JPH024373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot straightening device for two-layer clad metal plates.

[Prior Art] Generally, in the rolling of thick plates, warpage produced in a finishing mill is hot-straightened using a hot leveler, and warpage produced on a cooling table is further cold-straightened using a cold leveler.

By the way, as shown in FIG. 6, the base material 1A and
In the manufacturing process of a two-layer clad metal plate 1 such as a two-layer clad steel plate made of a laminated material 1B, the base material 1
Due to the difference in coefficient of linear expansion between A and laminate material 1B, the temperature of the metal plate suddenly decreases after rolling, and as a result,
Large warpage occurs in both the width direction and the longitudinal direction of the metal plate 1 as shown in FIG. The amount of warpage that occurs in the metal plate 1 depends on the materials of the base material 1A and the laminated material 1B, the plate thickness,
Depending on the plate width and cladding ratio, for example, if the base material 1A is low carbon steel and the mating material 1B is austenitic stainless steel, the stainless steel side will have a
It may form a concave shape with a depth of mm.

That is, in the case of the two-layer clad metal plate 1,
Even if straightening is performed using a hot leveler at 400 to 500°C at the end of rolling, warping occurs again due to the temperature difference between the straightening end temperature and room temperature, significantly impairing handling on table rollers.

In addition, when the two-layer clad metal plate 1 is finished rolling, if the temperature of the metal plate 1 is lowered as much as possible by repeating straightening with the rolling mill while cooling with a mill descaling shower, the handling property on the table roller will be improved. However, rolling efficiency is significantly reduced. In this case as well, when the metal plate 1 reaches room temperature, it will warp again.

In addition, in the case of the two-layer clad metal plate 1, even during cold straightening, it is necessary to straighten the warp to a greater extent than in a normal metal plate, and the time required for straightening is long, resulting in poor productivity.

Therefore, the present applicant has already filed the
In 42122, a metal with a large amount of heat shrinkage located on the upper surface side of a metal plate in a hot straightening machine is forcibly cooled by cooling water spouted from a cooling header,
We have proposed a hot straightening device that provides a temperature difference between a base material and a laminated material to suppress the occurrence of warping of metal plates at room temperature.

According to the above-mentioned hot straightening apparatus, the metal plate is hot-straightened under conditions such that the metal plate after rolling has the same amount of warpage as after cooling to room temperature, and the warpage of the metal plate after cooling to room temperature is reduced. It can be suppressed. That is,
In this case, the metal plate will warp in the opposite direction (reverse warp) due to soaking immediately after hot straightening, but the amount of thermal contraction of the base material and composite material during subsequent cooling will be reduced. The difference reduces the above-mentioned reverse warpage, making it possible to obtain a metal plate that is substantially flat at room temperature.

[Problems to be Solved by the Invention] However, in the hot straightening device already proposed above, the cooling header simply removes the large amount of heat shrinkage located on the upper surface side of the two-layer clad metal plate. Since the cooling water is for cooling metal, the cooling water ejected from the cooling header flows from the top side of the metal plate to the bottom side, cooling the metal plate on the bottom side of the metal plate as well. It is difficult to provide a temperature difference of In this way, if a predetermined temperature difference is not provided between the base material and the laminated material of the two-layer clad metal sheet, there will be insufficient reverse warpage immediately after hot straightening, and the warpage of the metal sheet at room temperature will be sufficiently suppressed. It is not possible to do so, or it is not reasonable to create a complex strain state due to non-uniform cooling within the metal plate.

An object of the present invention is to reliably provide a temperature difference effective for straightening warp between the base material and the laminated material of a two-layer clad metal plate, and to reliably suppress the occurrence of warp in the metal plate at room temperature. do.

[Means for Solving the Problems] The present invention provides a cooling system in which cooling water is spouted in the width direction of the passing area of the metal plate in a hot straightening machine for a two-layer clad metal plate made of a base material and a laminated material. A header is arranged to forcibly cool the metal side of the metal plate that has a large amount of thermal contraction, and a temperature difference is created between the base material and the laminated material to suppress the occurrence of warping of the metal plate at room temperature 2
In the hot straightening apparatus for layered clad metal plates, nozzles are provided at a plurality of positions on a cooling header corresponding in the width direction to the passing area of the metal plate, and each nozzle is provided with an on-off valve.

[Function] According to the present invention, by controlling the opening and closing valves of each nozzle of the cooling header in accordance with the plate width of the two-layer clad metal plate, the cooling water spouted from the cooling header is applied to the cooling header. It is possible to reliably cool only the corresponding metal surface, reliably provide a temperature difference between the base material of the metal plate and the laminated material that is effective for straightening warpage, and reliably suppress the occurrence of warpage of the metal plate at room temperature. It becomes possible.

[Example] Fig. 5 is a layout diagram showing a production line for two-layer clad steel sheets to which the present invention is applied, Fig. 1 is a front view showing a hot straightening device 10 according to an embodiment of the present invention, and Fig. 2 The figure is a sectional view taken along the - line in FIG. 1.

In FIG. 5, reference numeral 11 denotes a rolling mill, and a thermometer 1 is provided on the exit side of the rolling mill 11 to measure the temperature of the two-layer clad steel sheet 12 rolled by the rolling mill 11.
3 is installed. On the entry side of the hot straightening device 10, a steel plate detector (hot lump detector) 14A for detecting the steel plate 12 entering the hot straightening device 10, and a steel plate 1
A thermometer 15 for detecting the temperature of No. 2 is installed. Further, on the exit side of the hot straightening device 10, there is a steel plate detector 14B for detecting the steel plate 12 that enters the hot straightening device 10 again from the exit side of the hot straightening device 10 during multi-pass straightening. A thermometer 16 is installed to detect the temperature of the steel plate 12 located on the exit side.

The hot straightening device 10 includes a leveler roll 17 inside the housing 10A, which flattens the steel plate 12 under plastic deformation by repeatedly bending the steel plate 12. Leveler roll 17
consists of a plurality of lower rollers 17A and a plurality of upper rollers 17B. Further, in the hot straightening apparatus 10, a lower cooling header 18A is disposed between each of the lower rollers 17A, and an upper cooling header 18B is disposed between each of the upper rollers 17B. Each lower cooling header 18A is equipped with a spray nozzle 19A that sprays cooling water in the width direction of the passing region of the steel plate 12. Further, each upper cooling header 18B is provided with a spray nozzle 19B that sprays cooling water in the width direction of the passing area of the steel plate 12.
Each lower cooling header 18A is connected to a lower water supply header 20.
A collectively connected to each lower cooling header 18A
An electromagnetic on-off valve 21A is installed in each of the water supply channels formed between the lower water supply header 20A and the lower water supply header 20A.
Each upper cooling header 18B is connected to an upper feeding header 20.
B collectively connected to each upper cooling header 18B
An electromagnetic on-off valve 21B is installed in each of the water supply channels formed between the upper water supply header 20B and the upper water supply header 20B.
Note that an orifice 22, a flow rate regulating valve 23, and an electromagnetic on-off valve 24 are provided on the upstream side of each water supply header 20A, 20B.

Also, spray nozzles 19 of each cooling header 18A, 18B are located corresponding to the area excluding the minimum plate width W of the steel plate 12 in the hot straightening device 10.
A and 19B are provided with electromagnetic on-off valves 25A and 25B, respectively. Each electromagnetic on-off valve 25A,
25B is interposed between the water supply channels 26A, 26B connected to the spray nozzles 19A, 19B in each cooling header 18A, 18B.

Next, the operation of the above embodiment will be explained.
Note that in this embodiment, the hot straightening device 10
For the reason described later, the steel plate 12 can be straightened in multiple passes, and in the initial straightening stage (for example, the first pass) of the steel plate 12, the cooling headers 18A and 18B are used for metals with a large amount of thermal contraction of the steel plate 12, for example, in this implementation. In the example, only the lower cooling header 18A side is operated, and after the initial straightening stage of the steel plate 12 has passed, it is possible to operate both cooling headers 18A and 18B.

When the temperature of the steel plate 12 after rolling by the rolling mill 11 is measured by the thermometer 13, a process computer or the like uses various values according to the measured temperature, the material of the steel plate 12, the plate width, the plate thickness, and the cladding ratio. The amount of cooling water and the sheet passing speed (cooling time) of the cooling headers 18A and 18B are calculated and instructed. The above cooling water amount and sheet threading speed are checked again based on the temperature measurement result of the steel sheet 12 by the thermometer 15 installed on the entry side of the hot straightening device 10. Hot straightening device 10
The calculated amount of cooling water can be established by adjusting the opening degree of the electromagnetic on-off valves 21A and 21B,
By adjusting the feeding speed of the table roll, the calculated sheet passing speed can be set. Thereby, after the hot straightening device 10 detects the tip of the steel plate 12 with the steel plate detector 14A, the cooling headers 18A and 18B which are arranged adjacent to each other in the passing direction of the steel plate 12 are detected by a timer or the like. Solenoid on-off valve 2
1A and 21B are sequentially opened in response to the passing of the tip of the steel plate 12, and each cooling header 1 on the steel plate 12 is opened.
Cool the metal surfaces corresponding to 8A and 18B. In addition, after the hot straightening device 10 detects the rear end of the steel plate 12 with the steel plate detector 14A, the hot straightening apparatus 10 detects the rear end of the steel plate 12 using a timer or the like, and then detects each of the cooling headers 18A and 18B which are arranged adjacent to each other in the passing direction of the steel plate 12. Solenoid on-off valve 2
1A and 21B are sequentially closed in response to passage of the rear end of the steel plate 12.

The hot straightening device 10 uses the steel plate detector 14B to detect the rear end of the steel plate 12 that reenters the hot straightening device 10 from the exit side of the hot straightening device 10 when straightening the steel plate 12 in multiple passes. , electromagnetic on-off valves 21A, 21B for each cooling header 18A, 18B
Control opening and closing in the same way as above.

Further, when the temperature of the steel plate 12 after straightening in the hot straightening device 10 is measured by the thermometer 16, the amount of warpage of the steel plate 12 that will occur at room temperature is predicted by a process computer etc. Using this predicted value, a process computer etc. uses each cooling header 18 necessary for straightening the next material.
Correct the calculation of the amount of cooling water for A and 18B.

However, in the hot straightening device 10,
Before the steel plate 12 enters, the spray nozzles 19 in each cooling header 18A, 18B are automatically or manually operated according to the width of the steel plate 12.
Controls the opening and closing of the electromagnetic on-off valves 25A and 25B of A and 19B.

As a result, the steel plate 1 in the hot straightening device 10
In the first pass of step 2, the cooling water jetted from the spray nozzle 19A of the lower cooling header 18A reliably cools only the metal side of the corresponding steel plate 12 that has a large amount of thermal contraction, and lowers the temperature of the metal on the opposite side that does not correspond to the metal side. It does not change the state. Therefore, the temperature difference necessary to suppress the occurrence of warping at room temperature is reliably provided between the base material of the steel plate 12 and the laminated material, and the hot straightening device 10 can reduce the amount of heat shrinkage of the steel plate 12. The metal is stretched in a state that cancels out the thermal contraction of the metal, and the two metals are straightened into the same shape under a state where a certain temperature difference is applied to the two metals. In addition, the hot straightening device 10 is configured to use the spray nozzles 19 of both the upper and lower cooling headers 18A and 18B during straightening after the second pass following the one-sided cooling of the steel plate 12 in the first pass.
A and 19B supply an appropriate amount of cooling water only to the base metal side or the laminating metal side of the corresponding steel plate 12, allowing the steel plate 12 to quickly reach room temperature and making a flat plate.

In addition, in the hot straightening apparatus 10, the reason why multiple pass straightening is adopted, which consists of a first pass by operating only the lower cooling header 18A, and a second pass and subsequent passes by operating both the upper and lower cooling headers 18A and 18B. The explanation is as follows. That is, in the case of single-sided cooling of the steel plate 12 in the first pass, in principle, after the cooled steel plate 12 is reversely warped, the temperature at the end of cooling (for example, the plate thickness is Approximately 12mm thin steel plate
300° C. (approximately 400° C. for a thick steel plate with a thickness of 20 to 25 mm) is distorted again until it reaches room temperature, making it possible to flatten the above-mentioned reverse warpage of the steel plate 12. However, since the entrance temperature, plate thickness, plate width, cladding ratio, etc. of the steel plate 12 are mostly different from sheet to sheet, even if the cooling water amount and threading speed are controlled according to these conditions, straightening is not possible at room temperature. It is quite difficult to manufacture a plate that does not require this process. There is a difference between the conveyance route (that is, the one that is placed on the table roll for a long time and the one that is lowered quickly to the dirt floor), because at room temperature there will be a slight upward or downward warp, these plates need to be cold straightened. (cold leveling). In order to omit this cold straightening step, the steel plate 1 is
It is preferable to cool the steel plate 12 from the upper and lower surfaces of the steel plate 12 and quickly bring the steel plate 12 to room temperature. That is, according to the inventor's experimental results, the temperature of the steel plate 12 decreases by 100 to 150°C in a single-sided cooling pass, and the temperature of the steel plate 12 usually becomes around 550 to 400°C. Therefore, this steel plate 12
In order to bring the steel plate 12 to room temperature, the steel plate 12 is in the most efficient temperature range in the nucleate boiling region by water cooling. can be quickly brought to room temperature.

FIG. 3 is a front view showing a modification of the embodiment shown in FIGS. 1 and 2, and FIG. 4 is a sectional view taken along the - line in FIG. 3. This hot straightening device 30 differs from the hot straightening device 10 only in that the upper cooling header 18B is removed. That is, this hot straightening device 30 performs one-sided cooling on the metal side of the steel plate 12, which has a large amount of thermal contraction, by operating the lower cooling header 18A, and uses the spray nozzle 19B and the electromagnetic shut-off valve 25B. Therefore, as in the hot straightening apparatus 10, only the metal surface of the steel plate 12 corresponding to the cooling header 18A can be reliably cooled by the cooling water spouted from the cooling header 18A.

Therefore, after straightening, the steel plate 12 straightened by the hot straightening device 30 will be reversely warped due to recuperation due to the heat content of the uncooled metal side, but the reverse warp will reach room temperature. It becomes flat by then.

In addition, in implementing the present invention, if the masking of the metal plate passing area by the nozzle of the cooling header and the on-off valve is excessive (cooling an area smaller than the width of the metal plate), the ear part of the metal plate Since a part that cannot be reversely warped is generated, the setting of this masking area needs to be done minutely.

[Effects of the Invention] As described above, the present invention provides a cooling method in which cooling water is spouted in the width direction of the passing area of the metal plate in a hot straightening machine for a two-layer clad metal plate made of a base material and a laminated material. A two-layer cladding in which a header is arranged to forcibly cool the metal side of the metal plate that has a large amount of thermal contraction, and to create a temperature difference between the base material and the laminated material that suppresses the occurrence of warping of the metal plate at room temperature. In the hot straightening apparatus for metal plates, nozzles are provided at a plurality of positions on a cooling header corresponding in the width direction to the passing area of the metal plate, and each nozzle is provided with an on-off valve. Therefore, it is possible to reliably provide a temperature difference effective for straightening warp between the base material and the laminated material of the two-layer clad metal plate, and to reliably suppress the occurrence of warp in the metal plate at room temperature.

[Brief explanation of drawings]

FIG. 1 is a front view showing a hot straightening device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG. 3 is a front view showing a modification of the present invention.
FIG. 4 is a sectional view taken along the - line in FIG. 3, FIG. 5 is a layout diagram showing a production line for a two-layer clad metal plate to which the present invention is applied, and FIG. 6 is a cross-sectional view showing a two-layer clad metal plate. 7 are cross-sectional views showing the state in which warpage occurs in a two-layer clad metal plate. 1...Two-layer clad metal plate, 1A...Base material, 1
B... Laminated material, 10, 30... Hot straightening device,
18A, 18B... Cooling header, 19A, 19
B...Spray nozzle, 25A, 25B...Solenoid on-off valve.

Claims (1)

[Claims] 1 A cooling header that sprays cooling water in the width direction of the passing area of the metal plate is placed in a hot straightening machine for a two-layer clad metal plate consisting of a base material and a laminated material, and the amount of heat shrinkage of the metal plate is reduced. A hot straightening device for two-layer clad metal plates that forcibly cools the larger metal side and provides a temperature difference between the base metal and the laminated metal plate that suppresses the occurrence of warpage at room temperature. A hot straightening device for a two-layer clad metal plate, characterized in that nozzles are provided at a plurality of positions on a cooling header corresponding to the width direction of the plate area, and each nozzle is provided with an on-off valve.