JPH10202413A - Rotary cutting device and rotary cutting method for hot plate material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary cutting device for a hot plate material such that a hunting phenomenon is prevented from being induced in a resonance and under oil pressure control system of a machine system. SOLUTION: A rotary cutter 1 is constituted so that it is supported by a multi-step lift cylinder 6 and side locked by a clamp cylinder 3 inserting an orifice in a rod side head side pipe. A head side pressure in a step with a rod of the lift cylinder fully extended is set to a hydraulic source maximum pressure or a head side pressure or more in the next step, a pull back pressure is always applied to a rod side in the last end, and the pull back pressure is always applied to a rod side of the clamp cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cutting device and a rotary cutting device for a hot plate material for cutting and removing a ridge formed on a joint surface of a plate material which is sequentially joined in series and continuously hot-rolled. Related to cutting method.

[0002]

2. Description of the Related Art Conventionally, in a hot rolling line for a slab, a slab to be rolled has been heated, rough-rolled and finish-rolled one by one to finish a hot-rolled sheet having a desired thickness. In the rolling method, it is inevitable that the line is stopped due to poor rolling material in the finish rolling, and the yield is significantly reduced due to poor shape of the leading and trailing ends of the rolling material. Prior to finish rolling, the so-called endless rolling method, in which the leading and trailing ends of a billet to be rolled are joined and continuously supplied to a hot rolling line for rolling, has been adopted. . Japanese Patent Application Laid-Open Nos. 4-94609 and 5-185109 are referred to as prior arts in this regard.

In order to join the preceding and succeeding slabs in endless rolling, each slab is clamped and supported by a clamp in the vicinity of its end, and each end face is heated and heated by a heating means. It was common to then press, but especially in the pressing process, the butted part was raised (10% or more of the thickness of the plate, depending on the pressing force, the raised width was 10% or more of the width of the plate) This affects the rolling force of the rolling mill and the tension of the plate, and there is a disadvantage that the plate is broken during rolling,
When the roll is rolled, the bumps generated at the time of joining are removed because the impact at the time of the roll biting the roll causes damage to the roll and poor thickness, and also causes the generation of barbed flaws. There is a need to. As a rotary cutting device of a hot plate material for performing such a removal of a raised portion, Japanese Patent Application Laid-Open No. 7-241713 discloses a raised steel plate having a plurality of helical blades, which is a kind of a milling type cutting device. A part cutting device has been proposed.

[0004]

The rotary cutting device for a hot plate material is capable of cutting a cylindrical body (rotary blade) having a cutting edge on the outer peripheral surface and having a body length equal to or larger than a maximum plate width at an extremely high peripheral speed (50 m / s to 50 m / s). Ten
Since it rotates at 0 m / s), strict adjustment of dynamic balance is required. On the other hand, the existing rotary cutting device is configured to support the rotary blade so as to be able to move up and down by a hydraulic cylinder, and the lifting operation of the hydraulic cylinder is controlled by a hydraulic pressure reduction control system.

[0005] However, the cutting edge that is repeatedly performed wears the cutting edge, and the dynamic balance is lost, causing resonance of the mechanical system. In addition, when the vertical movement is fast, the hunting phenomenon of the hydraulic pressure reduction control system is frequently induced. There was a problem that would occur. Accordingly, an object of the present invention is to provide a rotary cutting apparatus and a rotary cutting method for a hot plate material that solves this problem and does not induce resonance of a mechanical system and a hunting phenomenon of a hydraulic pressure reduction control system.

[0006]

According to a first aspect of the present invention, a rear end portion of a preceding material is joined to a front end portion of a succeeding material on the exit side of a rough rolling mill. A device for simultaneously cutting from the front and back surfaces of the joining ridges of the hot plate material facing the finish rolling mill over the entire width from the front and back surfaces, and having a housing, in which a cutting edge for performing the cutting is provided on an outer peripheral surface. Incorporates a rotary cutter in the shape of a cylinder, a bearing box that rotatably supports the rotary cutter, a hydraulic lifting cylinder that supports the bearing box so as to be able to move up and down, and a hydraulic clamp cylinder that presses the bearing box from the side to the housing. In a rotary cutting apparatus for hot plate material, the lifting cylinder is a multi-stage cylinder in which a rod of the next stage is included in each stage rod. is there.

A second aspect of the present invention is the rotary cutting apparatus for hot plate material according to the first aspect of the present invention, wherein a hydraulic pipe connected to the rod side and the head side of the clamp cylinder has an orifice immediately near the connecting portion. . A third aspect of the present invention is a rotary cutting method of a hot plate material using the rotary cutting device according to claim 1 or 2, wherein when the rotary blade is lifted and lowered using the multi-stage cylinder, each step is performed. The pressure at the head side of the stage where the rod is fully extended is set to the maximum pressure of the hydraulic pressure source or equal to or higher than the pressure of the head at the next stage, and the pullback pressure is constantly applied to the rod at the final stage. This is a rotary cutting method for the intermediate plate.

According to a fourth aspect of the present invention, there is provided a rotary cutting method for a hot plate using the rotary cutting device according to the first or second aspect of the present invention, wherein a pullback pressure is constantly applied to the rod side of the clamp cylinder. This is a method for cutting the surface of a hot plate material. A fifth aspect of the present invention is the rotary cutting method for hot plate material according to the third aspect of the present invention, wherein a pullback pressure is constantly applied to the rod side of the clamp cylinder.

[0009]

FIG. 5 is a schematic view showing an example of a continuous hot rolling line suitable for carrying out the present invention. In FIG. 5, 4 is a hot plate (hot steel strip), 11 is a heating furnace, 12 is a group of rough rolling mills, 13 is a coil box, 14 is a crop shear of a joint, 15 is a joining device, and 16 is rotary cutting. The apparatus, 17 is a finishing mill group, 18 is a strip shear, 19 is a high-speed threading guide, and 20 is a winding machine.

[0010] The billets sequentially extracted from the heating furnace 11 are roughly rolled by a rough rolling mill group 12 and then wound in a coil shape by a coil box 13. It is cut by the joint crop shear 14, and the rear end of the preceding material and the front end of the succeeding material are joined by the joining device 15 to form the continuous hot steel strip 4. This hot steel strip 4 is cut and removed by a rotary cutting device 16 on a ridge (joint ridge) formed on the upper and lower surfaces of a joint, and then sent to a finishing mill group 17 to be finish-rolled and stripped. While being appropriately cut by the shear 18 and guided by the high-speed threading guide 19, it is wound by the winder 20.

The rotary cutting device 16 used in such a continuous hot rolling line generally has a housing (in a solid state) having a cutting edge on the outer peripheral surface in the housing. ), A bearing box for rotatably supporting the rotary blade, a hydraulic lifting cylinder for supporting the bearing box so as to be able to move up and down, and a hydraulic clamp for pressing the bearing box from the side to the housing. A cylinder is incorporated.

In general, the vibration frequency of a mechanical system depends on the supporting rigidity of the rotating body, that is, the spring constant. The smaller the spring constant is, the lower the resonance frequency is. Therefore, in the present invention, the spring constant is increased and the resonance frequency is increased. Resonance is prevented in the range of the rotation speed of the high-speed rotating body. In the case of a single-stage cylinder, when the oil column becomes high (the oil column length L becomes large), the following equation is obtained.
As is clear from the inverse proportional relationship shown in (1), the spring constant K is reduced, and hunting is likely to occur.

K = H × A / L (1) where: K: spring constant of cylinder H: bulk modulus of oil (increases when oil column rises) A: cross-sectional area of cylinder L: cylinder Oil column length determined by the stroke of the first invention, the lifting cylinder is a multi-stage type in which the rod of the next stage is included in the rod of each stage, the oil column is divided into two or more, so from the base stage side Sequentially set the head side pressure to the maximum pressure or higher than the next stage head side pressure, and only the final stage head side pressure directly receiving the mechanical reaction force is a pressure balanced with the mechanical reaction force, and is higher than the maximum pressure of the hydraulic source. Since the pressure can be supported as a small pressure, the spring constant of the lifting cylinder can be increased, and a rotary cutting device excellent in vertical vibration resistance can be realized.

By the way, the outer diameter of the rotary blade changes from, for example, a new one of 1000 mm to a replacement part of 600 mm due to wear of the cutting edge. The outer diameter range of 600 mm to 1000 mm is determined by the amount of rotational energy consumed by the cutting tool during cutting, but if the outer diameter is less than 600 mm, the rotating peripheral speed drops to 60 m / s or less, and cutting chips are attached to the cutting edge. If the outer diameter exceeds 1000mm, it takes too much time to increase the rotation speed to a predetermined value because it is proportional to the fourth power of the outer diameter of the blade when the outer diameter exceeds 1000mm. Outside diameter is 1000mm ~ 600mm
It is desirable to manage within the range. Its outer diameter wears out due to repeated cutting, and changes 400 mm in diameter (200 mm in radius) within several re-blades. On the other hand, the rotating blade must be 200 mm to 400 mm above and below the plate surface because it is necessary to leave a space up to about 200 mm above and below the plate for stable hot plate passing. It is necessary to move up and down within a range from the standby position to a work position where the joint ridge of the plate is rotationally cut. Therefore, the length of the oil column of the lifting cylinder is desirably 200 mm to 400 mm.

On the other hand, a hydraulic clamp cylinder for pressing the bearing housing of the rotary blade from the side against the housing is provided to suppress the horizontal movement of the rotary blade. Conventionally, the hydraulic column connected to the head has a long oil column length L, so that conventionally, the vibration resistance was insufficient. On the other hand, in the second aspect of the present invention, in addition to the first aspect of the invention, an orifice is provided in the vicinity of the connecting portion of these pipes to substantially reduce the length of the oil column in the pipe, so that the vertical and horizontal This realizes a rotary cutting device for hot plate materials having excellent vibration resistance.

In the third aspect of the present invention, the pressure of the head at the stage where the rod is fully extended is set to the maximum pressure of the hydraulic pressure source or equal to or higher than the pressure of the head at the next stage. In this method, the spring constant K is increased by constantly applying a pullback pressure to the rod side of the step, thereby effectively utilizing the property that the bulk modulus H of the oil increases with the oil pressure.

In particular, when the rotary blade is held in the middle of the stroke (between the contraction and extension of the rod), the spring constant K is determined by the sum of the head-side spring constant and the rod-side spring constant. Therefore, by constantly pressing the rod side as much as possible, the spring constant K can be kept large, so that the vibration resistance in the vertical direction increases. Further, a fourth invention is a method of constantly applying a pullback pressure, which has been hardly applied to the rod side, to the clamp cylinder, thereby increasing a spring constant when vibration occurs. In addition, the horizontal vibration resistance can be remarkably improved. In addition, hydraulic pressure is fully applied to the head side.

The fifth aspect of the present invention is a method in which the third and fourth aspects of the present invention are used in combination. This method is most preferable because the vibration resistance in both the vertical and horizontal directions is improved.
As described above, according to the present invention, since the spring constants of the lifting cylinder and the clamp cylinder are maintained at a high value (high rigidity state) and mechanical vibration can be absorbed, there is no fear of mechanical breakage due to resonance in both horizontal and vertical directions. A rotary cutting device for a hot plate material is realized without causing hunting due to the hydraulic pressure reduction control system becoming a vibration system due to rapid expansion and contraction operation.

Although the present invention relates to a rotary cutting device for hot plate material, a multi-stage cylinder or a clamp cylinder and a control method therefor according to the present invention are applied to a high-speed rotating body other than a rotary blade, for example, a hot and cold rotating body. Needless to say, the present invention can be easily applied to a hydraulic cylinder for supporting a high-speed rotating roll used in a cold rolling mill or the like, preferably having an oil column length of 50 mm or more, and a hydraulic pressure reduction control system.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention was applied to a rotary cutting device 16 of a continuous hot rolling line shown in FIG. FIG. 1 is a side view of the rotary cutting device according to the embodiment. In FIG. 1, 1 is a rotary blade, 2 is a blade shaft, 3 is a clamp cylinder, 4 is a hot plate, 5 is a bearing box, 6 is a lifting cylinder, 7 is a housing,
Numeral 8 denotes a chip collecting device for cutting the cut and raised portion, and numeral 10 denotes a table roll for conveying a hot plate material.

This apparatus is a hot plate material 4 having a maximum plate width of 1900 mm.
In order to cut the joint raised portion from the front and back simultaneously over the entire width, the cylindrical rotary blade 1 having a body length of 2000 mm and having an iron-based cutting edge on the outer peripheral surface is provided. The outer diameter of the rotary knife 1 is 950
mm, and the tool shaft 2 is rotatably held by the bearing housing 5 and can rotate at a maximum rotation speed of 2000 rpm.
The reason why the upper limit of the rotation speed is set to 2000 rpm is that if the rotation speed exceeds this value, the universal joint connecting the electric motor and the blade may reach the resonance frequency, and the rotation speed exceeds the limit rotation speed of the cross-section bearing.

The upper and lower bearing housings 5 are pressed against the housing 7 by the clamp cylinders 3 from the sides, and the surfaces opposite to the hot plate 4 are raised and lowered by the lifting / lowering cylinders 6 so that the cutting edge of the rotary blade 1 has a plate surface. It is supported so that it can be reciprocated (elevated) at any time between a work position corresponding to the position and a standby position 200 mm in the height direction from the work position.

Conventionally, the lift cylinder 6 has a single stage, but the lift cylinder 6 of the embodiment has a maximum oil column length of 310 mm.
It is a stage type, and the oil column length of the first stage rod is 160 mm and the oil column length of the second stage rod is 150 mm. FIG. 2 is a schematic sectional view showing the configuration of a two-stage cylinder. In FIG. 2, 61
Is the first stage rod, 62 is the second stage rod, and 61H and 62H are the first stage rods.
The stage and the second stage head side piping and 6R are rod side piping.
The second stage rod 62 is configured to be included in the first stage rod 61,
The rod side pipe 6R is shared by the first stage and the second stage.

Using the two-stage lifting cylinder 6, the surface of a joint to which, for example, 20 steel slabs are joined is
The procedure for cutting by setting the maximum pressure of the hydraulic pressure source to 210 kg / cm ² and the pull-back pressure of the rod side piping to 80 kg / cm ² will be described in detail. Before starting the cutting of the joined billet, a pullback pressure is applied to the rod-side pipe 6R, and the first-stage head-side pipe 61H is applied.
The first stage rod 61 and the second stage rod 62 are shortened by releasing the hydraulic pressure of the second stage and the hydraulic pressure of the second stage side pipe 62H. This state is the state of the standby position.

In cutting the surface of the joined steel slab from the standby position, the first stage rod 61 is extended by applying hydraulic pressure to the first stage head side pipe 61H before the joint reaches the cutting position. When the first-stage rod 61 extends by the oil column length of 160 mm, which is the stroke limit, the first-stage head-side piping 61
The hydraulic pressure of H is set to the maximum pressure of the hydraulic pressure source. In this state, the first
The step rod 61 extends by an oil column length of 160 mm, which is the stroke limit, and the hydraulic pressure at the first stage head side is the maximum pressure of the hydraulic pressure source, and a pull-back pressure is applied to the rod side common to the first and second stages. ing. Still, the hydraulic pressure of the second stage head side piping 62H has been released.

Next, in order to cut the surface of the joint of the billet, the second-stage rod 62 is extended by a predetermined length, for example, 40 mm.
At this time, considering the working force required for the cutting work, for example, the maximum pressure of the hydraulic pressure source is 210 kg / cm ² in the second stage head side pipe 62H.
The surface of the joint is cut by applying a hydraulic pressure of 105 kg / cm ² equivalent to 50%. This state is the state of the work position. After cutting the surface of the joint, the hydraulic pressure of the second stage head side pipe 62H is released to reduce the second stage rod 62 by 40 mm.

Next, in the same manner as described above, the second-stage rod 62 is extended by 40 mm to cut the surface of the joint, and then reduced by 40 mm to the second joint. After the same procedure is repeated to cut all the surfaces of the joints, the hydraulic pressure of the first-stage head-side piping 61H and the hydraulic pressure of the second-stage head-side piping 62H are all released, and the state is set to the standby position with the shortening limit. .

One lifting cylinder is 200 mm as described above.
Since the cylinder is extended and retracted and placed vertically above and below the billet, the distance between the upper and lower blades will open and close by 400 mm. By the way, the conventional single-stage cylinder whose cylinder cross-sectional area is equal to that of the second stage of the two-stage cylinder is in the working position with the oil column length of 200 mm, and the hydraulic pressure is reduced to the rod side similarly to the present embodiment. 80kg / cm ² for pullback pressure of piping,
Considering the case where the head side hydraulic pressure is set to 105 kg / cm ² , the spring constant of this single-stage cylinder is set to K ₀ .

At this time, the second stage cylinder of the two-stage cylinder has the same pullback pressure and the second stage head side oil pressure and the oil column length is five times that of the single stage cylinder. , (1) the spring constant K ₂ of the second stage cylinder from the equation becomes 5 times the K _0. That is, K ₂ = 5 · K ₀ (2) Further, since the first-stage cylinder of the two-stage cylinder includes the second-stage cylinder, With the same pullback pressure and a larger cylinder cross-sectional area (α (> 1) times), the higher the first stage head side hydraulic pressure, the higher the bulk modulus of the oil (β (> 1))
And the oil column length is 4/5 times,
(1) the spring constant K ₁ of the first-stage cylinder from the equation K ₀
(5/4) ・ α ・ β times. That is, K ₁ = (5/4) · α · β · K ₀ (3) The relationship between the spring constants K ₁ and K ₂ of each stage of the two-stage cylinder and the total spring constant Kt is as follows. It is expressed by equation (4).

1 / Kt = (1 / K ₁ ) + (1 / K ₂ ) (4) Therefore, from equations (2), (3) and (4), the total spring constant Kt is
It is given by the following equation (5). _{Kt = 5 · K 0 / (} 1 + 4 / a) ......... (5) where, a = α · β> 1 than this, the total spring constant of the two-stage cylinder in this embodiment, the conventional single-stage cylinder Obviously, it is larger than the spring constant.

In this example, the maximum pressure of the hydraulic pressure source is set to 21.
Although described as 0 kg / cm ² , this value should be changed as appropriate from the viewpoint of the cylinder outer diameter and the required force, the reliability against oil leakage of hydraulic piping, and the cost of equipment, and the present invention is limited to this value. It is not something to be done. However, the cylinder outer diameter of the final stage is determined in advance so that the pressure of the head-side hydraulic pressure at the final stage directly receiving the mechanical reaction force becomes smaller than the maximum pressure of the hydraulic pressure source.

As described above, the cylinder is made into a multi-stage type having two or more stages, and the resonance oil column value which is lower than the rotation frequency of the entire mechanical system including the spring constant of the cylinder is obtained. By defining the stroke of the first stage and setting the hydraulic pressure on the head side to the hydraulic source maximum pressure, a spring constant higher than that of a conventional single-stage cylinder can be obtained.

On the other hand, as shown in FIG. 3, the clamp cylinder 3 is provided with an orifice 22 immediately near the connection between the head side pipe 3H and the rod side pipe 3R and the clamp cylinder 3, and the rod side pipe 3R has an orifice 22 of 80 kg / h. the cm ^2, head side pipe 3
The hydraulic pressure source maximum pressure is always applied to H. FIG. 4 is a graph showing the relationship between the rotation speed of the blade of the rotary cutting device and the vibration speed in the example and the conventional example. The conventional example shows a calculation curve for a rotary cutting device in which the lifting cylinder 6 has a single stage and the clamp cylinder 3 does not have the orifice 22, and the embodiment shows an actual measurement curve (discrete measurement points are smoothly connected by a vibrometer). Curve), and the vibration speed was shown at the maximum speed. Calculations were also made for the examples, but the calculated curves almost coincided with the actually measured curves. The range where the vibration speed exceeds about 7 m / s is set as the vibration danger area.

As shown in the figure, in the conventional example, resonance occurs in the vertical direction at 80 to 90% of the maximum rotation speed (2000 rpm) and in the horizontal direction at 65 to 70% of the maximum rotation speed (2000 rpm). While the speed entered the vibration danger region, it was confirmed that, in the example, even when operated at the maximum rotation speed, no resonance occurred in both the vertical and horizontal directions, and the rotary blade could be stably held.

[0035]

As described above in detail, according to the present invention, the spring constants of the lifting cylinder and the clamp cylinder are maintained at a high value (high rigidity state), and mechanical vibrations can be absorbed. A remarkable effect of realizing a rotary cutting machine for hot plate material that is free from mechanical damage due to resonance in both directions and hunting due to the hydraulic pressure reduction control system becoming a vibration system due to rapid expansion and contraction operations. Play.

[Brief description of the drawings]

FIG. 1 is a side view of a rotary cutting device according to an embodiment.

FIG. 2 is a schematic cross-sectional view of a lifting cylinder (two-stage cylinder) according to the embodiment.

FIG. 3 is a schematic sectional view of a clamp cylinder of the embodiment.

FIG. 4 is a graph showing the relationship between the rotation speed of a blade and the vibration speed of a rotary cutting device in an example and a conventional example.

FIG. 5 shows a continuous hot rolling line 1 suitable for carrying out the present invention.
It is a schematic diagram which shows an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary blade 2 Tool shaft 3 Clamp cylinder 3H Head side piping 3R, 6R Rod side piping 4 Hot plate (hot steel strip) 5 Bearing box 6 Lifting cylinder 7 Housing 8 Chip recovery device 10 Table roll 11 Heating furnace 12 Rough Rolling mill group 13 Coil box 14 Joint crop shear 15 Joining device 16 Rotary cutting device 17 Finishing rolling mill group 18 Strip shear 19 High speed threading guide 20 Winding machine 22 Orifice 61 First stage rod 62 Second stage rod 61H 1st stage head side piping 62H 2nd stage head side piping

Continued on the front page (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Inside Kawasaki Steel Works Chiba Works (72) Inventor Shigeru Isoyama 1 Kawasaki-cho, Chuo-ku, Chiba City, Chiba Prefecture Kawasaki Steel Co., Ltd. (72) Inventor Kanji Hayashi 4-6-2-2 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd.Hiroshima Works (72) Inventor Katsumi Tashiro 4-2-2 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture No. Mitsubishi Heavy Industries, Ltd. Hiroshima Works

Claims (5)

[Claims] 1. A hot plate material which is disposed between a rough rolling mill and a finishing rolling mill and has a rear end portion of a preceding material and a leading end portion of a succeeding material joined on the exit side of the rough rolling mill and is heading toward the finishing rolling mill. Is a device for simultaneously cutting from the front and back surfaces over the entire width of the joint protruding portion, comprising a housing, a cylindrical rotary blade provided with a cutting edge for performing the cutting on an outer peripheral surface, and a rotatable rotary blade. Rotary cutting device for hot plate material, incorporating a bearing box that supports the bearing box, a hydraulic lifting cylinder that supports the bearing box so as to be able to move up and down, and a hydraulic clamp cylinder that presses the bearing box from the side to the housing. 3. The rotary cutting apparatus for a hot plate material according to claim 1, wherein the lifting cylinder is a multi-stage cylinder in which a rod of a next stage is included in a rod of each stage. 2. The rotary cutting apparatus for a hot plate material according to claim 1, wherein a hydraulic pipe connected to the rod side and the head side of the clamp cylinder has an orifice in the vicinity of the connection portion. 3. A rotary cutting method for a hot plate material using the rotary cutting device according to claim 1 or 2, wherein when the rotary blade is raised and lowered using the multi-stage cylinder, a rod at each stage is provided. The hot plate material characterized in that the pressure on the head side of the extended stage is set to the maximum pressure of the hydraulic pressure source or equal to or higher than the pressure on the next stage head side, and the pullback pressure is constantly applied to the final stage rod side. Rotary cutting method. 4. A rotary cutting method for a hot plate using the rotary cutting device according to claim 1, wherein a pullback pressure is constantly applied to a rod side of the clamp cylinder. Surface cutting method for plate material. 5. The method for rotary cutting of a hot plate material according to claim 3, wherein a pullback pressure is constantly applied to a rod side of the clamp cylinder.