JPH02153024A - Continuous soaking method of thin metallic sheet - Google Patents

Abstract

PURPOSE:To continuously heat a thin metallic sheet without generating unequal heating in the metallic sheet by executing induction heating of the metallic sheet in follow up to and coincidence with the center line in the longitudinal direction of the metallic sheet to be heated which fluctuates during traveling on the electrical center line of a conductor coil. CONSTITUTION:The conductor coil 2 is energized and the metallic sheet 1 is made to travel in the coil, by which the induction heating thereof is executed. The position detection signal in the transverse direction of the metallic sheet 1 is outputted by a metallic sheet position detector 12 to a position deviation computing element A. A computing element B compares and computes the respective arbitrarily set central position quantities of the metallic sheet 1 and the coil 2 by the deviation signal of the computing element A and the position signal of a metallic coil position setter F and determined the transverse direction of the coil 2 with respect to the metallic sheet 1 and the follow up quantity thereof. This follow up quantity is inputted to a servo amplifier C. On the other hand, the position signal of a conductor coil position detector 11 is converted to a deviation signal by a computing element D and is inputted to the servo amplifier C which compares the respective signals and controls the driving of a servo valve for controlling a hydraulic cylinder 10. The coil 2 is continuously moved to follow up the metallic sheet 1 in the transverse direction thereof via a coil support 3 in this way. The metallic sheet 1 is thus heated with the excellent uniformity.

Description

[Detailed description of the invention] Industrial field of application This invention is a continuous heating method that aims to scorch a thin metal plate in the width direction by using a transverse magnetic flux induction heating method when heating a continuously running metal plate. This problem occurs when the continuously running metal plate changes its position in the width direction by making the conductor coil facing the metal plate movable in the width direction of the metal plate and always moving it to follow the center line of the metal plate. This invention relates to a continuous soaking method for thin metal plates that prevents uneven heating.

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 achieve continuous heating with excellent uniformity regardless of the plate thickness dimension. As a result of various studies for the purpose of uniform heating, we decided to make the conductor coil facing the metal plate movable in the width direction of the metal plate, and by always moving it to follow the center line of the metal plate, it was possible to move the conductor coil facing the metal plate in the width direction of the continuously running metal plate. The present invention was completed based on the finding that excellent heat uniformity in the width direction of the plate can be obtained by preventing uneven heating that occurs due to positional fluctuations.

This 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. A series of thin metal plates, characterized in that induction heating is performed by aligning the electrical center line of the conductor coil, which is movable in the width direction, with the longitudinal center line of the metal plate to be heated, which changes during running. This is a soaking method.

■ 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 ■ A position detector of the coil is provided on the conductor coil or supporting portion that is movable in the width direction of the metal plate. , ■The comparison calculation controller calculates the width direction positional deviation amount of the metal plate from a preset arbitrary position based on the signal from the metal plate position detector, and determines the width direction tracking amount of the conductor coil with respect to the metal plate. death,
While comparing with the position signal from the conductor coil position detector,
The position of the conductor coil in the width direction of the metal plate is controlled so that the electrical width center line of the conductor coil matches the current center line of the metal plate.

Further, in the above configuration, a traveling speed meter is provided on the side of the metal plate to detect the traveling 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 This is a continuous soaking method for a thin metal plate in which the amount and speed of movement of a 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 This invention makes it possible to move a conductor coil facing a metal plate in the width direction of the metal plate, and moves it to follow the center line of the metal plate whose position changes in the width direction of the metal plate during continuous running. The present invention is characterized in that heating unevenness due to directional positional fluctuations is prevented, and 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,
In addition to detecting the positional deviation of the running metal plate 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 and adjusts the set metal plate width. Calculate the center of the plate according to the width of the metal plate and center the conductor coil on that center line, or use a pair of sensors placed at a predetermined interval to detect the edge position of the line drawing on the metal plate and calculate the center of the plate width. 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.

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.

As shown in the example, the mechanism that supports the conductor coils arranged opposite to each other on the upper and lower surfaces of the metal plate and allows them to move in the width direction of the plate includes:
The coil support is made to be able to cantilever a pair of conductor coils and to be slidable in the vertical axis direction so as to be able to move close to and away from the metal plate, and further made to be slidable in the width direction of the metal plate, that is, in the horizontal axis direction. In addition to the axial sliding mechanism, a known moving means can be employed, and as a drive source, a hydraulic device such as a hydraulic cylinder, a step motor, a servo motor, or an electric motor can be used as appropriate depending on the moving means.

A position detector that detects the position of a running metal plate in the width direction of the plate may be equipped with a following roller that combines a differential transformer and a copying roller, etc., if it can detect positional deviation from a preset reference position. Although a sensor can be used, a non-contact optical linear sensor is preferable 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 mounting table, etc., and measurement and detection of 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, a metal plate traveling speed meter can also use a signal from a metal plate coil unwinding machine. to correct the position deviation signal of the metal plate,
Alternatively, it is also good to improve the measurement accuracy of positional deviation.

It is better to use a conductor coil movement speed meter to directly measure the movement speed of the conductor coil itself, or to measure the movement speed of the coil support, its 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.

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

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 a sliding table (6), and the slider (7) on the bottom of the sliding table (6) moves the metal plate (1) placed on the base (8) in the plate width direction. It is configured to be slidable by gripping the horizontal rail (9).

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.

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.

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 (2) placed close to the upper and lower surfaces of the
Set the position of the electrical center line arbitrarily.

After the above settings, the conductor fill (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 the position deviation calculator (A).

Based on the deviation signal input 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. Comparison calculation with the position amount is performed to determine the width direction of the conductor coil (2×2) with respect to the metal plate (1) and the amount of follow-up thereof.

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, a position signal from the conductor coil position detector (11) is converted into a deviation signal by a position deviation calculator (D) 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 (
10) Drive and control the servo valve (E) that controls the servo valve (E).

Therefore, the deviation amount obtained by the comparator (B) can be calculated by sliding the slide table (6) in the required direction and by the required amount by operating the hydraulic cylinder (lO) through the coil support (3). Then, the conductor coil (2×2) is continuously moved to follow the width direction of the metal plate (1).

By the above control, the longitudinal center line of the metal plate (1) and the electrical center line 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).

EXAMPLE A coil of 18-8 series stainless steel having a width of 300 mm and a thickness of 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/see.

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

The following detectors were used: metal plate position detector: optical linear sensor coil position detector: potentiometer type metal plate running speed detector: optical pulse counter.

Temperature distribution in the width direction of the metal plate in the case of the induction heating method of moving the conductor coil according to the plate width method according to the present invention and in the case of the conventional induction heating method under the above-mentioned running conditions and induction heating conditions of the metal plate. The situation is shown in the graph of Figure 3.

Further, Table 1 shows the temperature difference in the width direction of the heated material and the heating efficiency when induction heating is performed by the continuous soaking method according to the present invention and the conventional method.

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, 3b, and 3c are graphs showing the temperature distribution in the width direction of the metal plate. DESCRIPTION OF SYMBOLS 1... Metal plate, 2... Conductor coil, 3... Coil support body, 4, 7... Slider 5... Vertical rail,
6... Sliding table 8... Base, 9... Horizontal rail, 10... Hydraulic cylinder, 11... Conductor coil position detector, 12... Metal plate position detector, 13... ...Stand, 1
4... Traveling speed meter, A, D... Position deviation calculator, B... Comparison calculator, C
... Servo amplifier, E... Servo valve, F...
Position setting device.

Claims (1)

[Scope of Claims] 1. A continuous soaking 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 procedures. A thin-walled metal, characterized in that induction heating is performed by aligning the electrical center line of the conductor coil, which is movable in the width direction of the metal plate, with the longitudinal center line of the metal plate to be heated, which changes during running. Continuous soaking method for plates. (1) A position detector of the metal plate is arranged at both ends or one end side of the metal plate facing the width of the metal plate; (2) The position of the coil is placed on the conductor coil or support part that is movable in the width direction of the metal plate. A detector is provided, and (3) the comparison calculation controller uses the signal from the metal plate position detector to
Calculate the widthwise positional deviation of the metal plate from a preset arbitrary position, determine the widthwise follow-up amount of the conductor coil with respect to the metal plate, and compare it with the position signal from the conductor coil position detector to determine the positional deviation of the conductor coil. The position of the conductor coil in the width direction of the metal plate is controlled so that the electrical width center line matches the current center line of the metal plate. 2. A travel speed meter is provided on the side of the metal plate to detect the running speed of the metal plate, or a travel speed meter is further provided to detect the moving speed of the conductor coil in the width direction of the metal plate, and the conductor coil is moved in accordance with the metal plate travel speed. 2. The method of continuously soaking a thin metal plate according to claim 1, wherein the amount and speed are determined and the conductor coil is caused to follow the movement of the metal in the width direction to perform induction heating.