Technical field
[0001]The present invention, when producing steel, it relates to a cooling apparatus and a cooling method for cooling the steel after the finish rolling.
BACKGROUND
[0002]In production of large H-beams, such as those used in the beams and columns of buildings, in recent years, in particular ultra as tall buildings for, suppressing the alloy cost high-strength H form by performing the accelerated cooling treatment after finish rolling a method of manufacturing the steel has been developed.
[0003]
　As a cooling apparatus for performing accelerated cooling process of such H-shaped steel, it is known those disclosed in Patent Documents 1-3.
　Cooling apparatus of Patent Document 1 is one having a second injection unit for cooling the first injection unit to cool the outer flange portion of the H-shaped steel, the inner and web portion of the flange portion.
　Cooling device Patent Document 2, the web center and two R portions on both sides in each of one surface and the back surface of the H-beam web, provided three sets of nozzles which do not interfere cooling water from each other, further, two each outside of the flange portion, in which respectively the three sets of nozzles cooling water do not interfere with each other.
　Cooling device Patent Document 3, the flange outer surface of the H-shaped steel water density 1000L / min · m 2 was strongly cooled above, the web portion, an upper surface spray nozzle or mist nozzle and air injection nozzles for cooling, the lower surface cooled in a spray nozzle or mist nozzle is intended to be lower than the flange portion water density of the web portion.
[0004]
　Furthermore, although not related to the cooling of the H-shaped steel, a method of cooling a steel sheet, it is known those disclosed in Patent Documents 4-5.
　Patent Document 4, a method of cooling the steel sheet while accelerating the sheet passing speed of the steel sheet as follows is disclosed. That is, in the cooling method of Patent Document 4, measured before the from the tip of the steel sheet to the rear into a plurality of segments, the steel sheet thickness direction average temperature of the cooling device inlet side of each segment is charged to a cooling device It predicted based on the temperature of the steel strip. Then, the prediction based on the result, calculates the optimum cooling time required for each segment, for cooling the steel plate while increasing the strip running speed acceleration determined based on the optimum cooling time required.
　Patent Document 5, so that the cooling end temperature of the tip portion and the rear end portion of the steel plate is matched to a predetermined temperature, to calculate the cooling start the conveying speed of the cooling end, from the start of cooling to the end of cooling constant acceleration in the cooling method of steel plate to control the steel sheet transport speed is disclosed. Further, this cooling method, while controlling the bank of the cooling device at a predetermined cooling pattern, and controls the cooling start the conveying speed of the cooling at the end.
CITATION
Patent Document
[0005]
Patent Document 1: Korean Patent Publication 2013-0034216 No.
Patent Document 2: Japanese Chinese Patent Publication No. 103 357 678
Patent Document 3: Japanese Patent No. 3546300 discloses
Patent Document 4: JP 60-87914 JP
Patent Document 5: JP 10-71416 JP
Summary of the Invention
Problems that the Invention is to Solve
[0006]
　Incidentally, what has been developed in recent years as a high-strength H-shaped steel skyscraper buildings for the thickness of the flange portion is very large. Thus, when the thickness of the flange portion is large and is cooled while conveying the large steel requests cooling rate at a constant speed, since the steel material is hard to be cooled, it passes through the cooling zone over a long cooling time in one pass since it is necessary to, the time difference from the time the leading end portion of the steel material has entered the cooling zone to the tail portion enters the cooling zone becomes larger. When the time difference is large, the difference in cooling time, temperature difference between the tip and the tail end (hereinafter, the temperature difference between the previous tail) for increases, there is a problem that product performance is deteriorated.
[0007]
　Patent Documents 1 to 3 relates to the problem according to the temperature difference above the previous tail end, not in any way disclosed.
　Incidentally, it is possible to prevent by applying the method of cooling steel plate of Patent Document 4-5 in the cooling of the flange portion thickness is greater H-beams, such as described above, that the temperature difference in the previous tail occurs. However, in the cooling method of Patent Document 4, a steel sheet thickness direction average temperature of the cooling device inlet side of each segment to be cooled steel there is need to calculate repeat play with prediction, is complicated. Further, in the cooling method disclosed in Patent Document 5, the convergence calculation of the transport speed of the cooling start, the convergence calculation of the transport speed of the cooling termination is performed and optimization calculations of the cooling pattern. That is, in the cooling method of Patent Document 5 has been three repetitive calculation, which is also troublesome. In such a Patent Documents 4-5 cooling methods are performed complicated calculations, processing cost.
[0008]
　The present invention has been made in view of the foregoing, during cooling after finish rolling of steel, under conditions calculated by a simple method, to be cooled so that the temperature difference in the previous tail does not occur and to provide a cooling apparatus and cooling method can. Here, the "simple method" is meant to reduce the processing costs by omitting significantly repetitive calculations disclosed in Patent Document 4 and Patent Document 5.
Means for Solving the Problems
[0009]
　To solve the above problems, the present invention provides an apparatus for cooling a steel material after hot finish rolling, cooling and transport mechanism for transporting while accelerating the steel, the steel being conveyed by the conveying mechanism a water cooling mechanism which, so as to satisfy the following formula (1) cooling is performed on the steel, and a control unit for controlling the water cooling mechanism and the conveying mechanism, a water cooling time in the following formula (1) the reduction rate gamma, the water cooling system is time Δt required to cool the tip portion of the length and the steel water cooling zone provided to a target temperature C , characterized in that it is determined on the basis of (0), Incidentally, the water cooling zone, when the cooling water supplied from the water cooling system strikes the steel, a region from the conveying direction front of the impact area of the cooling water in the steel to the end portions.
　Delta] t C (x) = Delta] t C (0)-gamma · x ... formula (1)
where, x: position of the transport direction of the steel relative to the distal end portion of the steel material, Delta] t C (x): the steel is the time it takes the site of position x to cool to the target temperature.
[0010]
　The water cooling time reduction rate γ may satisfy the following formula (2).
　= p · gamma L C q1 · Delta] t c (0) q2 ...　Equation (2)
where, L C : length of the water cooling zone, p, q1, q2: a constant factor.
[0011]
　The steel is H-shaped steel, the water cooling system may cool the flange portion of the H-shaped steel. The cooling device of steel, in the water-cooled zone, the air blowing mechanism for blowing compressed air towards the web upper surface of the H-shaped steel, before and after the water-cooled zone in the conveying direction of the H-beam, of the H-beam and dewatering mechanism portion for discharging water of the web top surface on the outside of the H-shaped steel, it may have. The draining mechanism, the air blowing air to the web upper surface of the H-beams - a draining mechanism, the air - at a position close to the water cooling zone than draining mechanism, water in the web upper surface and a flange inner surface of the H-beams water blowing - and draining mechanism, may be provided with a. The water amount density of the cooling water of the water cooling system is 0.5 m 3 / min / m 2 or more, the water - jet pressure of water draining mechanism is 0.1 ~ 0.5 MPa, the air - the draining mechanism ejection pressure of the air may be 0.02 ~ 0.3 MPa. Air jet pressure of the air blow mechanism may be 0.02 ~ 0.3 MPa.
[0012]
　The present invention, while conveying accelerating steel after hot finish rolling, the water cooling system and a control method at the time of cooling the steel material, the length of the water cooling zone the water cooling mechanism is provided and the the distal end portion of the steel time Δt required to cool to the target temperature C based on the (0),
　Delta] t C (x) = Delta] t C (0)-gamma · x ... formula (1)
where, x: position of the transport direction of the steel relative to the distal end portion of the steel material, Delta] t C (x): the steel is the time it takes the site of position x to cool to the target temperature.
　In such a case, the water cooling time reduction rate γ may satisfy the following formula (2).
　= p · gamma L C q1 · Delta] t c (0) q2 ...　Equation (2)
where, L C : length of the water cooling zone, p, q1, q2: a constant factor.
The invention's effect
[0013]
　According to the present invention, during cooling after finish rolling of steel, only determined numerically or entity measures the water cooling time of the distal end portion of the steel material, be determined without using a repeating calculating the water cooling time over steel total length becomes possible, it can be greatly reduced computational costs. Further, in the thus-determined conditions it can be cooled so that the temperature difference in the previous tail of the steel material does not occur.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
The conveying direction position in FIG. 1] H-beam is a graph showing a simulation result of the relationship between the time required for the flange portion at each part in the conveying direction of the H-shaped steel is cooled to the target temperature.
Is a graph showing an example of the relationship between [2] water cooling time of the flange portion of the front end portion of the H-shaped steel and water-cooled time reduction rate.
[Figure 3] for water cooling time reduction rate, and the simulation result is a graph for comparing the calculation results based on the regression equation.
It is a flow chart of the cooling control method [Fig. 4] H-section steel.
5 is a diagram showing a schematic configuration of a hot rolling facility provided with a cooling device according to an embodiment of the present invention.
It is a side view schematically showing a cooling device according to the embodiment of FIG. 6 the present invention.
7 is a cross-sectional view of a water cooling zone as viewed from line A-A of FIG.
It is a cross-sectional view of a drained mechanism - [8] water as viewed from line B-B of FIG.
It is a cross-sectional view of a drained mechanism - [9] air seen from line C-C in FIG.
DESCRIPTION OF THE INVENTION
[0015]
　Hereinafter, the embodiments of the present invention will be described with reference to FIG. In the specification and drawings, in the elements having substantially the same function and structure are a repeated explanation thereof by referring to the figures.
[0016]
　First, a description will be given cooling control method of the steel according to the present embodiment. Here, the steel will be described when it is H-shaped steel. The rolling equipment of H-shaped steel, and heating of the slab in the heating furnace, rough rolling mill, the rolling in the intermediate mill and the finishing mill, and cooling of the H-beam in the cooling device, the saw of H-beams in sawing device is the cross-sectional are sequentially performed. In the cooling device performs the accelerated cooling treatment after the finish rolling, is described below cooling control method in this.
[0017]
　The present inventors, when the accelerated cooling treatment after finish rolling of H-shaped steel, for cooling so that the temperature difference between the flange portion of the previous tail of H-beams does not occur at the time of water cooling termination by the aforementioned cooling device in was simulated regarding conveying speed and the water cooling time rate of decrease in H-section steel (conveyance acceleration). Specifically, when the cross-section average temperature of the flange portion at each part in the conveying direction of the H-beam during water cooling termination becomes constant at the target temperature from the tip of the H-beam to the tail end, each site the water cooling time was simulated in transient thermal analysis one-dimensional and only considering the thickness direction of the flange portion.
[0018]
　The conditions of the simulation, it is assumed steels is carbon steel, time or empty run time from the heating furnace to the start cooling by the cooling device is assumed to be 60 seconds. Further, in the simulation, the thickness of the flange portion of the H-shaped steel, the length of the H-shaped steel, the length of the water cooling zone, water density, and the target temperature of the cross-section average temperature of the flange portion in the respective portions at the time of water cooling termination (hereinafter, the target temperature) as, using a plurality of values. However, each of the values used in the simulation, the flange thickness: 20 ~ 120 mm, the length of the H-beam: 0 ~ 300 meters, the length of the water cooling zone: 5 ~ 20 m, water density: 0.5-2. 0 m 3 / min / m 2 , the target temperature: 500 ~ 700 ℃, the condition that. Incidentally, the water cooling zone, when the cooling water supplied from the water cooling system of the cooling device impinges on H-beam, is in the region of the conveying direction front of the impact area of the cooling water in the H-beam to the end portion . In the following description, "the temperature of the flange portion" means "cross average temperature of the flange portion."
　Furthermore, in the simulation, and conveyed while accelerating the H-shaped steel ended rolled at 900 ° C., by the cooling water for both outer and inner surfaces of the flange portion, and shall be water-cooled H-beams in one pass. Incidentally, and no heat transfer between the web and flange in the simulation.
[0019]
　Figure 1 is a graph showing an example of the above-described simulation results. The horizontal axis of FIG. 1, the transport direction position of the H-beam relative to the distal end portion of the H-beam (x = 0), the vertical axis, the target temperature of the flange portion at each part in the conveying direction of the H-shaped steel until shows the time required for being cooled. Further, the simulation results of FIG. 1, the target temperature of 600 ° C., the length of the water cooling zone 10 m, the thickness of the flange portion is obtained when the 80 mm.
[0020]
　According to the simulation results of FIG. 1, the time required for the flange portion of the conveyance direction position x of the H-section steel [m] it is cooled to the target temperature (hereinafter, water cooling time) Delta] t C (x) [s] is It decreases substantially at a constant rate with respect to the conveying direction position x. Although the percentage of reduction varies with water density, water cooling time Delta] t C phenomenon (x) Furthermore, although not shown, the target temperature, the length of the water cooling zone, even a simulation of the time having different thickness of the flange portion, as described above, water cooling time Δt regardless of the water density C (x) is constant trend can be seen that the decrease in the ratio of.
　In other words, the conveyance direction position x and the water cooling time of the H-shaped steel Delta] t C relationship between (x) Incidentally, γ [s / m] denotes a water cooling time reduction rate.
　Derutati C (X) = Derutati C (0) -Ganma · X ... formula (1)
[0021]
　2, water cooling time of the flange portion of the front end portion of the H-shaped steel Delta] t C is a graph showing an example of the relationship between (0) Simulation results of FIG. 2, the length Lc of the water cooling zone was 5 m, 10 m, with each constant 20 m, thickness of the flange portion, the length of the H-shaped steel, but in the case of changing the water density and the target temperature is there. However, respectively the values used in the simulation, the flange thickness: 20 ~ 120 mm, the length of the H-beam: 0 ~ 300 meters, water density: 0.5 ~ 2.0 m 3 / min / m 2 , the target temperature : 500 ~ 700 ℃, the condition that.
　According to the simulation results of FIG. 2, the water cooling time of the flange portion of the front end portion of the H-shaped steel (hereinafter, the tip water cooling time) Delta] t C relationship between (0) and cooled time reduction rate γ, the tip water cooling time Delta] t C ( 0) cooled time reduction rate γ is related to increased upon increased. That is, FIG. 2, the water cooling time reduction rate γ tip water cooling time Delta] t C indicates that a relation of exponential function with base (0). Furthermore, the exponential regression coefficient is the length Lc of the water cooling zone 5 m, 10 m, vary depending on changing to 20 m, the relation of exponential function water cooling time reduction rate γ is a base of length Lc of the water cooling zone also it shows that.
[0022]
　From the above regression analysis, the tip water cooling time Delta] t C relationship between (0) and cooled time reduction rate gamma, and the length L of the water-cooled zone C relationship between the water cooling time decrease rate gamma is a constant factor p, q1 , can be favorably regression equation (2) below using q2. Incidentally, formula (2) is derived, for example, using a linear least squares method.
　= p · gamma L C q1 · Delta] t c (0) q2 ...　　Equation (2)
　In addition, the constant coefficient p, q1, q2 of formula (2) is, 0.001 ≦ p ≦ 0.010, -1.5 ≦ q1 ≦ -0.2,0.5 ≦ q2 ≦ 5 and in many cases made.
[0023]
　Here, to verify the above formula (2). 3, the simulation result of FIG. 1 and FIG. 2 described above is a graph for comparing the calculation results based on equation (2) above. The horizontal axis of FIG. 3 shows a water-cooled time reduction rate γ calculated by simulation, and the vertical axis indicates the water cooling time reduction rate γ'calculated by applying the equation (2) the same conditions as the simulation. That is, the water cooling time reduction rate of the horizontal axis gamma, according to the cross-sectional position in the conveying direction of the H-shaped steel, to simulate a variety of cooling conditions, and is calculated separately. So to speak, water cooling time reduction rate gamma, a raw data is calculated for each cooling condition. On the other hand, water-cooling time reduction rate γ'the vertical axis and is calculated from equation (2).
[0024]
　As shown, the water cooling time reduction rate was calculated based on the equation (2) gamma prime shows almost the same value as the water-cooled calculated time reduction rate γ by simulation. That is, the straight line L in the figure shows a gamma = gamma prime. This is the horizontal axis water cooling time reduction rate γ and the vertical axis the water cooling time reduction rate γ'the underlying simulation results of in FIG. 3 are the same, the water cooling time reduction rate γ by a simple equation (2) which means that can be calculated. That is, it is possible on the basis of a simple equation (2), to accurately calculate the proper water cooling time reduction rate. Therefore, it is possible to accurately calculate the conveying speed of the H-beam in a suitable water-cooled.
[0025]
　As described above, by using the above formula (1) and (2), water cooling time of the end portion of the H-shaped steel Delta] t C is the only (0) (x) is made possible to determine without using a repetitive calculation can be greatly reduced computational costs.
[0026]
　Then, based on the above findings, a description will be given of a specific cooling control method. Figure 4 is a flow chart of the cooling control method for H-section steel.
[0027]
(Step S1)
　First, the flange thickness of the H-shaped steel, the overall length of the H-shaped steel, rolling end temperature, cooling start target temperature of the tip cooling end target temperature of H-shaped steel, the total length of the water cooling zone, water density pattern, etc. read of the cooling conditions.
(Step S2)
　assumed from the cooling conditions, the cooling starting conveying speed V of the tip portion (0). However, prior to the actual cooling control, based on such past accelerated cooling performance or simulation in advance, determines a certain range transport speed V should assume for each of the cooling conditions (0).
(Step S3)
　conveying speed V (0) of the cooling starting assumed tip in step S2 and on the basis of such a rolling end temperature, the cooling start temperature of the tip portion is estimated at cool simulated calculation. In this cool simulation calculation is carried out by arbitrarily selecting known calculation method. In step S3, cooling start temperature of estimated tip, to confirm that the range of the cooling start target temperature of the tip.
　Cooling start temperature of the tip, when it is confirmed that there is no the range of the cooling start target temperature of the tip, according to the difference of the two temperatures, re-assuming the cooling start conveying speed V of the tip (0) and, re-estimating the cooling start temperature of the tip in the method. Cooling start temperature of the tip, until the range of the cooling start target temperature of the tip, performs repetitive calculations. Incidentally, albeit at a conveying speed V (0) as soon as assumed in step S2, the frequency of performing repetitive calculations on cooling start temperature of the tip portion in step S3 is normally less. Therefore, in the following, assuming you do not do this repetitive calculations, to evaluate, such as the number of repetitions.
(Step S4)
　Based on the cooling start temperature of the tip estimated in step S3, the cooling end temperature of the tip portion is estimated based on the water-cooled simulation calculation or past the cooling performance. Incidentally, the water-cooled simulation calculation is carried out by arbitrarily selecting known calculation method.
(Step S5)
　cooling end temperature of the tip portion estimated in step S4 is, to verify that the range of cooling end target temperature of H-beams.
　In step S5, the cooling end temperature of the tip which is estimated in step S4, if it is confirmed not in the range of cooling end target temperature of H-shaped steel, the process returns to step S2, in accordance with the difference of the two temperatures, the tip re assumed parts cooling starting conveyance speed V (0). Subsequently, sequentially performs steps S3 ~ S5. Then, repeating these steps S2 ~ S5, to a cooling termination temperature of the tip portion is in the range of cooling end target temperature of H-beams.
(Step S6)
　In step S5, the cooling end temperature of the tip portion is confirmed to be in the range of cooling end target temperature of H-section steel, based on the equation (1) and (2), water-cooled time reduction rate water cooling time of the position x of γ and H-beams Delta] t C calculates the (x).
[0028]
　Here, in the cooling method of Patent Document 5 described above, the convergence calculation of the carry speed Vin of the cooling start, the convergence calculation of the carry speed Vout of the cooling completion of the optimization calculation of the cooling pattern, three repetitive calculations It is carried out. Specifically, as shown in FIG. 4 of Patent Document 5, the cooling end temperature of the tip portion performs repetitive calculations Step3 ~ 8 to fall within the target range, to calculate the carry speed Vin of the cooling start ing. Also performs repetitive calculations Step3 ~ 10 to accommodate the cooling end temperature of the rear end portion within the target range, in encompassing format convergence calculation of carry speed Vin of the cooling start, the carry speed Vout of the cooling termination It is calculated. Furthermore, performs repetitive calculations Step3 ~ 14, which derives the optimum cooling pattern. To perform such a three repetitive calculation, the calculation is complicated, consuming and processing costs.
[0029]
　In contrast, in the present embodiment, it is performed repetitive calculation to pay cooling end temperature of the tip within the target range as described above, repeating calculation is only this one. Therefore, as compared with the conventional, can complete the calculation in an extremely short time, the processing cost can be reduced dramatically.
[0030]
　Incidentally, simulation shown in FIGS. 1 and 2 is a simulation of the case where the cooling of both outer and inner surfaces of the flange portion of the H-shaped steel, the present inventors have external or internal surface of the flange portion of the H-shaped steel It was also carried out simulation in the case where the cooling either one side of the. Further, the present inventors, when a steel material is not H-shaped steel, was also simulated in the case of, for example, steel plate (thick plate). In either case, the simulation results and similar results shown in FIGS. 1 and 2 is obtained.
[0031]
　In other words, the cooling control method of this embodiment is not limited to the case of cooling the both sides of the H-shaped steel, and the case of cooling one side of the H-beam, is also applicable to steel other than H-shaped steel. The steel other than H-shaped steel, long steel, for example steel sheets continuously performing insert and the heat treatment and the temperature adjusted to a water-cooled zone (thick or thin), pipes, round steel, such as rails and the like.
[0032]
　Next, to realize the cooling control method for H-beam as described above, it will be described rolling facility and cooling device of the H-shaped steel.
[0033]
　Figure 5 is an explanatory diagram showing a schematic configuration of rolling facilities 1 of H-shaped steel. Rolling equipment 1, the transport direction in order, a heating furnace 2 for heating the slab, the heating furnace 2 rough rolling mill rolling a heated slab into a substantially H shape 3, an intermediate rolling mill for rolling further H shape close to a product shape 4, finishing mill 5 for rolling finished product shape, a cooling device 6 for cooling the H-beams 10 that are finish rolling by the finishing mill 5 to a predetermined temperature, the H-beams 10 which are cooled by the cooling device 6 predetermined and a sawing device 7 for sawing a length of. Incidentally, the rolling facilities 1 of the above is a typical system configuration, rolling equipment of H-shaped steel to which the present invention is applied is not limited to this. H-beams cooling device 6 of the present invention is applied, for example, a flange thickness of 20mm or more 140mm or less, the flange width is generally 200mm or more, the web height is approximately 400mm or more, more large web height is not less than 600mm the H-shaped steel as the main subject.
[0034]
　Figure 6 is a side view showing a cooling device 6 according to the embodiment of the present invention, FIG. 7 is a sectional view taken along line A-A of FIG. Cooling device 6, while the H-shaped steel 10 which is conveyed by the conveying roller 8 constituting a transport mechanism according to the present invention passes through the water-cooled zone 20, mainly water-cooling mechanism 21 of the flange portion 11 is water-cooled, water-cooled zone 20 and a air blow mechanism 22 for blowing compressed air to the web upper surface 12a of the H-beam 10 passing through the. Further, before and after the water cooling zone 20 in the conveyance direction, and a draining mechanism 23. Incidentally, the water-cooled zone 20, when the cooling water supplied from the nozzle 41, 42 and 43 to be described later collides with the flange portion 11, from the conveying direction front of the impingement area of ​​the cooling water in the flange portion 11 to the end portion which is the area. The length of the water-cooled band 20 is, for example, 5 ~ 20m.
[0035]
　Water cooling mechanism 21, as shown in FIG. 7, the outer surface of the flange portion 11 of the H-beam 10, the web portion 12 of the inner surface of the flange portion 11 the upper, the web portion 12 of the inner surface of the flange portion 11 the lower, respectively, a nozzle header 31, 32, 33 provided with a nozzle for the cooling water jetting. Each nozzle headers 31, 32, 33, cooling water is supplied.
[0036]
　First, water flow rate required to achieve a uniform strong cooling of the flange portion 11 of the H-beams 10 (cooling water per unit area in the water cooled surface; m 3 / min / m 2 ) and material performance (tensile strength and toughness When checking the relationship between the like) at billet test, water density sufficient accelerated cooling effect is obtained on the flange portion 11 is 0.5 m 3 / min / m 2 was more. Thus, the water cooling zone 20, the nozzle for cooling water injection to achieve this water density is placed. Incidentally, the water density is different depending on the material and size of the H-beams 10.
[0037]
　In the present invention, the arrangement of the nozzles to cool the flange portion 11 of the water cooling system 21 is not limited, in order to perform to strongly cool achieve sufficient water density of a predetermined amount, the non-collision portion area of ​​the cooling water jetting surface it is desirable to arrange so that minimal. More specifically, for example, the type of nozzle and full cone nozzle ellipse or perfect circle, and in a staggered arrangement by shifting the vertical position of the nozzles adjacent to the conveying direction, the flanges of the H-shaped steel 10 passing through the water cooling zone 20 it is preferable that the gap without cooling water reaches section 11 throughout. Moreover, the injection surface is arranged nozzles so do not interfere, so that the flange portion 11 is uniformly cooled. Further, to cool the flange outer surface 11a and the flange inner surface 11b in the same water flow rate, it is preferable that the temperature gradient is not generated in the thickness direction of the flange portion 11. Moreover, the side nozzles header 31 of the flange outer surface 11a side, to accommodate differences in the size of the H-beams 10, and a movable in the height direction of the web portion 12 of the H-beams 10 (horizontal direction in FIG. 7) as well as, on and off of each nozzle 41 of the side nozzle headers 31, it is sufficient to be controlled for each vertical position.
[0038]
　On the upper side of the web portion 12 of the inner surface of the flange portion 11, as shown in FIG. 7, the upper nozzle header 32 is arranged. Nozzle 42 of the upper nozzle header 32, the flange inner surface 11b and is provided so as to inject cooling water toward the R portion of the boundary between the flange inner surface 11b and the web top surface 12a. In large H-beam 10 is large thickness of the flange portion 11, because sufficient acceleration cooling at a cooling flange outer surface 11a only is not performed, the inner surface side like the outer surface strong cooling. The upper nozzle header 32, to accommodate differences in the dimensions of the flange portion 11 of the H-shaped steel 10 to be cooled, it is sufficient to be able to control on and off of the nozzle 42 for each vertical position.
[0039]
　Further, on the upper side of the web portion 12, an air blow mechanism 22 is provided. Air blow mechanism 22 has a compressed air ejection plate 37 and the fixed frame 38 blown toward the web upper surface 12a of the water-cooled zone 20 throughout the compressed air supplied from the compressed air supply pipe 36. Compressed air ejection plate 37 and the fixed frame 38, the compressed air ejection plate 37 so as to be positioned from the web upper surface 12a, for example, in 20 ~ 50 mm approximately upward, it is located above the web upper surface 12a over the entire length of the water cooling zone 20. The compressed air ejection plate 37 has ejection ports is opened at appropriate intervals throughout the entire surface. Therefore, the compressed air in the fixed frame 38 from the compressed air supply pipe 36 is supplied, via the spout of the compressed air ejection plate 37, the compressed air is blown to the web upper surface 12a. Compressed air supply pipe 36, one position in the center of the fixed frame 38, or may be appropriately connected to a plurality of positions depending on the length, etc. of the water-cooled zone 20.
[0040]
　The air blow mechanism 22, by blowing compressed air towards the web upper surface 12a, the cooling water of the flange inner surface 11b can be released to the outside of the H-beam 10 as shown by an arrow D in FIG. Thus, the cooling water is prevented from or retained or flowed to the web upper surface 12a, preventing the over-cooling of the web top surface 12a. Ejection pressure of the air by the air blow mechanism 22 is preferably set to 0.02 ~ 0.3 MPa. According to experiments by the inventors, draining of the web upper surface 12a becomes insufficient is less than these lower limit values, also turbulent flow of the water cooling unit scattering of the cooling water exceeds these upper limit flange inner surface 11b becomes violently while not preferred for results in these upper limit or less, the ejection pressure of the lower limit or more, the cooling water is found to be completely prevented from or retained or flowed to the web upper surface 12a.
[0041]
　The lower web portions 12 of the inner surface of the flange portion 11, as shown in FIG. 7, the lower nozzle header 33 is arranged. The lower nozzle header 33, the flange inner surface 11b, R portion of the boundary between the flange inner surface 11b and the web lower surface 12b, and the nozzle 43 towards the web lower surface 12b is provided.
[0042]
　In the present embodiment, does not perform injection of cooling water to the web upper surface 12a, and compressed air, cooled slightly water and later to water invading flange inner surface 11b - the water from the water-shielding mechanism 24, the web top surface 12a There is a slight cooling. Therefore, as it does not occur distortion of dimensions temperature gradient occurs in the thickness direction of the web portion 12, performs water cooling the web lower surface 12b. There are no particular restrictions on details of the arrangement of the nozzles 43 of the lower nozzle header 33, the injection of cooling water to the flange inner surface 11b is performed in the same manner as the upper nozzle header 32, for the web underside 12b, the temperature of the web top surface 12a to avoid supercooling as a weak cooling degree commensurate with reduced. The arrangement of the nozzles 43 for cooling the web lower surface 12b, placed by one position to the front and rear ends of the water cooling zone 20 may be further added about 1 to 3 places in the water cooling zone 20 as required.
[0043]
　In the embodiment shown in FIG. 7, the upper nozzle header 32, to use a fabricated for each dimension of the web section 12. The lower nozzle header 33 is used which was produced for each size of both the flange portion 11 and web portion 12. Alternatively, by separating the upper nozzle header 32 and air blowing mechanism 22, by further respective installation position variable may correspond to the H-beam 10 of arbitrary size. The lower nozzle header 33 also connects the cooling nozzle for cooling the nozzle and the web lower surface 12b of the flange inner surface 11b to another pipe, the respective installation position by a variable, of any size H-beam 10 It can also be made to correspond to.
[0044]
　Further, in this embodiment, prevents the outflow of water back and forth of the cooling device 6, in order to sweep out the residual water in the web upper surface 12a, as shown in FIG. 6, the draining mechanism 23 in both front and rear sides of the water cooling zone 20 It is provided. Draining mechanism unit 23, water is provided before and after the water cooling zone 20 - the draining mechanism 24, both sides of the water - draining mechanism air provided at a position away from the water-cooled zone 20 than 24 - a draining mechanism 25, both sides water - in close proximity to draining mechanism 24 water - draining than mechanism 24 and a stop plate 26 dam provided at a position of the water-cooled zone 20 closer. Air - draining mechanism 25 alone, it is possible to sweep residual water be supplied compressed air sufficient pressure and air volume, when sweeping beginning a large amount of residual water strong water cooling conditions, water - draining mechanism preferably used in combination 24.
[0045]
　Water - draining mechanism 24, the entire inner surface of the upper part of the H-beam 10, i.e., by spraying water toward the upper side of the flange inner surface 11b and the web top surface 12a of the web portion 12, the cooling water by the water cooling mechanism 21, is intended to suppress the flow into the web upper surface 12a of the front and rear of H-beams 10 passing through the water cooling zone 20. Water - draining mechanism 24, as shown in FIG. 8, and has a draining nozzle header 51 disposed above the web portion 12. Draining nozzle header 51 includes a horizontal header 52 parallel to the web upper surface 12a, made from the right and left sides of the flange portion 11 two vertical header 53 parallel to each, for example, column by column, a nozzle 61 is arranged there. A draining nozzle header 51, the cooling water is supplied from the water supply header (not shown). Jetting direction of water from each nozzle 61 is inclined to the water-cooled zone 20 side is preferred, the entire upper part of the inner surface of the H-beams 10, so that no gaps water arrives. Accordingly, water flowing from the water cooling zone 20 is discharged to the outside of the H-beam 10, to prevent water from being supercooled accumulated in the web upper surface 12a of the front and rear H-beam 10 of the cooling device 6 can.
[0046]
　Blocking plate 26, from also e.g. 20mm approximately above the web upper surface 12a, to a position higher than the upper end of the H-beam 10 to be conveyed, is provided over the entire (lateral direction during conveying) substantially the height of the web portion 12 .
[0047]
　Air - draining mechanism 25, by injecting compressed air toward the web upper surface 12a, a water cooling mechanism 21, water - and discharged to the outside of the draining mechanism 24 H-section steel 10 water flowing along the web upper surface 12a from it is intended to cut off the flow of water back and forth of the cooling device 6. Air - draining mechanism 25, as shown in FIG. 9, it has a draining pipe 54 connected to the Eahedda (not shown). Draining pipe 54 is made parallel to the horizontal pipe to the web upper surface 12a, outlet of the compressed air towards the web upper surface 12a is formed a plurality of locations in the height direction of the web portion 12 (horizontal direction in FIG. 9) there. Incidentally, draining mechanism unit 23, water - draining but may be only the mechanism 24, an air - it features an draining mechanism 25 is improved further draining capacity.
[0048]
　When using a combination of draining mechanism 25, water - - ejection pressure of water or air draining mechanism 23 varies depending on the type and accelerated cooling conditions H-beam 10 or the like, water - draining mechanism 24 and the air draining mechanism ejection pressure of water 24, for example 0.1 ~ 0.5 MPa, air - air jet pressure of the draining mechanism 25 is for example 0.02 ~ 0.3 MPa are preferred. Further, the draining mechanism 23 water - when only draining mechanism 24, it is preferable that the ejection pressure of water and 0.2 ~ 0.6 MPa. According to our experiments, the draining is insufficient is less than these lower limit values, also undesirable because the scattering of the cooling water exceeds these upper limit disturbs the flow of the vigorous becomes water cooling unit respect, these upper limit or less, the ejection pressure of the lower limit or more, it has been found that Hakidaseru completely retained water.
[0049]
　The cooling device 6, as shown in FIG. 6, the control unit 71 is provided. Control unit 71 is, for example, a computer and has a program storage unit (not shown). The program storage unit, a program for executing a cooling control method shown in FIG. 4 are stored. The program storage unit also stores a program that controls the conveying roller 8 and the water cooling mechanism 21 is the conveyance mechanism.
[0050]
　In the cooling device 6 according to the present embodiment, the control unit 71, the length L of the water-cooled zone 20 C , and the tip water cooling time Delta] t C 4 using from (0), the above equation (1) and (2) with reference to the flowchart of a water-cooled time reduction rate gamma, and water cooling time of the position x of the tip H-beams Delta] t C calculates the (x). The control unit 71 further these water cooling time reduction rate γ and a water cooling time Delta] t C from (x), The cooling device 6 is cooled while conveying the H-beams 10.
[0051]
　Therefore, according to the cooling device 6 according to this embodiment, it can be cooled so that the temperature difference does not occur in the previous tail of H-section steel after the completion of cooling. Therefore, it is possible to obtain the H-shaped steel satisfying the required performance over the entire length.
[0052]
　The average velocity u in accelerated cooling conveying direction position x of the H-beam 10 R (x) can be expressed by the following equation (3).
　u R (x) = L C / Delta] t c (x) ... Equation (3)
　Thus, the above equation (1), (2) and cooled while adjusting the conveying speed of the H-beam 10 on the basis of (3) by, the temperature difference between the previous tail of cooling after the end of the H-beam can be obtained minimizing the H-shaped steel.
[0053]
　Incidentally, after the web thickness for large H-shaped steel is thinner is greater than the flange thickness, and is easy to residual water after cooling reservoir in the web upper surface 12a, in the cooling method of a conventional H-shaped steel, the web portion 12 It was to be supercooled. According to the present invention, the flange portion 11 from both the inside and the outside water flow rate 0.5 m 3 / min / m 2 with strong water cooling above, it is possible to suppress the supercooling of the web portion 12. That is, to ensure material performance by implementing a strong cooling by controlling the cooling rate and the water cooling stop temperature at the time of accelerated cooling of H-beam 10, and the web waves by preventing supercooling of the web portion 12 such a defective shape can ensure the saw cross resistance is suppressed. Therefore, as a large H-beams products used in such beams and columns of large buildings, can produce high quality products by accelerated cooling process while reducing the alloy costs.
[0054]
　Further, in the cooling device 6 according to the present embodiment, the conveying speed of the H-beam as a cooling condition can be easily determined from the regression equation based on the simulation results. Furthermore, the regression equation can be applied to the H-section steel of any length.
[0055]
　The cooling device 6 according to this embodiment, the case with respect to the entire length of the H-beam is smaller length of the cooling zone, in other words, the length of the cooling device 6 is provided rolling equipment 1 is small cooling zone If it is not possible to ensure a large, it is preferably used.
[0056]
　The tip water cooling time Delta] t C relationship between (0) and cooled time reduction rate gamma, and the length L of the water-cooled zone 20 C regression equation showing the relation between the water-cooled time decrease rate gamma is the above equation (2 ) in not limited. Steel and cooling conditions (e.g., the nozzle arrangement and type of the refrigerant, etc.) or using a different regression equation when is changed, by or adjust the even constant coefficients have the same regression formula, water cooling time it is possible to improve the regression prediction accuracy of reduction rate gamma. For example, if the cooling device the length of the water cooling zone is limited to several kinds, each length of the cooling zone, L from equation (2) C q1 formula excluding Section, or "gamma = p · Delta] t c (0 ) q2 and "may change the coefficients p and q2 each length of the cooling zone.
[0057]
　Having described the preferred embodiments of the present invention, the present invention is not limited to such an example. Those skilled in the art within the scope of the technical idea described in the claims, it is clear that could conceive various modifications, the technical scope of the present invention as for their It is understood to belong ones.
[0058]
　The technical idea of ​​the present invention is not limited to the cooling of the H-shaped steel. Long steel continuously performing insert and the heat treatment and the temperature adjusted water cooling zone, for example steel plate (thick plate or thin plate) and steel pipes, round steel, and rail, shorter than steel length while continuously conveying in the longitudinal direction in the art of cooling while passing through the cooling zone it is also applicable.
[0059]
　Also, application when there is a distribution of cooling ability in the water-cooling zone, i.e., even if the water flow rate is changed by the zone of the water-cooled zone, the present invention if its distribution is fixed during the cooling of the steel to be cooled possible it is. That is, in each zone, it is possible to apply the cooling control method described above.
Example
[0060]
　Examples of the present invention will be described. In the cooling device 6 in the rolling equipment 1, and the accelerated cooling 1000 the H-beam with cooling under the following conditions. At this time, the control unit 71 of the cooling device 6, with reference to the flowchart of FIG. 4 using the above formula (1) and (2) was carried out cooling control. As a result, it was possible to control the cooling end temperature of the tail end within the cooling end target temperature from the tip.
(Cooling condition)
the thickness of the flange portion 11: 20 ~ 120 mm
flange portion 11 of the Width: 300 ~ 450 mm
rolling equipment 1 of the rolling length: 250 meters
length of the water-cooled zone 20: 10 m
cooling start temperature: 800 ~ 950 ° C.
water cooling termination temperature : 500 ~ 700 ° C.
water density: 0.5 ~ 5 m 3 / min / m 2
Industrial Applicability
[0061]
　The present invention, in the production of large H-beams, such as those used in the beams and columns of high-rise buildings, can be applied to a cooling apparatus and cooling method for performing accelerated cooling process after the finish rolling. Further, even steel other than large H-shaped steel, steel (slab or sheet) and steel as described above, round steel, even for long steel products, such as rail, the present invention is applicable.
DESCRIPTION OF SYMBOLS
[0062]
1 rolling equipment
2 furnace
3 roughing mill
4 intermediate mill
5 finishing mill
6 cooling device
7 sawing device
8 transport roller
10 H-section steel
11 flange portion
11a flange outer surface
11b flange inner surface
12 the web portion
12a web upper surface
12b web lower surface
20 water-cooled zone
21 water cooling system
22 air blow mechanism
23 draining mechanism
24 water - draining mechanism
25 air - draining mechanism
26 blocking plate
31 side nozzle headers
32 upper nozzle header
33 lower nozzle header
36 compressed air supply pipe
37 the compressed air ejection plate
38 fixed frame
41, 42, 43 nozzle
51 draining nozzle header
52 horizontal header
53 vertical header
54 draining pipe
61 nozzle
71 control unit

The scope of the claims

[Requested item 1]An apparatus for cooling a steel material after hot finish rolling,
a transport mechanism for transporting while accelerating the steel,
and water cooling system for cooling the steel being conveyed by the conveying mechanism,
the following with respect to the steel as cooling satisfying the formula (1) it is performed, and a control unit for controlling the said conveying mechanism water cooling system
has a
water-cooled time reduction rate γ in the following formula (1), wherein the water cooling mechanism is provided time Δt required to cool the tip portion of the length and the steel water cooling zone to the target temperature C , characterized in that it is determined on the basis of (0),
　Delta] t C (x) = Delta] t C (0)-gamma · x ... formula (1)
where, x: position of the transport direction of the steel relative to the distal end portion of the steel material, Delta] t C (x): the steel is the time it takes the site of position x to cool to the target temperature.
[Requested item 2]
The water cooling time reduction rate γ and satisfies the following formula (2), the cooling apparatus of steel according to claim 1.
　= p · gamma L C q1 · Delta] t c (0) q2 ...　Equation (2)
where, L C : length of the water cooling zone, p, q1, q2: a constant factor.
[Requested item 3]
The steel is H-shaped steel,
the water cooling system is characterized by cooling the flange portion of the H-shaped steel, a cooling device of steel according to claim 1 or 2.
[Requested item 4]
In the water-cooled zone, the and air blowing mechanism toward the web upper surface of the H-shaped steel blowing compressed air,
the before and after the water-cooled zone in the conveying direction of the H-shaped steel, the water of the web top surface of the H-shaped steel H and dewatering mechanism for discharging to the outside of the shaped steel
and having a cooling device of steel according to claim 3.
[Requested item 5]
The draining mechanism, the air blowing air to the web upper surface of the H-beams - a draining mechanism, the air - at a position close to the water cooling zone than draining mechanism, water in the web upper surface and a flange inner surface of the H-beams spraying water - a mechanism dewatering, characterized in that it comprises a cooling device of steel according to claim 4.
[Requested item 6]
The water amount density of the cooling water of the water cooling system is 0.5 m 3 / min / m 2 or more, the water - jet pressure of water draining mechanism is 0.1 ~ 0.5 MPa, the air - the draining mechanism wherein the ejection pressure of the air is 0.02 ~ 0.3 MPa, the cooling apparatus of steel according to claim 5.
[Requested item 7]
Wherein the air jet pressure of the air blow mechanism is 0.02 ~ 0.3 MPa, the steel of the cooling device according to any one of claims 4-6.
[Requested item 8]
While conveying accelerating steel after hot finish rolling, a control method at the time of cooling the steel material by water-cooling mechanism,
target the tip length and the steel water-cooled zone in which the water cooling mechanism is provided time Δt required to cool to a temperature C based on the (0), and determining the water cooling time reduction rate gamma,
so as to satisfy the following equation (1) using the water cooling time reduction rate gamma, of the steel and controlling the cooling,
it has a cooling control method for a steel material.
　Delta] t C (x) = Delta] t C (0)-gamma · x ... formula (1)
where, x: position of the transport direction of the steel relative to the distal end portion of the steel material, Delta] t C (x): the steel is the time it takes the site of position x to cool to the target temperature.
[Requested item 9]
The water cooling time reduction rate γ and satisfies the following formula (2), the cooling control method for a steel product according to claim 8.
　= p · gamma L C q1 · Delta] t c (0) q2 ...　Equation (2)
where, L C : length of the water cooling zone, p, q1, q2: a constant factor.