CN1473669A - Rolling mill and rolling method - Google Patents

Abstract

It is an object of the present invention to provide a steel rolling mill and a rolling method capable of reducing costs by using small equipment while obtaining a desired steel sheet shape with high reaction. The steel rolling mill of the present invention has: a work roll for rolling a rolled steel material, a coolant device for supplying a coolant at least on an input side of the rolled steel material, a shape detector for measuring the shape of a rolled steel plate, and a mechanical control device for controlling the shape of the steel plate , the diameter of the aforementioned work roll is more than 0.16 times and less than 0.3 times the maximum width of the steel plate that can be rolled. The plurality of coolant flow rate and temperature supply systems include a control device for controlling the machine control device and the coolant device based on the detection value of the shape detector.

Description

Rolling mill and rolling method

technical field

The invention relates to a rolling mill and a rolling method.

Background technique

As a shape control method for forming the rolled steel sheet into a desired steel sheet shape, the rolled shape is measured with a shape detector, and the curling or curling of the rolled material is corrected using a mechanical control device such as a roll bender or a movement. For simple shapes such as intermediate elongation, in order to correct local elongation or complex elongation that is difficult to correct, the flow distribution of coolant to the work roll is changed, and automatic control is performed to minimize the deviation from the target shape. Known techniques for changing the flow rate distribution of coolant are described in JP-A-2-229612 and JP-A-4-127909.

On the other hand, when rolling a foil with a very thin steel plate, there is a method of supplying a high-temperature coolant to the work roll area on the outer side of the plate width to correct the shape of the steel plate. Such techniques are described in JP-A-60-180611 and JP-A-3-297507.

However, the above-mentioned prior art has the following problems, that is, the yield rate is low due to the slow response of the shape change, the scope of modification and the introduction cost are enlarged due to the increase of the total amount of coolant, and the temperature difference given to the coolant is increased. Increased operating costs caused by large and so on.

Contents of the invention

An object of the present invention is to provide a steel rolling mill and a rolling method which can obtain a desired steel sheet shape with high reaction and can reduce costs with small equipment.

The machine control device and coolant control are performed based on the detected steel plate shape so that the diameter of the work roll is within the desired range.

Description of drawings

Fig. 1 is a block diagram showing a 6-stage steel rolling mill according to an embodiment of the present invention.

Fig. 2 is a configuration diagram showing a coolant nozzle flow rate and temperature adjusting device and a coolant head row.

Fig. 3 is a graph showing changes in average roll temperature.

Fig. 4 is a graph showing changes in thermal expansion of rolls.

Fig. 5 is a graph showing the gradient of change in thermal expansion of a roll.

Fig. 6 is a graph showing the relationship between the ratio of the work roll diameter Dw to the maximum steel plate width Bmax and the shape response speed.

Fig. 7 is a graph showing the influence of the roll diameter on the sweep profile.

Fig. 8 is a diagram showing an embodiment of flow rate and temperature adjustment in a two-system coolant supply system and its results.

Fig. 9 is a graph showing the effect of the diameter of the intermediate roll on the shape control capability of a 6-stage rolling mill.

Fig. 10 is a diagram showing an embodiment of flow rate and temperature adjustment in a three-system coolant supply system and its results.

Fig. 11 is a graph in the width direction showing various factors affecting the shape of a rolled steel sheet.

Fig. 12 shows a modified example of the coolant nozzle flow rate and temperature adjusting device and the coolant head row.

Fig. 13 is a layout diagram showing a row of coolant heads.

Fig. 14 is a diagram showing an embodiment of flow rate and temperature adjustment in a two-system coolant supply system and its results.

Fig. 15 is a diagram showing an embodiment of flow rate and temperature adjustment in a two-system coolant supply system and its results.

Fig. 16 is a diagram showing an embodiment of flow rate and temperature adjustment in a two-system coolant supply system and its results.

Detailed ways

Fig. 1 shows an example of the configuration of a rolling mill of the present invention. In FIG. 1, the rolling mill has a work roll 11 that directly contacts a rolling material 14 for rolling, an intermediate roll 12 that supports the work roll in the vertical direction, a reinforcement roll 13 that supports the intermediate roll 12 in the vertical direction, and a test roll. Shape detector 15 for material shape.

A work roll bending device 33 for applying a bending force to the work roll 11 and intermediate roll 12, an intermediate roll bending device 34, and an intermediate roll moving device 35 for moving the roll in the axial direction on the intermediate roll 12 are respectively provided. The operations of the work roll bending device 33 , the intermediate roll bending device 34 , and the intermediate roll moving device 35 are controlled by the bending and moving control device 32 . Furthermore, the bending/movement control device 32 is controlled by a signal from the bending/movement control amount calculation device 31 .

In addition, this facility is provided with coolant head rows 45a, 45b for spraying coolant to the work rolls 11, and each nozzle constituting the coolant head rows 45a, 45b is adjusted independently by an adjustment device 43 for adjusting the flow rate and temperature. Supply coolant. The flow temperature adjustment device 43 is controlled by the coolant control device 42 . Furthermore, the coolant control device 42 is controlled by a signal from the coolant control amount calculation device 41 .

In addition, the bending and movement control amount calculation means 31 calculates the bending and movement control amount based on the signal from the shape correction calculation means 21 . In addition, the coolant control amount calculation device 41 is controlled by a signal from the shape correction calculation device 21 .

What Fig. 2 shows is a configuration example of the flow rate temperature adjustment device 43 and the coolant head columns 45a, 45b, by controlling the flow rate of the coolant on the coolant flow regulator 432a, 432b from the coolant tank to the pump, cooling The coolant temperature regulators 433a and 433b control the temperature of the coolant, and are composed of two coolant supply systems having different flow rates and temperatures, and a device 434 for selectively supplying coolant from the two supply systems. In addition, in the coolant selective supply device 434, the coolant supply of both systems may be stopped.

The operation and effect of the present embodiment configured as above will be described in (1) to (5) below.

(1) The high reactivity of the shape control effect will be described. When using a fluid to heat or cool a solid, if the flow rate and temperature of the external fluid are constant, if the heat capacity of the solid is large, it will take a long time for the heating or cooling effect to penetrate from the surface layer to the interior. On the contrary, if the heat capacity of the object is small , can quickly penetrate into the interior. The same is true when using coolant to heat or cool the rolling roll. If the roll diameter is large and the heat capacity is large, it will take time to realize the heating or cooling effect. On the contrary, if the diameter is small and the heat capacity is small, the heating or cooling effect can be realized in a short time. However, when changing the distribution of thermal expansion (temperature) of the rolls to control the shape of the rolled steel sheet regardless of heating or cooling, different roll diameters have different effects. The present inventors paid attention to the recognition that there is an appropriate roll diameter for obtaining the desired steel sheet shape control effect. Since the above-mentioned existing technology does not consider any applicable roll diameters for shape control, when the existing technology is applied to different types of rolling mills or different roll diameters, the shape of the steel plate cannot be corrected with high responsiveness, so that The longitudinal shape of the steel sheet is not stable, not only the desired shape of the steel sheet cannot be ensured, but also the yield is lowered.

The high response in the embodiment of the present invention will be described. FIG. 3 shows changes in the average roll temperature due to differences in roll diameters when the rolling reduction and cooling conditions (total flow rate of coolant) during rolling are the same. In addition, the cooling in the lateral direction is the same, and after a certain period of time, the total flow rate of the coolant is doubled. It takes a long time for the heating and heat dissipation balance to reach the equilibrium state when the roll diameter is large, and it takes a short time for the small roll diameter. The temperature of the rolls in the equilibrium state is almost the same value. Due to the subsequent change in cooling conditions (the flow rate is doubled), the time to reach the next equilibrium state sequentially from the one with the smaller roll diameter is short. Therefore, it can be seen that due to the different sizes of the work rolls, the time to reflect the cooling effect is different.

Figure 4 below converts the average temperature of the rolls shown in Figure 3 into thermal expansion. In the equilibrium state, the average temperature of the rolls is the same, so it can be seen that the value is proportional to the roll diameter. When the roll diameter is large, the thermal expansion is large, and when the roll diameter is small, the thermal expansion is small. The inclination (absolute value) of the change in the amount of thermal expansion due to subsequent cooling conditions (the flow rate is doubled) varies depending on the diameter. The inclination is gentle when the roll diameter is large, and the inclination is large when the roll diameter is small. The change in thermal expansion when the equilibrium state is reached is proportional to the roll diameter, but the change inclination (absolute value) immediately after the cooling condition is changed is that the smaller the roll diameter, the larger the inclination, and high response can be obtained.

Figure 5 shows the slope of thermal expansion of each roll diameter. It can be seen that as the diameter of the roll becomes smaller, the slope of thermal expansion increases gradually, and the diameter of the roll increases significantly in the field of less than 400 mm. However, in the steel plate shape control method using the thermal expansion change of the roll, the shape response speed (shape change amount per unit time [I-unit/sec]) is different depending on the roll diameter. Generally speaking, the smaller the roll diameter, the faster the shape response speed. The larger the value, the quicker the ability to correct the steel plate shape deviated from the target shape, and the yield of the longitudinal steel plate shape can be improved.

FIG. 6 plots the ratio of the diameter Dw of the work roll to the maximum steel sheet width Bmax that can be rolled by the rolling mill on the horizontal axis, and the vertical axis on the shape response rate (shape change amount per unit time [I-unit/sec]). In the design of various rolling mills (4-heavy, 6-heavy, etc.), when increasing the maximum steel plate width Bmax that can be rolled, in order to ensure the rigidity of the rolling mill, the diameter Dw of the work roll is also increased. The above ratio is roughly maintained In the case of the value of the same degree, select the roll diameter. At this time, even if the above-mentioned ratio is approximately constant, there may be a difference in the slope of the roll thermal expansion change shown in Fig. 5 due to the change of the work roll itself. The specifications are also changed (strengthened), so the relationship between the shape response speed and the ratio (roll diameter Dw/maximum steel plate width Bmax) shown in FIG. 6 is not affected as much as shown in the figure. From the relationship diagram of the ratio of the shape response speed and (roll diameter Dw/maximum steel plate width Bmax) sorted out above, when the ratio of the work roll diameter Dw to the maximum steel plate width Bmax is less than 0.3, the shape response speed can be guaranteed to be 0.1 [I -unit/sec], compared with the state where the above-mentioned ratio is larger, a higher reactivity can be secured and a shape control effect can be obtained.

On the one hand, as the ratio of (roll diameter Dw/maximum steel plate width Bmax) is reduced, horizontal bending occurs on the work roll, which becomes an external force disturbance on the control of the steel plate shape. In order to suppress this horizontal bending, it is essential to install back-up rolls that support the work rolls in the horizontal direction. However, since the back-up rolls are provided, the impact of the coolant on the roll surfaces is prevented, and it is difficult to control the shape of the steel plate with high precision by cooling the rolls. The lower limit of negligible horizontal bending without such a support roll is the lower limit of the ratio (roll diameter Dw/maximum steel plate width Bmax) derived from structural conditions, and the value is 0.16 or more.

In the above-mentioned embodiment, the relationship between the shape reaction speed and the ratio (roll diameter Dw/maximum steel plate width Bmax) was investigated when the flow rate of the roll coolant was doubled, and the (roll diameter Dw) that can obtain a better effect was limited. /Maximum steel plate width Bmax) ratio range. Of course, if the flow rate is tripled or quadrupled, the values of the vertical axes shown in Figs. The trend of the curve shown is almost unchanged, and the limited range of the (roll diameter Dw/maximum steel plate width Bmax) ratio remains unchanged.

This basic principle is shown in Newton's cooling law (Morikiku Press, Heat Transfer Engineering P31), and heat transfer to a fluid on a solid wall surface is represented by Q=h·S·Δθ (Formula 1). Here, Q is the amount of heat transferred per unit time, h is the heat transfer coefficient, S is the surface area, and Δθ is the temperature difference between the solid wall surface and the fluid. If this principle is applied to rolling rolls and roll coolants, it can be seen that the heat transfer coefficient h is roughly proportional to the factorial (0.5-0.6) of the coolant flow rate. By increasing the fluid flow rate, the cooling capacity can be increased. From the roll The amount of heat moved by the surface also increases in proportion to the heat transfer coefficient h.

Similarly, as the temperature of the roll coolant decreases, the temperature difference Δθ of the above formula increases, and the heat transferred from the roll surface also increases in proportion to the heat transfer coefficient h, and the ability to control the shape of the steel plate using the roll coolant also increases, but is different from that of the roll It is the same when the flow rate of the coolant is increased, the trend of the curve shown in Fig. 6 is roughly unchanged, and the limited range of the (roll diameter Dw/maximum steel plate width Bmax) ratio remains unchanged.

In addition, by increasing the temperature of the roll coolant, heat can be transferred from the coolant to the roll surface contrary to the cooling time. At this time, the temperature of the roll coolant is increased similarly, and by increasing the absolute value of the temperature difference Δθ, the amount of heat transferred to the roll surface can be increased. Even in this case, since the fundamental principle remains unchanged, the trend of the curve shown in FIG. 6 remains substantially unchanged, and the limited range of the ratio (roll diameter Dw/maximum steel plate width Bmax) remains unchanged.

Through the above content, when the thermal expansion of the work roll is controlled by the flow rate or temperature of the roll coolant, higher reactivity can be ensured, and the ratio of (roll diameter Dw/maximum steel plate width Bmax) that can obtain the shape control effect is 0.16≤Dw/ The range of Bmax<0.3 (Formula 2).

(2) The reduction of introduction and operation costs will be described. Using the well-known techniques described in JP-A-2-229612 and JP-A-4-127909 that change the flow distribution of the coolant, it can be easily estimated that when solving the problem of low yield due to slow response to shape change Increase the total flow of the roll coolant, thereby improving the roll width direction and local cooling capacity. However, the modification accompanying the increase in the total flow rate of the coolant involves not only the supply system but also equipment such as filters and recovery pipes for the coolant recovery system that was originally designed, resulting in an increase in cost. In addition, even in the case of resetting, the cooling effect is different due to the different diameters of the applicable rolls. When the diameter of the roll is large, in order to obtain the desired effect of controlling the shape of the steel plate, a very large flow rate is required. In addition, if the diameter of the roll is small, the impact of the roll coolant on the roll surface is hindered due to the installation of the support roll to control the bending of the roll in the horizontal direction, resulting in the problem that the desired cooling effect cannot be obtained.

In the present embodiment, the shape response speed in the range of (roll diameter Dw/maximum steel plate width Bmax) ratio defined in Formula 2 is roughly twice or more than the shape response speed outside the range. Therefore, if the speed of the shape response outside the range is to be increased, the heat transfer coefficient needs to be ensured to about twice the degree. As described above, since the heat transfer coefficient h is approximately proportional to the factorial (0.5 to 0.6) of the flow rate, three to four times the flow rate is required as the flow rate. If the required flow rate is three to four times larger, the coolant supply pump, the diameter of the supply and recovery pipes, heat exchangers, filters, and tanks will need to be enlarged accordingly, and the cost of introduction will be very high, which is not a good solution.

Comparing the (roll diameter Dw/maximum steel plate width Bmax) ratio range specified in formula 2 with that outside the range, the same steel plate width, the working roll diameter is smaller, which also contributes to the miniaturization of the rolling mill as a whole, and has the effect of reducing the cost of the rolling mill body Effect.

Also, even when cooling and heating the work rolls is performed with a temperature difference Δθ, the necessary temperature difference outside the range of the (roll diameter Dw/maximum steel plate width Bmax) ratio defined in Equation 2 is deduced from Equation (1). A difference of Δθ by two times leads to enlargement of the heat transfer area of the heat exchanger for heating and cooling of the coolant, introduction of increased capacity, and increase in operating costs. In addition, depending on the type of coolant, there may be wear loss of lubricity in high and low temperature regions and the risk of fire in high temperature regions, which may be unfavorable for operation. According to the present invention, if the temperature difference Δθ is about 1/2 of the conventional one, the effect of shape control can be fully exerted, so the operation cost can be reduced.

In addition, because the existing technology does not consider the diameter of the work roll, the form of the rolling mill and the ratio of the roll diameter, there is the following problem, that is, the diameter of the work roll is relatively large compared to the width of the steel plate. The shape of the 4-stage rolling mill requires a very large flow rate to obtain the desired shape control effect, and the combination with the shape control effect using coolant cannot achieve the desired capacity, but in this embodiment, with the appropriate flow rate Appropriate control capability can be obtained.

In addition, when using the well-known techniques described in JP-A-60-180611 and JP-A-3-297507 that change the temperature distribution of the coolant, it is easy to infer that the temperature difference of the roll coolant is increased to increase the heating capacity. . However, increasing the temperature difference of the coolant causes an increase in energy consumption cost during operation. When using the stock solution of oil as a coolant, the temperature of the oil cannot be raised arbitrarily from the viewpoint of preventing a fire caused by the temperature rise of the oil. In addition, when using an emulsion in which a few percent of oil is emulsified in water, the risk of fire is reduced compared with the stock solution, but once it leaves the emulsification stable area of the emulsion, the separation of oil and water is accelerated, resulting in cooling performance and The problem of unstable lubricating performance and unstable rolling can be solved in this embodiment.

(3) Improvement of shape control capability by combination with a mechanical control device will be described. As mentioned above, in order to ensure higher reactivity, the ratio range of (roll diameter Dw/maximum steel plate width Bmax) in which the effect of shape control is obtained has been clarified. The work roll bending force, in the case of a 6-heavy rolling mill, is used to control the shape of the steel sheet in combination with a mechanical control device such as the work roll and intermediate roll bending force. Here, it was first investigated how the thermal expansion curves of the rolls during rolling differ due to different roll diameters.

Fig. 7 shows the roll curve after 60 minutes in the change curve of thermal expansion of the roll shown in Fig. 4 . As the roll diameter shrinks, from the center of the steel plate to the end of the steel plate, the lateral position where the inclination of the roll curve tends to change moves toward the end of the steel plate. In the roll diameter range where the shape reactivity is high by cooling or heating the roll, the roll curve tends to change rapidly near the edge of the steel plate, so it is necessary to re-examine the combination with the mechanical control device.

In general, as the deformation of the work roll that greatly affects the shape of the rolled steel plate, there are thermal expansion curves, bending due to rolling load, and flat surface. In the case of thin steel plates such as cold rolling, the major controlling factors are Thermal expansion curve and bending. Compared with the thermal expansion curve, the surface flattening does not matter even if it is negligible because the deviation within the width of the steel plate is small. Figure 11(a) is an excerpt of the thermal expansion curve of the work roll with a diameter of Φ340mm shown in Figure 7, and the thermal expansion curve only within the width of the steel plate. Figure 11(b) shows the roll deflection Pδ caused by the rolling load P. Therefore, it is necessary to control the curve overlapping the curves of Fig. 11 (a) and (b) through the mechanical control device and the change of the thermal expansion curve of the roll coolant.

When considering a 4-heavy rolling mill (called 4Hi rolling mill), the representative mechanical control device is the work roll bending device. The influence of the work roll bending device on the roll bending WRδ is shown in Figure 11(c). Its control The range is limited to the vicinity of the end of the steel plate (outside 2/3 of the width of the steel plate). Therefore, it is difficult to use work roll bending to control the bending that changes smoothly from the vicinity of the center of the steel plate width, such as roll bending Pδ due to rolling load, as shown in Fig. 11(b), and it is necessary to use roll coolant to control this bending. However, the roll bending Pδ caused by the rolling load is very large. In order to control it by utilizing the thermal expansion change of the roll coolant, it is necessary to introduce coolant equipment with unrealistic heating and cooling capabilities.

On the one hand, when using a 6-heavy rolling mill (called 6HiUC rolling mill) equipped with an intermediate roll bending device, the roll bending WRδ caused by intermediate roll bending is shown in Fig. 11(d), and the control characteristics of the intermediate roll bending device are, It is possible to control the roll deflection Pδ caused by the rolling load shown in Fig. 11(b), which smoothly changes from the vicinity of the center of the steel sheet width. Therefore, compared with the 4Hi rolling mill, not only the burden on the equipment for the roll coolant is reduced, but also the functions can be shared according to the control characteristics of various shape control devices. That is, the work roll bending device controls the shape of the steel plate near the end of the steel plate, the intermediate roll bending device controls the shape of the steel plate near the center of the steel plate width, and the roll coolant is used to correct the local shape that is difficult to control with the work roll and intermediate roll bending device.

Next, assuming that the injection conditions of the work roll and the roll coolant are the same, the control capabilities of the 4Hi rolling mill and the 6HiUC rolling mill are compared.

Figure 8 is a comparison of the correction effect of the steel plate shape when the same coolant is sprayed.

The dotted line in the figure is the initial state before starting the control, and the deviation between the elongated side and the supporting side of the steel plate shape is about 160 [I-unit] (-100 [I-unit] to +60 [I-unit]). 4Hi rolling mill is within 110[I-unit](-70[I-unit] to +40[I-unit]), 6HiUC rolling mill is within 60[I-unit](-40[I-unit] to +20 [I-unit]), the shape of the steel plate can be flattened. As mentioned above, it can be seen that the 4Hi rolling mill cannot get sufficient control ability due to the lack of mechanical control ability. The deviation required in actual operation is about 20[I-unit] (-10[I-unit] to +10[I-unit]), so even a 6HiUC rolling mill is not sufficient.

Figure 14 below shows the result of doubling the roll coolant that produces the elongated parts of the steel plate shape. 4Hi rolling mill is within 80[I-unit](-50[I-unit] to +30[I-unit]), 6HiUC rolling mill is within 20[I-unit](-10[I-unit] to +10 [I-unit]) can reduce the deviation of the steel plate shape in the width direction.

Fig. 15 shows the result of lowering the roll coolant at the part where the steel plate shape elongation occurs 10°C lower than the surrounding area. 4Hi rolling mill is within 70[I-unit](-45[I-unit] to +25[I-unit]), 6HiUC rolling mill is within 15[I-unit](-10[I-unit] to +5 [I-unit]) can reduce the deviation of the steel plate shape in the width direction.

Fig. 16 shows the result of raising the roll coolant outside the edge of the steel plate where the shape of the steel plate is supported by 20°C higher than that within the width of the steel plate. 4Hi rolling mill within 50[I-unit](-20[I-unit] to +30[I-unit]), 6HiUC rolling mill within 15[I-unit](-5[I-unit] to +10 [I-unit]) can reduce the deviation of the steel plate shape in the width direction.

In any case, the 6HiUC rolling mill can achieve the deviation required by the actual operation, which is about 20 [I-unit] (-10 [I-unit] to +10 [I-unit]), by combining with a mechanical control device such as a work roll bending device and an intermediate roll bending device, sufficient effects can be obtained, and the effect can be approximately 4 times that of a 4Hi rolling mill.

In general, when using a 6HiUC rolling mill, in order to control the bending that changes smoothly from near the center of the steel plate, it is necessary to make the diameter of the intermediate roll larger than the diameter of the work roll, and distinguish the bending characteristics caused by bending force from the bending characteristics of the work rolls. When the diameters of the work rolls and the intermediate rolls are almost equal, there is little difference in the bending characteristics, and the effect obtained is mainly to remove the harmful contact portion caused by the movement of the intermediate rolls. Therefore, in order to control the bending up to the vicinity of the width center of the steel plate, it is necessary to study the ratio of the diameter of the middle roll to the diameter of the work roll.

Figure 9(a) shows the steel plate shape control effect when the diameter of the work roll is Φ340 and the diameter of the intermediate roll is Φ340, Φ380, and Φ440, respectively. As the ratio of the diameter Di of the intermediate roll to the diameter Dw of the work roll approaches 1, the control range becomes narrow, and it is difficult to control the vicinity of the width center of the steel plate, and the correction effect of the shape of the steel plate is also small. Fig. 9(b) assumes the ratio of (intermediate roll diameter Di to work roll diameter Dw) on the horizontal axis and the relative value of the shape control ability of the 4Hi rolling mill on the vertical axis to investigate various roll diameter ratios. It can be seen that the roll diameter ratio exceeds the range of 1.2, and the capacity is significantly improved, with a capacity of more than 4 times. Therefore, when controlling the shape of the steel plate, it is preferable to use a 6-stage rolling mill equipped with a work roll bending device, an intermediate roll bending device, and an intermediate roll moving function in combination with a shape control device using roll cooling. Dw1.2 times the range.

(4) The enhancement of the shape control ability by the selective supply of temperature from the three systems will be described. In addition, by combining the implementations of Fig. 15 and Fig. 16, a more ideal shape control effect can be obtained. Fig. 10 is an example in which a coolant of 60°C higher than the roll surface temperature is supplied to the outside of the edge of the steel plate, and a coolant of low temperature is supplied to the elongated portion within the width of the steel plate. At this time, by using the coolant selection supply device 434, the supply coolant is selected from the three system temperatures, the total amount of coolant remains unchanged, and there is no need to modify the pump, recovery system, filter, tank, etc., only the supply system is changed to The structure shown in FIG. 2 or FIG. 10 is enough.

In this way, by using the work roll bending device and supplying high-temperature coolant to correct the supporting shape near the end of the steel plate, using the intermediate roll bending device to correct the overall large shape of the steel plate, and using the low-temperature coolant to correct the local elongated shape within the width of the steel plate, it is possible Correct to a roughly flat steel plate shape as shown.

(5) Modifications of the coolant head structure will be described. FIG. 12 is a modified example of the flow rate temperature adjustment device 43 and the coolant head rows 45a, 45b shown in FIG. 2. The difference between the two is that the coolant selection supply device 434 is separated up and down (434a, 434b). Considering the cost, the benefit of sharing the upper and lower parts as shown in Figure 2 is to reduce the number of parts. However, when the coolant selection supply device 434 is shared up and down, since the selection supply device 434 is arranged on the upper or lower part of the rolling mill, the length of the pipes reaching the coolant head rows 45a, 45b sometimes differs up and down. There is a difference in the time at which the flow or/and temperature actually changes. In order not to cause such a time difference, the coolant selection supply device 434 is separated up and down, and the length of the pipes reaching the coolant head rows 45a, 45b is set at the shortest position.

Fig. 13(a) is an application example. On the input side, two pairs of coolant head columns 451a, 451b, 452a, 452b for spraying coolant to the work rolls are arranged up and down. In the case of small, ensure the injection area.

Fig. 13(b) and Fig. 13(c) are the embodiments when the present invention is applied using the existing coolant supply device. The original coolant supply equipment 45c shown in Figure 13(b) is to supply the coolant to the width direction with the same flow rate and temperature on both sides of the input and output of the rolled material. Lubrication between the roll and the rolled material, flushing the iron powder and matte powder remaining on the surface of the steel plate on the output side. Here, by adding or modifying the nozzle head 451a, 451b on the input side and the nozzle head 452a, 452b on the output side of the present invention, the thermal expansion of the roll is controlled to control the shape of the steel plate.

Fig. 13(c) is the case where the original coolant supply equipment is retained on the input side, and the coolant head rows 45a, 45b of the present invention are applied on the output side. Generally speaking, the surface of the roll just after rolling is high temperature, if it is cooled before the heat is transferred to the radial direction, the cooling effect will be improved. Applying the present invention to the output side of the rolled material can also improve the shape control effect of the steel plate.

According to the present invention, it is possible to provide a steel rolling mill and a rolling method capable of reducing costs by using small equipment while obtaining a desired steel sheet shape with high reaction.

Claims (8)

1. rolling mill, have: the work roll of rolling steel rolling material, supply with the coolant apparatus of cooling agent, the SHAPE DETECTION device of measuring the steel plate shape after rolling and the machine control unit of control steel plate shape at the input side of steel rolling material at least, it is characterized in that

The diameter of aforementioned work roll is 0.3 times of rolling possible more than 0.16 times of steel plate Breadth Maximum, a less than,

In aforementioned coolant apparatus, be arranged on a plurality of feed systems that the steel plate width direction disposes the cooling agent head row of a plurality of nozzles and has the device of adjusting coolant flow and temperature respectively,

Have detected value, control the control device of this machine control unit and this coolant apparatus according to the aforementioned shapes detector.

2. rolling mill, have: a pair of up and down work roll, central roll, reinforcement roll, and the bending apparatus of axial mobile device, work roll and the central roll of central roll, and at least the input side of rolling stock supply with cooling agent coolant apparatus, and measure the steel plate shape after rolling the SHAPE DETECTION device, and the aforementioned central roll of control moves, the device of the action of work roll bending, central roll bending apparatus and cooling agent feedway, it is characterized in that

The diameter of aforementioned work roll is 0.3 times of rolling possible more than 0.16 times of steel plate Breadth Maximum, a less than,

Aforementioned cooling agent feedway has: dispose a pair of at least up and down above cooling agent head row of a plurality of nozzles, the horizontal measuring interval of steel plate of this nozzle correspondence aforementioned shapes detector in the steel plate width direction; And have a plurality of feed systems of the device of adjusting coolant flow or temperature respectively;

Aforementioned central roll moves, work roll bending, central roll bending control device and cooling agent control device, has based on the output signal of aforementioned SHAPE DETECTION device and the deviation of target shape, the device that each controlled quentity controlled variable is handled in calculation; And aforementioned cooling agent control device has the cooling agent of selecting 1 system from aforementioned a plurality of coolant supply systems, the device of supplying with each nozzle of aforementioned cooling agent head row.

3. rolling mill as claimed in claim 2 is characterized in that, the diameter of aforementioned central roll surpasses 1.2 times of aforementioned work roll diameter.

4. rolling mill as claimed in claim 2, it is characterized in that, aforementioned cooling agent feedway has: a pair of at least up and down cooling agent head that disposes a plurality of nozzles in the steel plate width direction is listed as, the horizontal measuring interval of steel plate of the corresponding aforementioned shapes detector of this nozzle; And having two feed systems of the device of adjusting coolant flow respectively, it is many that the flow of each nozzle of flow-rate ratio the 1st feed system of each nozzle of the 2nd feed system is wanted.

5. rolling mill as claimed in claim 2, it is characterized in that, aforementioned cooling agent feedway has: a pair of at least up and down cooling agent head that disposes a plurality of nozzles in the steel plate width direction is listed as, the horizontal measuring interval of steel plate of the corresponding aforementioned shapes detector of this nozzle; And having two feed systems of the device of adjusting coolant temperature respectively, the temperature of the 2nd feed system is lower than the temperature of the 1st feed system.

6. rolling mill as claimed in claim 2, it is characterized in that, aforementioned cooling agent feedway has: a pair of at least up and down cooling agent head that disposes a plurality of nozzles in the steel plate width direction is listed as, the horizontal measuring interval of steel plate of the corresponding aforementioned shapes detector of this nozzle; And have three feed systems of the device of adjusting coolant temperature respectively, and the temperature of the 2nd feed system is lower than the temperature of the 1st feed system, and the temperature of the 3rd feed system is than the temperature height of the 1st feed system.

7. the milling method of a rolling mill, this rolling mill has: the work roll of rolling steel rolling material, supply with the coolant apparatus of cooling agent, the SHAPE DETECTION device of measuring the steel plate shape after rolling and the machine control unit of control steel plate shape at the input side of steel rolling material at least, the diameter of aforementioned work roll is 0.3 times of rolling possible more than 0.16 times of steel plate Breadth Maximum, a less than, it is characterized in that

In aforementioned coolant apparatus, when adjusting the flow of this cooling agent and temperature respectively, from a plurality of feed systems, dispose the cooling agent head row of a plurality of nozzles to the steel plate width direction and supply with cooling agent,

By this machine control unit and this coolant apparatus, according to the detected value of aforementioned shapes detector, control steel plate shape.

8. control device that rolling mill is used, this rolling mill has: supply with the coolant apparatus of cooling agent, the SHAPE DETECTION device of measuring the steel plate shape after rolling and the machine control unit of control steel plate shape at least in the input of steel rolling material, the diameter of the work roll of rolling steel rolling material is 0.3 times of rolling possible more than 0.16 times of steel plate Breadth Maximum, a less than, it is characterized in that

Aforementioned coolant apparatus, have when adjusting this coolant flow and temperature respectively, from a plurality of feed systems, be provided with the device of the cooling agent head row supply cooling agent of nozzle to the steel plate width direction, by this machine control unit and this coolant apparatus, according to the detected value of aforementioned shapes detector, control steel plate shape.

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