JPH02153025A - Continuous soaking method for thin metallic sheet - Google Patents

Abstract

PURPOSE:To prevent the unequal heating of a thin metallic sheet by the fluctuation in the transverse direction thereof by providing a mechanism which moves a conductor coil for induction heating of the thin metallic sheet horizontally back and forth at the required amplitude with respect to the metallic sheet. CONSTITUTION:The conductor coil 2 is energized and the thin metallic sheet 1 is made to travel therein by which the induction heating is executed. The transverse direction detection signal of the metallic sheet 1 from a detector 12 is sent to a computing element A and the deviation signal thereof is changed by a relational computing element B to the coil follow up quantity. This follow up quantity is sent to a servo amplifier C. The position signal of the coil 2 is sent from the detector 11 to a computing element D and the deviation signal thereof is sent to the servo amplifier C so that the coil 2 is moved by a hydraulic cylinder 10 so as to follow up the metallic sheet 1. On the other hand, the position signal of the coil 2 from a forward and backward movement detector 25 installed to a servo motor 24 is inputted to a forward and backward quantity computing element G, by which the signal is compared with a set value. The horizontal forward and backward movement quantity of the coil 2 is thus corrected. Further, a relational computing element K outputs the correction value to a servo amplifier I from the speed signal of the metallic sheet 1 from a traveling speedometer 14 and the speed signal of the coil 2 from a forward and backward speed detector 26, thereby correcting the horizontal forward and backward movement.

Description

[Detailed description of the invention] Industrial field of application This invention is a continuous heating method that uses a transverse magnetic flux induction heating method to uniformly heat a thin metal plate in the width direction when heating a continuously running metal plate. Continuously running metal can be made by making the conductor coil movable in the width direction of the metal plate and constantly reciprocating it horizontally with the required amplitude, or by moving the center of the conductor coil to follow the center line of the metal plate and making it reciprocate horizontally. The present invention relates to a continuous heating method for a thin metal plate that prevents uneven heating caused by positional fluctuation of the plate in the width direction.

BACKGROUND ART In general, induction heating methods for thin metal plates are classified into longitudinal magnetic flux methods and transverse magnetic flux methods, depending on how the material to be heated intersects with the magnetic flux of the thin metal plate.

Thin metal plates using the longitudinal magnetic flux method are limited to magnetic materials, and as the plate thickness becomes thinner, frequencies of several hundred kHz to several MHz are required, making it difficult to accommodate this in terms of equipment and leading to a decrease in heating efficiency. do.

Therefore, regardless of whether the material is magnetic or non-magnetic, even if the plate thickness is thin,
A transverse magnetic flux type induction heating method that allows heating at a frequency of 3 kHz or less is preferred.

However, the induction heating method using the transverse magnetic flux method has not been put to practical use in industrial mass production operations because the temperature distribution in the width direction of the thin metal plate is poor and it is difficult to obtain uniform heat.

In other words, due to the bending (camber) in the longitudinal direction of the thin metal plate caused by the unwinding of the coil, the widthwise position (passing position) of the conductor coil and thin metal plate constantly fluctuates. For example, the optimum heating position of
If the centers of the metal plate and the coil are shifted by only about 1% of the width of the metal plate, a temperature difference of several tens of degrees to over 100 degrees will occur on both sides of the metal plate, which will greatly affect the thermal uniformity in the width direction of the metal plate. There was a problem.

On the other hand, as an improvement to the above-mentioned transverse magnetic flux method, a method has been proposed in which an auxiliary inductor is attached to the conductor coil to equalize the heat of the thin metal plate.

However, in the transverse magnetic flux method using the auxiliary inductor, it is necessary to adjust the position of the auxiliary inductor to accurately match the material, width, and thickness of the thin metal plate that is the material to be heated. Although it is convenient for heating thin metal plates of the same material and size, there are many problems in general heating of thin metal plates of different materials and dimensions.

Purpose of the Invention The present invention is capable of preventing uneven heating due to positional fluctuations in the width direction of a continuously running thin metal plate when heating a metal plate using a transverse magnetic flux type induction heating method, and is capable of preventing uneven heating due to positional fluctuations in the width direction of a thin metal plate that is continuously running. Summary of the Invention The present invention aims to provide a continuous heating method that can realize continuous heating with excellent heating uniformity regardless of the plate thickness dimension. As a result of various studies aimed at equalizing heat, we decided to make the conductor coil facing the metal plate movable in the width direction of the metal plate, and by constantly reciprocating horizontally with the required amplitude, temperature gradients in the width direction of the metal plate were prevented. However, by moving the center of the conductor coil to follow the center line of the metal plate and moving it back and forth horizontally, it has become impossible to prevent uneven heating that occurs due to positional fluctuations in the width direction of the continuously running metal plate. This invention was completed after discovering that uniformity of heat in the width direction of the plate can be obtained.

This invention makes it possible to move the metal plate in the width direction in a continuous heating method for a thin metal plate, in which conductor coils are arranged facing each other on the upper and lower sides of a running thin metal plate and are heated by induction by applying a transverse magnetic flux. This continuous heating method for a thin metal plate is characterized in that the conductor coil is horizontally reciprocated with respect to the metal plate at a required amplitude to perform induction heating.

In addition, the present invention provides a continuous heating method for a thin metal plate, in which conductor coils are arranged facing each other on the upper and lower surfaces of a running thin metal plate, and a transverse magnetic flux is applied to inductively heat the thin metal plate, using the following means and steps. The electrical center line of the conductor coil, which is movable in the width direction of the metal plate, is made to follow and match the center line in the longitudinal direction of the heated metal plate, which changes during running, and the conductor coil is moved relative to the metal plate. This is a continuous heating method for a thin metal plate, which is characterized by horizontal reciprocating motion at a required amplitude and induction heating.

■ A metal plate position detector is provided at both ends or one end of the metal plate facing the width of the metal plate, and ■ A coil position detector is installed on the conductor coil or coil support that is movable in the width direction of the metal plate. ■The comparator calculates the positional deviation in the width direction of the metal plate from an arbitrarily set position in advance based on the signal from the metal plate position detector, and determines the amount of follow-up in the width direction of the conductor coil with respect to the metal plate. ■The controller adjusts the metal plate width of the conductor coil so that the electrical width center line of the conductor coil matches the center line of the running metal plate while comparing the position signal from the conductor coil position detector. Control the position of the direction.

Furthermore, in the above structure, the present invention provides a traveling speed meter on the side of the metal plate for detecting the traveling speed of the metal plate, or further a traveling speed meter for detecting the moving speed of the conductor coil in the width direction of the metal plate. This is a continuous heating method for thin metal plates in which the horizontal reciprocating speed of the conductor coil is determined according to the traveling speed, and the conductor coil follows the movement of the metal in the width direction to perform induction heating.

Structure of the Invention The present invention is characterized in that a conductor coil facing a metal plate is movable in the width direction of the metal plate, and the conductor coil is horizontally reciprocated with a required period and amplitude with respect to the surface of the metal plate. However, it is necessary to appropriately select the reciprocating range and the reciprocating speed depending on the width of the metal plate.

In addition to the horizontal reciprocating motion of the conductor coil in the width direction of the metal plate, the present invention also allows the conductor coil to move to follow the center line of the metal plate whose position changes in the width direction of the metal plate during continuous running, thereby preventing positional fluctuations in the width direction of the metal plate. When controlling the position of the conductor coil, the position reference to be controlled is, for example, the center line of the running line of the metal plate, and the positional deviation of the running metal plate with respect to this is determined. In addition to detecting and centering the conductor coil at the center of the metal plate, it also detects the position of one end of the metal plate that passes between the required width of the running line,
Calculate the center of the plate according to the set width of the metal plate and center the conductor coil on the center line, or detect the edge position of the line drawing on the metal plate with a pair of detectors placed at a predetermined interval. Any control standard or means can be used as long as the conductor coil can always be moved to follow the center line of the metal plate, such as by calculating the center of the plate width.

Further, in the present invention, the centering accuracy can be improved by linking with a position adjustment device for the metal plate on the travel line when unwinding the metal plate coil.

The method of the present invention can be applied even when the thin metal plate to be heated is a single plate or a plurality of plates made of different materials with similar electrical resistances.

The mechanism that supports the conductor coils arranged oppositely on the upper and lower surfaces of the metal plate and allows them to move in the width direction of the plate includes a mechanism that cantilevers a pair of conductor coils and slides them in the vertical axis direction so that they can approach and leave the metal plate. The coil support that has been made possible is further expanded in the width direction of the metal plate.
In other words, in addition to a two-axis sliding mechanism that is capable of sliding in the horizontal axis direction, any known moving means can be employed, and the driving source may include hydraulic equipment such as a hydraulic cylinder, stave motor, or servo motor, or an electric motor. It can be used as appropriate depending on the means of transportation.

In addition, as shown in the example, the mechanism that supports the conductor coil and makes it movable in the width direction of the plate and capable of reciprocating movement is a two-stage horizontal sliding mechanism using sliders and rails, and the centering with respect to the center line of the metal plate is used. The drive source for this and the drive source for the reciprocating motion can be made independent.

The position detector that detects the position of a traveling metal plate in the width direction of the plate can be any type of sensor, such as a tracking roller that combines a differential transformer and a copying roller, as long as it can detect positional deviation from a preset reference position. Although it can be used, it is preferable to use a non-contact type optical linear sensor because a metal plate runs.

The conductor coil position detector may be of any configuration, such as a potentiometer or a pulse type position oscillator, as long as it can detect the position deviation from a preset reference position. Various means can be employed, such as moving the coil itself, moving the coil support, its mounting table, etc., and measuring and detecting the amount of rotation and movement of the actuator of the moving mechanism.

The comparison calculator calculates the amount of width direction positional deviation of the metal plate from a preset arbitrary position based on the signal from the metal plate position detector, and determines the amount of width direction tracking of the conductor coil with respect to the metal plate. If the positional deviation can be calculated using the detector or other arithmetic unit, it is sufficient to simply determine the amount of follow-up, and it is also possible to configure a controller for the movement drive source of the conductor coil, which will be described later. .

As the controller, a drive controller for a hydraulic, electric, or electromagnetic actuator can be appropriately selected depending on the above-mentioned moving mechanism of the conductor coil or its support and its drive source.

In addition to measuring near the conductor coil, the metal plate traveling speed meter can also use the signal from the metal plate coil unwinding machine, and further inputs the signal of the metal plate coil unwinding position to the comparison calculator. to correct the position deviation signal of the metal plate,
Alternatively, it is also good to improve the measurement accuracy of positional deviation.

A conductor coil movement speed meter not only directly measures the movement speed of the conductor coil itself, but also measures the movement speed of its coil support, mounting table, etc., or measures the movement speed of the coil support, mounting table, etc.
Means such as detection or calculation based on rotation amount and movement amount signals from a position detector or the like can be adopted as appropriate.

The relationship between the width (1) of the conductor coil and the width (L) of the heated material in this invention depends on the material, plate thickness, width, etc. of the heated material, but it is generally preferable that the diameter of the hole is 0.9:1.1. .

Further, in the present invention, the range of the horizontal reciprocating motion (amplitude) of the conductor coil in the width direction of the metal plate is preferably in the range of 0.05W to 0.20W when the width of the metal plate is 2W.

Based on the Drawings (Disclosure of the Invention) FIG. 1 is a perspective explanatory view of an induction heating apparatus for carrying out the continuous soaking method according to the present invention.

FIG. 2 is a block diagram showing a control system of the induction heating apparatus shown in FIG. 1.

The conductor coils (2) disposed close to the upper and lower surfaces of the metal plate (1) of the material to be heated are spirally arranged steel pipes through which cooling water can pass.

A pair of upper and lower conductor coils (2 x 2) is connected to a coil support (3) consisting of a box body and a slider (4) provided at the top and bottom.
It is possible to adjust the position in the vertical direction by gripping the vertical rail (5) provided on the side surface and using a locking mechanism (not shown).

The coil support (3) is placed on the sliding table (6) via the reciprocating table (20), and is mounted on the slider (7) on the bottom of the sliding table (6).
) is configured to be slidable by gripping a horizontal rail (9) in the width direction of the metal plate (1) laid on the base (8).

Furthermore, a reciprocating table (20
) is a horizontal rail (22) in the width direction of the metal plate (1) that the slider (21) on the bottom of the metal plate (1) laid on the sliding table (6)
It is configured so that it can be gripped and slid freely.

The sliding table (6) is slidably moved in the horizontal direction by a hydraulic cylinder (10) placed on a base (8), that is, the conductor coil (2) is moved by controlling the operation of the hydraulic cylinder (10). ) moves in the width direction of the metal plate (1).

In addition, a position detector (1) using a position sensor such as a potentiometer placed on the base (8) and connected to the sliding table (6)
In step 1), the current position of the conductor coil (2×2) is detected.

The reciprocating table (20) is driven by a converter (23) such as a crank mechanism that converts rotational force into linear reciprocating motion.
) and a servo motor (24) as a drive source are placed on a sliding table (6) and reciprocated in the width direction of the metal plate (1) with a predetermined amplitude.

The servo motor (24) is equipped with a conductor coil reciprocating amount detector (25) such as an optical pulse counter and a reciprocating speed detector (26), and the conductor coil (2×2) is connected to the reciprocating drive source. It consists of a configuration that detects position and speed.

Here, the reciprocating motion detector (25) attached to the servo motor (24) obtains the position signal of the conductor coil (2X2), and the speed detector (26) detects the speed. The configuration can be such that the position and speed of the conductor coil (2×2) are detected.

Further, optical position detectors (12) for detecting the widthwise position of the metal plate (1) are arranged at positions opposite both ends of the metal plate (1) on the upstream side of the conductor coil (2X2), It is also fixed to the sliding table (6) via the stand (13).

Further, near the metal plate (1) on the downstream side of the conductor coil (2×2), a traveling speed meter (14) for measuring the traveling speed of the metal plate (1) is disposed.

An example of implementing the continuous soaking method of the present invention using the induction heating device having the above configuration will be described.

An example in which the conductor coil (2X2) is horizontally reciprocated with a predetermined amplitude while always aligning the electrical center of the conductor coil (2X2) with the center line of the metal plate (1) will be described below.

Before heating, the center line of the thin metal plate (1), which has been passed through the required line to be unwound and wound up, and the metal plate (1)
) transverse magnetic flux conductor coils (2X
2) Arbitrarily set the position of the electrical center line.

After the above settings, the conductor coil (2×2) is energized and the metal plate (1) is run to perform induction heating.

Next, a metal plate position detector (12) disposed at a portion opposite to the moving metal plate (1) in the width direction detects the position of the metal plate (1).
A position detection signal in the width direction is output to a position deviation calculator (1).

Based on the deviation signal output from the position deviation calculator (A) and the position signal from the metal coil position setting device (F) attached to the metal plate coil unwinding device, the comparison calculator (B) calculates the arbitrarily set center. A comparison calculation with the position is performed to determine the direction and amount of movement of the conductor coil (2×2) with respect to the metal plate (1).

Signals of the determined moving direction of the conductor coil (2×2) and its tracking amount are input to a servo amplifier (C) serving as a drive controller.

On the other hand, the position signal from the conductor coil position detector (11) is converted into a deviation signal by a position deviation calculator (in the position deviation calculator) and input to the servo amplifier (C).

The servo amplifier (C) compares the follow-up amount signal with the deviation signal of the conductor coil (2) position, and compares it with the hydraulic cylinder (
By driving and controlling the servo valve (E) that controls the coil support body (
3), the conductor coil (2×2) is continuously moved to follow the width direction of the metal plate (1).

By the above control, the longitudinal centerline of the metal plate (1) and the electrical centerline of the conductor coil (2X2) match a preset positional relationship, that is, the conductor coil (2X2)
The coil support (3) can be centered so that it always coincides with the center line of the metal plate (1).

During the control, separately, a conductor coil (2X2)
The horizontal reciprocating motion of the robot is controlled. That is, the required reciprocating amount is set in advance from the reciprocating amount setting device (H) to the reciprocating amount calculator (G), and the servo amplifier (I) is set in advance according to the set value.
) and a servo driver (J) to control the rotation of the servo motor (24).

At this time, the reciprocating amount calculator (G) is the servo motor (2
4) The reciprocating amount is corrected by receiving the position signal of the conductor coil (2 to 2) from the reciprocating amount detector (25) attached to the reciprocating amount detector (25).

Furthermore, the comparator (K) uses the speed signal of the metal plate (1) from the travel speedometer (14) and the speed signal of the servo motor (24).
) is compared with the speed signal of the conductor coil (2) (2) from the reciprocating speed detector (26) attached to the reciprocating speed detector (26), and a corrected value is output to the servo amplifier (I) so that a preset relationship is achieved. The amount of reciprocating movement described above is corrected.

Through such control, the conductor coil (2X2) is connected to the metal plate (
The reciprocating motion of the conductor coil (2 1)
The transverse magnetic flux of the conductor coil (2 x 2) acts uniformly across the width of the metal plate (1), resulting in uniform induction heating and no temperature gradient across the plate as in conventional methods. .

Here, the servo amplifier (I) is the reciprocating motion amount calculator (G)
We have shown an example in which the control is controlled by signals from the comparator (K) and the comparator (K).
The configuration may be such that the position signal of 2) and the speed signal of the metal plate (1) are input, necessary comparison calculations are performed, and a control signal is output to the servo amplifier (I).

Example A coil of 18-8 stainless steel with dimensions of width 300 mm and thickness 2.5 mm was used as the metal plate of the material to be heated, and the coil was fed out at a speed of 0.1 m/sec.

A spiral coil made of steel pipe was used as the conductor coil.

Each detector includes: Metal plate position detector: Optical linear sensor Coil position detector: Potentiometer type Metal plate running speed detector: Optical pulse counter Reciprocating amount detector: Optical pulse counter Reciprocating speed detector: Optical A formula pulse counter was used.

Under the above-mentioned running conditions and induction heating conditions for the metal plate, there is a continuous soaking method according to the present invention, that is, a case in which the conductor coil is reciprocated in the width direction of the plate (invention 1), and a case in which the conductor coil is reciprocated in the sheet width direction, and a case in which the conductor coil is reciprocated while following the center of the metal plate. In the case of an induction heating method in which the
) and the conventional induction heating method, and Table 1 shows the width direction and longitudinal direction (conductor coil length ) and heating efficiency, and Figure 3 shows the temperature distribution in the width direction of the metal plate after induction heating by the conventional method (Figure a) and the present invention 2 (Figure b). ) is shown.

Table 1

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view of an induction heating apparatus for carrying out the continuous soaking method according to the present invention. FIG. 2 is a block diagram showing a control system of the induction heating apparatus shown in FIG. 1. Figures 3a and 3b show the temperature gradient in the width direction of the metal plate after induction heating by the conventional method and the method of the present invention. l... Metal plate, 2... Conductor coil, 3... Coil support, 4, 7.21... Slider 5... Vertical rail, 6... Sliding base 8... Base Stand, 9...Horizontal rail, 10...Hydraulic cylinder, 11...Conductor coil position detector, 12...Metal plate position detector, 13...Stand, 1
4... Traveling speed meter, 20... Reciprocating table, 23... Converter, 24... Servo motor, 25... Reciprocating amount detector, 26...
Reciprocating speed detector, A, D...position deviation calculator, B...comparison calculator, C
... Servo amplifier, E... Servo valve, F...
Position setting device, G... Reciprocating amount calculator, H... Reciprocating amount setting device, ■... Servo amplifier, J... Servo driver, K... Comparison calculator. Agent Patent Attorney Push 1) Good Kyūyomon No. 3 Ash (a) (b) Noshi 1 Metal plate width direction CM) Metal plate width direction (M)

Claims (1)

[Scope of Claims] 1. A continuous soaking method for a thin metal plate in which conductor coils are disposed facing each other on the upper and lower sides of a running thin metal plate and are heated by induction by applying a transverse magnetic flux, which is movable in the width direction of the metal plate. A continuous heating method for a thin metal plate, characterized in that said conductor coil is horizontally reciprocated with a required amplitude relative to the metal plate to perform induction heating. 2. In a continuous soaking method for a thin metal plate, in which conductor coils are arranged facing each other on the upper and lower sides of a running thin metal plate and a transverse magnetic flux is applied to inductively heat the thin metal plate, the method and procedure described below are used to heat the thin metal plate in the width direction of the metal plate. The electrical center line of the movable conductor coil is made to follow and match the longitudinal center line of the heated metal plate which fluctuates during running, and the conductor coil is aligned horizontally with the required amplitude with respect to the metal plate. A continuous heating method for thin-walled metal plates characterized by reciprocating motion and induction heating. (1) A position detector of the metal plate is provided at both ends or one end of the metal plate facing the width of the metal plate, and (2) a coil is mounted on the conductor coil or coil support that is movable in the width direction of the metal plate. A position detector is provided, and (3) the comparator calculates the widthwise positional deviation amount of the metal plate from a preset arbitrary position based on the signal from the metal plate position detector, and Determine the width direction tracking amount, and (4) use the controller to match the electrical width center line of the conductor coil with the center line of the running metal plate while comparing it with the position signal from the conductor coil position detector. Thus, the position of the conductor coil in the width direction of the metal plate is controlled. 3 A traveling speed meter is provided on the side of the metal plate to detect the running speed of the metal plate, or a traveling speed meter is further provided to detect the moving speed of the conductor coil in the width direction of the metal plate, and the horizontal movement of the conductor coil is determined according to the running speed of the metal plate. 3. The method of continuously soaking a thin metal plate according to claim 2, wherein the reciprocating speed is determined and the conductor coil is caused to follow the movement of the metal in the width direction to perform induction heating.