JP7533503B2 - Method for setting work roll speed, rolling method, method for manufacturing rolled steel plate, and rolling equipment - Google Patents

Description

The present invention relates to a method for setting the speed of a work roll, a rolling method, a method for manufacturing rolled steel plate, and rolling equipment.

In the past, various rolling mills capable of achieving large reductions of approximately 60% or more have been developed for the purpose of simplifying the equipment of the rolling line, reducing the number of rolling mill stands, and controlling the processed material in hot rolling of steel sheets. For example, the roll-cast type planetary mill described in Patent Document 1 and Patent Document 2 is a rolling mill in which four to eight work rolls arranged around the main shaft revolve at high speed while rotating independently, and forge-rolls the rolled material at a low speed by the centrifugal force of the work rolls without backup rolls. It has the characteristic that the mechanism is simpler than other planetary mills such as those described in Patent Document 3, and therefore the equipment maintenance is easier. On the other hand, since the rolled material receives a force from the work rolls of the planetary mill in the opposite direction to the rolling direction, the planetary mill alone cannot draw in the rolled material, and it is known that rolling is performed while pushing the rolled material toward the planetary mill by a pair of feed rolls arranged on the entrance side of the planetary mill, which are opposite to each other and sandwich the rolled material.

Japanese Unexamined Patent Publication No. 59-85305 Japanese Unexamined Patent Publication No. 51-14755 Japanese Patent Application Publication No. 176603/1983

However, if the force with which the pair of feed rolls press the rolled material into place is insufficient compared to the force with which the feed rolls push the rolled material towards the planetary mill, slippage may occur between the rolled material and the feed rolls, making it difficult to achieve stable rolling.

The present invention has been made in view of the above, and its purpose is to provide a method for setting the speed of a work roll, a rolling method, a method for manufacturing rolled steel plate, and rolling equipment that enable stable rolling.

In order to solve the above-mentioned problems and achieve the object, the method of setting the work roll speed of the present invention is characterized in that in a planetary mill in which two or more work rolls arranged around each of a pair of main shafts opposing each other across the rolled material rotate while revolving around the main shafts to roll the rolled material, the rolling speed determined from the orbital speed of the work rolls and the rotational speed of the work rolls is set so as to be greater than the maximum speed of the rolled material at the exit side of the planetary mill.

The method for setting the work roll speed according to the present invention is characterized in that, in the above invention, the rolling material speed at the exit side of the planetary mill is determined by an actual measurement value or a calculated value.

Furthermore, the work roll speed setting method according to the present invention is characterized in that, in the above invention, when the rolling material speed at the delivery side of the planetary mill during contact between the work roll and the rolled material is _v1 , the entry thickness of the rolled material is _h0 , the delivery thickness of the rolled material is _h1 , the work roll contact time/revolution period is a, and the average sheet speed is _v1m , the rolling material speed _v1 is calculated using the formula _v1 = { _h0 - (1 - a) × _h1 } / _ah0 × _v1m .

The rolling method according to the present invention is characterized in that the rolling material is rolled by the planetary mill at a rolling speed set using the work roll speed setting method of the above-mentioned invention.

The method for manufacturing rolled steel plate according to the present invention is characterized in that the rolled steel plate is manufactured using the rolling method of the above-mentioned invention.

In addition, the rolling equipment of the present invention comprises a planetary mill that rolls the rolled material using two or more work rolls arranged around each of a pair of main shafts that are arranged opposite each other with the rolled material in between, and a feed roll for transporting the rolled material that is arranged upstream of the planetary mill in the direction of movement of the rolled material, and is characterized in that the rolling speed, determined from the orbital speed of the work rolls and the rotation speed of the work rolls, is faster than the maximum speed of the rolled material after rolling.

The work roll speed setting method, rolling method, rolled steel plate manufacturing method, and rolling equipment according to the present invention have the effect of enabling stable rolling.

FIG. 1 is a schematic diagram of a rolling facility equipped with a planetary mill according to an embodiment. FIG. 2 is a diagram showing the action of forces when the work rolls in a planetary mill are not driven to rotate. FIG. 3 is a diagram showing the action of forces when the work rolls in a planetary mill are driven to rotate at a rolling speed that is slower than the exit strip speed of the rolled material. FIG. 4 is a diagram showing the action of forces when the work rolls in a planetary mill are driven to rotate at a rolling speed that is higher than the exit strip speed of the rolled material. FIG. 5 is a schematic diagram for explaining the change in speed during rolling in a planetary mill. FIG. 6 is a diagram for explaining a method for acquiring the rolling material speed in this embodiment. FIG. 7 is a schematic diagram of speed fluctuations in an embodiment of the present invention. FIG. 8 is a diagram showing the results of an investigation into the occurrence of slippage in an embodiment of the present invention. FIG. 9 is a diagram showing the results of an investigation into the occurrence of slippage in an embodiment of the present invention.

Below, the embodiment of the work roll speed setting method, steel plate manufacturing method, and rolling equipment according to the present invention will be described. Note that the present invention is not limited to this embodiment. In addition, in this embodiment, a hot rolling equipment for manufacturing hot-rolled steel plates will be described as an example. Note that the present invention can also be applied to rough rolling equipment in a hot rolling line, thick plate rolling equipment for manufacturing thick steel plates, cold rolling equipment for manufacturing cold-rolled steel plates, and hot rolling lines directly connected to thin slab continuous casting machines, and is not limited by the difference between thick steel plates and thin steel plates, the equipment connection layout with casting, or the difference between hot and cold.

Figure 1 is a schematic diagram of a rolling facility equipped with a planetary mill 10 according to an embodiment. The planetary mill 10 according to an embodiment is equipped with revolution axes 2A, 2B, which are a pair of main shafts facing each other with a rolled material 3 in between, and multiple work rolls 1A, 1B arranged on the outer periphery of each of the revolution axes 2A, 2B. The work rolls 1A, 1B are provided so as to be rotatable by motor drive. The planetary mill 10 rotates each of the work rolls 1A, 1B on their own axes while revolving a work roll group consisting of multiple work rolls 1A, 1B around the revolution axes 2A, 2B, and rolls the rolled material 3 by sandwiching it between the work rolls 1A and 1B.

The revolution direction of the work rolls 1A and 1B is the direction of rotation that sends out the rolled material 3 in the rolling direction, as shown by the arrow in FIG. 1. The rotation direction of the work rolls 1A and 1B is the opposite direction to the revolution direction, as shown by the arrow in FIG. 1, and the work rolls rotate so as to roll on the surface of the deformed part of the rolled material 3. In this embodiment, the above-mentioned rotation direction (i.e., the direction of the arrow in FIG. 1 for each roll/plate) is defined as the positive rotation speed for each of the revolution direction and rotation direction of the work rolls 1A and 1B. In the following description, the work roll 1A of the upper work roll group arranged around the revolution axis 2B arranged on the upper side with respect to the rolled material 3 and the work roll 1B of the lower work roll group arranged around the revolution axis 2B arranged on the lower side with respect to the rolled material 3 are also simply referred to as work roll 1 when there is no particular distinction.

The planetary mill 10 according to the embodiment is a roll-cast type planetary mill, which is a rolling mill that performs rolling while rotating the work roll 1 by driving rotation driven by a motor, and is distinguished from planetary mills in which the work roll 1 rotates without being driven by a motor. In the following description, the planetary mill 10 is also simply referred to as a rolling mill, and the rolling mill entry side refers to the upstream side of the planetary mill 10, which is the rolling mill, in the direction of movement of the rolled material 3, and the rolling mill exit side refers to the downstream side of the planetary mill 10, which is the rolling mill, in the direction of movement of the rolled material 3.

In the planetary mill 10 according to the embodiment, two to eight work rolls 1A and 1B can be arranged around the revolution axis, and the total number of work rolls is four to sixteen when the work roll 1A arranged around the upper revolution axis 2A and the work roll 1B arranged around the lower revolution axis 2B are combined. FIG. 1 shows a case where four work rolls 1A and 1B are arranged around the revolution axis. The rolling speed of the work roll 1 is defined as the revolution speed of the work roll 1 minus the rotation speed of the work roll 1 as the net rolling speed for the surface of the rolled material 3. The rolling speed of the work roll 1 is the speed on the revolution envelope diameter of the work roll 1. The positive and negative definitions of the rolling speed of the work roll 1 are the same as those of the revolution speed of the work roll 1. The rolling speed is set to be a positive value because it needs to be in the same direction as the exit plate speed of the rolled material 3.

A pair of feed rolls 4A, 4B are arranged upstream of the planetary mill 10 in the direction of movement of the rolled material 3, facing each other with the rolled material 3 in between. The feed rolls 4A, 4B push the rolled material 3 toward the planetary mill 10 while restraining it with a pressing force in the vertical direction (thickness direction of the rolled material 3). In the following description, when there is no particular distinction between the feed roll 4A arranged above the rolled material 3 and the feed roll 4B arranged below the rolled material 3, they are also simply referred to as feed rolls 4.

Downstream of the planetary mill 10 in the direction of movement of the rolled material 3, a pair of measuring rolls 5A and 5B are arranged facing each other with the rolled material 3 in between. The measuring rolls 5A and 5B have roller encoders. The measuring rolls 5A and 5B contact the upper and lower surfaces of the rolled material 3, respectively, and rotate with the surface movement of the rolled material 3 to measure the rolled material speed after rolling of the rolled material 3 by the planetary mill 10. In the following description, when there is no particular distinction between the measuring roll 5A arranged above the rolled material 3 and the measuring roll 5B arranged below the rolled material 3, they are also simply referred to as measuring rolls 5. Note that, although a measuring roll 5 is used in FIG. 1, the method of measuring the rolled material speed is not limited to this.

Next, the inlet push-in force required for rolling in the planetary mill 10 will be described. Figure 2 is a diagram of the force acting when the work roll 1 in the planetary mill 10 is not driven to rotate. Figure 3 is a diagram of the force acting when the work roll 1 in the planetary mill 10 is driven to rotate at a rolling speed that is smaller than the exit plate speed of the rolled material 3. Figure 4 is a diagram of the force acting when the work roll 1 in the planetary mill 10 is driven to rotate at a rolling speed that is larger than the exit plate speed of the rolled material 3.

Note that Figures 2 to 4 show the rolling equipment (work roll 1A, revolution shaft 2A, feed roll 4A, and measuring roll 5A) above the rolled material 3, and omit the illustration of the rolling equipment (work roll 1B, revolution shaft 2B, feed roll 4B, and measuring roll 5B) below the rolled material 3. Also, "p" in Figures 2 to 4 is the rolling load acting from the rolled material 3 towards the center of the work roll 1A. Also, "θ" in Figure 2 is the angle between the direction in which the rolling load acts and the vertical direction. 2 to 4, the rolling equipment (work roll 1A, revolution shaft 2A, feed roll 4A, and measuring roll 5A) above the rolled material 3 will be described as an example, but the same explanation applies to the rolling equipment (work roll 1B, revolution shaft 2B, feed roll 4B, and measuring roll 5B) below the rolled material 3, and the explanation will be omitted as appropriate.

As shown in FIG. 2, when the work roll 1A rotates without being driven, the rolled material 3 receives a vertical downward rolling force of pcosθ from the work roll 1A, and the work roll 1A does not generate a force pulling the rolled material 3 in. Therefore, the rolled material 3 needs to be rolled while being pushed toward the planetary mill 10 by the feed roll 4A from the entry side of the rolling mill. In this embodiment, the force with which the feed roll 4A pushes the rolled material 3 toward the planetary mill 10 is defined as the entry side pushing force.

On the other hand, as shown in Figures 3 and 4, when the work roll 1A rotates by the driving rotation, the work roll 1A and the surface of the rolled material 3 slip depending on the speed difference between the rolling speed of the work roll 1A and the exit plate speed of the rolled material 3. Therefore, a friction force μp cos θ is generated according to the sliding direction, and the required entry push-in force differs from the case where the work roll 1A rotates by no driving rotation. Here, the sliding friction coefficient between the work roll 1 and the rolled material 3 is μ.

As shown in FIG. 3, when the rolling speed of the work roll 1A is smaller than the exit plate speed of the rolled material 3, that is, when the revolution speed of the work roll 1A is small or the rotation speed of the work roll 1A is large, the sliding direction between the work roll 1 and the rolled material 3 is the direction of pushing the rolled material 3 back from the planetary mill 10. Therefore, the required entry pushing force increases compared to when the work roll 1A is rotated without being driven.

Conversely, as shown in FIG. 4, when the rolling speed of the work roll 1A is greater than the exit plate speed of the rolled material 3, that is, when the revolution speed of the work roll 1A is small or the rotation speed of the work roll 1A is small, the sliding direction between the work roll 1A and the rolled material 3 is the direction that pulls the rolled material 3 into the planetary mill 10. Therefore, the required entry pushing force is reduced compared to when the work roll 1A is rotated without being driven.

As described above, depending on the setting of the rolling speed of the work roll 1, the required entry side pushing force becomes larger than expected, and if the restraining force of the rolled material 3 by the feed rolls 4A and 4B at the entry side of the rolling mill (the vertical rolling force by the feed rolls 4A and 4B) is insufficient, the feed rolls 4 slip on the surface of the rolled material 3, causing surface defects. Even if an attempt is made to increase the rolling force of the feed rolls 4 to increase the restraining force of the rolled material 3 by the feed rolls 4, not only are there problems with the equipment upper limit of the rolling force and the thermal load on the feed rolls 4, but there are also cases where the required restraining force cannot be obtained because the rolled material 3 is hot and has low deformation resistance. For these reasons, the vertical rolling force by the feed rolls 4A and 4B is preferably about 0.05 [tonf/mm] to 0.2 [tonf/mm] per unit plate width.

Figure 5 is a schematic diagram explaining the speed change during rolling in a planetary mill 10. In the planetary mill 10, the contact between the work roll 1 and the rolled material 3 is intermittent processing. Therefore, as shown in Figure 5, the rolling material speed varies periodically depending on the contact position between the work roll 1 and the rolled material 3. For this reason, depending on the setting of the rolling speed of the work roll 1, the sliding direction between the work roll 1 and the surface of the rolled material 3 is not stable, which makes it difficult to set the appropriate rolling speed of the work roll 1.

The inventors of the present application conducted detailed research and discovered that in a roll-cast type planetary mill 10, the entry push-in reaction force can be stably reduced by setting the rolling speed of the work roll 1 so that it is always faster than the exit plate speed of the rolled material 3.

In a roll-cast type planetary mill 10, in order to reduce the entry-side push-in reaction force and to make it stable, it is necessary to keep the sliding direction between the work roll 1 and the surface of the rolled material 3 constant. The exit plate speed of the rolled material 3 while the work roll 1 and the rolled material 3 are in contact is maximum when the work roll 1 is located at the bottom dead center, and this speed is the same as the rolled material speed (exit plate speed of the rolled material 3) at the exit side of the rolling mill. Therefore, to keep the sliding direction between the work roll 1 and the surface of the rolled material 3 constant, it is sufficient for the rolling speed of the work roll 1 to be faster than the rolled material speed at the exit side of the rolling mill.

Next, the method of acquiring the rolling material speed in this embodiment will be described. Figure 6 is a diagram for explaining the method of acquiring the rolling material speed in this embodiment.

As shown in FIG. 6, the rolling material speed after rolling by the planetary mill 10 can be measured at the exit side of the rolling mill using measuring rolls 5A and 5B. The measurement sampling period of the rolling material speed is approximately one-fifth of the contact time between the work roll 1 and the rolling material 3 in order to capture the speed fluctuation during contact between the work roll 1 and the rolling material 3. The rolling speed for the time equivalent to one contact between the work roll 1 and the rolling material 3 is measured for at least one cycle, and the maximum value during that period is defined as the maximum rolling material speed. The method of acquiring the rolling material speed is not particularly limited, and for example, a well-known method of acquiring the rolling material speed using a laser Doppler meter can be adopted.

The contact time between the work roll 1 and the rolled material 3 is equivalent to the time during which the rolling load is generated, and can be confirmed from the output of the load cell that measures the rolling load. For example, when a roll-cast type planetary mill 10 with four work rolls 1A and 1B, each with a diameter of 400 mm, and four work rolls 1A and 1B on the top and bottom and an orbital diameter of 1500 mm is used to roll a rolled material 3 with a thickness of 100 mm at an orbital speed of 50 rpm, the contact time between the work roll 1 and the rolled material 3 is approximately 0.06 s. The rolling material speed during this time is measured every approximately 0.01 s, which is sufficient to capture the maximum value of the rolling material speed.

The rolling speed of the work roll 1 is the revolution speed of the work roll 1 minus the rotation speed, so both the revolution speed and the rotation speed must be determined. First, the revolution speed is inversely proportional to the amount of deformation of the rolled material 3 per contact between the work roll 1 and the rolled material 3, so the faster the revolution speed, the smaller the rolling load, such as the rolling load and rolling torque. Therefore, it is determined according to the main engine capacity and speed responsiveness of the revolution drive motor. However, the revolution speed of the work roll 1 does not need to be uniquely determined, and may be changed during rolling.

The rotation speed of the work roll 1 is faster than the rolled material speed after rolling (at the exit of the rolling mill). By determining the rolling speed of the work roll 1 to be greater than the maximum value of the rolled material speed, the sliding direction between the work roll 1 and the surface of the rolled material 3 can be always kept constant, and the reaction force of the entry-side pushing force can be stably reduced. The rolled material speed is determined according to the amount of deformation of the rolled material 3 per contact with the work roll 1, and does not change even if the rotation speed of the work roll 1 is changed. Therefore, the maximum value of the rolled material speed can be obtained for each contact between the work roll 1 and the rolled material 3, but it is not necessary to change the rotation speed of the work roll 1 for each contact. The rotation speed of the work roll 1 can be changed only when there is a change in the rolled material speed at the entry side of the rolling mill.

The upper limit of the rolling speed of the work roll 1, i.e., the lower limit of the rotation speed of the work roll 1, is determined according to the occurrence of surface defects of the rolled material 3. It is known that a high sliding speed between the work roll 1 and the surface of the rolled material 3 causes surface defects such as surface defects, and the upper limit of the rolling speed of the work roll 1 can be set based on the past occurrence history of surface defects (surface defects). For example, in the case of hot rolling of general carbon steel, the upper limit of the rolling speed of the work roll 1 is approximately 80 mpm.

The rotation speed of the work roll 1 at the start of rolling may be set, for example, to the same as the past rolling results, or may be set equal to the rotation speed of the feed rolls 4A and 4B, which is equivalent to the rolling material speed at the entry side of the rolling mill. Alternatively, it may be set in advance without measuring the rolling material speed, according to the predicted calculated value of the rolling material speed, as described below.

When the revolution period of the same work roll 1 in the work roll group is Δt, the mass flow ΔV ₀ at the entry side of the rolling mill per unit plate width is expressed by the following formula (1) when the entry side rolling material speed is v ₀ and the entry side plate thickness is h ₀ .

On the other hand, the mass flow _ΔV1 on the delivery side of the rolling mill is given by the following formula (2), where a is the work roll contact time/rotation period and _v1 is the rolling material speed on the delivery side of the rolling mill during contact between the work roll 1 and the rolled material 3.

Here, if the sheet width expansion due to rolling is ignored, the mass flow ΔV ₀ on the inlet side of the rolling mill and the mass flow ΔV ₁ on the outlet side of the rolling mill are equal, and therefore the following formula (3) is obtained.

Here, the work roll contact time/rotation period a is given by the following formula (4) when the work roll revolution envelope radius is R and the number of work rolls is N, so that the rolling material speed _v1 at the delivery side of the rolling mill during contact between the work roll 1 and the rolled material 3 can be easily found.

If the average speed of the rolled material on the delivery side of the rolling mill is v _1m (=v ₀ ×h ₀ /h ₁ ), then the following formula (5) is obtained.

For example, assuming that the work roll revolution envelope radius R = 2000 [mm], the number of work rolls N = 4, the entry plate thickness _h0 = 150 [mm], and the delivery plate thickness _h1 = 95 [mm], the following formula (6) is obtained, and it is possible to predict the fluctuation of the rolling speed with respect to the average speed during contact of the work rolls.

From the above, the rolling speed of the work roll 1 can be determined so as to exceed the rolling material speed _v1 at the delivery side of the rolling mill. In addition to the prediction calculation of the rolling material speed using the above formulas (1) to (6), a prediction value of the rolling material speed based on past rolling results under other conditions, for example, using machine learning or a multiple regression equation, may also be used.

In addition, to prevent the feed rolls 4 from slipping at the entry side of the rolling mill, it is also effective to increase the rolling force of the feed rolls 4, but there are often restrictions on the upper limit of the rolling system equipment, and when the rolled material 3 is hot and has low deformation resistance, the rolling force of the feed rolls 4 can cause thinning, which can also be a factor in thickness fluctuations in the planetary mill 10.

As described above, by setting the rotation speed of the work roll 1 so that the rolling speed of the work roll 1 exceeds the rolling material speed at the exit side of the rolling mill, the slip direction between the work roll 1 and the surface of the rolled material 3 can be always kept constant, and the reaction force of the entry side push-in force can be stably reduced. As a result, by adopting a rolling method in which the rolling material 3 is rolled by the planetary mill 10 at the rolling speed set using the speed setting method of the work roll 1 according to the embodiment, slip of the feed roll 4 at the entry side of the rolling mill can be avoided and stable rolling can be achieved. In addition, by using the rolling method to manufacture rolled steel plates such as hot-rolled steel plates, thick steel plates, and cold-rolled steel plates, the occurrence of surface defects such as surface flaws in the rolled steel plates can be suppressed, and stable rolled steel plates can be efficiently manufactured.

An embodiment of the present invention is shown below. Here, we explain an embodiment in which the present invention is applied to a hot rolling line for hot-rolled steel sheets.

The rolling equipment of this embodiment has the same configuration as the rolling equipment shown in FIG. 1, and a roll-cast type planetary mill 10 having four upper and lower work rolls 1 with a roll diameter of 500 mm and a revolution envelope diameter of 2000 mm rolls a rolled material 3 made of general low carbon steel with a plate thickness of 200 mm. Feed rolls 4A and 4B that feed the rolled material 3 into the rolling mill are arranged upstream of the rolling mill. Measuring rolls 5A and 5B that measure the rolling material speed are arranged downstream of the rolling mill. The speed setting of the feed roll 4 is 5 mpm, and the upper and lower work roll gaps are adjusted so that the plate thickness at the exit of the rolling mill is 50 mm. The revolution speed of the work roll 1 is set to 628 mpm on the work roll revolution envelope diameter. As shown in FIG. 7, the rolling speed of the rolling mill at the exit side fluctuates periodically between 5 mpm and 70 mpm, and in this case, the maximum rolling speed is 70 mpm.

As shown in Figure 8, the rolling force of the feed roll 4 and the rolling speed of the work roll 1 were changed to investigate whether or not the feed roll 4 slipped on the surface of the rolled material 3. At this time, the revolution speed of the work roll 1 was fixed at 628 mpm, and only the rotation speed of the work roll 1 was changed.

When the rolling speed of the work roll 1 is always lower than the rolling speed of the rolled material 3, that is, when it is lower than the minimum speed, the restraining force of the rolled material 3 by the feed roll 4A and the feed roll 4B is smaller than the necessary pushing force at the entry side of the rolling mill, and the feed roll 4 slips on the surface of the rolled material 3. In addition, when the rolling speed of the work roll 1 is set to about the middle of the fluctuation of the rolling speed of the rolled material 3, the feed roll 4 slips on the surface of the rolled material 3. On the other hand, when the rolling speed of the work roll 1 is higher than the maximum speed of the rolled material 3, the feed roll 4 does not slip on the surface of the rolled material 3. Furthermore, when the rolling force of the feed roll 4 is extremely small, the feed roll 4 slips on the surface of the rolled material 3 regardless of the rolling speed of the work roll 1. These results mean that when the rolling speed of the work roll 1 is greater than the maximum speed of the rolled material 3, the sliding direction between the work roll 1 and the rolled material 3 is always the direction in which the rolled material 3 is pulled in, so the necessary pushing force at the entry side of the rolling mill is steadily reduced. Note that under the conditions of this embodiment, when the rolling speed of the work roll 1 exceeded 120 mpm, surface defects occurred on the rolled material 3.

As described above, by setting the rotation speed of the work roll 1 so that the rolling speed of the work roll 1 exceeds the rolling material speed at the exit side of the rolling mill, stable rolling is possible without slippage of the feed roll 4 on the surface of the rolling material 3.

In addition, in the same hot rolling line as above, the rotation speed of the work roll 1 was determined according to the rolling material speed at the delivery side of the rolling mill calculated using the above-mentioned prediction calculation formulas (1) to (6), and rolling was performed. FIG. 9 shows the results of an investigation into the occurrence of slippage at that time. The rolling material 3 is a general low carbon steel with a plate thickness of 220 [mm], and the upper and lower work roll gaps were adjusted so that the delivery side plate thickness was 60 [mm]. The rotation speed of the feed roll 4 is 5 [mpm], and the revolution speed of the work roll 1 is 628 [mpm]. In this case, the rolling material speed v ₁ at the delivery side of the rolling mill can be calculated from the above-mentioned formula (3).

Here, the work roll contact time/rotation period a can be calculated from the above formula (4), so the rolling material speed _v1 at the delivery side of the rolling mill is 57 mpm.

In addition, when rolling was performed with the revolution speed of the work roll 1 fixed and the rotation speed of the work roll 1 changed, the occurrence of slippage of the feed roll 4 on the surface of the rolled material 3 was investigated. It was found that by setting the rolling speed of the work roll 1 faster than the rolling material speed at the exit side of the rolling mill, slippage of the feed roll 4 on the surface of the rolled material 3 did not occur.

As shown by the above results, by setting the rotation speed of the work roll 1, it is possible to reduce the entry push force required for rolling, even under large reduction conditions in hot rolling, and to avoid slippage of the feed rolls 4A and 4B at the entry side of the rolling mill, thereby achieving stable rolling.

1, 1A, 1B Work rolls 2A, 2B Revolution shaft 3 Rolling material 4A, 4B Feed rolls 5A, 5B Measuring roll 10 Planetary mill

Claims (6)

A method for setting the speed of work rolls in a planetary mill in which two or more work rolls arranged around each of a pair of main shafts opposing each other across the rolled material rotate while revolving around the main shafts to roll the rolled material, characterized in that a rolling speed determined from the orbital speed of the work rolls and the rotational speed of the work rolls is set so as to be greater than the maximum speed of the rolled material at the exit side of the planetary mill. The method for setting the work roll speed according to claim 1, characterized in that the rolling material speed at the exit side of the planetary mill is obtained by an actual measurement value or a calculated value. 3. The method for setting a work roll speed according to claim 1 or 2, characterized in that the rolling material speed v1 is calculated using the formula _v1 = { _h0 - (1 - a) × _h1 } / ah0 × _v1m , where _v1 is the rolling material speed at the exit side of the planetary mill during contact between the work roll and the rolled material, _h0 is the entry thickness of the rolled material, _h1 is the exit thickness of the rolled _material , _a is the work roll contact time/revolution period, and _v1m is the average plate speed. A rolling method characterized in that the rolling material is rolled by the planetary mill at a rolling speed set using the work roll speed setting method described in any one of claims 1 to 3. A method for producing rolled steel plate, comprising the steps of: producing a rolled steel plate using the rolling method according to claim 4; a planetary mill that rolls a rolled material using two or more work rolls that are disposed around each of a pair of main shafts that are disposed opposite each other with the rolled material therebetween;
a feed roll for conveying the rolled material, the feed roll being disposed upstream of the planetary mill in a moving direction of the rolled material;
Equipped with
1. A rolling facility comprising: a rolling speed determined by the revolution speed of said work rolls and the rotation speed of said work rolls, said rolling speed being faster than a maximum speed of the rolled material after rolling.

Images