JPH05178509A - Floating feed method for steel sheet - Google Patents

Abstract

PURPOSE:To enable a steel sheet to be easily prevented from meandering by jetting a fluid toward the edge section of the sheet separately from a fluid jet from a fluid pressure pad in a device where the sheet is made afloat and carried via a noncontact fluid pressure pad. CONSTITUTION:When this method is applied to a 180 degree change-direction section for a steel sheet S, there is provided a box shape of noncontact fluid pressure pad 1 having a strip of circular arc surface 1a on top along a change- direction locus of the sheet S and a fluid pressure chamber inside. A slit 1b for jetting a fluid is drilled through the circular arc surface 1a for communication with the internal pressure chamber. Also, a side gas pad 2 is provided at both sides of the pad 1 at the crest of the surface 1a, and a slit 2a sloped inside is formed at a position faced to the pad 1 via a gap. In addition, flows from both slits 1b and 2a are caused to collide and meet with each other, thereby forming a rising flow for clamping and holding the sheet S at both sides, and preventing the meandering motion thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for floating a thin steel sheet, and more particularly to a method for passing a thin steel sheet which can be prevented from meandering.

[0002]

2. Description of the Related Art For example, in a vertical continuous annealing furnace for thin steel sheets, a method of repeating rising and lowering at a constant height is adopted as a sheet passing line for thin steel sheets, and its direction changing portion is
Instead of the contact type roll type, a box type non-contact fluid pressure pad is used which has an arcuate surface when viewed from the sheet passing line of the thin steel plate and has a slit for ejecting fluid on this arc surface. This non-contact pad is extremely effective in terms of improving the surface properties of thin steel sheets and reducing the height of processing equipment.

However, in recent years, there have been cases where the speeding up of the line aimed at improving the productivity cannot be dealt with by the conventional non-contact pad for the direction changing section. That is, due to the non-uniformity of the gap between the arc surface of the non-contact pad and the thin steel plate surface due to high-speed passage of the thin steel plate (occurs in both the width direction and the longitudinal direction of the thin steel plate), and the deviation in the width direction of the thin steel plate, Since the thin steel plate meanders, it becomes impossible to stably pass the thin steel plate, and in some cases, the thin steel plate may come into contact with the pad, which may hinder the transportation.

Conventionally, in order to solve such inconvenience,
Attempts have been made to prevent the meandering of the thin steel plate by providing a side wall parallel to the plate passing direction on the side of the arc surface of the non-contact pad (see JP-A-63-176435).

[0005]

However, it has been found that the above-mentioned method of providing the side wall has the following problems and is not very useful for the actual prevention of meandering. It is not possible to change the width of thin steel sheets. Since the side wall is fixed and its position is determined by assuming the maximum width of the steel sheet to be passed, it is not suitable for a thin thin steel sheet. The side wall alone has a weaker meandering prevention force and cannot be applied to high-speed passing as it is at present, and the steel plate may come into contact with the wall and the edge part of the steel plate may be damaged. Optimal control according to the amount of meandering is impossible. If the distance between the thin steel plate and the side wall is not small, the effect of preventing meandering cannot be expected. Therefore, as the width of the thin steel sheet becomes smaller, the anti-meandering force is lost.

The present invention solves such a problem and can be applied to a thin steel sheet of any width, and also enables fine control corresponding to the amount of meandering and enables floating of the thin steel sheet at high speed. The purpose is to provide a method of threading.

[0007]

According to the present invention for achieving the above object, a non-contact fluid pressure pad is arranged at an arbitrary position in a conveyance path of a thin steel sheet and the thin steel sheet is floated in a longitudinal direction in a longitudinal direction. In the floating plate passing method, the fluid directed toward the edge portion of the thin steel plate is jetted separately from the jet fluid from the pad at the fluid pressure pad position, and the jet flow and a thin layer from the pad and the thin steel sheet are ejected. It is characterized in that the thin steel plate is held by colliding with a jet flow from a pad flowing out in the width direction of the steel plate to form a fluid wall near the edge portion of the thin steel plate.

In the above, the non-contact fluid pressure pad is an arcuate one provided at a position for changing the passage direction of the thin steel plate, and it is preferable to apply the present invention to the thin steel plate in the direction changing portion. Further, the flow rate of the fluid jet from the outside can be adjusted according to the width of the thin steel plate or the meandering condition.

As described above, the present invention is optimally applied to the strip passing direction conversion portion where the meandering of the thin steel sheet is apt to occur, but of course the present invention is not limited to this, and the meandering is performed at the horizontal or inclined conveying portion of the thin steel sheet. It can also be used in places where there is a risk of

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The illustrated example shows a case where the present invention is applied to a 180 ° direction changing portion of a thin steel plate. As shown in FIG. 1 and FIG. 2, the arc-shaped non-contact fluid pressure pad 1 has a box-shaped arc surface 1a having a strip-shaped arc surface 1a along the direction change locus of the steel plate S on its upper surface and its side surface and bottom surface closed. It is formed in a shape and the inside is configured as a fluid pressure chamber. The arc surface 1a is provided with a slit 1b for ejecting a fluid, which communicates with an internal fluid pressure chamber, and the steel sheet is floated and held by the static pressure generated by the fluid ejected from the slit. Such a non-contact fluid pressure pad is not limited to the one shown in the drawing, and there are various structures and slit shapes, all of which are publicly known.

The fluid jetted from the slit 1b of the non-contact pad to the back surface of the steel plate S produces a static pressure between the pad surface and the steel plate surface, but a part of the fluid flows in the width direction of the steel plate and flows out from the edge portion to the outside. To do. In the present invention, another fluid is sprayed from a separate jet source toward the edge portion of the steel plate from which the fluid flows. As this separate fluid ejection means, for example, as shown in the drawing, the arc surface 1a of the non-contact pad 1 is used.
The side gas pads 2 provided on both sides of the top part of the can be considered. The gas pad 2 has a slit 2a inclined inward at a position facing the surface of the non-contact pad 1 with a gap.
As shown in FIG. 3, the fluid flow 3 ejected from the slit 2a is directed to the edge of the steel plate S, collides with and joins with the fluid flow 4 ejected from the non-contact pad 1 and flowing out from the steel plate edge, It rises in one stream. This rising collision fluid flow holds the thin steel plate S so as to sandwich it from both sides, and as a result, meandering is prevented.

Regarding the installation range of the side gas pad 2, as shown in FIGS. 2 (a), 2 (b) and 2 (c), the top portion of the non-contact pad 1 may be partially or entirely covered, or may be inserted. Although various modes are conceivable such as dividing into the side and the outlet side, any one may be selected according to the type of the target steel sheet, the processing purpose, and the like.

In the present invention, the mutual relationship between the flow rates Q _C and Q _G from the non-contact pad and the gas pad 2, the distance α between the steel plate edge and the gas pad nozzle, and the height H of the gas pad from the non-contact pad. It is not necessary to specifically define the range, but according to experiments by the present inventors, it is desirable to maintain the following relationships and ranges for the purpose of achieving the present invention. Q _G = (1/10 to 1/2) Q _C α = 15 to 200 mm H = 2 to 50 mm

Next, the function of the present invention with respect to the width variation of the steel sheet to be passed will be described with reference to FIG. The flow rate Q _C from the non-contact pad 1 is constant. FIG. 4A shows a case where the width of the steel plate S is narrow and the distance α from the gas pad 2 nozzle is large. In this case, when the gas flow rate Q _G from the gas pad is insufficient, the steel plate is likely to meander. _G should be big. Further, in the case of FIG. 4B, the steel plate width is average, and at this time, Q _G is smaller than that in FIG. Further, FIG. 4C shows the case where the steel plate width is wide and α is small. At this time, Q _G can hold the steel plate in the center even when the flow rate is almost zero.

When a gas of a proper flow rate is ejected from the gas pad nozzle, even if the steel sheet meanders due to some cause, it returns to the center position again, thereby exerting a centering effect. For example, if the steel plate approaches the right side of the drawing in a meandering state while traveling as shown in FIG. 5, the supporting force of the approaching one (illustrated by cross hatching) is the supporting force of the other side (illustrated by hatching). It becomes larger and the steel plate is lifted as shown by the broken line. Due to this lifting, the steel sheet is returned to the opposite side, so that the meandering is corrected.

FIG. 6 shows the distance α between the steel plate and the two nozzles of the gas pad.
Is a graph showing the relationship between the total flow rate Q and
It can be seen that it is desirable to maintain the mutual relation of (Q _G / Q _C ) within the appropriate range indicated by the diagonal lines in order to keep the steel sheet stable.

[0017]

As described above, according to the floating plate passing method of the present invention, since the gas flow rate of the side gas pad can be controlled, it is possible to pass a steel plate of any width in a stable state. , Even if the steel plate is meandering, it has a centering function to correct it. Therefore, it is very effective if the present invention is applied at the position of the direction change portion of the steel plate where the meandering becomes a problem.

When the present invention as described above is applied to various treatments of a steel sheet, the line speed can be increased and the productivity can be greatly improved, and its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a sectional view showing a specific example of an apparatus for carrying out a plate passing method according to the present invention.

2 (a) is a side view of FIG. 1, (b) and (c) are (a).
The side view which shows another aspect of FIG.

FIG. 3 is a partial enlarged view for explaining the operation of the present invention.

4 (a), (b), and (c) are explanatory views of the function of the present invention with respect to variations in the width of the steel sheet to be passed.

FIG. 5 is an explanatory view showing a correction function when the steel plate meanders in the method of the present invention.

FIG. 6 is a graph showing the relationship between the distance α between the steel plate and the gas pad nozzle and the total flow rate Q.

[Explanation of symbols]

 1 Non-contact fluid pressure pad 1a Band-shaped arc surface 1b Non-contact fluid pressure pad slit 2 Side gas pad 2a Side gas pad slit 3 Fluid flow from non-contact fluid pressure pad slit 4 Fluid flow from side gas pad slit S steel plate

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Noriyuki Hanada 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Corporate Technology Development Division

Claims (3)

[Claims] 1. A floating plate passing method in which a non-contact fluid pressure pad is arranged at an arbitrary position in a transport path of a thin steel sheet and the thin steel sheet is transported in a longitudinal direction in a floating state. Separately from the fluid ejected from the pad, a fluid directed toward the edge portion of the thin steel plate is jetted, and the jet flow and the jet flow from the pad flowing out in the widthwise direction of the thin steel sheet from between the pad and the thin steel sheet are collided with each other, A method of levitating a thin steel sheet, characterized in that a fluid wall is formed near the edge of the thin steel sheet to hold the thin steel sheet. 2. The plate passing method according to claim 1, wherein the non-contact fluid pressure pad has an arcuate shape provided at a position for changing the plate passing direction of the thin steel plate. 3. The plate passing method according to claim 1, wherein the flow rate of the fluid jet from the outside is adjusted according to the width of the thin steel plate or the meandering condition.