JPH0618643Y2 - Run-out table on the exit side of hot finishing mill - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a transport table for transporting hot steel strips or steel plates by a group of rollers, and more particularly to a hot steel strip rolled by a hot finish rolling mill or The present invention relates to a run-out table that sends a steel plate to a winder.

[Conventional technology]

For example, in the run-out table, the rollers are arranged over 100 m to 200 m, and nozzles for spraying or spraying cooling water on the strip (rolled steel plate) are provided between the rollers above the roller row and below the roller row. The strips are arranged in the width direction of the strip, and the strips rolled by the hot finishing mill are cooled and sent to the winder.

In the hot finishing mill that sends out the rolled steel strip, in order to obtain good metallurgical properties of the rolled steel sheet, it is necessary to roll it at a temperature higher than a predetermined value, and as a result, it is sent to the run-out table. The temperature of the rolled steel strip is relatively high, for example, 700 to 900 ° C. The delivery speed is also relatively high, for example 10
High speed near m / sec. Rolled steel strip is run out
In the table, take-up temperature below a relatively low specified value
It reaches the winder (coiler) cooled to 500-700 ℃ and is wound up on it.

Therefore, the transport speed of the rolled steel strip on the run-out table is a high value, for example, around 10 m / sec, and the minimum thickness of the rolled steel strip is around 1 mm, so the so-called stiffness is relatively weak at a relatively thin thickness, Flying (a phenomenon in which the tip floats up and rises) and accordion-like waviness are likely to occur.

If the conveying speed of the hot strip is too fast, and if the tip of the hot strip is lifted, the lift amount will increase as the steel strip progresses, causing it to warp and the winder to fold the strip. It may not be able to be wound up in the state that it was taken up. Thus, after the tip of the hot strip passes through the final stand of the hot finish rolling mill, until the winding on the winder, and after the trailing edge of the strip passes through the final stand, the tension of the strip is almost constant. Since it would be in a free state, the transport speed had to be reduced. Also, when the tension of the steel strip is almost free, the shape of the steel strip will be disturbed by the accordion-like waveform, etc., and if the shape is disturbed, the cooling water and its flow on each part of the steel strip will be uniform. As a result, temperature unevenness occurs and uniform quality cannot be ensured. Furthermore, as the thickness of the steel strip becomes thinner, the tip of the strip becomes easier to lift, and the transport speed is reduced in advance in consideration of folding, defective winding on the pinch roll, etc. It was associated with disability and reduced yield.

Such floating of steel strips, especially instability due to floating phenomenon of ultra-thin materials on the run-out table, has been an obstacle to production.

Therefore, in the past, firstly, an attempt was made to dispose a linear motor between rollers (Japanese Patent Publication No. 51-41988), and secondly,
An attempt to dispose an electromagnet between rollers (Japanese Patent Publication No. 61-10206) and a third attempt to dispose an electromagnet roll (Japanese Unexamined Patent Publication No. 54-77262) have been proposed.

However, in both cases, since the linear motor and the electromagnet need to give a strong electromagnet to the rolled steel sheet, it has a relatively large iron core (magnetic core), resulting in high cost.

In the former two cases, the arrangement of cooling nozzles between most of the rolls of the run-out table becomes complicated or difficult, and the electromagnets placed between the rolls rather than on the transport rolls where the absorption of the steel strip is originally desired. Since it occurs concentratedly on the upper part, only the part of the generated suction force that acts on the transport roll is effective. Due to such a reduction in the efficiency of the suction force and the local concentration force, it is not possible to expect uniformity in the width direction.

In the former third party, since a large current is caused to flow through the electromagnet in the transport roll, which is a rotating body, there are many failures due to the slip ring and the rotary transformer, and there is a problem in terms of maintenance. In addition, in order to make this roll group with a built-in electromagnet, the existing roll must be removed and replaced with that roll, and the increase in GD ² accompanying the built-in electromagnet will increase the capacity of the drive motor and increase the burden of equipment costs. There is also a problem. Further, as shown in FIG. 8 and FIG. 10 of the former third party (Japanese Patent Laid-Open No. 54-77262), the direction of the electromagnet in the magnet roller of the third party is the original desired shape, that is, each magnet. A uniform force is not always generated on the roll in the same direction and in the plate width direction, but it is the direction of the roll axis of the magnet roll, or the direction changes with rotation. There were also many restrictions.

In view of this, the applicant of the present application has proposed, in Japanese Patent Application No. 63-173087, a configuration in which an electric coil for winding a transport roll of a run-out table is arranged as shown in FIG. By energizing this electric coil, an electromagnet having the transport roll as an iron core is formed.

Although FIG. 2 illustrates an example in which the electric coils are wound around all the transport rolls of the runout table, in practice,
If the electric coil is wound around the conveyor roll in a partial section corresponding to a convenient place, one that prevents the tip of the strip from flying and one that acts from the tail end not to swing good.

According to this configuration, since an additional iron core is not required, the cost is relatively low, and it is possible to easily install the cooling nozzle in a small space between the transfer rolls and the point of action of electromagnetic force. There are many advantages such as being efficient on the conveyor roll.

[Problems to be solved by the device]

The above-mentioned method usually adds the effect of generating electromagnetic force to the transport rolls that are provided for the purpose of transporting the steel sheet while cooling it. There is a need to. However, the aforementioned Japanese Patent Application No. 63-183087 has not yet reached such a study.

Therefore, an object of the present invention is to provide a run-out roller equipped with a carrier roll having a material and a structure suitable for a carrier roll that is required to carry a steel sheet and generate an electromagnetic force.
To serve a table.

[Means for Solving the Problems]

The present invention has been made in view of the above-mentioned objects.
In the configuration, a plurality of hot-rolled steel strips having a length equal to or greater than the width of the steel strip are provided at predetermined intervals in the transport direction Y, and a rotary shaft is provided in a direction X orthogonal to the transport direction Y. A magnetic transport roll, an electric coil that winds a transport roll of at least a part of the transport roll with a direction Z orthogonal to the directions X and Y as a coil central axis, and the hot-rolled steel strip. In the run-out table on the delivery side of the hot finish rolling mill, the electric coil is wound, the driving means rotating and driving the conveying roll in the conveying direction The body of the carrier roll has a single-layer structure of cast iron.

The second configuration is characterized in that the body portion of the transport roll around which the electric coil is wound has a two-layer structure including an outer layer of cast iron and an inner layer of stainless steel.

[Action]

FIG. 1 (a) shows a plan view of three transport rolls constituting the runout table. Conveyor rolls usually have an outside diameter of 300 m
It has a hollow structure of about m, and both sides are made smaller in diameter and are rotatably supported by bearings.The drive roll is connected to the motor by a coupling, and the part excluding both ends in the axial direction of the roll is called the body part, It is the part that comes into contact with. A sectional view taken along the line AA of FIG. 1 (a) is shown in FIG. 1 (b), and the transport roll around which the left coil is wound is an example of a two-layer hollow roll having an outer layer and an inner layer. The one on the right side is an example of a single layer structure having only an outer layer.

As a transport roll for a normal run-out table, contact with the steel strip, that is, no damage to the steel strip,
And strength is required.

Further, as the transport roll that generates the electromagnetic force, it is necessary that the generated electromagnetic force is larger than the applied current. Furthermore, the braking force acts by rotating the transport roll that is rotated by the motor while cutting the magnetic flux, and the power consumption of the motor increases. In other words, it is necessary that the electromagnetic force generation efficiency is high. It is said that

As will be described in detail later, the present inventor compared some practical cases by combining theoretical calculation and experiment, and as a result, the two-layer structure roll consisting of the outer layer of cast iron and the inner layer of structural steel currently in use is The authors clarified that the power consumption of the motor is increasing due to the large eddy current flowing in the inner layer, devised a countermeasure against it, and simulated it to find that the above-mentioned configuration is optimal.

〔Example〕

FIG. 2 shows a side surface of the run-out table 2 which is an embodiment of the present invention. The rolled steel strip sent from the hot finish rolling mill 1 is sent to the winder 3 by the run-out table 2 and wound into a coil by the winder 3. In the run-out table 2, the transport (magnetic material) roller 2 ₁
Each of the electric coils 20 _{1 to} 20 _n is installed in each of the to 2 _n .

Conveying the arrangement of such electrical coil 20 ₁ for (magnetic) roller 2 _1, etc. shown in Figure 3.

The long sides of the electrical coil 20 ₁ extends in the axial direction X of the magnetic roller 2 _1, apart from the side surface of the roller 2 _1. Electric coil 20
Short side of ₁ extends parallel to the end face of the roller 2 _1, apart from the end face. Some of the upper peripheral surface of the roller 2 ₁ protrudes slightly upward from the electrical coil 20 _1.

Fig. 4 shows the thickness of the hollow carrier roll with an outer diameter of 300 mm when the outer 10 mm is cast iron and the inner 5 mm is structural steel.
FIG. 6 is a characteristic diagram showing the results of measuring the armature currents of the drive motors 30 ₁ to 30 _n at each coil current value for each rotation speed for a steel plate of 2 mm.

According to FIG. 4, it is considered that the braking force acts on the rotation of the roll as the coil current increases, and the current of the drive motor increases. Therefore, if a material having a large braking force at the same current value is selected as the material of the roll, a drive motor having a large driving force is required, which is not preferable.

Further, as a matter of course, a material having a large electromagnetic force generated at the same current value is preferable. Regarding the contact property with the steel strip, it has been conventionally known that the material of the surface of the roll is preferably cast iron.

From the above viewpoints, some realistic materials are selected, and the results of calculating the suction force and the power consumption of the motor by theoretical calculation are shown in the following table together with other evaluation items.

Here, in the comprehensive evaluation, the ⊚ mark represents the optimum, the ○ mark represents the suitable, the Δ mark represents the usable and the X mark represents the unsuitable, the ○ mark in the strength and the contact property indicates no problem, and the △ mark. The mark indicates that there is a problem.

The simulation calculation of the suction force and the motor power consumption was performed as follows.

Maxwell's electromagnetic equations are vectors of electric field, magnetic flux density, electric flux density, magnetic field, and current density, respectively. If the charge is ρ Can be written as

Here, limiting to an eddy current field in a metal body having a certain velocity distribution V, assuming a relatively low frequency region (<MHz), the following vector potential And a scalar potential φ is introduced.

As a result, the following basic equation is obtained.

However Where σ is the conductivity, μo is the vacuum permeability, Is the magnetization vector.

In the above basic equation (7), the finite element method is applied to the spatial partial differential, the weighted average approximation method is applied to the temporal partial differential, and the convergence calculation is performed by the Newton-Raphson method to perform the simulation calculation.

According to the results in the previous table, No. 5 which is currently widely used
Compared with No. 3, 6 and 7, that is, in the case of only one layer of cast iron (No. 3, 6), the motor power consumption is 1/15 to 1
/ 30, and in the case of a two-layer structure consisting of an outer layer of cast iron and an inner layer of stainless steel (No.7), the motor power consumption is 1/1
Since it decreased to about 50, it was found to be excellent overall.

[Advantages of the Invention] As described above, according to the present invention, a structure suitable for a run-out table is provided, in which an electric coil is wound around a transport roll and energized to attract a steel plate to prevent flying and corrugation. A run-out table with a transport roll is provided.

[Brief description of drawings]

FIG. 1 is a structural view of a carrier roll according to an embodiment of the present invention, FIG. 2 is a view showing an embodiment of the present invention, and FIG. 3 is a view showing an arrangement relationship between a magnetic roller and an electric coil. Fig. 4 is a diagram showing the armature current characteristics of the drive motor at each coil current. In the diagram, 1 ... hot finish rolling mill, 2 ... run-out table, 3 ... winder, 2 ₁ ~2 _n ...... conveying roller, 20 ₁ ~20 _n ...... electric coil.

Claims (2)

[Scope of utility model registration request] 1. A plurality of hot-rolled steel strips arranged at a predetermined interval in the transport direction Y with a length equal to or greater than the width of the steel strip, and having a rotation axis in a direction X orthogonal to the transport direction Y. Magnetic transport rolls, an electric coil that winds a transport roll in at least a part of the transport rolls with a direction Z orthogonal to the directions X and Y as a coil central axis, and the hot-rolled steel. A run-out table on the delivery side of a hot finish rolling mill, comprising: a drive unit that rotationally drives the transport rolls in a strip transport direction; and an energizing unit that applies a current to the electric coil. The run-out table on the delivery side of the hot finish rolling mill is characterized in that the body of the transport roll is made of a cast iron monolayer structure. 2. A plurality of hot-rolled steel strips arranged at predetermined intervals in the transport direction Y with a length equal to or greater than the width of the steel strip and having a rotation axis in a direction X orthogonal to the transport direction Y. Magnetic transport rolls, an electric coil that winds a transport roll in at least a part of the transport rolls with a direction Z orthogonal to the directions X and Y as a coil central axis, and the hot-rolled steel. A run-out table on the delivery side of a hot finish rolling mill, comprising: a drive unit that rotationally drives the transport rolls in a strip transport direction; and an energizing unit that applies a current to the electric coil. The run-out table on the delivery side of the hot finish rolling mill is characterized in that the body of the transport roll has a two-layer structure consisting of an outer layer of cast iron and an inner layer of stainless steel.