JPH0819478B2 - Structure to prevent temperature difference deformation of strip support rolls - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for preventing temperature difference deformation of a strip supporting roll provided in a furnace for heat-treating continuously conveyed strips.

[0002]

2. Description of the Related Art In the conventional continuous annealing equipment for strips,
There is one in which the strip plate is continuously passed through each of a heating furnace, a soaking furnace, a primary cooling furnace, an overaging furnace, and a secondary cooling furnace, and heat treated according to a predetermined heat cycle. The strip heated in the heating furnace and kept in a predetermined high temperature state in the soaking furnace is cooled to a predetermined temperature in the next primary cooling furnace. In the primary cooling furnace, a plurality of strip plate support rolls are arranged in rows at predetermined intervals in the top and bottom of the furnace so that the strips are conveyed while meandering up and down in the furnace. Some are arranged.

The strip is carried into the primary cooling furnace at a relatively high temperature as described above, and is gradually cooled while being conveyed between the plurality of gas jet coolers arranged in the vertical and horizontal directions in the furnace. , It is carried out from the primary cooling furnace to the next furnace. By the way, the strip plate will be wrapped around the strip plate support roll of the primary cooling furnace, but the strip plate support roll becomes the same as the furnace temperature of the primary cooling furnace lower than the furnace temperature of the soaking furnace. There is. Therefore, the contact portion of the strip supporting roll nearer the inlet of the primary cooling furnace with the strip is heated by the hot strip, and the non-contact portions on both sides of the strip are at the ambient temperature in the vicinity. Therefore, if the temperature difference between the two is large, the amount of thermal deformation of the roll greatly differs in the width direction, which is the axial direction.

By the way, in order to stably convey the strip plate, the central portion of the roll is expanded by a predetermined amount from both side portions thereof. Further, in consideration of the thermal deformation amount, the initial shape of the central portion of the roll is taken into consideration. It is good to set. However, when various strips having different plate thicknesses are switched and continuously transported, the amount of thermal deformation of the strip contact portion of the roll varies depending on the transported strips. If the amount of diameter expansion is too large, a problem that a so-called heat buckle occurs on the strip plate occurs, and if the center portion of the roll becomes concave due to overcooling, the strip plate meanders and stabilizes the strip plate. There arises a problem that it cannot be transported.

In order to solve the above problem, for example, Japanese Patent Publication No. 59-43981 discloses a device for controlling a belt plate supporting roll so that it is heated by a heater, and, for example, Japanese Patent Publication No. 62-256922. It is disclosed that the gas corresponding to the temperature of the strip is blown into the roll chamber that receives the strip support roll. However, according to these structures, in order to reduce the temperature difference between the contact portion and the non-contact portion of the strip in the roll, the roll temperature is increased by using a heater, and the atmospheric gas in the furnace is passed through the heat exchanger. There is a problem in that the equipment configuration is complicated because a heater heated to a predetermined temperature is blown into the vicinity of the roll, and a heater, a heat exchanger, a blower and a temperature control device are required.

[0006]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the main object of the present invention is to provide a strip supporting roll provided in the furnace for heat treating the strip. An object of the present invention is to provide an improved temperature difference deformation preventing structure for a strip plate support roll so as to prevent large thermal deformation between the contact portion and the non-contact portion.

[0007]

According to the present invention, there is provided a first furnace for carrying out heat treatment while transporting a strip by means of a plurality of strip supporting rolls arranged in the furnace. When,
A second furnace for heat-treating the strip at a temperature different from that of the heat treatment in the first furnace, and the strip corresponding to the upstream side of conveyance of the strip in the second furnace A roll chamber provided in the second furnace so as to substantially isolate the support roll from the other parts in the furnace, and further to connect the roll chamber and the first furnace to each other. A communication passage provided between the second furnace and the second furnace for introducing the atmospheric gas in the first furnace into the roll chamber through the communication passage.
And a means for reducing the internal pressure of the strip to a pressure lower than the internal pressure of the first furnace .

[0008]

[Action] In this way, the strip support roll provided strip conveyance upstream temperature difference increases between the strip to be conveyed to the first furnace, the first furnace to the role chamber By introducing the atmospheric gas inside, the temperature inside the first furnace can be brought close to the inside temperature of the first furnace. Can be brought closer to each other, and the difference in thermal deformation between the strip contact portion and the non-contact portion of the strip support roll can be reduced.
In particular, by using the internal pressure difference between both furnaces,
The atmospheric gas in the No. 1 furnace can be introduced into the roll chamber.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 is a side sectional view schematically showing the inside of a soaking furnace 1 as a first furnace and a cooling furnace 2 as a second furnace of a continuous annealing equipment to which the present invention is applied. The strip 3 is continuously fed into the soaking furnace 1 from a heating furnace (not shown) installed on the left side of the drawing. In the soaking furnace 2, the temperature of the strip plate 3 heated in the heating furnace is maintained at a predetermined value, and in the next cooling furnace 2, the strip plate 3 is lowered to a predetermined temperature toward the subsequent overaging furnace. The strip 3 is heat treated according to a predetermined thermal cycle through a secondary cooling furnace after the overaging furnace, sent to a skin pass mill and temper-rolled, and then the defective portion is checked by an inspection and conditioning device. It is removed and wound on a tension reel.

In the lower part of the left end wall of the cooling furnace 2 in the figure, a strip plate 3 sent from the soaking furnace 1 is carried in the lower part of the soaking furnace 1 as a communication passage so as to be carried into the furnace. 1 is provided with a carry-in port 5 connected so as to communicate with each other via a conduction path 4 of the cooling furnace 2. A strip plate cooled in the furnace is conveyed to the lower end wall on the right side of the drawing. An unloading port 6 is provided for unloading 3 toward a next-stage furnace, for example, an overaging furnace. In order to convey the strip 3 in the cooling furnace 2 by vertically flipping the strip 3 alternately between the bottom wall 2a and the top plate 2b, the lower inlet port on the bottom wall 1a side is conveyed. 5
From the top to the carry-out port 6 on the side of the top plate 2b, as shown in the figure, two upper and lower strip plate support rolls 7a to 7d are arranged in a zigzag pattern at a predetermined pitch interval. Are arranged as follows. The strip 3 is wound around the strip support rolls 7a to 7d so as to meander vertically as described above, and the strip 3 is conveyed from the carry-in port 5 side toward the carry-out port 6 side.

In the cooling furnace 2, the strip plate supporting rolls 7a.about.
A plurality of gas jet coolers 8 are arranged along the surface of the strip plate 3 conveyed in the up-down direction between 7d and so as to sandwich the portion extending in the up-down direction of the strip plate 3. The strip 3 is conveyed so as to pass through between the gas jet coolers 8 and is cooled to a predetermined temperature between the carry-in port 5 and the carry-out port 6. A lower shield plate 9 is formed in the lower part of the cooling furnace 2 so as to separate the lower strip plate supporting rolls 7a and 7c from other parts in the cooling furnace 2 except for the passage of the strip plate 3. In addition to being provided, in the upper part of the cooling furnace 2,
Among the upper strip plate support rolls 7b and 7d, the strip plate support roll 7b corresponding to the upstream side of the transport of the strip plate 3 transported in the cooling furnace 2 is separated from the other parts in the cooling furnace 2, An upper shield plate 10 is provided which is formed except the passage of the strip 3. In this way, the lower shielding plate 9 forms the lower roll chamber 11 for separating the lower strip supporting rolls 7a and 7c, and the upper roll chamber 12 for separating the upper strip supporting roll 7b.

The furnaces 1 and 2 are filled with an atmospheric gas, which may be nitrogen gas, in order to prevent oxidation and decarburization of the strip 3 in a relatively high temperature state. Atmosphere gas is supplied to each gas supply pipe 13 connected to a proper place on the side wall of each furnace 1 and 2.
It is supplied into the furnace by a.13b.
Further, the upper part of the soaking furnace 1 and the upper roll chamber 12 are connected to each other via a conducting pipe 14 as a communication passage.

By the way, the strip plate 3 wound around the strip plate supporting rolls 7a to 7d has an axis line of the strip plate supporting roll 7b as shown in FIG. 2 which is a partially enlarged view as seen from the line II in FIG. It is supported at the central portion with respect to the width direction, which is the direction. Further, the strip plate supporting rolls 7a to 7a are heated by the atmospheric gas in the cooling furnace 2 cooled by the gas jet cooler 8.
d is at a low temperature to some extent. Since the initial temperature of the strip plate 3 entering the cooling furnace 2 is relatively high, for example, in the strip plate supporting roll 7b of FIG. 2, the contact portion 15 with the strip plate 3 has a relatively high temperature. Non-contact part 1 which is heated by the plate 3 but does not contact the strips 3 on both sides of the contact part 15.
6 has the same temperature as the atmosphere gas in the vicinity thereof, and when the temperature difference between both portions 15 and 16 is large, the difference in the amount of thermal deformation between the two portions becomes large. Then, when the strip plate 3 is conveyed by the strip plate support roll 7b having a large thermal deformation difference between the portions 15 and 16, the strip plate 3 as shown in the conventional example depends on the degree of deformation of the central portion of the roll 7b. Meandering or buckling of the strip 3 causes a so-called heat buckle phenomenon due to wrinkles along the transport direction.

[0015] However, while, in the present invention, the cooling furnace 2 strips supporting rolls 7a~7c the temperature difference increases between the strip 3 which is conveyed, each roll chamber 11 · 1 as described above
The inside of the cooling furnace 2 is isolated from the relatively low temperature part of the cooling furnace 2. By the way, the atmospheric gas temperature in the soaking furnace 1 is, for example, 700 to 800 ° C., and the atmospheric gas temperature in the cooling furnace 2 is, for example, 200 to 400 ° C. Further, in the present invention,
The gauge pressure in the soaking furnace 1 is, for example, 20 mmAq, and the gauge pressure in the cooling furnace 2 is, for example, 15 mmAq. Therefore, the high-temperature atmosphere gas of the soaking furnace 1 is supplied to the lower roll chamber 11 through the passage 4 due to the internal pressure difference between the two furnaces 1 and 2, and similarly, in the upper roll chamber 12,
A high-temperature atmosphere gas of the soaking pit 1 is supplied through a conduit tube 14, so that the roll chambers 11 and 12 are constantly kept at a relatively high temperature with respect to a low-temperature portion in the cooling furnace 2 .

FIG. 3 shows a roll ambient temperature (solid line in the figure) according to the positions of the strip plate supporting roll 17 and the strip plate supporting rolls 7 a to 7 d provided at the carry-out port of the soaking furnace 1 and the strip plate 3. It is a graph which shows each change with temperature (dashed-dotted line of a figure). FIG.
In the above, the portion indicated by the imaginary line of the roll ambient temperature corresponding to the strip plate support rolls 7a to 7c shows the case where the roll chambers 11 and 12 are not provided, but in this case, the strip plate support rolls are provided. A relatively large temperature difference occurs between the ambient temperature of 7a to 7c and the temperature of the strip plate 3, and a large thermal deformation difference occurs between the contact portion 15 and the non-contact portion 16 of the strip plate 3, As I did, a heat buckle will occur.

In the present invention, a high-temperature atmosphere gas is supplied into each of the roll chambers 11 and 12 for receiving the strip plate supporting rolls 7a to 7c which come into contact with the relatively high temperature portion of the strip plate 3, As shown in FIG. 3, the ambient temperature of each of the upper strip supporting rolls 7a to 7c is close to the upstream side portion of the strip 3 in the furnace where it is conveyed. For example, since the roll ambient temperature is raised so as to have a temperature difference of 250 ° C. or less, which is not a practical problem with respect to the temperature of the strip plate 3, the strip plate contact rolls 15 of the strip plate support rolls 7 a to 7 c are A large thermal deformation caused by the temperature difference between the non-contact portion 16 and the non-contact portion 16 can be prevented, and the strip 3 can be stably conveyed.

In the above embodiment, both furnaces 1 and 2 are provided adjacent to each other, but the two furnaces to which the present invention is applied may not be adjacent to each other, and the roll chamber and the other furnace It suffices that both of them be communicated with each other through the communication passage. Also,
If the temperature of the atmosphere gas is appropriate, it is not limited to introducing the atmosphere gas in the furnace in the previous step to the furnace provided with the roll chamber.
The atmosphere gas in the furnace in the subsequent process may be introduced into the roll chamber.

[0019]

As described above, according to the present invention, the strip plate supporting roll on the upstream side of the strip plate conveyance, which has a large temperature difference from the strip plate conveyed in the first furnace, is installed in the first furnace. Since the atmospheric gas is guided to the roll chamber to reduce the temperature difference with the strip plate, it is preferable and simple to use the internal pressure difference between both furnaces without providing a complicated device such as a temperature control device. With such a structure, the temperature difference between the strip contacting portion and the non-contacting portion of the strip supporting roll can be reduced, a large thermal deformation difference between the two can be prevented, and meandering and heat buckling can be prevented. The plate can be stably transported, and the quality of the strip in the heat treatment process can be improved.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a structure of a heating furnace to which the present invention is applied.

FIG. 2 is a partially enlarged view seen from a line II in FIG.

FIG. 3 is a diagram showing a change between a roll ambient temperature and a strip plate temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Soaking furnace 2 Cooling furnace 2a Bottom wall 2b Top plate 3 Strip plate 4 Conducting path 5 Carrying port 6 Carrying port 7a-7d Strip plate supporting roll 8 Gas jet cooler 9 Lower shielding plate 10 Upper shielding plate 11 Lower roll chamber 12 Upper part Roll chamber 13a / 13b Gas supply pipe 14 Conducting pipe 15 Contact part 16 Non-contact part 17 Strip support roller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Nobuo Uematsu Inventor Nobuo Uematsu 1-1-1 Emitsu, Hachimanto-ku, Kitakyushu-shi, Fukuoka Inside the Engineering Department, Nippon Steel Corporation (72) Akira Kawabata Hachiman-higashi, Kitakyushu, Kitakyushu, Fukuoka 1-1-1 Kuedamitsu, Nippon Steel Works Ltd. (72) Inventor Sadahiro Murata 46-59, Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture (59) Nihon Plant Design Co., Ltd. (72) Inventor Satoshi Komori 46-59 Nakahara, Tobata-ku, Kitakyushu, Fukuoka Prefecture Nippon Steel Plant Design Co., Ltd. (56) References: Kaikaihei 3-53545 (JP, U)

Claims (1)

[Claims] 1. A first furnace for heat-treating a strip while being conveyed by a plurality of strip-supporting rolls arranged in the furnace, and a heat treatment for the strip in the first furnace. Separates the second furnace for heat treatment at different temperatures and the strip plate supporting roll corresponding to the upstream side of the transport of the strip in the second furnace from other parts in the oven. Therefore, the first
A roll chamber provided in the second furnace, and a communication passage provided between the roll chamber and the first furnace so as to communicate the roll chamber and the first furnace with each other; and the first chamber in the roll chamber. The internal pressure of the second furnace for guiding the atmospheric gas in the furnace through the communication passage is lower than the internal pressure of the first furnace.
A structure for preventing deformation due to temperature difference of a strip plate supporting roll, characterized in that it has a breaking means.