JPH02153026A - Continuous soaking method for thin metallic sheet - Google Patents

Abstract

PURPOSE:To prevent unequal heating in the transverse direction of a metallic sheet and to improve the soaking property thereof by changing the forward and backward moving center of a conductor coil according to the position of the metallic sheet by the signals of position detectors for the metallic sheet disposed at both opposite ends in the transverse direction of the metallic sheet. CONSTITUTION:The conductor coil 2 is energized and the metallic sheet 1 is made to travel therein by which induction heating is executed. A forward and backward movement quantity computing element A receives the position signal of the conductor coil 2 from the forward and backward movement quantity detector 20 and corrects the horizontal forward and backward movement quantity of the conductor coil 2 according to the set value of the forward and backward movement quantity of a setter B. A relational computing element E corrects the forward and backward movement quantity from the metallic sheet speed signal of a traveling speedometer 14 and the speed signal of the conductor coil 2 of the detector 21. On the other hand, the forward and backward movement quantity computing element A makes comparison and computation with the set central position quantity by the deviation signal from a position deviation computing element F and the forward and backward movement quantity signal and determines the follow-up quantity of the conductor coil 2 with the metallic sheet 1 in such a manner that the amplitude center at the time of the forward and backward movement of the conductor coil 2 coincides with the center line of the metallic sheet 1 at all times. The induction heating is thus executed while the conductor coil 2 is moved horizontally back and forth.

Description

[Detailed description of the invention] Industrial field of application This invention is a continuous heating method that aims to equalize the temperature in the width direction of a thin metal plate by using a transverse magnetic flux induction heating method when heating a continuously running metal plate. The method involves making a conductor coil capable of reciprocating in the width direction of the metal plate, always horizontally reciprocating with the required amplitude, and moving the amplitude center of the conductor coil to follow the center line of the metal plate, thereby making it possible to continuously move metal. 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 (threading position) of the conductor coil and the thin metal plate constantly fluctuates. For example, the optimum heating position of
If the center 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 more than 100 degrees will occur on both sides of the metal plate, causing a big problem in heat uniformity in the width direction of the plate. there were.

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 for the purpose of soaking up heat, we found that temperature gradients in the width direction of the metal plate can be prevented by horizontally reciprocating the conductor coil facing the metal plate at the required amplitude at all times in the width direction of the metal plate. At this time, by moving the amplitude center of the conductor coil to follow the center line of the metal plate and causing horizontal reciprocation,
The present invention was completed based on the discovery that it is possible to prevent uneven heating that occurs due to positional fluctuations in the width direction of a continuously running metal plate and to obtain excellent heat uniformity in the width direction of the plate.

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 placed 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. When performing induction heating while horizontally reciprocating the conductor coil at a required amplitude around a preset center line with respect to the metal plate, This continuous heating method for a thin metal plate is characterized in that the center of reciprocating motion of a conductor coil is changed according to the position of the running metal plate using a signal from a position detector.

Further, in the above configuration, the present invention captures the current center line position of the metal plate by a signal from a position detector of the metal plate disposed at both ends or one end of the metal plate opposite to the width of the metal plate, and This continuous heating method for a thin metal plate is characterized in that the center of the reciprocating motion of a conductor coil is changed so that the center line of the reciprocating motion of the conductor coil coincides with the center line of the metal plate.

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 continuous heating method for a thin metal plate is characterized in that induction heating is performed by determining the horizontal reciprocating speed of a conductor coil according to the traveling speed.

Structure of the Invention This invention makes a conductor coil facing a metal plate movable in the width direction of the metal plate, causes it to horizontally reciprocate with a required period and amplitude with respect to the surface of the metal plate, and in addition to the horizontal reciprocating movement, For example, by moving the amplitude center of the conductor coil to follow the center line of the metal plate whose position changes in the width direction of the metal plate during continuous running, uneven heating caused by positional changes in the width direction of the plate is prevented. In addition, when the thickness of the metal plate differs in the width direction, the conductor coil is The special feature is to always shift the center of amplitude of the metal plate by the required amount from the center of the metal plate, and to perform horizontal reciprocating motion with the required period and amplitude to prevent uneven heating caused by variations in plate thickness in the width direction of the plate. .

When controlling the center position of the reciprocating motion of the conductor coil, the position reference to be controlled is, for example, the center line of the running line of the metal plate, the positional deviation of the running metal plate with respect to this is detected, and the conductor coil is moved to the center of the metal plate. In addition to centering on the center line, it also detects the position of one end of the metal plate passing between the required width of the running line, calculates the center of the plate according to the set metal plate width, and centers the conductor coil on the center line. If the conductor coil can always be moved to follow the center line of the metal plate, such as by detecting the width edge position of the metal plate with a pair of detectors placed at a predetermined interval and calculating the center of the plate width, it is possible to Any control standard or means may be used, and the reciprocating range and moving speed must be appropriately selected depending on the width of the metal plate, traveling speed, etc.

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 can slide in the horizontal axis direction, any known moving means can be used, and the driving source can be a hydraulic device such as a hydraulic cylinder, a step motor, a servo motor, or an electric motor. It can be used as appropriate depending on the moving means.

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 movement of the coil itself, movement of its coil support, mounting table, etc., and further measurement and detection of the amount of rotation and movement of the actuator of the moving machine groove.

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. .

Furthermore, when the thickness of the metal plate differs in the width direction, the comparator calculates the metal thickness according to the thickness distribution signal measured and set in advance or automatically measured by a detector, or from a position arbitrarily set in advance. While capturing the positional deviation in the width direction of the plate, the amount of deviation of the amplitude center of the conductor coil from the center of the metal plate is calculated based on a pattern arbitrarily set in advance, and horizontal reciprocation is performed at the required period and amplitude.

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.

In addition to directly measuring the speed of movement of the conductor coil itself, a speed meter for moving conductor coils measures the speed of movement of its mounting table, etc., or measures the speed of rotation and movement from a drive actuator, position detector, etc. , detection, calculation, or other means 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 1/L is generally 0.9:1.1. is preferred.

Further, in the present invention, the range of the horizontal reciprocating 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.

The upper and lower pairs of conductor coils (2 x 2) are connected to a coil support (3) consisting of a box-shaped slider (4) installed 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 attached to the base (
8) and the slider (7) on the bottom of the reciprocating 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).

The reciprocating table (6) converts the rotational force placed on the base (8) into linear reciprocating motion using a converter (10) such as a crank mechanism and a servo motor (11) as a driving source. The servo motor (11
), the conductor coil (2) is moved in the width direction of the metal plate (1) and reciprocated in the width direction of the metal plate (1) with a predetermined amplitude.

The servo motor (11) is equipped with a conductor coil reciprocating motion amount detector (20) such as an optical pulse counter and a reciprocating motion speed detector (21), and the conductor coil (2×2) is connected to the reciprocating motion drive source. It consists of a configuration that detects position and speed.

Here, the reciprocating motion amount detector (20) attached to the servo motor (11) obtains the position signal of the conductor coil (2X2), and the speed detector (21) detects the speed. The position and speed of the conductor coil (2X2) can be detected with the width of the metal plate (1). An optical position detector (12) for detecting directional position is provided and is fixed to the reciprocating table (6) via a 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 in which the continuous soaking method of the present invention is applied to a metal plate having a uniform thickness in the width direction using the induction heating device having the above configuration will be described.

Below, while always aligning the amplitude center of the conductor coil (2X2) during reciprocating motion with the center line of the metal plate (1),
An example in which a conductor coil (2×2) is horizontally reciprocated with a predetermined amplitude will be described.

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) The electrical center line, that is, the position of the amplitude center during reciprocating motion is arbitrarily set.

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

First, the horizontal reciprocating motion of the conductor coil (2×2) is controlled. That is, the required reciprocating amount is set in advance in the reciprocating amount calculator (A) from the reciprocating amount setting device (B), and the servo amplifier (C) and servo driver (
D) controls the rotation of the servo motor (11).

At this time, the reciprocating amount calculator (A) is the servo motor (1
The reciprocating amount is corrected by receiving the position signal of the conductor coil (2X2) from the reciprocating amount detector (20) attached to 1).

Furthermore, the comparator (E) receives the speed signal of the metal plate (1) from the travel speedometer (14) and the speed signal of the servo motor (11).
The speed signal of the conductor coil (2X2) from the reciprocating speed detector (21) attached to the is compared with the speed signal of the conductor coil (2X2), and a corrected value is outputted to the servo amplifier (C) so that a preset relationship is achieved.
The amount of reciprocating movement described above is corrected.

In addition to the above control, the metal plate position detector (12) disposed on the widthwise opposite part of the running metal plate (1) detects the widthwise position of the metal plate (1) and detects the position. It is output to the deviation calculator (F), and the position deviation signal is manually input to the reciprocating amount calculator (A).

In the reciprocating motion amount calculator (A), when correcting the reciprocating amount, the position deviation calculator (F) is operated so that the amplitude center during reciprocating motion of the conductor coil (2X2) always matches the center line of the metal plate (1).
Comparison calculations are performed with the set center position amount using the manually inputted deviation signal, position signal and reciprocating motion amount signal of the conductor coil (2X2), and the metal plate (2X2) of the conductor coil (2X2) is compared with the set center position amount.
1), and by such control, the conductor coil (2X2) moves the plate width relative to the surface of the metal plate (1) at a predetermined amplitude and speed according to the traveling speed of the metal plate (1). Furthermore, the center of the reciprocating motion of the conductor coil (2) (2) always coincides with the center line of the metal plate (1), and the transverse magnetic flux of the conductor coil (2X2) It acts uniformly in the width direction, the induction heating is uniform, and there is no temperature gradient in the width direction of the plate unlike in conventional methods.

Here, the servo amplifier (C) is the reciprocating l operator (A)
We have shown an example in which the control is performed using signals from the comparator (E) and the comparator (E).
It is possible to adopt a configuration in which the position signal of 2) and the speed signal of the metal plate (1) are manually input, necessary comparison calculations are performed, and a control signal is output to the servo amplifier (C).

EXAMPLE A coil of 18-8 series stainless steel having 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; A formula pulse counter was used.

Under the above-mentioned metal plate running conditions and induction heating conditions, the continuous soaking method according to the present invention, that is, the induction heating method in which the metal plate is reciprocated while following the center, and the conventional induction heating method were carried out. Table 1 shows the temperature difference in the width direction and longitudinal direction (conductor coil length) of the heated material when induction heating is performed by the continuous soaking method according to the present invention and the conventional method, and the heating efficiency. 2 shows the temperature distribution in the width direction of the metal plate (0 in the figure is the longitudinal direction) after induction heating I- by the conventional method 2 (Figure a) and the method of the present invention (Figure b) in Table 1.

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. FIGS. 3a and 3b are graphs showing 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. DESCRIPTION OF SYMBOLS 1... Metal plate, 2... Conductor coil, 3... Coil support body, 4, 7... Slider 5... Vertical rail,
6... Reciprocating table 8... Base, 9... Horizontal rail, 10... Converter, 11... Servo motor 12...
・Metal plate position detector, 13... stand, 14...
Traveling speed meter, 20... Reciprocating motion amount detector, 21... Reciprocating motion speed detector, A... Reciprocating motion amount calculator, B... Reciprocating motion amount setting device, C... Servo amplifier, D.・Servo driver E
...Comparison calculator, F...Position deviation calculator.

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. When performing induction heating while horizontally reciprocating the conductor coil with the required amplitude around a preset center line with respect to the metal plate, the conductor coil is placed at both ends or one end of the metal plate across the width of the metal plate. A method for continuously soaking a thin metal plate, characterized in that the center of reciprocating motion of a conductor coil is changed according to the position of a running metal plate using a signal from a position detector for the metal plate installed. 2 The center line position of the running metal plate is captured by the signal from the position detector of the metal plate arranged at both ends or one end side of the metal plate opposite to the width of the metal plate, and the center line of the reciprocating motion of the conductor coil is aligned with the metal plate. 2. The method for continuously soaking a thin metal plate according to claim 1, wherein the center of reciprocating motion of the conductor coil is changed so as to coincide with the center line of the plate. 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 1, wherein the induction heating is performed by determining a reciprocating speed.