JP7198252B2 - Temperature measuring device in heat treatment furnace - Google Patents

Description

The present invention relates to a temperature measuring device in a heat treatment furnace for heat treatment of metal strip.

A metal strip is an object to be heat treated while being transported in a heat treatment furnace. Infrared radiant temperature sensors are commonly used to measure the temperature of conveyed metal strips. However, with an infrared radiation temperature sensor, it is necessary to appropriately correct the emissivity according to the material and surface condition of the object to be measured, so accurate temperature measurement is difficult. Therefore, as in Patent Documents 1 and 2, temperature measurement is performed by bringing a contact temperature sensor into contact with the transported metal strip.

Patent document 3 discloses preventing the surface of the metal strip from being scratched by raising and lowering the contact temperature sensor as needed.

Japanese Patent Publication No. 63-16448 Japanese Patent No. 2521579 JP-A-06-31229

When the metal strip hangs away from the transport rollers that support the transported metal strip, the metal strip vibrates slightly in the direction perpendicular to the transport direction, making the contact of the contact-type temperature sensor to the metal strip unstable. The temperature measurement of the metal strip is therefore inaccurate. In addition, the contact temperature sensor may be damaged due to the influence of vibration. Furthermore, if the metal strip has a seam, such as a weld, the contact temperature sensor is more likely to be damaged by hitting the seam and receiving a large impact.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a temperature measuring device for a heat treatment furnace that accurately and stably measures the temperature of a metal strip.

In order to solve the above problems, a temperature measuring device in a heat treatment furnace according to one aspect of the present invention includes:
a heat treatment zone for heat treating the conveyed metal strip;
a conveying roller disposed in the heat treatment zone and supporting the metal strip;
A heat treatment furnace comprising a temperature measuring device for measuring the temperature of the metal strip being heat treated while being transported,
The temperature measuring device has a contact temperature sensor that measures temperature by contacting the metal strip, and a driving unit that moves the contact temperature sensor to a contact position or a separation position with respect to the metal strip,
The contact-type temperature sensor is characterized in that it is arranged around the conveying roller, which is less susceptible to vibrations of the conveyed metal strip.

According to the present invention, the contact-type temperature sensor is arranged around the conveying roller, which is less susceptible to the vibration of the conveyed metal strip, so that the temperature of the metal strip can be accurately and stably measured. can be done.

It is a sectional view showing typically a part of heat treatment furnace concerning one embodiment. FIG. 2 is a functional block diagram of the heat treatment furnace shown in FIG. 1;

An embodiment of a temperature measuring device 7 in a heat treatment furnace 1 according to the present invention will be described below with reference to the drawings.

[Embodiment]
A heat treatment furnace 1 according to one embodiment will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a cross-sectional view schematically showing part of a heat treatment furnace 1 according to one embodiment. FIG. 2 is a functional block diagram of the heat treatment furnace 1 shown in FIG.

A heat treatment furnace 1 shown in FIG. 1 continuously heat-treats a metal strip 3 supported by conveying rollers 5 . The heat treatment furnace 1 performs, for example, bright annealing using a reducing gas as the heat treatment.

The heat treatment furnace 1 includes a furnace body 10 , a conveying roller 5 , a temperature measuring device 7 , a heat treatment zone 9 , a welding detector 15 and a controller 20 . The heat treatment furnace 1 shown in FIG. 1 is a horizontal furnace in which a furnace body 10 extends laterally (horizontally). The transport rollers 5 are arranged in the heat treatment zone 9 .

In the example shown in FIG. 1, the metal strip 3 is transported horizontally, for example from left to right, and then from top to bottom by transport rollers 5 . The metal strip 3 is, for example, SUS304 of austenitic stainless steel or SUS430 of ferritic stainless steel. The metal strip 3 has a leading strip 3a, a trailing strip 3b and a weld 3c. The weld 3c is formed by superimposing and welding the leading strip 3a and the trailing strip 3b. Therefore, the welded portion 3c is thicker than the preceding strip 3a and the succeeding strip 3b, and has a step with respect to the preceding strip 3a and the succeeding strip 3b.

The furnace body 10 is made of a steel box, and has a heat treatment zone 9 and a cooling zone (not shown) provided downstream of the heat treatment zone 9 in the conveying direction. The heat treatment zone 9 extends in the lateral direction (horizontal direction) and is provided on the upstream side of the metal strip 3 in the conveying direction (the entry side of the metal strip 3). The heat treatment zone 9 is heated by the heating section 12 . The heating unit 12 is, for example, an electric heater. Based on the temperature measured by the temperature measuring device 7, the control unit 20 controls the heat treatment zone 9 to reach a predetermined annealing temperature (here, the temperature in the heating step out of the heating step and the cooling step in the annealing treatment). controlled to be

A welded portion 3c is formed by welding the rear end of the leading strip 3a and the front end of the trailing strip 3b with a welding machine (not shown). A weld marker (not shown) for identifying the weld 3c is formed on the weld 3c. For example, a through hole can be used as the welding marker.

A welding detector 15 can be provided on the upstream side of the furnace body 10 in the conveying direction. The welding detection unit 15 is a detection unit capable of detecting the welding portion 3c (that is, welding marker), and is, for example, an optical sensor. The welding detection unit 15 provides the control unit 20 with position information (passage information) of the welding portion 3c (that is, the welding marker).

A temperature measuring device 7 is provided on the downstream side of the furnace body 10 in the conveying direction. The temperature measuring device 7 has a contact temperature sensor 30 , a support bar 32 , a drive section 34 and a flexible tube 37 .

The contact-type temperature sensor 30 is positioned inside the furnace body 10 and, for example, at the center in the width direction of the metal strip 3 and extends toward the metal strip 3 . The contact temperature sensor 30 is a sensor that measures the temperature of the metal strip 3 by contacting the surface of the metal strip 3 with its tip, and is, for example, a thermocouple. The contact temperature sensor 30 is covered with a protective tube (not shown). The drive unit 34 is a drive member that is positioned outside the furnace body 10 and drives the support bar 32, and is, for example, an actuator having a fluid cylinder, an electric motor, or the like. The drive unit 34 moves the contact temperature sensor 30 to a contact position where it contacts the metal strip 3 or a separation position (shown by a dotted line) where it separates from the metal strip 3 .

The support bar 32 connects the contact-type temperature sensor 30 and the drive rod of the drive unit 34 and is supported so as to rotate about a fulcrum 38 like a seesaw. For example, when the outer end of the support bar 32 is pushed down by the drive unit 34, the contact temperature sensor 30 moves to the separated position, and when the outer end of the support bar 32 is pushed up by the drive unit 34, the contact temperature sensor 30 moves to the contact position. The drive portion 34 side of the support bar 32 is hermetically sealed with a seal flange 36 .

The flexible tube 37 is a connecting member made of metal having flexibility and heat resistance, and has a bellows-shaped hose portion that can be freely bent and two pipe joint portions. One pipe joint portion is connected to a flange 35 provided on the furnace body 10 , and the other pipe joint portion is connected to a seal flange 36 . According to this configuration, even if the support bar 32 moves, the bellows hose portion and the other pipe joint portion move in accordance with the movement of the support bar 32, so that the atmosphere of the furnace body 10 is kept sealed.

As shown in FIG. 2 , contact-type temperature sensor 30 and drive unit 34 of temperature measurement device 7 , heating unit 12 , and welding detection unit 15 are electrically connected to control unit 20 . The control unit 20 can be configured using a computer or the like including a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory).

The control unit 20 receives the temperature of the metal strip 3 measured by the contact temperature sensor 30 of the temperature measuring device 7 . The control unit 20 controls the heat treatment temperature (eg, annealing temperature) in the heat treatment zone 9 based on the temperature of the metal strip 3 measured by the contact temperature sensor 30 . That is, the control unit 20 controls the heat treatment temperature (for example, the annealing temperature) in the heat treatment zone 9 by controlling the amount of power input to the heating unit 12 .

[Disengagement control of contact temperature sensor]
The control unit 20 controls the movement of the driving unit 34 to move the contact temperature sensor 30 to a contact position with the metal strip 3 or a separation position where the contact temperature sensor 30 is separated from the metal strip 3. to control.

Further, the control unit 20 receives the position information of the welded portion 3c detected by the welding detection unit 15. FIG. The control unit 20 controls the movement of the drive unit 34 based on the positional information of the welded portion 3c detected by the welding detection unit 15. As shown in FIG. That is, when the position of the welded portion 3c detected by the welding detector 15 approaches the contact temperature sensor 30, the controller 20 controls the contact temperature sensor 30 to move from the contact position to the separated position. This can prevent the contact temperature sensor 30 from colliding with the welded portion 3c and damaging the contact temperature sensor 30 .

The contact temperature sensor 30 is arranged around the transport roller 5 which is less susceptible to vibrations of the metal strip 3 being transported. The periphery of the conveying roller 5 that is not easily affected by the vibration of the conveyed metal strip 3 includes the portion where the conveyed metal strip 3 contacts the conveying roller 5 and the portion where the conveyed metal strip 3 contacts the conveying roller 5 . and a peripheral portion which is less susceptible to vibrations of the metal strip 3 being conveyed. Thereby, the temperature measurement of the metal strip 3 can be performed accurately and stably.

Preferably, the contact temperature sensor 30 is arranged where the metal strip 3 contacts the transport roller 5 . Thereby, the temperature measurement of the metal strip 3 can be performed more accurately and more stably.

By the way, contact marks are formed on the surface of the metal strip 3 by the contact temperature sensor 30 contacting the surface of the metal strip 3 . The traces of contact result in product defects on the metal strip 3 and must be discarded. Separately, the welded portion 3c of the metal strip 3 and the front and rear portions thereof in the conveying direction are the portion X to be discarded due to their heterogeneity. discarded. Therefore, the contact timing of the contact temperature sensor 30 with the metal strip 3 is preferably immediately before or after the welded portion 3c. In other words, when the metal strip 3 has the welded portion 3c, the preferable contact timing of the contact-type temperature sensor 30 with the metal strip 3 is the timing just before the welded portion 3c or the timing just after the welded portion 3c. . In this way, if the temperature is measured using the portion X of the metal strip 3 to be discarded, it is possible to suppress the influence of contact traces on product defects, thereby reducing product defects due to contact traces.

Based on the distance between the welding detection unit 15 and the contact temperature sensor 30 and the conveying speed of the metal strip 3, the arrival time when the welded portion 3c detected by the welding detection unit 15 reaches the position of the contact temperature sensor 30. time is calculated. Then, the temperature of the metal strip 3 is measured by moving the contact-type temperature sensor 30 to the contact position before and after the arrival time.

Since the welded portion 3c has a step, if the contact temperature sensor 30 is always in contact with the surface of the metal strip 3, the contact temperature sensor 30 will collide with the step and be damaged. comes to the contact temperature sensor 30, the contact temperature sensor 30 moves to the separated position. Therefore, "the contact timing of the contact temperature sensor 30 with the metal strip 3 is immediately before or after the welded portion 3c" does not include the timing at which the welded portion 3c comes to the contact temperature sensor 30 position.

The heat treatment is bright annealing treatment. This stabilizes the quality of the metal strip 3 with a mirror-like surface gloss.

Although specific embodiments of the present invention have been described, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

In the above-described embodiment, the position of the welded portion 3c is detected by the welding detector 15 provided on the upstream side of the furnace body 10 in the conveying direction. However, based on the length of the furnace body 10, the installation positions of the contact temperature sensor 30, the welding machine (not shown), and the welding marker forming machine (not shown), and the conveying speed of the metal strip 3, the welded portion 3c The position of is both calculable and detectable.

The heat treatment furnace 1 of the present invention can also be applied to various heat treatments such as quenching treatment, annealing treatment, normalizing treatment and tempering treatment of the metal strip 3 .

As the contact-type temperature sensor 30, it is also possible to use a resistance temperature detector that uses the property that the resistance value of a metal changes with temperature, such as a platinum resistance temperature detector.

The present invention and embodiments are summarized as follows.

The temperature measuring device 7 in the heat treatment furnace 1 according to one aspect of the present invention is
a heat treatment zone 9 for heat treatment of the conveyed metal strip 3;
a conveying roller 5 disposed in the heat treatment zone 9 and supporting the metal strip 3;
In the heat treatment furnace 1 equipped with a temperature measuring device 7 for measuring the temperature of the metal strip 3 being heat treated while being conveyed,
The temperature measuring device 7 includes a contact-type temperature sensor 30 that measures temperature by contacting the metal strip 3 and a driving unit 34 that moves the contact-type temperature sensor 30 to a contact position or a separation position with respect to the metal strip 3. and
The contact-type temperature sensor 30 is characterized in that it is arranged around the conveying roller 5, which is less susceptible to vibrations of the metal strip 3 being conveyed.

According to the above configuration, it is possible to accurately and stably measure the temperature of the metal strip 3 .

Further, in the temperature measuring device 7 in the heat treatment furnace 1 of one embodiment,
The contact temperature sensor 30 is arranged where the metal strip 3 contacts the conveying roller 5 .

According to the above embodiment, the temperature measurement of the metal strip 3 can be performed more accurately and stably.

Further, in the temperature measuring device 7 in the heat treatment furnace 1 of one embodiment,
The metal strip 3 has a leading strip 3a, a trailing strip 3b, and a weld 3c where the leading strip 3a and the trailing strip 3b are connected by welding,
The heat treatment furnace 1 further includes a welding detector 15 that detects the position of the welded portion 3c,
When the position of the welded portion 3c detected by the weld detector 15 approaches the contact temperature sensor 30, the contact temperature sensor 30 moves from the contact position to the separated position.

According to the above embodiment, it is possible to prevent the contact temperature sensor 30 from colliding with the welded portion 3c and damaging the contact temperature sensor 30 .

Further, in the temperature measuring device 7 in the heat treatment furnace 1 of one embodiment,
The contact timing of the contact temperature sensor 30 with the metal strip 3 is immediately before or after the welded portion 3c.

According to the above embodiment, it is possible to reduce product defects due to contact traces.

Further, in the temperature measuring device 7 in the heat treatment furnace 1 of one embodiment,
The heat treatment is a bright annealing treatment.

According to the above embodiment, the quality of the metal strip 3 having a mirror-like surface gloss is stabilized.

DESCRIPTION OF SYMBOLS 1 -- Heat treatment furnace 3 -- Metal strip 3a -- Leading strip 3b -- Subsequent strip 3c -- Welding part 5 -- Conveyance roller 7 -- Temperature measuring device 9 -- Heat treatment zone 10 -- Furnace body 12 -- Heating part 15 -- Welding detection part 20 -- Control part REFERENCE SIGNS LIST 30 Contact temperature sensor 32 Support bar 34 Actuator 35 Flange 36 Seal flange 37 Flexible tube 38 Fulcrum X Part to be discarded

Claims (4)

a heat treatment zone for heat treating the conveyed metal strip;
a conveying roller disposed in the heat treatment zone and supporting the metal strip;
A heat treatment furnace comprising a temperature measuring device for measuring the temperature of the metal strip being heat treated while being transported,
The temperature measuring device has a contact temperature sensor that measures temperature by contacting the metal strip, and a driving unit that moves the contact temperature sensor to a contact position or a separation position with respect to the metal strip,
The contact temperature sensor is arranged around the transport roller, which is less susceptible to vibration of the metal strip being transported ,
the metal strip has a leading strip, a trailing strip, and a weld where the leading strip and the trailing strip are connected by welding;
The heat treatment furnace further includes a welding detection unit that detects the position of the weld,
When the position of the weld detected by the welding detection unit approaches the contact temperature sensor, the contact temperature sensor moves from the contact position to the separated position . Temperature measuring device. 2. The temperature measuring device in a heat treatment furnace according to claim 1, wherein said contact-type temperature sensor is disposed where said metal strip contacts said conveying roller. 3. The temperature measuring device for a heat treatment furnace according to claim 1 , wherein the contact timing of the contact temperature sensor with respect to the metal strip is immediately before or after the welded portion. 4. The temperature measuring device for a heat treatment furnace according to claim 1 , wherein said heat treatment is bright annealing treatment.

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