CN114728320A - Steel plate manufacturing equipment and manufacturing method - Google Patents
Steel plate manufacturing equipment and manufacturing method Download PDFInfo
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- CN114728320A CN114728320A CN202080081150.3A CN202080081150A CN114728320A CN 114728320 A CN114728320 A CN 114728320A CN 202080081150 A CN202080081150 A CN 202080081150A CN 114728320 A CN114728320 A CN 114728320A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 185
- 239000010959 steel Substances 0.000 title claims abstract description 185
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 41
- 238000001816 cooling Methods 0.000 claims abstract description 68
- 238000010438 heat treatment Methods 0.000 claims abstract description 68
- 238000010791 quenching Methods 0.000 claims abstract description 56
- 230000000171 quenching effect Effects 0.000 claims abstract description 56
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 14
- 238000005096 rolling process Methods 0.000 description 10
- 239000000498 cooling water Substances 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 230000007547 defect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000005452 bending Methods 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 3
- 238000005098 hot rolling Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005541 quenching (cooling) Methods 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0056—Furnaces through which the charge is moved in a horizontal straight path
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D1/00—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling
- B21D1/05—Stretching combined with rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/60—Aqueous agents
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/62—Quenching devices
- C21D1/63—Quenching devices for bath quenching
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0242—Flattening; Dressing; Flexing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
- B21B2001/221—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by cold-rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D1/00—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling
- B21D1/02—Straightening, restoring form or removing local distortions of sheet metal or specific articles made therefrom; Stretching sheet metal combined with rolling by rollers
Abstract
The invention provides a manufacturing device and a manufacturing method of a steel plate, which can perform more uniform cooling during the heat treatment of the steel plate and can manufacture a flat and homogeneous steel plate. A manufacturing facility (heat treatment facility (1)) of a steel sheet (2) according to one embodiment of the present invention is a manufacturing facility of a steel sheet (2) for heat-treating a steel sheet (2), and is provided with a heating furnace (3) for heating the steel sheet (2) at 100 ℃ or lower; a first shape straightening device (4) for straightening the heated steel sheet (2) in a flat manner; a quenching device (5) for quenching the straightened steel plate (2); and a second shape straightening device (6) that straightens the quenched steel sheet (2) flat.
Description
Technical Field
The present invention relates to a steel sheet manufacturing apparatus and a steel sheet manufacturing method.
Background
In the production of steel sheets such as thick steel sheets, cooling from a high temperature is often performed in order to adjust mechanical properties such as strength. Cooling is roughly classified into an online water cooling method and an offline water cooling method. In the line-type water cooling method, a water cooling apparatus disposed on line is used to perform water cooling of a hot-rolled steel sheet. In the off-line water cooling method, the rolled material is once cooled to room temperature, and is heated and water-cooled again in a heat treatment furnace disposed off-line. The inline water cooling method is advantageous from the viewpoint of energy cost, but since warping of the steel sheet is likely to occur during rolling, a cooling device cannot be disposed near the rolling mill. As a result, the temperature decreases during the time until the steel is conveyed to the cooling device after rolling, and therefore, there is a problem that water cooling at an appropriate temperature is not performed.
On the other hand, the off-line water cooling method is advantageous for adjusting mechanical properties because the cooling device is disposed on the outlet side of the heating furnace, and quenching can be started from a temperature almost equal to the heating temperature.
Generally, a hot-rolled steel sheet is likely to have temperature unevenness during cooling due to differences in the temperature distribution, shape, or surface state of the steel sheet after rolling. Also, temperature unevenness of the steel sheet may be caused by the performance of the cooling device. Further, if the temperature of the steel sheet is not uniform, deformation, residual stress, material variation, and the like of the steel sheet occur after cooling. As a countermeasure, cooling apparatuses capable of performing various types of uniform cooling have been developed. However, methods have been developed which only improve the cooling device, and in particular do not completely achieve the flattening of the cooled steel sheet. The defective shape of the steel sheet after cooling is a cause of operational troubles such as a trouble in passing the steel sheet through a production line, and the steel sheet needs to be pressurized in a subsequent step and subjected to a finishing treatment by a leveler, which increases the cost.
The causes of the temperature unevenness of the steel sheet include the design of the cooling nozzle and the shape of the steel sheet during rolling. Depending on the design of the cooling nozzle, temperature variation of the upper and lower surfaces, temperature unevenness in the width direction, and the like occur. On the other hand, if the shape of the steel sheet is deteriorated during rolling, cooling water flows unevenly over the steel sheet, and the cooling capacity varies depending on the location, resulting in temperature unevenness.
Here, many techniques are known for suppressing temperature unevenness caused by the cooling nozzle, such as temperature variation of the upper and lower surfaces and uniformity in the width direction. On the other hand, there are almost no many techniques for suppressing temperature unevenness that occurs from a shape defect occurring during rolling, and as a corresponding technique, a method of performing shape straightening before an accelerated cooling device to flatten the shape and secure uniformity during cooling is known (patent documents 1 and 2). Patent documents 1 and 2 aim at a degree of sufficient water removal by passing a shape straightening blade of a steel sheet through a water removal roller of a cooling device by a first shape straightening device.
Documents of the prior art
Patent document
Patent document 1: japanese laid-open patent publication No. 2002-11515
Patent document 2: japanese patent laid-open publication No. 2005-74480
Disclosure of Invention
However, in recent years, production lines in which the technologies of patent documents 1 and 2 are actually used, in which a linear leveler is installed before a cooling device, have been increasing. However, in hot rolling, the temperature deviation is large in principle due to descaling during rolling, water cooling for temperature adjustment, and the like, and the temperature deviation occurring in the sheet surface becomes a difference in the amount of heat shrinkage. Therefore, even if the shape is straightened by heating, there is a problem that the shape is deformed again when the temperature is lowered.
Further, patent documents 1 and 2 propose an in-line process in which straightening is performed by a first shape straightening apparatus, followed by accelerated cooling, and then final straightening is performed by a second shape straightening apparatus. However, any of the techniques alone cannot provide a satisfactory effect on the occurrence of temperature unevenness due to the cooling nozzles, such as the temperature deviation of the upper and lower surfaces and the uniformity in the width direction, and the cooling strain caused by the temperature unevenness.
Conventional off-line heat treatment facilities are arranged in this order according to a heating furnace, a quenching apparatus, and a shape straightening apparatus. Since the quenching apparatus is cooled to 100 ℃ or lower, and even if the cooling uniformity cannot be ensured, the steel sheet can be cooled to a low temperature close to the water temperature of the cooling water, and therefore the final cooling stop temperature of the steel sheet is constant. Therefore, the uniformity of cooling is not considered. In recent years, from the viewpoint of improving quality, there has been an increasing demand for reducing variations in cooling rate in the plate surface during quenching, and it has become important to perform uniform cooling by off-line heat treatment capable of ensuring temperature uniformity before quenching. Even if the off-line heat treatment is used, the cooling can be finished at a temperature higher than room temperature, such as 100 ℃. In this case, if the cooling is not uniform, the steel sheet temperature after the cooling is finished varies, and therefore, not only is it impossible to ensure a predetermined quality, but also the steel sheet is strained due to a difference in thermal expansion in the plane of the steel sheet temperature.
The present invention has been made in view of such circumstances, and an object thereof is to provide a steel sheet manufacturing apparatus and a steel sheet manufacturing method that can perform more uniform cooling and can manufacture a flat and homogeneous steel sheet in heat treatment of the steel sheet.
According to one aspect of the present invention, there is provided a steel sheet manufacturing apparatus for heat-treating a steel sheet, comprising: a heating furnace for heating the steel sheet at 100 ℃ or lower; a first shape straightening device for straightening the heated steel sheet flatly; a quenching apparatus for quenching the straightened steel sheet, and a second shape straightening apparatus for straightening the quenched steel sheet flatly.
According to one aspect of the present invention, there is provided a method for manufacturing a steel sheet by heat-treating a steel sheet, the method including: a heating step of heating the steel sheet at 100 ℃ or lower; a first straightening step of straightening the steel sheet in a flat state after the heating step; a quenching step of quenching the steel sheet after the first straightening step; and a second straightening step of straightening the steel sheet flatly after the quenching step.
According to one embodiment of the present invention, there are provided a manufacturing facility and a manufacturing method of a steel sheet, which can perform more uniform cooling during heat treatment of the steel sheet and can manufacture a flat and homogeneous steel sheet.
Drawings
Fig. 1 is a schematic configuration diagram of a heat treatment facility of a steel sheet manufacturing facility according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a detailed configuration of the first shape straightening device and the quenching device.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments described below are examples of apparatuses and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention are not limited to the following embodiments in terms of the material, shape, structure, arrangement, and the like of the constituent members. In addition, the drawings are schematic. Therefore, the relationship, ratio, and the like between the thickness and the plane size are different from the actual ones, and the drawings also include portions having different dimensional relationships and ratios from each other.
(Steel plate manufacturing facility)
Fig. 1 is a schematic configuration of a heat treatment facility 1 for a thick steel plate 2 as a steel plate manufacturing facility according to an embodiment of the present invention, and fig. 2 shows detailed configurations of a first shape straightening device 4 and a quenching device 5 according to the embodiment. In the present embodiment, in order to ensure a homogeneous temperature and shape, attention is paid to adjusting the mechanical properties of the material by an off-line type heat treatment facility that is not directly connected to the rolling line, and the heat treatment facility 1 is not directly connected to the rolling line. The heat treatment facility 1 is a facility for heat treating a thick steel plate 2 as a steel plate, and includes a heating furnace 3, a first shape straightening device 4, a quenching device 5, and a second shape straightening device 6. Further, as shown in fig. 1, in the heat treatment facility 1, a heating furnace 3, a first shape straightening device 4, a quenching device 5, and a second shape straightening device 6 are arranged in this order from the upstream side in the conveying direction of the thick steel plate 2. Conveying rollers (not shown) for conveying the thick steel plate 2 are provided among the heating furnace 3, the first shape straightening device 4, the quenching device 5, and the second shape straightening device 6.
The heating furnace 3 heats the thick steel plate 2 of 100 ℃ or less, which has been hot rolled, to an austenite temperature region. The thick steel plate 2 is a steel plate having a plate thickness of 4.0mm or more.
The first shape straightening device 4 is a device for straightening the thick steel plate 2 heated by the heating furnace 3 in a flat state, and is provided between the heating furnace 3 and the quenching device 5. The first shape leveler 4 may be a skin pass leveler of a reduction type or a roll leveler of a repeating bending type. Further, for the reason described later, it is preferable that the first shape straightening device 4 is a roller leveler straightening device. Further, for the reason described later, when the roll leveler straightening apparatus is used, it is more preferable to further provide a pressing-type straightening mechanism or the like that can correct the warp at the leading end and the trailing end of the steel plate 2.
Here, the temperature of the steel plate 2 decreases as the steel plate 2 is taken out of the heating furnace 3 and reaches the first shape straightening device 4. If this temperature drop is smaller, the increase in deformation resistance of the thick steel plate 2 becomes smaller, and the shape can be straightened with a small straightening force. Therefore, the distance from the heating furnace 3 to the first shape straightening device 4 is preferably 4m or less. Further, in order to shorten the time required for the conveyance from the heating furnace 3 to the quenching apparatus 5, the first shape straightening apparatus 4 is preferably provided in a small size with a small space. In addition, in order to perform straightening of the thick steel plate 2 having a relatively low deformation resistance during heating, the first shape straightening device 4 preferably uses a shape straightening device having a lower load capacity than the second shape straightening device 6. The first shape straightening device 4 may have a load capacity of at least 500 tons, preferably about 3000 tons. In the present embodiment, ton means metric ton (metric ton).
The quenching apparatus 5 is an apparatus for quenching the steel plate 2, which has been shape-straightened by the first shape straightening apparatus 4, by water cooling. As shown in fig. 2, the quenching apparatus 5 includes an upper cooling nozzle 51 and a lower cooling nozzle 52 as an apparatus for rapidly cooling the steel plate 2 having the straightened shape. The upper cooling nozzles 51 and the lower cooling nozzles 52 are provided in plural in the width direction of the thick steel plate 2 so as to be vertically opposed to the conveyance line, and are arranged in parallel at predetermined intervals along the conveyance direction of the thick steel plate 2. Cooling water 53 is sprayed toward the steel plate 2 from each of the upper cooling nozzles 51 and the lower cooling nozzles 52. In the quenching apparatus 5, the constraining rollers 50 may be provided in front of and behind the upper cooling nozzle 51 and the lower cooling nozzle 52, respectively. By providing the restraining rollers 50, even if the thick steel plate 2 is deformed due to cooling unevenness, the thick steel plate 2 can be restrained to some extent, and therefore, out-of-plane deformation can be prevented.
The second shape straightening device 6 is a device for straightening the thick steel plate 2 quenched by the quenching device 5 in a flat state, and is provided on the exit side of the quenching device 5 (downstream side in the conveying direction of the thick steel plate 2). As the second shape leveler 6, a skin pass leveler of a reduction type, a roll leveler of a repeating bending type, or a press leveler can be used. Further, for the same reason as the first shape straightening apparatus 4, it is preferable that the second shape straightening apparatus 6 uses a roller leveler straightening apparatus. Further, from the same reason as that of the first shape straightening apparatus 4, when the roller leveler straightening apparatus is used, it is more preferable to further provide a pressing-type straightening mechanism or the like that can correct the warpage of the leading and trailing end portions of the steel plate 2. In addition, the second shape straightening device 6 is preferably high in straightening reaction force, and preferably has a load capacity of at least 2000 o' n, from the viewpoint of straightening the shape of the thick steel plate 2 at around room temperature.
(method of manufacturing Thick Steel plate)
In the method of manufacturing a thick steel plate according to the present embodiment, first, a cast slab or the like is hot-rolled in a hot rolling line (not shown) different from the heat treatment facility 1 to manufacture a thick steel plate 2 having a predetermined thickness (for example, 30mm) and width (for example, 2000 mm). Next, the hot-rolled thick steel sheet 2 is cooled to room temperature, and then the scale is removed by a surface scale removing device (not shown).
Then, the steel plate 2 from which the scale has been removed is charged into a heating furnace 3 and heated to an austenite temperature region (for example, around 910 ℃) (heating step).
Thereafter, the thick steel plate 2 is taken out of the heating furnace 3, conveyed to the first shape straightening device 4 by a plurality of table rolls (not shown) provided on the exit side of the heating furnace 3, and straightened (flattened) flatly by the first shape straightening device 4 (first straightening step).
Here, the reason why the first shape straightening device 4 is provided before the quenching apparatus 5 (on the upstream side in the conveying direction of the steel plate 2) will be described below. As described above, the thick steel plate 2 is hot-rolled in advance to a predetermined thickness and width in a hot-rolling line different from the heat treatment facility 1. At this time, when the thick steel plate 2 being rolled has a temperature variation, the degree of thermal shrinkage during cooling to room temperature differs depending on the portion of the thick steel plate 2, and thus a shape defect occurs after cooling. In the heat treatment facility 1, the thick steel plate 2 is inserted into the heating furnace 3 in a state where the shape defect occurs, and therefore, the shape defect remains even if the thick steel plate is uniformly heated by the heating furnace 3. Even if such a thick steel plate 2 is taken out from the heating furnace 3 and heat-treated by the quenching apparatus 5, the shape defect is not eliminated, but the treatment of the cooling water is not uniform, and the temperature unevenness is promoted. Therefore, the steel plate 2 having high flatness can be manufactured by heating the steel plate by the heating furnace 3 which ensures uniform heating, flattening the steel plate 2 by the first shape straightening device 4, and cooling the steel plate by the quenching device 5. That is, in order to obtain the effect of the present invention, it is necessary to flatten the shape (initial shape) of the thick steel plate 2 before entering the quenching apparatus 5.
Further, when the front end portion of the thick steel plate 2 is warped, the nozzle of the quenching apparatus 5 and the like may collide with the thick steel plate 2. Therefore, the first shape leveler 4 is preferably a roll leveler capable of repeating bending processing as compared to a skin pass leveler having a low straightening ability with respect to a longitudinal warp occurring at the leading end and the trailing end of the thick steel plate 2. The straightening apparatus of a roller leveler is a leveler that performs repeated bending by using a plurality of rollers (e.g., 4 rollers on the upper surface and 3 rollers on the lower surface), and the straightening effect is low at the distance of the space between the rollers. Therefore, when the straightening apparatus of the roller leveler is used, it is more preferable to further provide a pressing-type straightening mechanism or the like capable of correcting the warp of the leading end and the trailing end of the thick steel plate 2.
The temperature of the steel plate 2 during the shape straightening by the first shape straightening device 4 is preferably a temperature Ar at which the austenite phase of the steel plate 2 is transformed into ferrite3The temperature is within the range of +/-150 ℃. By setting the temperature to such a temperature, the yield stress of the thick steel plate 2 can be sufficiently reduced, and the reaction force at the time of straightening the shape can be reduced.
After the first straightening step, the thick steel plate 2 is quenched by the quenching apparatus 5 (quenching step).
After the quenching step, the thick steel plate 2 is straightened by the second shape straightening device 6 (second straightening step). It is difficult to control the flow rates of the cooling water 53 ejected from the upper cooling nozzle 51 and the lower cooling nozzle 52 in the width direction to be completely uniform in quenching (cooling) by the quenching apparatus 5. Therefore, slight warping may occur due to temperature unevenness during quenching, and it is necessary to further straighten the thick steel plate 2 by the second shape straightening device 6. Further, when the straightening is performed by the second shape straightening device 6, the temperature of the thick steel plate 2 is preferably 100 ℃ or lower.
< modification example >
The present invention has been described above with reference to specific embodiments, but the present invention is not limited to these descriptions. Other embodiments of the present invention, including the disclosed embodiments and various modifications, will be apparent to those skilled in the art from consideration of the specification of the invention. Therefore, it should be understood that embodiments of the invention described in the patent claims cover embodiments including these modifications described in the specification alone or in combination.
For example, although the thick steel plate 2 in which the steel plate has a plate thickness of 4.0mm or more is described in the above embodiment, the present invention is not limited to the above example. The thickness of the steel sheet may be less than 4.0 mm. The present invention is suitable for steel sheets having a thickness of 4.0mm or more, and more preferably, for steel sheets having a thickness of 6.0mm or more.
< effects of the embodiment >
(1) A steel plate (for example, a thick steel plate 2) manufacturing facility (heat treatment facility 1) according to an embodiment of the present invention is a steel plate manufacturing facility that performs heat treatment on a steel plate, and includes: a heating furnace 3 for heating a steel sheet at 100 ℃ or lower; a first shape straightening device 4 for straightening the heated steel sheet flatly; a quenching apparatus 5 for quenching the straightened steel sheet; and a second shape straightening device 6 that straightens the quenched steel sheet flatly.
According to the configuration of the above (1), the steel sheet is flattened by the first shape leveler 4, so that the cooling at the time of quenching can be made uniform. Therefore, the steel sheet can be made flat and homogeneous. Further, by flattening the steel sheet by the second shape straightening device 6 after quenching, even when unevenness occurs in cooling by the quenching device 5, the steel sheet finally manufactured can be flattened.
(2) In the above configuration (1), the load-bearing capacity of the first shape straightening device 4 is lower than that of the second shape straightening device 6.
According to the configuration of the above (2), the load-bearing capacity can be optimized according to the difference in deformation resistance caused by the temperature variation of the steel sheet, and since the first shape straightening device 4 does not use a straightening device having a high load-bearing capacity, the initial equipment introduction cost is low.
(3) In the above-described constitution of (1) or (2), the temperature of the steel sheet is Ar when the straightening is performed by the first shape straightening apparatus 43The temperature is within the range of +/-150 ℃.
According to the above configuration (3), the yield stress of the steel sheet is sufficiently low, and the reaction force during the shape straightening can be reduced.
(4) In any of the above configurations (1) to (3), the temperature of the steel sheet is 100 ℃ or lower when the steel sheet is straightened by the second shape straightening device 6.
According to the configuration of the above (4), the straightening temperature is almost room temperature, and re-deformation due to thermal shrinkage caused by further temperature drop does not occur after straightening, so that a good shape can be obtained.
(5) In any of the above configurations (1) to (4), the first shape straightening apparatus 4 and the second shape straightening apparatus 6 are roll straightening machine straightening apparatuses.
According to the configuration of the above (5), the warp of the leading end and the trailing end of the steel sheet can be straightened. Therefore, not only the warping of the steel sheet itself can be suppressed, but also contact with equipment such as cooling nozzles constituting the quenching apparatus 5 can be prevented during quenching.
(6) In any one of the above configurations (1) to (5), the quenching apparatus quenches the steel sheet by water cooling.
(7) A method for manufacturing a steel sheet according to an aspect of the present invention is a method for manufacturing a steel sheet by heat-treating a steel sheet, the method including: a heating step of heating the steel sheet 2 at 100 ℃ or lower; a first straightening step of straightening the steel sheet flat after the heating step; a quenching step of quenching the steel sheet after the first straightening step; and a second straightening step of straightening the steel sheet flat after the quenching step.
(8) In the above configuration of (7), in the first straightening step, the temperature of the steel sheet during straightening is Ar3The temperature is within the range of +/-150 ℃.
(9) In the above configuration (7) or (8), the temperature of the steel sheet in the second straightening step is 100 ℃ or lower.
According to the configurations (7) to (9), the same effects as those of the configurations (1), (3), and (4) can be obtained.
Examples
The present inventors have conducted an explanation of examples. In the examples, in the heat treatment facility 1 shown in FIG. 1, a room-temperature thick steel plate 2 (6 mm, 12mm, 25mm, 40 mm. times. plate width 3500 mm. times. plate length 7m) from which scale had been removed by sand blasting in advance was heated to 900 ℃ in a nitrogen atmosphere in a heating furnace 3. Is connected withThen, the heated steel plate 2 is taken out, the steel plate 2 is straightened by a first shape straightening device 4 (roller type straightening machine), and quenched to 100 ℃ or lower by a quenching device 5. Then, the steel plate 2 subjected to quenching is subjected to shape straightening again by the second shape straightening device 6. The quenching apparatus 5 uses spray nozzles as the cooling nozzles 51, 52. Ar of the material3The temperature was 800 ℃ and the temperature of the steel plate 2 taken out from the heating furnace 3 and straightened by the first shape straightening device 4 was about 860 ℃.
In the examples, the shape of the steel plate 2 when heat treatment was performed on the steel plate by the above-described equipment arrangement was examined. In the investigation, the thick steel plate 2 was placed on a surface plate, and the amount obtained by subtracting the plate thickness from the maximum height of the thick steel plate 2 with respect to the surface of the surface plate (referred to as a warpage amount) was measured, and the results are shown in examples 1 to 4 in table 1. The allowable value of the warpage amount of the thick steel plate 2 is 5mm or less. The steel plates 2 having thicknesses of 6mm, 12mm, 25mm and 40mm had good shapes (evaluation:. smallcircle.) in which all warpage amounts were 5mm or less.
As comparative examples, heat treatment was performed under the conditions that neither the first shape straightening apparatus 4 nor the second shape straightening apparatus 6 was used (comparative examples 1 to 4), under the conditions that straightening was performed using only the second shape straightening apparatus 6 without using the first shape straightening apparatus 4 (comparative examples 5 to 8), and under the conditions that straightening was performed using only the first shape straightening apparatus 4 without using the second shape straightening apparatus 6 (comparative examples 9 to 12). Then, the steel plate shape of the heat-treated thick steel plate 2 was examined in the same manner as in example. In addition to the above conditions, the heat treatment was performed under the same conditions as in examples. As shown in Table 1, in comparative examples 1 to 12, the warpage amount was more than 5mm under any conditions, and sufficient flatness could not be obtained as a product (evaluation: ×).
[ Table 1]
Description of the symbols
1 Heat treatment apparatus
2-thick steel plate
3 heating furnace
4 first shape straightening device
5 quenching device
50 constraint roller
51 upper side cooling nozzle
52 lower side cooling nozzle
53 Cooling water
6 second shape straightening device
Claims (9)
1. A steel plate manufacturing facility for heat-treating a steel plate, comprising:
a heating furnace for heating the steel sheet at 100 ℃ or lower;
a first shape straightening device that straightens the heated steel sheet flatly;
a quenching device for quenching the straightened steel plate; and
a second shape straightening device that straightens the quenched steel sheet flatly.
2. The steel sheet manufacturing apparatus according to claim 1, wherein a load capacity of the first shape straightening device is lower than a load capacity of the second shape straightening device.
3. The steel sheet manufacturing apparatus according to claim 1 or 2, wherein the temperature of the steel sheet is Ar at the time of straightening by the first shape straightening device3The temperature is within the range of +/-150 ℃.
4. The steel sheet manufacturing apparatus according to any one of claims 1 to 3, wherein the temperature of the steel sheet is 100 ℃ or less when the straightening is performed by the second shape straightening device.
5. The steel sheet manufacturing apparatus according to any one of claims 1 to 4, wherein the first shape straightening device and the second shape straightening device are roller straightening machine straightening devices.
6. The steel sheet manufacturing apparatus according to any one of claims 1 to 5, wherein the quenching device quenches the steel sheet by water cooling.
7. A method for manufacturing a steel sheet by heat-treating a steel sheet, comprising the steps of:
a heating step of heating the steel sheet at 100 ℃ or lower;
a first straightening step of straightening the steel sheet flat after the heating step;
a quenching step of quenching the steel sheet after the first straightening step; and
and a second straightening step of straightening the steel sheet flat after the quenching step.
8. The method of manufacturing a steel sheet according to claim 7, wherein in the first straightening step, the temperature of the steel sheet at the time of straightening is Ar3The temperature is within the range of +/-150 ℃.
9. The method of manufacturing a steel sheet according to claim 7 or 8, wherein the temperature of the steel sheet in the second straightening step is 100 ℃ or lower.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019212625 | 2019-11-25 | ||
| JP2019-212625 | 2019-11-25 | ||
| PCT/JP2020/043061 WO2021106723A1 (en) | 2019-11-25 | 2020-11-18 | Manufacturing equipment and manufacturing method for steel plate |
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| Publication Number | Publication Date |
|---|---|
| CN114728320A true CN114728320A (en) | 2022-07-08 |
Family
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| Application Number | Title | Priority Date | Filing Date |
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| CN202080081150.3A Pending CN114728320A (en) | 2019-11-25 | 2020-11-18 | Steel plate manufacturing equipment and manufacturing method |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP4066956A4 (en) |
| JP (1) | JP7173377B2 (en) |
| KR (1) | KR20220080174A (en) |
| CN (1) | CN114728320A (en) |
| WO (1) | WO2021106723A1 (en) |
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| JPS6272430A (en) * | 1985-09-26 | 1987-04-03 | Sumitomo Metal Ind Ltd | Straightening equipment provided with induction heating device |
| JP2005074480A (en) | 2003-09-01 | 2005-03-24 | Sumitomo Metal Ind Ltd | Facility for producing hot-rolled steel plate, and its production method |
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- 2020-11-18 KR KR1020227015900A patent/KR20220080174A/en not_active Application Discontinuation
- 2020-11-18 EP EP20893260.8A patent/EP4066956A4/en active Pending
- 2020-11-18 CN CN202080081150.3A patent/CN114728320A/en active Pending
- 2020-11-18 JP JP2021561349A patent/JP7173377B2/en active Active
- 2020-11-18 WO PCT/JP2020/043061 patent/WO2021106723A1/en unknown
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| JPS61126909A (en) * | 1984-11-21 | 1986-06-14 | Sumitomo Metal Ind Ltd | Working and heat treating installation in rolling line for thick plate |
| JP2002011515A (en) * | 2001-05-23 | 2002-01-15 | Nkk Corp | Line and method for manufacturing steel sheet |
| JP2005279703A (en) * | 2004-03-29 | 2005-10-13 | Jfe Steel Kk | Method and equipment for manufacturing steel sheet |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP7173377B2 (en) | 2022-11-16 |
| EP4066956A4 (en) | 2023-01-11 |
| WO2021106723A1 (en) | 2021-06-03 |
| EP4066956A1 (en) | 2022-10-05 |
| JPWO2021106723A1 (en) | 2021-06-03 |
| KR20220080174A (en) | 2022-06-14 |
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