JPH04293734A - Structure for preventing deformation due to temperature difference in supporting roll for strip - Google Patents

Abstract

PURPOSE:To prevent unfavorable-influence due to a thermal deformation in strip carrying by preventing large temp. difference between contact part and non-contact part in a strip supporting roll. CONSTITUTION:A roll chamber 10 separating the supporting rolls 6a-6b for strip at carrying-in hole 3 side having large temp. difference between the inside part of a heating furnace 1 and the strip 2 from the other part in the furnace is provided. New atmospheric gas is supplied in the roll chamber 10 from a gas supplying pipe 11a and the temp. in the roll chamber 10 is always lowered. Intrusion of the high temp. furnace gas into the roll chamber 10 is prevented and the supporting rolls 6a-6d for strip can suitable be cooled, and the temp. difference between the contact parts and the non-contact parts in respective supporting rolls 6a-6d for strip with the strip 2 is reduced.

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 deformation due to temperature differences in a strip support roll provided in a furnace for heat treating continuously conveyed strips.

0002

[Prior Art] In conventional continuous annealing equipment for strips,
There is a method in which the strip is continuously passed through a heating furnace, a soaking furnace, a primary cooling furnace, an overaging furnace, and a secondary cooling furnace, and is heat-treated according to a predetermined heat cycle. In order to heat the continuously conveyed strips to a predetermined temperature, the heating furnace used in the above equipment has a top part inside the furnace that is designed to convey the strips in a meandering manner up and down within the furnace. There is one in which a plurality of strip support rolls are arranged in rows at predetermined intervals from the bottom. The strip is carried into the heating furnace at a relatively low temperature, and is gradually heated while being conveyed between a plurality of radiant tubes arranged vertically and horizontally in the furnace, and then transferred from the heating furnace to the next furnace. It will be transported out. The temperature inside the heating furnace is extremely higher than the temperature outside the furnace, and the temperature of the strip support rolls is also the same as the temperature inside the furnace. In the strip support roll that is closer to a certain delivery entrance, the contact area with the strip is cooled by the unheated strip, and the non-contact areas on both sides of the roll are at the same ambient temperature in the vicinity. Therefore, if the temperature difference between the two is large, the amount of thermal deformation of the roll will vary greatly in the width direction, which is the axial direction.

By the way, in order to transport the strip stably, the center part of the roll is made larger in diameter by a predetermined amount than the side parts on both sides. It is better to make it larger. However, when heat-treating various strips such as those with different thicknesses, the amount of cooling varies depending on the strip being conveyed, so the amount of deformation of the strip contact area at the center of the roll may vary. Become. If the above-mentioned diameter expansion amount is too large, there will be a problem that so-called heat buckling will occur in the strip, and if the center of the roll becomes concave due to excessive cooling, the strip will meander and become unstable. A problem arises in that transportation becomes impossible.

In order to solve the above problem, for example, Japanese Patent Laid-Open No. 62-256922 discloses a system in which a gas corresponding to the temperature of the strip is blown into a roll chamber that receives the strip support roll. has been done. However, according to this structure, in order to reduce the temperature difference between the contact area and the non-contact area of the strip in the roll, the atmospheric gas in the furnace is blown into the vicinity of the roll through a heat exchanger.
There was a problem in that the equipment configuration was complicated because it required a heat exchanger, an air blower, a temperature control device, etc.

[0005]

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

[0006]

[Means for Solving the Problems] According to the present invention, the present invention provides a furnace for heat treating a strip while being conveyed by a plurality of strip support rolls disposed in the furnace. , a roll chamber that generally isolates the strip support roll corresponding to the upstream side of conveyance of the strip in the furnace from other parts of the furnace, and at least a new atmospheric gas to be supplied into the furnace. This is achieved by providing a structure for preventing temperature difference deformation of a strip supporting roll, which is characterized by having a means for feeding a portion of the roll into the roll chamber.

[0007]

[Function] With this method, it is possible to cool the strip supporting roll on the upstream side of strip transport, which has a large temperature difference with the strip, by intensively introducing, for example, a new atmospheric gas at room temperature into the roll chamber. As a result, the temperature of the strip support roll in the roll chamber can be brought close to the temperature of the strip conveyed into the furnace, and the temperature between the strip contact portion and the non-contact portion of the strip support roll can be brought close to the temperature of the strip conveyed into the furnace. The difference in thermal deformation can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below based on specific embodiments shown in the accompanying drawings.

FIG. 1 is a side sectional view schematically showing the inside of a heating furnace 1 of continuous annealing equipment to which the present invention is applied. A strip 2 is continuously supplied from a payoff reel (not shown) installed at the line entrance on the left side of the figure, and is subjected to cleaning and other treatments before being sent into a heating furnace 1 for heat treatment. . After the heating furnace 1, the strip 2 is heat-treated according to a predetermined heat cycle through a soaking furnace, a primary cooling furnace, an overaging furnace, and a secondary cooling furnace, and then sent to a skin pass mill where it is temper rolled. After that, defective parts are removed by an inspection and finishing device, and the material is wound onto a tension reel.

At the bottom of the left end wall of the heating furnace 1 in the figure, there is an inlet 3 for carrying the strip plate 2 being sent into the furnace.
A discharge port 4 is provided at the lower part of the end wall on the right side of the drawing for carrying out the heat-treated strip 2 while being transported in the furnace to the furnace for the next process. Inside the heating furnace 1, the strip plates 2 are conveyed in a meandering manner while being alternately reversed in the vertical direction between the bottom wall 1a and the top plate 1b.
Between the lower loading port 3 on the bottom wall 1a side and the loading port 4, ten lower band support rolls 5a to 5j are arranged at equal pitch intervals, and on the top plate 1b side Between a certain upper loading port 3 side and a loading port 4 side, 9 strips are arranged in a staggered manner with respect to the lower band support rolls 5a to 5j.
Upper band support rolls 6a to 6i are arranged at equal pitches. These rolls 5a to 5j and 6a to 6i
Then, the strips 2 are wrapped around them in order from the entrance 4 side in a meandering manner up and down as described above, and the strips 2 are wrapped around the entrance 3.
The strip plate 2 is conveyed from the side toward the outlet 4 side.

Inside the heating furnace 1, each strip supporting roll 5a to
A plurality of radiant tubes 7 are arranged along the surface of the strip plate 2 that is conveyed in the vertical direction between 5j and 6a to 6i. The strip plate 2 is conveyed so as to pass between adjacent radiant tubes 7, and is heated to a predetermined temperature while reaching from the carry-in port 3 to the carry-out port 4. In addition, each roll 5a to 5
A shielding plate 8 is provided between each of the adjacent radiant tubes 7 to prevent them from directly receiving heat. In addition, in order to isolate the fourth upper strip supporting rolls 6a to 6d from the loading port 3 side from other parts of the furnace, gaps between the corresponding shielding plates 8 are removed, excluding the passage of the strip 2. A plurality of partition plates 9 are provided for filling. Among these partition plates 9, the one between the fourth and fifth upper band support rolls 6d and 6e is the top plate 1b.
It is formed so as to extend to the top plate 1b so as to shield the space between the two. In this way, the shield plate 8 and the partition plate 9 form a roll chamber 10 that isolates the upper strip support rolls 6a to 6d from other parts of the furnace.

[0012] Also, inside the heating furnace 1, there is a strip plate 2 to be heated.
It is filled with an atmospheric gas, which may be nitrogen gas, to prevent oxidation, decarburization, etc. This atmospheric gas is supplied to, for example, four gas supply pipes 1 connected to appropriate positions on the side wall of the heating furnace 1.
1a to 11d to be supplied into the furnace. Note that one gas supply pipe 11a is connected to the roll chamber 10. Upstream of these gas supply pipes 11a to 11d,
They are combined into one line and connected to a new atmosphere gas supply facility (not shown). In addition, each gas supply pipe 11a to 11
d are provided with valves 12a to 12d, respectively, so that the amount of gas supplied into the heating furnace 1 from each gas supply pipe 11a to 11d can be adjusted.

By the way, each of the strip support rolls 5a to 5j.
The strip 2 wound around the strips 6a to 6i is centered in the width direction, which is the axial direction of the strip support roll 6a, as shown in FIG. supported by the department. Further, due to the atmospheric gas in the heating furnace 1 heated by the radiant tube 7, the upper band support rolls 6a to 6i on the top plate 1b side, where heat accumulates, tend to reach a certain degree of high temperature. Since the initial temperature of the strip 2 entering the furnace is relatively low, for example, as shown by the strip support roll 6a in FIG. 2, the contact portion 13 with the strip 2 is relatively low temperature. The non-contact parts 14 that do not contact the strip plate 2 on both sides of the contact part 13 are at the same temperature as the surrounding atmospheric gas, and if the temperature difference between the two parts 13 and 14 is large, The difference in the amount of thermal deformation between the two increases. When the strip plate 2 is conveyed by the strip support roll 6a in which a large difference in thermal deformation has occurred between both parts 13 and 14, the strip plate 2 is The so-called heat buckling phenomenon occurs in which the belt plate 2 meanders, buckling occurs in the belt plate 2, and wrinkles form along the conveyance direction.

However, in the present invention, the upper strip supporting rolls 6a to 6 have a large temperature difference with the strip 2 being carried in.
d, the heating furnace 1 is equipped with the roll chamber 10 as described above.
The roll chamber 10 is isolated from the relatively high-temperature parts of the furnace, and a part of the new atmospheric gas at a low temperature, for example, close to room temperature, is supplied from the gas supply pipe 11a to the roll chamber 10, and other parts of the furnace are In contrast, the inside of the roll chamber 10 is always kept at a relatively low temperature. By opening the valve 12a provided on the gas supply pipe 11a wider than the valves 12b to 12d of the other gas supply pipes 11b to 11d, it is possible to intensively supply the new atmosphere gas into the roll chamber 10. Since the high-temperature atmospheric gas in the furnace does not enter the roll chamber 10, the temperature of the atmospheric gas in the roll chamber 10 can be kept low.

FIG. 3 shows each upper strip support roll 6a to 6i.
It is a graph showing each change in the roll ambient temperature (solid line in the figure) and the temperature of the strip plate 2 (dotted chain line in the figure) according to the position of the roll. In FIG. 3, the portions indicated by imaginary lines of the roll ambient temperature corresponding to the upper strip support rolls 6a to 6d show the case where the roll chamber 10 is not provided. A relatively large temperature difference occurs between the ambient temperature of the rolls 6a to 6d and the temperature of the strip 2, and a large difference in thermal deformation occurs between the strip contact portion 13 and the non-contact portion 14.
The above-mentioned problem occurs.

In the present invention, the roll chamber 10 is provided in a place where the temperature difference is large, and new atmospheric gas is intensively supplied into the roll chamber 10 to bring the temperature of the atmospheric gas in the roll chamber 10 to a low temperature state. As shown in FIG. 3, the ambient temperature of each of the upper strip support rolls 6a to 6d approaches the low-temperature portion of the strip 2 on the upstream side of the conveyance in the furnace. For example, the temperature of the strip plate 2 does not pose a practical problem25.
Since the roll ambient temperature is lowered so that the temperature difference is within 0°C, the large temperature difference caused by the temperature difference between the strip contact portion 13 and the non-contact portion 14 of each upper strip support roll 6a to 6d. Heat deformation can be prevented, and stable conveyance of the strip 2 becomes possible.

[0017]

[Effects of the Invention] According to the present invention, the strip support roll on the upstream side of the strip transport where the temperature difference between the roll and the strip transported in the furnace is large is intensively cooled by the new atmospheric gas. The temperature difference between the strip contact area and the non-contact area of the strip support roll can be reduced by using a simple structure without installing a complicated device such as a temperature control device. It is possible to reduce the difference in thermal deformation between the two, prevent meandering and heat buckling, and transport the strip stably, improving quality in the heat treatment process of the strip. obtain.

[Brief explanation of drawings]

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

FIG. 2 is a partially enlarged view taken along the arrow II line in FIG. 1;

FIG. 3 is a diagram showing changes in roll ambient temperature and strip temperature.

[Explanation of symbols]

1 Heating furnace 1a Bottom wall 1b Top plate 2　Strip plate 3 Loading entrance 4 Exit 5a-5j Lower band support roll 6a-6i Upper band support roll 7 Radiant tube 8 Shielding plate 9 Partition plate 10 Roll room 11a-11d Gas supply pipe 12a-12d Valve

Claims (1)

[Claims] 1. A furnace for heat-treating a strip while being conveyed by a plurality of strip supporting rolls disposed in the furnace, which corresponds to the upstream side of the conveyance of the strip in the furnace. A roll chamber that generally isolates the strip support roll from other parts of the furnace, and means for supplying at least a portion of the new atmosphere gas to be supplied into the furnace into the roll chamber. A structure to prevent temperature difference deformation of the strip support roll.