JPS61162224A - Camber straightening method of double layer cladding metallic plate - Google Patents

Abstract

PURPOSE:To straighten so as to surely flatten various kinds of double layer cladding metal plates by performing forced cooling of the metal side having larger thermal shrinking quantity with performing hot straightening by using the cooling conditions to make the final camber quantity in zero and the set value of straightening conditions. CONSTITUTION:A hot straightening device 12 arranges a cooling header 14 between a hog leveller roll 13 and upper roll. The various sizes, quality and cladding ratio of a steel plate 11, the water flow density of the cooling header 14 necessary for making the final camber quantity in zero at room temp. time concerning the inlet side temp. and the plate passing speed of the hot straightening device 12 are stored in advance by equations, etc. in the water flow density and plate passing speed setting device 15. The straightening is performed by adjusting the water quantity of the cooling header 14 via a water quantity control device 18 also by operating a speed control device 19. The set conditions are corrected with the feedback via arithmetic unit 22 of the measured value of a deflection meter 21, etc. installed on the outlet side. Various kinds of double layer cladding metal plate can be thus flattened surely.

Description

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

[Prior art] Conventionally, when manufacturing two-layer clad metal plates such as two-layer clad steel plates where the laminating material is stainless steel, cupronickel, etc. and the base material is carbon steel, there is a difference in linear expansion coefficient of the art materials. However, there was a problem in that there was a difference in the amount of thermal shrinkage between the art materials after straightening with a hot leveler, and after cooling to room temperature, warping occurred with the member with the larger amount of shrinkage on the inside.

In response to this problem, the present inventors have developed a method for straightening warpage of a two-layer clad steel sheet as disclosed in Japanese Patent Application Laid-Open No. 59-42122, and have achieved results.

That is, in the method according to JP-A-5L42122, by forcibly cooling the steel plate side with a large amount of heat shrinkage before or during hot straightening, a temperature difference is created between the side of the steel plate with a small amount of heat shrinkage, In this method, the steel sheet is brought into a state in which the same amount of warpage as after cooling is achieved in advance, and then the steel sheet in this state is flattened using a hot leveler or the like, thereby making it possible to prevent the steel sheet from warping after being cooled to room temperature.

According to this method, the steel plate immediately after hot straightening will be warped in the opposite direction due to soaking, but after that, this warp will decrease due to the difference in the amount of heat shrinkage during cooling, and at room temperature At times, a nearly flat state can be obtained. Therefore, it is possible to reduce the burden of cold straightening after cooling and to omit the cold straightening process.

[Problems to be solved by the invention] However, the two-layer clad steel plate that actually undergoes straightening,
It is not a single type of material, but a variety of materials such as plate thickness, plate width, and cladding ratio (-
The material of the laminate (laminated material thickness/plate thickness) and the material of the laminate are variously different. Therefore, when carrying out the method according to JP-A-59-42122, when straightening a steel plate by simply creating a temperature difference between the front and back surfaces, although there are cases where the warpage is completely eliminated, the amount of warpage correction is insufficient. Problems arise such as there are cases where warpage remains, and cases where the amount of warpage correction is too large and warpage occurs in the opposite direction.

An object of the present invention is to make it possible to straighten various two-layer clad metal plates so that they are reliably flat at room temperature.

A first aspect of the present invention is a method for straightening a warp of a two-layer clad metal plate consisting of a base material and a laminate, which is performed before or during hot straightening of the two-layer clad metal plate. When forcibly cooling the metal side with a large amount of thermal contraction, the water flow density of the water cooling device and the sheet threading speed of the straightening device are set to make the final amount of warpage of the two-layer clad metal plate zero at room temperature. Based on the setting results, the water flow density of the water cooling device and the sheet passing speed of the straightening device are controlled.

The second aspect of the present invention is a method for straightening warpage of a two-layer clad metal plate consisting of a base material and a laminate material, in which the metal side having a large amount of heat shrinkage is used before or during hot straightening of the two-layer clad metal plate. When forcedly cooling the two-layer clad metal plate, the water flow density of the water cooling device and the sheet passing speed of the straightening device necessary to make the final amount of warpage of the two-layer clad metal plate zero at room temperature are set. In addition to controlling the water flow density and the sheet passing speed of the straightening device, the final amount of warpage of the metal sheet at room temperature is predicted from the plate information after equalization and reheating obtained at the exit side of the hot straightening device, and this predicted value is calculated. is used to correct the calculation of the water flow density of the water cooling device and the sheet passing speed of the straightening device necessary for straightening the next material.

[Function] According to the present invention, the metal side of the two-layer clad metal plate having a large amount of thermal contraction is forcedly cooled to a necessary and appropriate state, and various two-layer clad metal plates can be reliably flattened at room temperature. It becomes possible to correct the problem.

[Embodiment] FIG. 1 is a control system diagram showing a warpage correction device 10 used for implementing the present invention.

The two-layer clad steel plate 11 is made of a fiJ material and a laminated material. For example, the base material is carbon steel, which has a relatively small amount of thermal contraction (coefficient of linear expansion), and the base material is carbon steel, which has a relatively large amount of thermal contraction (coefficient of linear expansion). The material is stainless steel.

The steel plate 11 is rolled in a rolling mill, subjected to hot straightening in a hot straightening device 12, and then conveyed to a subsequent process by table rollers.

The hot straightening device 12 has a hot leveler roll 13, and a cooling header 14 is disposed between the first roller of the hot leveler roll 13. cooling header 1
4 is opposed to a metal with a large amount of heat shrinkage (line 1 tensile modulus), that is, stainless steel, which is located on the - side of the steel plate 11, and the steel plate 1 is removed by the hot leveler roll 13.
During the hot straightening of step 1, the ``-marked down'' of the steel sheet 11 is straightened and cooled, making it possible to provide a temperature difference between the base material and the laminate material necessary to suppress warping of the steel sheet 11 at room temperature.

The warpage correction device 10 includes a water flow density/sheet threading speed setting device 15
have. The water flow density/threading speed setting device J & 15 is necessary to make the final amount of warpage of the steel sheet 11 zero at room temperature, regarding various dimensions, materials, cladding ratios, and entrance temperature to the hot straightening device 12 of the steel sheet 11. cooling header 1
The water flow density of 4 and the sheet passing speed of the hot straightening device 12 are stored in advance in a form such as a numerical formula or a diagram.

Here, the information on the steel plate 11 held by the water flow density/threading speed setting device 15, the water flow density of the ladder 14,
Threading speed IJIIk of hot straightening device 12 and steel plate 11
The relationship between the final warpage and the final warpage at room temperature is as follows.

In other words, in Figures 2 (A) to (D), a stainless clad steel plate is selected as a representative example of a two-layer clad metal plate, and the base metal made of carbon steel and the mating metal made of stainless steel are shown. Among the four conditions: difference in linear expansion coefficient △α, average linear expansion coefficient d of both metals, cladding ratio (thickness of laminate/total thickness of plate) a, and hot straightening entry temperature TO, other conditions are This shows the results of hot straightening using the equipment shown in Figure 1, using a water cooling equipment to change the temperature difference △T between the front and back surfaces of both metals, for materials with one condition changed from the standard conditions. .

The standard conditions are △α-Q, 4 x 10 (1/'C
), each = 1. fli X1O(1/'O), a
=0.3, To =400°C. In the figure, “×j
The mark indicates that warpage exists at room temperature (warpage with the metal with a large coefficient of linear expansion on the inside), and the "+" mark indicates that there is reverse warpage (warpage with the metal with a large coefficient of linear expansion on the outside) at room temperature. )
The "0" mark indicates that the temperature is approximately flat I at room temperature. As can be seen from Figure S2, in order to reduce the final amount of warpage to zero at room temperature,
It is necessary to give the temperature difference ΔT between the front and back surfaces given by 4-j during hot straightening, for example, by a function represented by the following equation (1), which is composed only of the above factors.

△T-J(△α, q, a, To) ... value]) △α
: Difference in coefficient of linear expansion of both metals, A: Average coefficient of linear expansion of both metals a: Cladding ratio (thickness of laminated material/total thickness of plate) To: Hot straightening entrance temperature Figure 2 (A) ~ ( For example, if we estimate the function of equation (1) from D), we get △T=, △α (?M degree difference is proportional to the linear expansion coefficient difference between the two metals) -21/a (temperature difference is , an example of reverting to the average line 1 tension of both metals) - to 3 a (1-a) (the temperature difference is expressed as a quadratic function of the cladding ratio) = % To (the temperature difference is the hot straightening (proportional to the inlet temperature) (kI"k4 is a proportionality constant), so if expressed as one equation, it becomes the following equation (2).

Here, ko for making the steel plate substantially flat I at room temperature is a value of "4 to 6" from FIG.

However, kO in the range where the effect of this method exists, that is, the range in which the final amount of warpage can be made smaller than the final amount of warpage when this method is not used at all, may be a value of "1 to 11". Note that the above formula (2) is only 1, which is constructed using basic factors.
A method of controlling the temperature difference using an equation that includes other factors in addition to this hole is included within the scope of the method of the present invention.

Note that FIGS. 2(A) to 2(D) are for stainless clad steel plates as representative examples of two-layer clad metal plates; however, according to the inventor, FIGS. (D
) is widely recognized to hold true in general two-layer clad metal plates.

By the way, the specific operation for making it possible to give the steel plate 11 the temperature difference ΔT calculated by equation (1), more specifically, equation (2), is to adjust the water cooling time and heat transfer to the steel plate 11 The coefficients will need to be adjusted.

That is, Fig. 3 is a diagram showing the effect of water cooling time on the temperature difference ΔT, and Fig. 4 is a diagram showing the effect of water cooling time on the temperature difference ΔT, and Fig. 4 shows the heat transfer coefficient
It is a diagram showing the influence on T. According to FIG. 3, the temperature difference between the front and back surfaces during cooling of the steel plate 11 increases as time passes, and it is recognized that the temperature difference between the front and back surfaces can be controlled by the water cooling time. Furthermore, according to Fig. 4, increasing the heat transfer coefficient increases the rate of increase in the temperature difference on the surface, making it possible to overcome a large temperature difference in a longer time. It is recognized that the temperature difference between the front and back surfaces can also be controlled by the transfer coefficient. By the way, in the actual hot straightening apparatus 12, in order to adjust the water cooling time and the heat transfer coefficient, it is necessary to control the following two items.

(a) By changing the sheet passing speed of the straightening device 12, the copper plate 11
Control the water cooling time by varying the amount of time each point above exists in the cooling region.

(b) The water flow density is changed by adjusting the amount of water while considering the area of the water cooling region, that is, the heat transfer coefficient is controlled by changing the amount of water that comes into contact with each point of the steel plate per unit area per unit time. That is, the control of the above two items (threading speed and water flow density) is easy to concretely execute as means for adjusting the temperature difference ΔT between the front and back surfaces. In addition, in addition to the above-mentioned second time, for example, as for the cooling time, a longer straightening device is manufactured as shown in Fig. 6, and the nozzle is turned on.
It is also possible to change the cooling time by turning it off and changing the cooling zone length. Regarding the heat transfer coefficient, it is also possible to change the size of the hole at the tip of the nozzle or the cooling method itself (mistake) (from cooling to spray cooling, from spray cooling to laminar cooling). Significant equipment changes are required compared to Section 2.1. It is also possible to adjust the water temperature or forcibly heat the metal side of the steel plate 11 with a smaller thermal contraction JjV, but this also requires significant equipment changes.

Therefore, this warp straightening device 10 processes the various dimensions, materials, cladding ratios, and entrance temperature of the hot straightening device 12 of the steel plate 11 using the equation (1), more specifically, the equation (2). , calculate T to the temperature difference between the front and back surfaces necessary to make the final amount of warpage of each copper plate 11 zero at room temperature,
Furthermore, the water flow density, that is, the water amount Q of the cooling header 14 necessary to make it possible to apply the humidity difference ΔT to the steel plate 11, and the strip threading speed V of the hot straightening device 12 are determined as described above. It is held in the speed setting device 15.

Therefore, the water flow density/threading speed setting device engineer 5 determines the dimensions of the steel plate 11 input into the line computer 16,
Based on the materials of the base material and the cladding material, the cladding ratio, and the temperature To of the steel plate 11 on the entry side of the hot straightening device 12 measured by the entry side thermometer 17, the final amount of warpage of the steel plate 11 at room temperature is set to zero. Cooling header 1 required for
4, the water amount Q and the sheet passing speed V of the hot straightening device 12 are set.

As a result, the warp straightening device 10 controls the water flow rate control device 1 based on the setting result of the water flow density/sheet threading speed setting device 15.
8 to adjust the amount of water in the de-cooling header 14, and the speed control device 19 to adjust the sheet passing speed of the hot straightening device 12.

By the way, in the warpage correction device 10, the steel plate 11
By measuring the final amount of warpage of the steel plate 11 at room temperature after completing the straightening work for the steel plate 11 and adaptively correcting the above control, it is possible to perform more accurate control on the subsequent material. However, in reality, it is not appropriate to wait until the clad steel plate 11 reaches room temperature because it would take too much time for adaptive repair. On the other hand, according to the present inventor, it has been recognized that there is a certain relationship between the plate temperature, the amount of warpage, and the final warpage immediately after uniform reheating of the steel plate 11 on the exit side of the hot straightening device 12. ing. Figure 5 shows a plate thickness of 20 mm and a plate width of 3.
．． This figure shows the relationship between the warpage after equalization and recuperation of a stainless steel clad steel sheet with a thickness of 0.000 mm and a cladding ratio of 30% and the average temperature of the sheet material. As is clear from FIG. 5, the gradients of temperature change and warp change are the same for the same material, and if the warp and temperature can be measured immediately after uniform reheating, the final amount of warp can be estimated.

Therefore, in this warp straightening device 10, an exit side thermometer 20 and a warp meter 21 are arranged on the exit side of the hot straightening device 12, and the temperature T The amount of warpage Δym can be transmitted to the final warp calculation device 22. The final warpage calculation device 22 calculates the final warpage amount Δ from the temperature Tl11, the warpage amount Δym, and board information (board thickness, board width, cladding ratio, material of art materials, etc.) from the line computer.
It is possible to calculate yr and transmit the @ calculation result to the water flow density/sheet threading speed setting device 15. The water flow density and sheet threading speed setting device 15 is capable of adaptively correcting the settings of the water MQ and sheet threading speed V so as to make this final warpage Δyf zero. Thereby, the warpage correction device 10 can perform the most appropriate warpage correction, and can always keep the final warpage to approximately zero.

Here, the correction of the calculation of the water amount Q and the sheet threading speed V by the water density and sheet threading speed setting device 15 is performed, for example, as follows. Regarding water 1 full Q, let the calculated final warpage amount when the water amount is zero (when this method is not used) be yo, and calculate the final warpage amount for the actual water amount QR so that the final warp h (is zero). Assume that the amount of warpage is YR.In other words, the calculated warpage improvement amount (calculated improvement amount) for the water amount QR is yo, and the actual warpage improvement amount for the water amount QR is yo-yR, so the correction coefficient of equation (1) below is k
By calculating Q and multiplying the set water flQ for the next material by kQ, it becomes possible to perform more appropriate straightening.

kQ = yo / (yo - yR) - (1) Also, regarding the threading speed V, the calculated final warpage amount when this method is not used is yO, and it is actually set so that the final warpage amount is zero. The final warpage amount is Y for the threading speed VR.
Suppose it was R. In other words, the calculated warpage improvement amount for the sheet threading speed VR (improvement amount in calculation) is yO1 sheet threading speed V
Since the actual warpage improvement amount for R is yo-yR, more appropriate correction can be performed by calculating the correction coefficient kV from the following formula (2) and multiplying the set threading speed ■ for the next material by kV. becomes.

kV=(yo-yR)/yo (2) In the implementation of the present invention, 1 ton of water is calculated by the final warp calculation device 22.
Q. It is not necessary to make adaptive corrections to the threading speed ■.

Further, in the implementation of the present invention, the water flow density and sheet threading speed setting device δ15 may be configured to keep one of the water flow density and the sheet threading speed constant and adjust the other.

Hereinafter, specific implementation results for stainless clad steel sheets will be explained. Plate thickness 20mm, cladding ratio 1030
Using the equipment shown in Figure 1, a 50% stainless steel clad steel plate is used for the conventional method of forced cooling and hot straightening at a constant water flow density and threading speed, and for warping by controlling the water flow density and threading speed. Straightening was performed using the method of the present invention in which hot straightening is performed by changing the amount of warpage, and the amount of warpage was compared.

Conventional method (threading speed 30m/min, water flow density 7oo9./m
When the temperature at the entrance of the hot straightening device was 700°C, the hot straightening was completed and flattened by cooling one side of the stainless steel side even when the cladding ratio was 103050%. On the other hand, in the present invention, the water flow density and the threading speed are controlled. When the threading speed is kept constant at 30 m/min and only the water flow density is controlled, the water flow density is 300 m/min at a cladding ratio of 10%.
17 m'min, water flow density at 30% cladding ratio is 700 m/m'min, water density at 50% cladding ratio is 1,000 m'min.
The hot straightening was completed at fL/m' minutes, and the surface became flat. In addition, when controlling only the threading speed, the water density should be set to 700.
! : When the clad ratio is 10%, the threading speed is 60 m/min, and when the cladding ratio is 30%, the threading speed is 3 m/min.
At 0 m/min and 50% cracking ratio, the threading speed is 10 m/min.
The hot straightening was completed within minutes and the surface became flat. Changes in the amount of warpage over time after hot straightening are shown in FIG. 7 for the method of the present invention, and FIG. 8 for the conventional method. In the conventional method,
Since the temperature difference between the front and back surfaces of each steel plate was the same during straightening,
The amount of warpage caused by soaking the front and back surfaces is also approximately the same for the three types of cladding ratios, and the amount of warpage is approximately 180 mm.

However, the subsequent change in warpage due to the difference in thermal expansion coefficient between the stainless steel and carbon steel inner steel materials differs depending on the cladding ratio, and the final warpage was almost zero at a cladding ratio of 30%, but At a cladding ratio of 10%, 100 mm of warpage caused by single-sided cooling straightening remains.
In addition, when the cladding ratio was 50%, the warpage due to the difference in thermal expansion coefficient between the two steel materials was large, and the warpage in the opposite direction to that of the steel was 35 mm.
Occurred. On the other hand, in the present invention, since the water cooling density and threading speed are controlled by the cladding ratio, the amount of warpage caused by soaking the steel materials on the front and back surfaces is 70 mm at a cladding ratio of 10%.
(Water flow density control), 80mm (Threading speed control)
, 180+nm at clad ratio 30%, clad ratio 50
% 210mm (water flow density control), 200mm
The amount of warpage is different from the amount of warpage (threading speed control). Therefore, the final amount of warpage was almost zero, regardless of the cladding ratio.

Note that when the sheet metal thickness is as thin as 10 mm, the temperature difference can be freely changed at high temperatures using water flow density control, but when using sheet threading speed control, if the sheet metal threading speed is lowered in an attempt to create a large temperature difference, the sheet metal body will not be cooled. There are cases where the plate progresses too far and cannot be completely flattened with a hot leveler, so if the plate thickness is too thick, it is necessary to deal with this mainly by controlling the water flow density.

According to the present invention, it is possible to obtain a flat two-layer clad steel plate that does not warp after cooling even when the plate thickness, cladding ratio (=laminated material thickness/plate thickness), material of laminate material, edge start temperature, etc. are different. I can do it. For this reason, it has become possible to omit the cold straightening process that is performed on all two-layer clad steel sheets after cooling.

It is clear that the present invention can in principle be applied to two-layer clad metal plates made of any combination of different metals with different coefficients of thermal expansion, and is not limited to clad steel plates.

[Effects of the Invention] As described in 1- below, the first aspect of the present invention is a method for straightening warpage of a two-layer clad metal plate made of an art material and a laminate material, which is performed before or after hot straightening of the two-layer clad metal plate. When forcibly cooling the metal side with a large heat shrinkage area, I7. Determine the water flow density of the water cooling device and the sheet passing speed of the straightening device necessary to make the final amount of warpage of the two-layer clad metal plate zero at room temperature. The water flow density of the water cooling device and the sheet passing speed of the straightening device are controlled based on the setting results.

The second aspect of the present invention is a method for straightening warpage of a two-layer clad metal plate made of A7 material and a laminated material, in which a metal with large heat shrinkage stitches is formed before or during hot straightening of the two-layer clad metal plate. When forcedly cooling the side, the water flow density of the water cooling device and the sheet passing speed of the straightening device required to make the final warpage of the two-layer clad metal plate zero at room temperature are set, and the setting results are used to adjust the water cooling device's flow rate. In addition to controlling the water flow density and the sheet passing speed of the straightening device, the final amount of warpage of the metal sheet in the normal temperature section is predicted from the sheet information after uniform reheating obtained at the exit side of the hot straightening device, and this predicted value is This is used to correct the calculation of the water flow density of the water cooling device and the sheet passing speed of the straightening device necessary for straightening the next material.

Therefore, it is possible to straighten various two-layer clad metal plates so that they are reliably flat at room temperature.

[Brief explanation of the drawing]

Fig. 1 is a control system diagram showing the warp straightening device used to carry out the present invention, and Fig. 2 (A) is a diagram showing the relationship between the linear expansion coefficient difference between the two metals, the temperature difference between the front and back surfaces, and the final warp. , Figure 2 (B
) is a line showing the relationship between the average coefficient of linear expansion of both metals, the temperature difference between the front and back surfaces, and the final warpage, and Figure 2 (C) is a line showing the relationship between the cladding ratio, the temperature difference between the front and back surfaces, and the final warp. Figure, Figure 2 CD
) is a diagram showing the relationship between the temperature at the entrance of the hot straightening device, the temperature difference between the front and back surfaces, and the final warpage. A diagram showing the relationship between the transfer coefficient and the temperature difference between the front and back surfaces, Fig. 5 is a diagram showing the relationship between the average temperature of the plate material and the amount of warpage, Fig. 6 is a schematic diagram showing another hot straightening device, and Fig. 7 The figure is a diagram showing the change in the amount of warpage according to the present invention, and FIG. 8 is a diagram showing the change in the amount of warp according to the conventional method. 10... Warp straightening device, 11... Two-layer clad steel plate, 12... Hot straightening device, 14... Cooling header,
15...Water flow density/threading speed setting device, 18...Water flow control device, 19...Speed control device, 20...Output side thermometer, 21...Warp meter, 22...Final Warp calculation device. Agent Patent Attorney Osamu Shiokawa Beat Fig. 2 (A) Old Fig. 2 (B> a also me 1σ? (1/・C) Fig. 2 (C) h Cladding' ratio (combined stroke M/, m's Total thickness) Figure 2 (D) Hanging hot straightening entry side 5H Liao T ("C"1 Figure 5 Figure 6 Figure 7 Time t (minutes) Figure 8 Time t (minutes)

Claims (2)

[Claims] (1) In a method for straightening warpage of a two-layer clad metal plate consisting of a base material and a laminate, when forcedly cooling the metal side with a large amount of heat shrinkage before or during hot straightening of the two-layer clad metal plate, The water flow density of the water cooling device and the sheet passing speed of the straightening device necessary to make the final amount of warpage of the two-layer clad metal plate zero at room temperature are set, and the water flow density of the water cooling device and the straightening device are determined based on the setting results. A method for straightening warpage of a two-layer clad metal plate, characterized by controlling the threading speed. (2) In the method for straightening the warpage of a two-layer clad metal plate consisting of a base material and a laminate, when forcedly cooling the metal side with a large amount of thermal contraction before or during hot straightening of the two-layer clad metal plate, The water flow density of the water cooling device and the sheet passing speed of the straightening device necessary to make the final amount of warpage of the two-layer clad metal plate zero at room temperature are set, and the water flow density of the water cooling device and the straightening device are determined based on the setting results. In addition to controlling the sheet threading speed, the final amount of warp of the metal sheet at room temperature is predicted from the sheet information after uniform reheating obtained at the exit side of the hot straightening device, and this predicted value is used to straighten the next material. A method for straightening a warp of a two-layer clad metal plate, which comprises correcting calculations of the water flow density of a water cooling device and the sheet passing speed of a straightening device, which are necessary for the straightening.