JPH03279148A - Gas bearing device for turning direction of running strip - Google Patents

Abstract

PURPOSE:To prevent a strip from being scratched, by individually controlling the gas pressure of a gas pad section and the gas pressure of a guide nozzle so as to turn the running direction of the strip while it is held in a non-contact condition during running. CONSTITUTION:Gas is fed at a flow rate Q2 which is controlled independently from a flow rate Q2 of gas fed into a gas pad section 2, from guide nozzles 5-1, 5-2. Accordingly, a strip 1 defines a gas cushion having a thickness of d0 which is measured at the center of the strip 1, along the gas pad section 2, and then defines a running path having a gap d2 (d2>d0) between itself and the gas pad section 2, at the lower end 6 of the gas pad section 2. Accordingly, by setting this value d2 to be greater than the height d1 of a salvage wave 7, the strip 1 can be prevented from making contact with the gas pad section 2 even though the salvage wave 7 of the strip comes to the lower end 6 of the gas pad section 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] For example, in a vertical heat treatment furnace for steel strips, the steel strip is raised and then lowered, or lowered and then raised and run. The present invention relates to a gas support device for changing the direction of a traveling strip used, for example, when supporting this steel strip using a gas cushion.

[Prior Art] For example, in a vertical steel strip heat treatment furnace, a rolled steel strip that has not been subjected to shape correction is raised and then lowered and run. FIG. 5 is a diagram showing an example of the shape of the running steel strip at this time. Since the shape of the steel strip is not corrected, the running steel strip has the ear waves shown in FIG. 5(A) and the 51i!
Shape defects such as twisting shown in (B) and warping shown in FIG. 5(C) are observed.

JP-A-62-139832, JP-A-62-142
No. 728 and Japanese Unexamined Patent Publication No. 62-202031 relate to a floating support device for changing the direction of a running steel strip. The prior art describes floating support devices for redirection of steel strips that do not have geometrical defects. However, according to the findings of the present inventors, as will be described later, since the shape-corrected steel strip has shape defects as illustrated in FIG. This device has a problem in that the traveling steel strip comes into contact with the direction-changing floating support device, and the steel strip is scratched due to this contact.

[Problems to be Solved by the Invention] The present invention is a gas support device that uses gas pressure to support a strip that travels by descending after ascending or by ascending after descending, and which has undergone shape correction. It is an object of the present invention to provide a gas support device for direction change in which a band plate does not come into contact with the gas support device even if the band plate has a shape defect due to the absence of the band plate.

[Means for Solving the Problems] FIG. 1 is an explanatory diagram of an example of the gas support device of the present invention, and (
A) is a front view, and (B) is a sectional view taken in the direction of the arrow 1. In the present invention, the strip plate 1 moves upward in the direction of arrow 8 and then descends.6 The gas support device of the present invention has a convex It has a gas pad part 2 consisting of an arcuate surface.

A gas injection port 3 is arranged in the gas pad portion, and gas is injected from the gas injection port 3 onto the strip plate 1. The purpose of the gas pad section 2 is to float the strip plate 1 and keep it out of contact with the gas pad section 2. 1-1 is an example of the running path of the strip plate 1 without shape defects,
The gas pad portion 2 has such a structure that a uniform gas cushion layer with a thickness of d is formed between the strip plate 1 and the gas pad portion 2 when the strip plate with no shape defects is run. A gas injection port 3 is arranged on the surface. In the example shown in FIG. 1, the gas injection port 3 is shown as a rectangular slit-like example, but the present invention does not limit the shape of the gas injection port 3, and it is possible to run a strip plate with no shape defects. In this case, it is sufficient that the band plate 1 runs without coming into contact with the gas pad portion 2, but it is preferable to form a gas cushion layer with a uniform thickness do.

In the present invention, guide nozzles are arranged below the gas pad part, at a distance Q from the lower end of the gas pad part within 300 mm, on the inlet side and the outlet side of the strip plate, respectively, as shown in 5-1.5-2. do. The guide nozzles 5-1 and 5-2 both have a horizontal slit shape and eject gas onto the strip plate 1. 1-2 is an example of the running path of the strip plate 1 with a shape defect. In order to jet gas to the strip plate 1 from the guide nozzles 5-1 and 5-2, the running path of the strip plate 1 is formed by the guide nozzle 5-1. .Compared to 1-1, which is the running path of the steel strip 1 when 5-2 is not used, it bulges outward and the guide nozzle 5
-1. Between strip 1 and gas support device at position 5-2*
dffi is the gas 27212 formed by gas pad 2
It becomes larger than the layer thickness dl.

As already mentioned, the gas pressure in the gas pad portion 2 is such that the strip 1 does not come into contact with the gas pad portion 2 when the strip 1 having no shape defects is run. Further, as will be described later, the gas pressure of the guide nozzle is a gas pressure that is adjusted and set depending on the shape defect when the strip 1 having the shape defect is run. Therefore, the gas amount Q fed into the gas pad section 2 and the gas amount Q2 fed into the guide nozzles 5-1 and 5-2 are controlled separately to control the gas pressure in the gas pad section and the gas pressure in the guide nozzle. and separately controlled.

In Fig. 1, the gas pad section 2 and the guide nozzle 5-1.5-2
Although an example in which the gas pad portion 2 and the guide nozzle 5-1, 5-2 are formed integrally has been described, it goes without saying that the present invention includes a gas support device in which the gas pad portion 2 and the guide nozzle 5-1, 5-2 are formed separately.

[Function] The present inventors have developed a conventional gas support device which consists of only an arcuate gas pad portion 2 with a convex upper surface and does not have a guide nozzle 5-1. As a result of conducting research on changing the direction of Second
The figure is a diagram showing an example.

For example, the strip shown by the dotted line 1 in FIG. 2, having an ear wave 7 of height d□, is supported by the gas pad 2 and runs in the direction of the arrow 8. As the strip l travels, the ear wave 7 reaches the lower end 6 of the gas pad section. The average thickness between the strip 1 and the gas pad portion 2 is d. gas cushion has already been formed,
Even when the ear wave 7 reaches the lower end 6 of the gas pad, there is no significant change in the course of the strip 1. Therefore, if the height dl of the ear wave is greater than the average thickness do of the gas cushion, the ear wave is a gas cushion. Contact the bottom edge of the pad section.

As the strip travels further in the direction of the arrow 8, the ear wave 7 moves into the gas cushion, for example at 7-2 in FIG. When the ear wave 7 moves into the gas cushion of the curved portion, the ear wave of the strip becomes smaller as it is bent as shown by the dotted line in FIG.

For this reason, within the gas cushion, contact of the ear waves 7 with the gas cushion portion 2 is naturally prevented.

As already described with reference to FIG. 5, shape defects such as ear waves, twisting, and warping are observed in a steel strip that has not undergone shape correction. In addition, below the lower end 6 of the gas pad portion 2 shown in FIG. 2, the strip plate 1 is less constrained, so that disturbances such as ear waves, twisting, and warping are formed.

This disturbance directly reaches the lower end of the N gas pad section 2, and the strip plate 1 comes into contact with the lower end of the gas pad section 2. This disturbance moves into the gas cushion, but within the gas cushion at the curved part, the band plate is bent, so the ear wave 7 becomes smaller, and the band plate 1 comes into contact with the arc surface of the gas pad portion 2. prevent.

FIG. 3 is an example using the guide nozzle 5-1.5-2 of the present invention. From the guide nozzle 5-1.
Inject a large amount of gas. Therefore, the strip plate 1 forms a gas cushion having a thickness of dll at the center of the strip plate in the gas pad portion 2, and the distance between the strip plate 1 and the gas pad portion 2 is smaller than do at the lower end 6 of the gas pad portion 2. Also forms a running path of large d2. Therefore, by setting d2 to be larger than the height dl of the ear wave 7, the ear wave 7 of the band plate can be adjusted to the lower end 6 of the gas pad portion 2.
Even when the temperature reaches 1, the strip plate 1 does not come into contact with the gas pad portion 2.

As already mentioned, when the ear wave 7 moves into the gas cushion, the ear wave part 7 becomes smaller as shown by the dotted line in FIG. 3, so the layer thickness d0 of the gas cushion becomes the ear wave height dl.
Even if it is equal to or slightly smaller than , the strip plate 1 does not come into contact with the arcuate surface of the gas pad portion 2 .

In the present invention, the distance Q between the lower end 6 of the gas pad section 2 and the guide nozzle 5-1.5-2 in FIG. 3 is set to be 300 square centimeters or less. FIG. 4 is a diagram showing an example of this distance Q and the running path of the strip plate 1. If the distance Q is too large, exceeding 300 mm, as shown in FIG. , the effect of using the guide nozzle 5-1.5-2 is reduced.

The present inventors investigated steel strips with shape defects, and found that by setting the interval Q within 300 mm, an appropriate amount of gas is ejected from the guide nozzle, and the steel strip travels along the course of the gas. I was able to easily inflate it without touching the pad.

In the present invention, the guide nozzles 5-1, 5-2 are shaped like horizontal slits, and the horizontal slit-shaped nozzles are designed to eject gas onto the strip 1 with uniform pressure in the width direction of the strip 1. suitable for

The present inventors used the gas support device of the present invention shown in FIG. 1 to study the relationship between the injection amount Q2 of gas injected from a guide nozzle on one side and d2 using a strip steel plate 1. However, it has been learned that the distance d2 between the strip steel plate 1 and the gas support device is expressed by the above equation (1).

d2=4.19X(T-tb/Q,")""'X (
B /1000)''...(1) However, d2: Distance between the steel strip and the gas support device (+am) Q2: Amount of gas injected from the guide nozzle on one side (Nm'/length 1n) T: Steel strip Tension (kgf/1111") tb: Thickness of the steel strip (1111") B: Width of the steel strip (am)
Measure the ear wave height d in the figure, adjust Q2 using equation (1) so that d2 is 61 or more, and inject air from the guide nozzle 5-1.5-2.

Although the steel strip 1 was run, the steel strip 1 did not come into contact with the gas support device, and the gas support device was able to support the steel strip I changing direction without contact.

[Example] The present inventors set do to 5 to 10 mm using the gas support device of the comparative example shown in FIG. A 15 mm strip steel plate 1 was run, but the ear wave part of the strip steel plate 1 was connected to the gas support device 2.
A scratch occurred due to contact with the lower end 6 of the .

The present inventors used the gas support device of the present invention shown in FIG. 3, which has a guide nozzle, to
and from guide nozzle 5-1.5-2,
) A strip steel plate 1 having an ear wave height dl of 5 to 15 m was run by injecting air with d2=20 mm.

No scratches occurred on the strip steel plate 1 at all.

[Effects of the Invention] When the gas support device of the present invention is used to support a strip that descends after rising or a strip that rises after descending, it is possible to avoid strips that have shape defects due to lack of shape correction. Even when the belt is used, the strip is kept in contact with itself during running, and no scratches or the like occur on the strip.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of the gas support device of the present invention. FIG. 2 is an explanatory diagram of an example of the running path of the strip when a conventional gas support device is used. FIG. 3 is an explanatory diagram of an example of the running path of the strip when using the gas support device of the present invention. FIG. 4 is an explanatory diagram of an example of the position where the guide nozzle is arranged and the running path of the strip plate. FIG. 5 is a diagram showing an example of a shape defect in a steel strip that has not been subjected to shape correction. It is. 1: Band plate, 2: Gas pad part, 3: Gas injection port,
4: gas cushion, 5-1 (5-2): guide nozzle, 6: lower end of gas pad section, 7: ear wave, 8: running direction of the strip. Figure 1 (B) (A) Figure 7 (7・-2) ＼ Figure 4 Figure 4 (A) (B) (C)

Claims (1)

[Claims] A gas support device that uses gas pressure to support a strip that travels by descending after ascending or ascending after descending,
The gas support device has a gas pad portion made of a convex arc surface, and a horizontal slit-shaped guide nozzle is provided below the gas pad portion at a position within 300 mm from the lower end of the gas pad portion on the entrance and exit sides of the strip plate. A gas support device for changing the direction of a running strip, which separately controls the gas pressure of the gas pad portion and the gas pressure of the guide nozzle to change the running direction while keeping the strip in a non-contact manner.