JP2005298845A - Method of continuously bright-annealing stainless steel foil strip, and horizontal continuously bright-annealing furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably, continuously and massively bright-annealing a stainless steel foil strip in a horizontal continuously bright-annealing facility, and to provide a horizontal continuously bright-annealing furnace. <P>SOLUTION: In the method of continuously bright-annealing the stainless steel foil strip in the horizontal continuously bright-annealing furnace sequentially having a heating zone, an annealing zone and a cooling zone in series, this continuously bright-annealing method comprises cooling the foil strip on a hearth roll arranged on the heating zone and the annealing zone when the transfer for the foil strip is stopped, to break the shape of the foil strip; adjusting the tension of the foil strip in a longitudinal direction of the furnace higher than that during a transferring period; and rotating the hearth roll even while the transfer of the foil strip is stopped. The horizontal continuously bright-annealing furnace has nozzles for spraying a cooled atmospheric gas onto the foil strip existing ahead and behind the hearth roll which is arranged on the heating zone and the annealing zone. The hearth roll preferably has a major diameter in a range of 100 to 200 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for stably and continuously brightly annealing a stainless steel foil strip in a horizontal continuous bright annealing facility, and a horizontal continuous bright annealing furnace.

The present invention is directed to a considerably thin stainless steel foil strip having a thickness of about 0.015 to 0.1 mm. One such continuous bright annealing furnace for stainless steel foil strips is a horizontal continuous bright annealing furnace.
FIG. 2 shows a schematic cross-sectional view in the furnace length direction of a horizontal continuous bright annealing equipment of a general foil strip, where 1 is a foil strip, 2 is a heating strip, 3 is a slow cooling strip, 4 is a joining strip, and 5 is a cooling strip. The bands, and 8a and 8b are seal chambers. Further, a bridle roll 6a and a dancer roll 7 for applying tension to the foil strip 1 are provided in front of the bright annealing furnace, and a bridle roll 6b is provided in the rear. In the bright annealing furnace, the hearth roll 9 that supports and conveys the foil strip 1 has a large catenary depth in the seal chambers 8a and 8b, the tether strip 4, and the heating strip 2 and the slow cooling strip 3 in the foil strip 1. The minimum number is arranged at a constant pitch so as not to become.

  However, in such a horizontal continuous bright annealing furnace, it has been difficult to stably and continuously brightly anneal a stainless steel foil strip in a large amount. For example, in the invention described in Patent Document 1, the following technique is disclosed, assuming that the cause of difficulty in performing bright annealing of a stainless steel foil strip stably and continuously in large quantities is a defective shape. That is, the cause of the occurrence of the shape defect is that the compressive thermal stress acts on the foil strip in the cooling process of the foil strip at the time of annealing. As a slow cooling method in the front part of the slow cooling zone, only the radiant heat transfer from the foil strip is used without using forced cooling means, and the furnace temperature of the front part in the slow cooling zone is excessive. Set the temperature so that it does not cool. And, in order to perform the above slow cooling method, as the apparatus improvement, the same heat insulating material as the heating zone is used for the heat insulating material in the front part of the slow cooling zone, and the front part in the slow cooling zone is used. The furnace temperature control method is the same as that in the heating zone.

FIG. 3 is a schematic sectional view in the furnace length direction of the horizontal continuous bright annealing furnace described in Patent Document 1. In such an annealing furnace, since the foil strip 1 has a small rigidity in the plate width direction, support rolls 10a and 10b are arranged in the vicinity of the slow cooling start point in addition to the slow cooling means. The support rolls 10a and 10b increase the apparent rigidity of the foil strip, suppress deformation in the plate width direction, and suppress the occurrence of plate shape defects.
Also, Patent Document 2 proposes a technique for suppressing shape defects, but the annealing temperature is not higher than the recrystallization temperature and cannot be applied to the bright annealing of the stainless steel foil steel strip targeted by the present invention. .
JP-A-01-255628 JP-A-11-256247

However, even in the invention described in Patent Document 1, it is difficult to stably and continuously subject the stainless steel foil strip, which is the subject of the present invention, to bright annealing in large quantities. This factor will be described below.
1) The first factor is that a thermal stress is generated in the foil strip in the cooling process of the foil strip during bright annealing, and a shape defect is generated by this thermal stress.
2) The second factor is that when the foil strip conveyance is stopped, the foil strip adheres to the hearth roll placed in the heating zone and the slow cooling zone, and when the re-conveyance starts, the hearth roll winds up the foil strip and the foil strip breaks To do.

According to the prior art, the shape defect due to the thermal stress of 1) can be suppressed, but the foil band adhesion to the hearth roll or the support roll of 2) cannot be prevented. For example, in SUS304, the annealing temperature of the stainless steel foil strip is as high as a heating zone temperature of 1050 to 1150C. Hearth rolls or support rolls placed in the heating zone and slow cooling zone are not cooled by water so that the shape of the foil strip does not deteriorate due to temperature differences when transporting the foil strip, so the temperature is almost the same as the furnace temperature. ing. Therefore, the foil strip adheres to the hearth roll when the foil strip transport is stopped. Although the stoppage of the foil strip can be reduced by providing an accumulator, stoppage of the transport such as welding trouble cannot be avoided, and the stoppage of the foil strip always occurs.
Accordingly, the present invention advantageously solves the above problems and provides a method for stably and continuously brightly annealing a stainless steel foil strip in a horizontal continuous bright annealing facility and a horizontal continuous bright annealing furnace. It is an object to do.

The gist of the present invention for solving the above problems is as follows.
(1) In the continuous bright annealing method of a stainless steel foil strip using a horizontal continuous bright annealing furnace equipped with a heating zone, a slow cooling zone, and a cooling zone in series, it is arranged in the heating zone and the slow cooling zone when the foil strip is stopped. Stainless steel foil, which cools the foil strip on the hearth roll and breaks the foil strip shape, raises the foil strip tension in the longitudinal direction of the furnace from the time of transport, and rotates the hearth roll even after the foil strip transport is stopped Continuous bright annealing method for strips.
(2) In a horizontal continuous bright annealing furnace equipped with a heating zone, a slow cooling zone, and a cooling zone in series, a cold atmosphere gas is blown onto the foil strip before and after the hearth roll arranged in the heating zone and the slow cooling zone. A horizontal continuous bright annealing furnace for stainless steel foil strips, characterized in that a nozzle is installed.
(3) The horizontal continuous bright annealing furnace for stainless steel foil strips according to (2), wherein the outer diameter of the hearth roll is in the range of 100 to 200 mm.

  According to the present invention, in the continuous bright annealing of the stainless steel foil strip, it is possible to extremely effectively prevent the adhesion of the foil strip and the hearth roll that occurs when the foil strip is stopped. And mass production is possible.

Next, the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view in the furnace length direction showing an example of a horizontal continuous bright furnace of the stainless steel foil strip of the present invention. In the figure, 1 is a foil strip, 2 is a heating strip, 3 is a slow cooling strip, 4 is a joining strip, 5 is a cooling strip, 6a and 6b are bridle rolls, 7 is a dancer roll, 9 is a hearth roll, and 11 is A nozzle for spraying a cold atmosphere gas onto the foil strip.
The foil strip 1 is charged from the seal chamber 8a while being loaded with the required tension by the bridle rolls 6a and 6b and the dancer roll 7 arranged on the entry side and the exit side of the annealing furnace. It is discharged through the band 3, the connecting band 4, the cooling band 5, and the seal chamber 8b. Hearth roll 9a is provided in the seal chamber 8a, hearth roll 9e is provided in the seal chamber 8b, hearth roll 9d is provided in the connecting band, and hearth rolls 9b and 9c are provided in the heating zone 2 and the slow cooling zone 3, so that the catenary of the foil strip 1 is not increased. I support this. Around the hearth rolls 9b, 9c of the heating zone 2 and the slow cooling zone 3, nozzles 11 which are the greatest feature of the present invention are provided. The nozzle 11 is provided so that the cold atmosphere gas can be sprayed over the entire width of the foil strip. Then, the shutoff valve 12 is opened from the nozzle 11 during deceleration when the foil strip conveyance is stopped, and cold atmosphere gas is sprayed toward the foil strip 1 on the hearth rolls 9b and 9c. As a result, the shape of the foil strip 1 on the hearth rolls 9b and 9c can be broken, and adhesion of the hearth rolls 9b and 9c and the foil strip 1 can be prevented. In addition, the annealing furnace equipment is provided with a heater 13 for the foil strip 1, a slow cooling mechanism (not shown) and a cooling mechanism (not shown), respectively, heating zone temperature setting and adjustment, and cooling rate. Is set and adjusted. Furthermore, an in-furnace gas atmosphere adjustment mechanism (not shown) is provided as an apparatus for performing bright annealing.
Then, by using the horizontal continuous bright annealing furnace, the shutoff of the foil strip is stopped while the shutoff valve 12 is opened during deceleration, and the cold atmosphere gas is sprayed from the nozzle 11 toward the foil strip 1 on the hearth rolls 9b and 9c. By breaking the foil strip shape and increasing the tension, the contact area between the foil strip 1 and the hearth rolls 9b and 9c can be reduced, and adhesion can be prevented by continuing the rotation of the hearth rolls 9b and 9c.

In addition, when the conveyance is stopped, the foil strip in the bright annealing furnace is not a product and the yield is reduced. However, since the foil strip is originally quite thin, the yield drop is slight and does not cause a problem. Conventionally, continuous bright annealing equipment for stainless steel foil strips is often not provided with an accumulator from the viewpoint of quality, trouble prevention on the plate and reduction of equipment costs. The foil strip in the bright annealing furnace was not a product.
The hearth roll diameter is preferably as large as possible because it is used at a high temperature and without water cooling, but the contact area should be small in terms of preventing adhesion to the foil strip. As a result of various experiments based on this concept, the inventors of the present invention need a Hearth roll outer diameter of 200 mm or less for a stainless steel foil strip having a plate width of 150 to 550 mm and a plate thickness of 0.015 to 0.2 mm. It was found that 100 mm or more is sufficient.

Next, the present invention will be further described with reference to examples. Based on the above-described embodiment, the following test was performed. Using a horizontal continuous bright annealing furnace shown in FIG. 1, a foil strip having a thickness of 0.015 to 0.1 mm and a width of 420 mm as a target material is applied to the foil strip within the range of the heating zone set temperature of 1050 to 1150 ° C. Operation was performed at a load tension of 1.5 to 3.0 N / mm ² and a line speed of 10 to 50 m / min, and load bright annealing was performed while correcting the plate shape of the foil strip. As a result, adhesion of the foil strip and the hearth roll could be prevented when the foil strip conveyance was stopped, and bright annealing was stably and continuously performed in large quantities.

It is a furnace length direction schematic sectional drawing which shows one Example of the horizontal type | mold continuous bright annealing furnace of this invention. It is a schematic cross-sectional view in the furnace length direction of a general horizontal continuous bright annealing equipment. 1 is a schematic cross-sectional view in the furnace length direction of a horizontal continuous bright annealing furnace according to the invention described in Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Foil strip 2 Heating zone 3 Slow cooling zone 4 Tie zone 5 Cooling zone 6a, 6b Bridle roll 7 Dancer roll 8a, 8b Seal chamber 9, 9a, 9b, 9c, 9d, 9e Hearth roll 10a, 10b Support roll 11 Nozzle 12 Shut-off valve 13 Heater

Claims (3)

  In the continuous bright annealing method for stainless steel foil strips using a horizontal continuous bright annealing furnace equipped with a heating zone, a slow cooling zone, and a cooling zone in series, a hearth roll placed in the heating zone and the slow cooling zone when the foil strip transport is stopped A continuous stainless steel foil strip that cools the top foil strip and breaks the foil strip shape, raises the foil strip tension in the furnace longitudinal direction from the time of transport, and rotates the hearth roll even after the foil strip transport is stopped Bright annealing method.   In a horizontal continuous bright annealing furnace equipped with a heating zone, a slow cooling zone, and a cooling zone in series, a nozzle for spraying a cold atmosphere gas onto the foil strip before and after the hearth roll arranged in the heating zone and the slow cooling zone A horizontal continuous bright annealing furnace for stainless steel foil strips.   The horizontal continuous bright annealing furnace for a stainless steel foil strip according to claim 2, wherein the outer diameter of the hearth roll is in the range of 100 to 200 mm.

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