JPH0557319A - Method for compensating temperature of rolled stock - Google Patents

Abstract

PURPOSE:To compensate the deviation of temperature distribution of a rolled stock by heating the rolled stock in the pretreatment of rolling in a hot rolling process. CONSTITUTION:The interval between a roll electrode R2 on the inlet side and a roll electrode R4 on the outlet side is given by 40-60% of the interval between skid mark parts of the rolled stock W, when the skid mark part of the rolled stock W comes at the position of the roll electrode R2 on the inlet side, the power is supplied or the power is increased and when the skid mark part of the rolled stock W comes at the position of the roll electrode R4 of the rolled stock W at the outlet side, the power is stopped or the power is reduced. Since the skid mark part lowest in temperature is heated for the longest time and a low temperature part adjacent to the skid mark part is heated for a long time, the deviation of the temperature distribution of the rolled stock can be compensated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling method for compensating a temperature distribution of a rolled material by heating a mass-produced electrically conductive rolled material continuously and at high speed in a hot rolling process. The present invention relates to a temperature compensation method for materials.

[0002]

2. Description of the Related Art In a hot rolling process, it is required to heat a rolled material to be rolled. As a heating method in such a hot rolling process, heating by a gas furnace, induction heating, and electric heating are known. Heating by a gas furnace has a low heating rate, and inductive heating is inefficient, and the equipment cost is high because a high-frequency current is required, so heating by electric heating is relatively advantageous.

[0003]

By the way, in the rolled material supplied to the hot rolling step, for example, the temperature distribution is uneven due to skid marks generated in the portion located on the support roll during heating of the gas furnace. There is. Therefore, as a pre-process of the rolling process, it is required to compensate for such uneven distribution of the temperature distribution of the rolled material to make the temperature of the rolled material uniform and to make the dimension, material, etc. after rolling uniform.

In view of the above requirements, it is an object of the present invention to provide a rolling material temperature compensating method for compensating the deviation of the temperature distribution of the rolling material in the hot rolling process.

[0005]

According to the temperature compensation method for rolled material according to the present invention, the length of the heating zone of the heating device for heating the rolled material is set shorter than the interval of the lowest temperature portion of the rolled material. Starts or increases heating as the coldest portion of the sheet enters the heating zone and stops or decreases heating as the coldest portion of the rolled material exits the heating zone.

[0006]

According to the present invention, since the heating zone of the heating device has an interval shorter than the interval of the lowest temperature portion of the rolled material, the length heated by the heating device corresponds to the lowest temperature portion of the rolled material. Shorter than the interval. Such a heating zone initiates or increases heating when the coldest portion of the rolled material enters the heating zone and stops or decreases heating when the coldest portion of the rolled material exits the heating zone, The lowest temperature part of the rolled material is heated for the longest time as compared with the other parts. Therefore, it is possible to increase the temperature of the lowest temperature portion the most as compared with the other portions and to heat the portion having a low temperature close to the lowest temperature portion for a long time, so that the deviation of the temperature distribution can be compensated.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of a heating device used in a temperature compensation method for rolled material according to the present invention. On the inlet side of the feed path L of the rolled material W, an auxiliary roll R1 lined with a rubber material or the like and a conductive roll electrode R2 are provided.
They are arranged opposite to each other. Similarly, an auxiliary roll R3 and a roll electrode R4 are provided on the exit side so as to face each other. The distance between the roll electrode R2 on the entrance side and the roll electrode R4 on the exit side is set to be half the distance between the skid mark portions of the rolled material W. The rolled material W is, for example, a conductive metal plate such as a steel plate, and is preheated in a gas furnace or the like, and after being heated by this device,
It is sent to the rolling process. The conductive member 14 is connected between the roll electrodes R2 and R4 via the sliders S1 and S2.

The conductive member 14 connected to one end of the transformer 12 is a conductive member 14a1 arranged above and below the rolled material W.
And 14a2. Further, the conductive member 14 connected to the other end of the transformer 12 is connected to the conductive members 14b1 and 14b2. Conductive members 14a1 and 14b1
Are conductive members 14a near the energizing rolls R2 and R4, respectively.
2 and 14b2. The conductive member 14a2 is the slider S1 of the energizing roll R2, and 14b2 is the slider S2 of R4.
Connected to. The transformer 12 is connected to the AC power supply 10, the voltage supplied from the AC power supply 10 is transformed by the transformer 12, and the roll electrode R 2 is passed through the conductive member 14.
And R4.

An alternating voltage supplied from the roll electrodes R2 and R4 is applied to the rolled material W in a feed passage sandwiched by the auxiliary roll R1, the roll electrode R2, the auxiliary roll R3, and the roll electrode R4. Electricity is heated.

In this apparatus, the conductive member 14 is the rolled material W.
The vibrations of the rolled material W can be prevented because they are provided on both sides of the. Also, a choke CH is provided on the entrance side of the feed passage,
The voltage does not leak from the heating zone to the entrance side. Further, immediately before the choke CH, the ground roll R0
1, R02 are provided, and the entrance side is grounded to keep safety.

Roll electrodes R2, R4 and auxiliary roll R
Reference numerals 1 and R3 have an axial length that is equal to or larger than the width of the rolled material W, and the circumferential surfaces of the rolled material W sandwich the feed passage L and are separated by a predetermined gap through which the rolled material W can pass while being in contact with the respective circumferential surfaces. Are arranged facing each other. The conductive member 14 is formed of a good conductive material such as a copper material having a predetermined width and thickness.

The sliders S1 and S2 are respectively connected to both ends of the conductive member 14, and the roll electrode R2 and the roll electrode R4 can be slidably contacted with the power receiving portions provided on the rotating shafts of the rolls constituting each of them. Has been done.

Although not shown, a support roll such as a metal roll, a ceramic coating roll, or a ceramic roll may be provided in the feed passage of the rolled material W.

In this apparatus, an AC voltage is supplied from a power source 10, converted into a predetermined voltage by a transformer 12, and supplied to the roll electrodes R2 and R4 through a conductive member 14. As a result, an AC voltage is applied to the rolled material W passing through the feed passage between the roll electrodes R2 and R4, and the rolled material W is electrically heated.

Next, a method of compensating the temperature of the rolled material W, which is performed by using this apparatus, will be described. In the rolling material W, the portion located on the support roll is not heated to a large extent during heating in the gas heating furnace, so that this portion has the lowest temperature as the skid mark portion. In this method, the skid mark portion is heated more than other portions to compensate for temperature unevenness.

As shown in FIG. 5, the skid mark portion 40
When comes to the position of the roll electrode R2 on the entrance side, this is detected by a temperature sensor or the like, and the supply of electric power from the power source 10 is started. As a result, an AC voltage is supplied from the power source 10, converted into a predetermined voltage by the transformer 12, supplied to the roll electrodes R2 and 4 through the conductive member 14, and heating of the rolled material W is started.

When the rolled material W is fed and the skid mark portion 40 reaches the position of the roll electrode R2 on the output side as shown in FIG. 6, this is detected from the feeding speed of the rolled material W, and the power source 10
To stop the power supply. Therefore, as shown in FIG. 6, the skid mark portion 40 has the roll electrode R4 on the output side.
The heating of the rolled material W is stopped when it reaches the position.

Since the interval between the roll electrodes R2 and R4 is set to one half of the interval between the skid marks of the rolled material W, as shown in FIG. The next skid mark portion 42 has not yet reached the position of the roll electrode R2 on the entry side when it comes to the position. As shown in FIG. 7, when the next skid mark portion 42 reaches the position of the roll electrode R2 on the entry side, the supply of electric power from the power source 10 is started, and the rolled material W is heated again. Also in this case, when the skid mark portion 42 reaches the position of the roll electrode R4 on the output side, the power supply from the power source 10 is stopped.

As described above, the energization is started when the skid mark reaches the position of the roll electrode R2 on the entrance side, and the energization is stopped when the position of the roll electrode R4 on the exit side is reached. It is heated for a long time, and the heating time decreases as it goes away from the skid mark. Therefore, the temperature distribution of the rolled material W when the skid mark portion reaches the position of the roll electrode R2 on the entrance side as shown in FIG.
When the temperature reaches the position No., without heating, the temperature becomes as shown in FIG. 9, but the temperature distribution rising by heating becomes as shown in FIG. 10, so the temperature of the rolled material W after heating is as shown in FIG. 9 and FIG. The temperature is the combined temperature. Therefore, since the temperature of the skid mark part with the lowest temperature increases the most, the temperature of the skid mark part is compensated by heating,
The temperature distribution after heating becomes almost uniform.

FIG. 11 shows the temperature distribution of the rolled material W before heating,
FIG. 12 shows the temperature rise distribution due to heating. As can be seen from these figures, the temperature obtained by adding the temperature rise due to heating to the temperature of the rolled material W before heating becomes almost constant, so that the deviation of the temperature distribution can be compensated by heating.

In the present method, the distance between the roll electrode R2 on the entry side and the roll electrode R4 on the exit side is set to the rolling material W.
However, the length of the heating zone is not limited to ½ of the interval of the skid mark part, and the length of the heating zone is 40 to 60 mm of the interval of the skid mark part. It may be set in the range of%. If the length exceeds 60%, the amount of temperature rise in the high temperature portion between the skid mark portions becomes large, and it becomes difficult to make the temperature uniform. Therefore, it is desirable that the length be 60% or less. Further, if the interval is less than 40%, the temperature rise of the skid mark portion and the low temperature portion in the vicinity thereof will be insufficient, so it is desirable to set it to 40% or more.

In order to control the temperature of the rolled material W, any one of required power, required current, and required voltage which are preliminarily obtained from the size of the rolled material W, feed rate, specific heat, desired temperature rise, etc. is given to the rolled material W. When the temperature of the rolled material W is measured on the output side of the apparatus and the preset method in which the input to the transformer 12 is set in advance is operated, and there is a difference between the measured value and the planned temperature, , A power control switch is operated to adjust any of power, current, and voltage corresponding to the difference by a feedback method.

FIG. 2 is a diagram showing another example of a heating device used in the temperature compensation method for rolled material according to the present invention. In this apparatus, an annular transformer 20 is provided as a means for energizing the rolled material W. The annular transformer 20 is formed, for example, by forming a silicon steel plate having a property suitable as a magnetic path as a square-shaped member 22 as shown in FIG. 3 and laminating it, and winding it around an iron core having a predetermined length and the inner and outer circumferences of the ring. And a feed coil L for the rolled material W in the ring.
Is formed. That is, the size of the cross-sectional space in the ring is such that the rolling material W in motion moves in the width direction, that is, the rolling distance, vertical undulations, for example, corrugation and flapping of the plate generated in the case of a thin steel plate, and rolling due to catenary. In consideration of the bending of the material W and the like, the material W is set to pass in a non-contact state.

The annular transformer 20 may have the structure shown in FIG. That is, the inner space of the iron core 22 is made slightly larger, and the protective partition wall 2 has a ring shape concentric with the iron core 22 so as to surround the feed passage L of the rolled material W in the ring.
6 is provided. The protective partition 26 has one layer or two layers as shown. The protective partition 26 in the case of one layer is made of a non-magnetic material, for example, a metal material such as stainless steel,
This prevents the rolled material W from contacting the primary coil 24 and being damaged by swaying when passing through the transformer 20 or splashing in an accident such as breakage. In the case of the two-layer protective barrier 26, the non-magnetic metal material is used as the inner layer 26a and the heat insulating material such as heat insulating fiber is used as the outer layer 26b to prevent damage to the transformer and to radiate heat from the rolled material W. The primary coil 24 is prevented from being burnt out. If the rolled material W is not likely to damage the primary coil 24, only the heat insulating material is used.
A layer may be formed to prevent burnout of the primary coil 24. Note that the primary coil 24 may be a pipe material, and cooling water for cooling the primary coil 24 may pass through the pipe.

The annular transformer 20 is connected to the power source 10,
When a predetermined voltage is applied from the power supply 10 to the annular transformer 20, a secondary voltage is induced in the rolled material W corresponding to the secondary side of the transformer, and the rolled material W is electrically heated. The number of turns of the annular transformer 20 can be arbitrarily changed by a tap changer (not shown), and the voltage induced in the rolled material W can be adjusted. In addition, the ring transformer 20
Is powered by a power supply 10 having a power control switch.

In this apparatus, when power is supplied from the power source 10 to the annular transformer 20, a secondary voltage is induced in the rolled material W, and the secondary current generated in the rolled material W is passed through the sliders S1 and S2. It will flow through the connected conductive member 14 as a return line. In this case, the resistance of the conductive member 14 is set to be significantly smaller than the resistance of the rolled material W, so most of the current is consumed for heating the rolled material W, and the loss in the conductive member 14 is small. Therefore,
While efficiently heating the rolled material W by energization, most of the voltage generated in the rolled material W is consumed inside the rolled material W, and the voltage applied to the energizing rolls R2, R4 and the conductive member 14 is very low, and the heating is performed. It is possible to prevent damage to the equipment arranged around the device and to keep the safety of the operator.

In the above description, the case where the rolled material is heated by electric heating has been described, but the heating method used in the method of the present invention is not limited to electric heating, but may be induction heating or gas heating.

[0028]

According to the present invention, heating is started or increased when the lowest temperature portion of the rolled material enters the heating zone, and heating is stopped or heated when the lowest temperature portion of the rolled material exits the heating zone. Reduce. Since the length of the heating zone is shorter than the interval of the lowest temperature part of the rolled material,
It is possible to heat a portion having a low temperature, including the lowest temperature portion, to compensate for the deviation of the temperature distribution of the rolled material, and to obtain a uniform temperature distribution.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a heating device used in a temperature compensation method for rolled material according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a heating device used in the temperature compensation method for rolled material according to the present invention.

FIG. 3 is a cross-sectional view showing an annular transformer used in the heating device.

FIG. 4 is a cross-sectional view showing an annular transformer used in the heating device.

FIG. 5 is a diagram showing a heating start position of a rolled material.

FIG. 6 is a diagram showing a position where heating of a rolled material is stopped.

FIG. 7 is a diagram showing a position where heating of a rolled material is started.

FIG. 8 is a diagram showing a temperature distribution of a rolled material before heating.

FIG. 9 is a diagram showing a temperature distribution before heating of a rolled material at a position after heating.

FIG. 10 is a diagram showing a distribution of a rising temperature due to heating of a rolled material.

FIG. 11 is a diagram showing a temperature distribution of a rolled material before heating.

FIG. 12 is a diagram showing a temperature rise amount after heating a rolled material.

[Explanation of symbols]

 10 power supply 12 transformer 14 conductive member 20 annular transformer 40, 42 skid mark part R1, R3 auxiliary rolls R2, R4 roll electrodes S1, S2 sliding element W rolled material L feed path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsu Fukuyama 1 Fuji-machi, Hirohata-ku, Himeji City Nippon Steel Corporation Hirohata Works

Claims (5)

[Claims] 1. A temperature compensation of a rolled material for heating a continuously fed rolled material in a hot rolling process to compensate for a temperature distribution of the rolled material having periodic temperature fluctuations in the longitudinal direction of the material. In the method, in the method, the length of the heating zone of the heating device for heating the rolled material is set to be shorter than the interval of the lowest temperature portion of the rolled material, and the lowest temperature portion of the rolled material enters the heating zone. A method for compensating a temperature of a rolled material, wherein heating is started or increased at times and heating is stopped or reduced when the lowest temperature portion of the rolled material exits the heating zone. 2. The temperature compensation method for a rolled material according to claim 1, wherein the length of the heating zone is 40 to 60% of the distance between the lowest temperature portions of the rolled material. 3. The heating device is a device for electrically heating the rolled material by bringing the rolled material into contact with roll electrodes arranged on the inlet side and the outlet side of the feed passage of the rolled material and energizing the rolled material. Yes, the lowest temperature part of the rolled material starts energization or increases the energization current when passing the vicinity of the roll electrode arranged on the entrance side, the lowest temperature part of the rolled material is the roll arranged on the exit side The temperature compensation method for a rolled material according to claim 1 or 2, wherein energization is stopped or an energization current is reduced when passing the vicinity of the electrodes. 4. The roll electrodes arranged on the inlet side and the outlet side of the feed passage of the rolled material are arranged at an interval of 40 to 60% of the interval of the lowest temperature portion of the rolled material. The temperature compensation method for a rolled material according to claim 3. 5. The heating device is a device that induction-heats the rolled material by an induction furnace, and the induction furnace has a heating zone shorter than an interval of the lowest temperature portion of the rolled material. The temperature compensation method for a rolled material according to claim 1.