X297 mm).

Printed by Du Intellectual Property Department of the Intellectual Property Bureau of the Ministry of Economic Affairs-46- 565474 A7 B7 V. Description of Invention (44) "TS" in the table is tensile strength, "YP" is the drop point, "EL" means extension, "L "Direction" indicates the length direction (rolling method), and "C direction" indicates the width direction. (Please read the precautions on the back before filling out this page.) It was found that the grain size of any of the ferrite grains was sufficiently small. The fact that the steel sheet is excellent in mechanical properties. [Tables 3-7] Mechanical characteristics TS: Tensile strength, YP: Drop point, EL: Extension Example L direction C direction L direction L direction L direction C direction C direction C direction Comparative Example Particle size TS YP EL TS YP EL [// m] [// m] [MPa] [MPa] [%] [MPa] [MPa] Γ%] ^ A 4.5 4.5 519 431 34 528 495 34 _ B 7.6 8.0 487 345 29 489 368 29 _ C 6.6 6.7 519 387 26 530 419 25 _ D 6.6 6.7 530 394 24 537 444 22 _ Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

Fig. 19A, Fig. 19B, and Fig. 19C respectively show the steel plate obtained in Example D, and show the crystal near the upper surface, the position on the inner side of the thickness 1/4, and the thickness in the center of the space. Organization chart. A fine structure with an average grain size iron particle size of 5 to 10 A m is formed at a position of 1/4 thickness, and a fine structure with an average grain size iron particle size of 1 〇 // m or less is also formed in the center of the thickness. In addition, Figures 20 to 22 are shown in Example D or its rollers. -47- This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7 5. Description of the invention ( 45) Rolled steel plates under conditions and investigated other mechanical properties. (Please read the precautions on the back before filling in this page.) First, Figure 20 is a graph showing the relationship between the grain size of ferrous iron and the tensile strength and yield point of fine-grained steel plates. (The diameter d (// m) of the iron particles in the horizontal axis is multiplied by 1 1/2. Figure 21 shows the changes in the temperature of the Charpy impact and the changes in ordinary steel (non-fine-grained steel plates). Figure 22 shows the temperature dependence of the brittle fracture rate. For the same steel plate produced, the joint tensile test, joint bending test, joint impact test, micro test, hardness distribution test, etc. of the welded joint in accordance with JISZ 3004 "Confirmation Test Method for Welding Construction Method" are respectively plural. Each of the results obtained from the test pieces confirms the fact that the fine-grained steel sheet has excellent weldability. Printed by the Intellectual Property of the Ministry of Economy ¾ Employee Consumption Cooperative As mentioned above, in the continuous hot rolling method according to this embodiment, although the use of a plurality of rolling mills configured for the manufacture of thin plates is not used, it does not cause a shortage of torque The resulting unfavorable circumstances are available for the production of fine-grained steel plates for thick plates. The reason is that although the rolling mill in the last stage has a torque shortage, if the rolling mill is not used, in other words, only a drive system with a low speed specification and a high rolling torque can be used. In the rolling mill on the side of the rolling device of the rolling device, when the thick plate with arc length is contacted, it still does not become insufficient torque and can perform sufficient and sufficient rolling. Because the last roll is not used Rolling mills, etc., therefore, the rolling speed will not be high, but because the rolling speed is slow, it has the advantage of being easy to ensure, and due to the thick plate, the cooling time will be lengthened. As mentioned above, the reason for making rolled thick plates into fine-grained steel is: -48- This paper size applies the Chinese National Standard (CNS) A4 specification (210 × 297 mm) 565474 A7 B7 V. Description of the invention (46) (Please read the precautions on the back before filling this page.) The cumulative strain applied to the rolled material P is 0 · 25 or above (or the rolling reduction rate of the rolling mill in the last stage is above 12%). Rolling down ... and the exit side of the last rolling mill among the rolling mills used are cooled as described above for a sufficient time for the rolled mills; The more intense the above-mentioned cooling performed on the exit side of the rolling mill, the more fertile grains and fine grain steels having a small iron grain size can be obtained. In order to enhance the meaning of cooling, it is more appropriate to start cooling before the last rolling mill used, or to implement cooling at each exit side of a plurality of rolling mills in the subsequent stage. The continuous hot rolling method according to this embodiment is characterized in that the rolling completion temperature is characterized by not exceeding A I * 3 transformation point + 50 t. When the above-mentioned cooling strength is managed and the rolling completion temperature is set to the above, at least the vicinity of the surface of a steel plate (for example, a steel plate having a carbon content of 0.5% or less and an alloy element content of 5% or less) will be less than 10; / m of fine grains with a fine iron grain size. The temperature of the intellectual property airs of the Ministry of Economic Affairs (printed by the industrial and consumer cooperatives according to the temperature range suitable for large rolling is considered to be in the range of A r 3 abnormal point to A r 3 abnormal point + 50 0 t. According to the inventor In other tests, it is sufficient if the above-mentioned rolling completion temperature does not exceed the range of A 3 transformation point + 50 ° C. Although the surface temperature of the thick plate is lowered, the internal temperature is still maintained at The reason is near the abnormal point of AI * 3. In addition, the continuous hot rolling method of this embodiment uses a curtain wall type cooler 1 07 to strongly cool the rolled material P, so it can smoothly produce a special particle size. Fine fine-grained steel steel plate. Because it can achieve uniform cooling, it also has the full width of the steel plate to make the organization uniform. The paper size is applicable to China National Standard (CNS) A4 specification (210X297 mm) -49- 565474 A7 B7 The Intellectual Property Bureau of the Ministry of Economic Affairs (printed by the Industrial and Consumer Cooperatives, 5. Advantages of the invention description (47). The continuous hot rolling method according to this embodiment is especially the rolling carbon content of 0. 5% or less, alloy Element content below 5% It is characterized by being _rolled material P 'and having a thick steel plate with an average grain size of about 3 to 1 // m from the surface to the inside of the thickness of 1/4. It has such chemical composition and The fine-grained steel sheet with a grain size of fat and iron is high due to the balance of mechanical properties (tensile strength and extensibility, etc.), and it is excellent in low temperature toughness and weldability (refer to Figure 20 ~ (Figure 2 2). Therefore, its use is strong. It is relatively cheap, easy to obtain, and recyclable. Therefore, it has a high demand, so this type of steel plate has a great contribution to society, and its production will accompany it. Sufficient economic rationality is also provided. Brief Description of Drawings Figure 1 is a side view showing the overall arrangement of a hot rolling apparatus according to an embodiment of the present invention. Figures 2A, 2B, and 2C Each drawing is a schematic diagram illustrating the CVC function of the rolling device 1 in the previous stage of the rolling device shown in FIG. 1. FIG. 3 is a detailed illustration of the rolling device 6 in the last stage of the rolling device shown in FIG. Fig. 4 is a view of rolling using the roll shown in Fig. 1 Line diagram showing the relationship between the grain size of the crystal grains of the ferrous iron structure and the yield point on the manufactured steel plate. (Please read the precautions on the back before filling this page)

, ^ T This paper size applies Chinese National Standard (CNS) A4 (210x297 mm) -50- 565474 A7 ___ B7 V. Description of the invention (48) Figures 5A, 5B and 5C are about The steel plate manufactured by using the rolling device shown in FIG. 1 shows the crystal structure near the upper surface, near the center of the plate thickness, and near the lower surface. (Please read the precautions on the back before filling out this page.) Figure 6 is a line graph showing the relationship between the equivalent diameter of the processing rolls of the different-roller rolling mill and the rolling load. Fig. 7 is a diagram showing the reduction effect of the reduction in the thickness of the plate end of the reducer roll mill. Fig. 8 is a graph showing the effect of reducing the friction on the roller surface when a lubricant is used. Fig. 9 is a side view showing the overall arrangement of a hot rolling apparatus according to a modification of the embodiment shown in Fig. 1; Fig. 10 is a side view showing the overall arrangement of a hot rolling apparatus according to another embodiment of the present invention. Figures 11A, 11B, and 11C are explanatory diagrams of the CV C function of the rolling mill 10 in the preceding stage in the rolling device shown in Figure 10. Fig. 12 is a detailed side view of the rolling mills 40 to 60 and the vicinity thereof in the rolling device shown in Fig. 10; Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. Figure 13 is a line graph showing the relationship between the cumulative strain and the grain size of fertilized iron on various steel plates obtained by test rolling. Fig. 14 is a graph showing the relationship between the finishing temperature (rolling completion temperature) and the grain size of the ferrous iron with respect to various steel plates obtained by test rolling. Figure 15 is about various steel plates obtained by test rolling. Table -51-This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) 565474 A7 B7 V. Description of the invention (49) Line diagram of the relationship between the iron particle size and the tensile strength. Fig. 16 is a graph showing the relationship between the grain size of the ferrous iron and the elongation regarding various steel plates obtained by test rolling. (Please read the precautions on the reverse side before filling out this page) Figure 17 is a graph showing the relationship between the grain size of the ferrous iron and the tensile strength X elongation of various steel plates obtained by test rolling. FIG. 18A, FIG. 18B, and FIG. 18C show the steel plate obtained by using the rolling method of the rolling device of FIG. 10 according to the embodiment of the rolling method, which lies near the upper surface and is 1/4 of its thickness. Diagrams of crystalline structures near the inner side and everywhere near the center of the thickness. Fig. 19A, Fig. 19B, and Fig. 19C show the steel plate obtained according to the embodiment D of the present invention, which is near the upper surface and near the inner side of the thickness 1/4), and the thickness Diagram of the crystalline structure in various places near the center. Figure 20 is a graph showing the relationship between the grain size of ferrous iron and the tensile strength and yield point of the steel plate produced according to the embodiment of the present invention. Fig. 21 is a diagram showing changes in the Charpy impact strength of steel plates and ordinary steels (non-fine-grain steel plates) produced according to the embodiment of the present invention. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. Figure 22 is a graph showing the temperature change of the brittle fracture rate of the steel plate produced according to the embodiment of the present invention. Comparison table of main components P Rolled material 1 C v c Rolling mill la Processing roll -52- This paper size is applicable to China National Standard (CNS) A4 specification (210X297 mm) 565474 A7 B7

Five 'invention description (5Q Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, Industrial and Consumer Cooperatives, lb. Processing rolls 1 c Back support rolls Id Back support rolls CVC roll mills CVC roll mills Reducer roll mills Extremely small diameter rolls Roller processing rolls Processing rolls Processing rolls Processing roll back support roll back support roll reducer roll mill extremely small diameter roll roll processing roll processing roll back support roll back support roll e spray port f spray port g dewatering plate h dewatering plate i spray nozzle 2 3 4 4 a 4 a 4 b 4 b 4 c 4 d 55, 5 a 5 b 5 c 5 d (Please read the precautions on the back before filling out this page) This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm)- 53-565474 A7 B7 V. Description of the invention (51) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5 j Spray Nozzle 6 Reducing Roller Rolling Machine 6, Extremely Small Diameter Working Rolling Machine 6 a Working Roller 6 b Working Roller 6 c Back Support roller 6 d Back support roller 6 e Spray □ 6 f Spray P 6 g Dewatering plate 6 h Dewatering plate 6 i Spray nozzle 6 j Spray nozzle 7 A Curtain wall type cooler 7 B Curtain wall Type cooler 7 C curtain wall type cooler 7 B ca, 7 B b up and down head 8 water jet sprayer 8 a nozzle 8 b conveying roller 1 〇CVC IS car L machine 2 0 CVC rolling mill 3 0 CVC rolling mill 40 reducing roller Rolling mill (Please read the precautions on the back before filling this page)

This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) -54- 565474 V. Description of the invention (52) Intellectual property alrg of the Ministry of Economic Affairs (printed by Industrial and Consumer Cooperatives A7 _B7 5 0 Reduced-diameter roller mill 0 Reducer roll mill 1 0 1 a Processing roll 1 0 1 b Processing roll 1 0 1 c Backing roll 1 0 1 d Backing roll 1 0 4 a Processing roll 1 0 4 b Processing roll 1 0 4 c Backing Roller 1 0 4 d Backing roller 1 〇7 Curtain wall cooler 1 0 7 A Curtain wall cooler 1 0 7 B Curtain wall cooler 1 0 7 C Curtain wall cooler 1 〇7 D Curtain wall cooler 1 0 7 E Curtain Wall Cooler 1 0 7 F Curtain Wall Cooler 1 0 7 G Curtain Wall Cooler 1 0 7 H Curtain Wall Cooler 1 0 8 Water Jet Sprayer (Please read the precautions on the back before filling out this page)-Installation · 1 · ——The size of the paper used in this edition applies to the Chinese National Standard (CNS) A4 (210X297 mm) -55-

Claims (1)

565474 A8 Β8 C8 D8 6. Scope of patent application 1. A hot rolling device is mainly used in the hot rolling device for manufacturing steel sheet by rolling the rolled material, which is characterized by: (Please read the precautions on the back before (Fill in this page) Roller mills placed in the front section and rollers arranged in the rear section, and reducer rolls with different diameter processing rolls including one pair of equivalent roll diameters less than 600 mm _ Rolling mills, or rolling mills with extremely small-diameter processing rolls containing one pair of processing rolls of less than 60 mm in diameter, and the exit side of at least one of the above-mentioned rolling mills arranged at the latter stage for cooling the above-mentioned The cooling mechanism for rolled material, the cooling mechanism is a curtain wall type cooler. 2. The hot rolling device according to item 1 of the scope of the patent application, wherein the rolling mills arranged in the preceding or subsequent stage, at least the rolling mills arranged in the preceding stage are CVC rolling mills including multiple units. The hot rolling device according to item 1 of the scope of the patent application, wherein the above-mentioned pair of different-diameter processing rollers of the above-mentioned different-diameter processing rolls are printed by the consumer property cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs, or the above-mentioned The roll diameter of the above-mentioned working diameter of the ultra-small-diameter roll mill is less than or equal to 5 50 mm. 4. The hot rolling device according to item 1 of the scope of the patent application, wherein the processing rolls of the different-diameter roll mill or the processing rolls of the extremely small-diameter roll mill are given a CV C function and a bending function. 5. The hot-rolling device according to item 1 of the scope of the patent application, which is arranged in the above-mentioned rolling mills in the foregoing and subsequent stages, and is additionally attached to at least one of the rolling mills and the surface of the rolling mill for the above-mentioned rolling mills is provided. This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) -56- 565474 A8 B8 C8 _ D8 々 Lubricant supply agency for patent application scope for lubricants. (Please read the precautions on the back before filling in this page.) 6 • The hot rolling device described in item 5 of the scope of patent application, in which the lubricant supply mechanism is a lubricant that supplies particulate solid lubricant to butter. 7 · The hot-rolling device according to item 1 of the scope of the patent application, wherein the exit side of the rolling mill at the last stage is provided with a downstream side of the cooling mechanism arranged in the flow direction of the rolled material. A fluid spraying sprayer for spraying fluid on the rolled material to remove cooling water existing in the rolled material. 8. The hot rolling device according to item 7 of the scope of the patent application, wherein the fluid jet sprayer includes, for the material to be rolled, from above the material to be rolled, toward the flow direction of the material to be rolled. On the upstream side, a plurality of nozzles that spray pressurized water in a wide direction of the rolled material are opened diagonally downward. 9. A method for manufacturing fine-grained steel, which is mainly used in the production of fine-grained steel by rolling rolled materials, which is characterized in that the above-mentioned rollers to be heated are printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The rolling stock is supplied with a rolling device arranged at the front stage and a rolling device arranged at the rear stage. The rolling machine arranged at the rear stage of the rolling apparatus is equipped with a processing roll having a diameter of 5 50 mm or less. The rolled material is cooled before and after the flow direction of the rolling machine arranged at the rear stage of the rolling device, and the rolled material is cooled to the roll while the rolled material is able to reach 0.9 or more. Rolling. 10.—Manufacturing method of fine-grained steel. The I standard of this paper applies the CNS A4 ^ (210X297mm): -57- 565474 A8 B8 C8 ___ D8 VI. Application for patent scope Use of patent scope 1 The hot rolling device described in one of the items or even the eighth item makes the cumulative strain of the rolled material in the above-mentioned later stage of the rolling device to be 0.9. Rolling the rolled material above 9 is a feature. 1 1. The method for manufacturing a fine-grained steel as described in item 9 or item 10 of the scope of the patent application, wherein a temperature drop rate of more than 20 t per second is used to cool the final rolling mill from the last stand and then The rolled material. 12. The method for manufacturing fine-grained steel as described in item 9 or item 10 of the scope of the patent application, wherein the rolled material has a carbon content of 0.5% or less, and the alloy element content is 5% or less . 1 3 · A continuous hot rolling method, which is mainly a method for continuously manufacturing hot rolled rolled materials to produce steel plates, which is characterized in that the heated rolled materials are supplied to the front end in series. The rolling device of a plurality of rolling mills in the subsequent stages uses the above-mentioned rolling device so that the accumulated strain of the above-mentioned rolled device becomes 0.6 or more, while the above-mentioned rolled material is rolled, the other side lies in the above-mentioned rolling device. The above-mentioned one or more of the above-mentioned rolling mills are cooled on the exit side. The material to be rolled. 1 4 · The continuous hot rolling method described in item 13 of the scope of the patent application, wherein the rolling completion temperature of the above-mentioned rolled material is set to AI * 3. The abnormality point is above 50 ° C, and A r 3 is abnormal Point + 5 0 t or less. 1 5. The continuous hot rolling method described in item 13 or item 14 of the scope of patent application, wherein the average ferrous grain iron particle size inside the steel plate obtained by rolling the material to be rolled is 3 to 7 // m or so. The size of this sheet is applicable to China National Standard (〇 奶) 84 (210 \ 297 mm): -58- ^-^ ---- (Please read the precautions on the back before filling this page) Order the Ministry of Economic Affairs Printed by the Intellectual Property Bureau employee consumer cooperative 565474 A8 B8 C8 D8 々, patent application scope λ 1 6 ·-A continuous hot rolling method, mainly in the continuous hot rolling method of rolling the rolled material to manufacture thick plates, Its characteristics are: (Please read the precautions on the back before filling in this page) Rolling the rolled material to make a thin plate. The heated rolled material is supplied to a plurality of units arranged in series at the front and rear stages. The rolling device of the rolling mill does not use at least a part of the above-mentioned plurality of rolling mills arranged at the latter stage, but uses at least three rolling mills on the side of the rolling apparatus, While the accumulated strain of the above-mentioned rolled mill is 0.2 or less or the rolling reduction rate of the above-mentioned rolling mill at the last stage of the above-mentioned rolling mill for use is 12% or more, the above-mentioned rolled material is rolled on one side, One side is for use Above the rolling device and the upper side of the last segment of said roll to be cooled by the roller. i 7. The continuous hot rolling method according to item 16 of the scope of patent application, wherein the rolling completion temperature of the rolled material is not more than A r 3 abnormal point + 50 ° C. 18. The method for printing continuous hot rolling according to the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs described in item 16 or item 17 of the scope of patent application, wherein the above-mentioned thick plate obtained by rolling the above-mentioned rolled material is , The average ferrous grain iron particle size from its surface to the inside of its thickness 1/4 is about 3 ~ 1 0 // m. This paper size applies to China National Standard (CNS) A4 (210X297 mm) -59-