JPS63143227A - Floating and supporting device for changing direction of traveling steel strip - Google Patents

Abstract

PURPOSE:To prevent contact of a steel strip and floater and generation of flaws on the steel strip by providing the floater utilizing the gas cushion type nozzles which change the traveling direction of the steel strip while floating the steel strip by gas so that a hovercraft effect is obtd. CONSTITUTION:The traveling steel strip 1 is supported by the gaseous pressure of a floating and supporting device for changing direction, by which the direction thereof is changed. The gas jet nozzles which extend in the transverse direction of the strip and face each other are provided neat to the start and end points of the above-mentioned direction change. Plural columns of ribs (b) are projected in the transverse direction of the pressure receiving surface on the arc connecting these nozzles. >=1 column of the gas nozzles 4 are provided on the circumference arrayed in the transverse direction on the pressure receiving surface. The gas nozzles 4 and the above-mentioned ribs (b) are paralleled, by which the pressure is generated between the steel strip 1 and the pressure receiving surface 3 and the weight or tension of the steel strip 1 is applied to the steel strip.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is for tin plate blanks having a thickness of α1 to α6 or 04
This relates to a floating support device that non-contact supports a running steel strip in a continuous annealing furnace for cold-rolled steel sheets with a thickness of ~2.0 m.
It can also be applied to continuous annealing furnaces for copper and aluminum, paper processing equipment, etc.

[Conventional technology]

An overview of the conventional strip continuous annealing furnace for cold-rolled steel sheets is given in Part 7.
As shown in the figure. A strip 1 of cold-rolled steel sheet is supplied to a continuous annealing furnace through a louver, a cleaner 7, a dryer, etc. (not shown).

The strip 1 is filled with a reducing gas to prevent surface oxidation and is passed through the annealing furnace for about 20 m between the hearth rolls 10 arranged above and below the metal furnace at 200 to 500 rn/m.
It travels up and down at a speed of 1.5 in. and undergoes a predetermined heat treatment. Looking at this in terms of equipment, strip 1 is
First, the steel is heated in a heating belt 11 to about 650 to 900°C, although it varies depending on the steel type.

After that, it is soaked for several tens of seconds in soaking zone B, and then cooled at a cooling rate of 3 to 200 degrees Celsius per second in rapid cooling zone C.
It is rapidly cooled to about 50 to 400°C. Next, this 350~
After cooling at 400°C for about 2 minutes, it is subjected to an effect treatment and finally cooled to room temperature in a rapid cooling zone (■).

By the way, this hearth roll 10 has a diameter of 800 to 11
00Os, thickness 10~20m, length 2000~250
It is made of cast steel and has a cylindrical shell of 0.0 mm, and is driven by being directly connected to an electric motor whose rotation speed is controlled by frequency and voltage change methods. It is used in annealing furnaces.

[Mistakes to be Solved by the Invention] Although this is not a major problem at present in an annealing furnace equipped with a large number of hearth rolls as described above,
1000 to 2000 rn/win) 17 As the speed of the tong increases, it becomes necessary to synchronize the running speed of the plate with the circumferential speed of the hearth roll with very strict precision. Since the inertia of the rolls and the inertia of the motor are large, precise control is almost impossible. As a result, the slippage between the strip and the roll increases, causing scratches on the surface of the strip, and changing the length of the strip between the upper and lower rolls, causing vibration. In addition, in a continuous annealing furnace, in the high temperature range of 800°C or higher, the strip is exposed to push scratches (roll pick-up and There is a problem called (named), and countermeasures are also required. Further cooled in a heated roll with radiant tubes. (b) When the IJ1 comes into contact with the center, problems such as poor tracking occur due to thermal contraction of the center.

〔the purpose〕

The present invention provides a running steel strip that solves the above-mentioned problems by using a floater using a gas cushion nozzle that can change the running of the strip while levitating it with gas for the hearth roll in a continuous annealing furnace. It is an object of the present invention to provide a floating support device for direction change.

[Means for Solving the Problems] That is, the present invention is a floating support device that changes direction by supporting a traveling steel strip by gas pressure, and extends in the width direction of the strip near the start and end points of direction change. have gas jet nozzles facing each other, and have multiple rows of lips protruding along the width direction of the plate from the pressure receiving surface on the circular arc connecting the nozzles, and are lined up in the width direction of the plate on the pressure receiving surface. A running steel characterized by having at least one row of gas nozzles on the circumference of an ellipse, or having at least one row of gas nozzles on the circumference and ribs extending in the width direction of the plate between the rows. This is a floating support device for changing the direction of the belt.

A method of using a floater using a cushion type nozzle in place of the hearth roll, which is the basis of the present invention (Japanese Patent Application No. 6L-
40376) will be explained based on FIGS. 5 and 6.

FIG. 5 is a diagram showing a continuous annealing furnace in which a 70-meter according to the present invention is installed on the upper hearth roll of the furnace, and FIG. 6 is a sectional view taken along the line A of the furnace.

In Figures 5 and 6, 1 is S) IJ knob, 2
3 is a floater main body, 3 is a pressure receiving surface of the floater, 4 is a gas nozzle, 21 is a gas supply pipe, 22 is a gas discharge pipe, 26 is a blower, 24 is a support, 25 is a furnace shell, and 26 is a heat insulating material.

Gas pressurized by the blower 23 is ejected from the gas nozzle 4 of the main body 2. This ejected gas is sucked through the exhaust pipe 22 and returned to the blower 23. At this time, as shown in FIG. 6, the gas nozzles 4 each face upward in the region a in FIG. 6, and receive force from the nozzles to generate static pressure. This generated static pressure supports the tension acting on the strip 1 and the weight of the strip 1. In the case of gas juts colliding at an angle θ,
The pressure generated in this region a can be calculated using the following equation (1).

P: Pressure V: Nozzle flow rate: Constant h: Flying height T: Specific weight of gas δ: Nozzle width t: Acceleration of gravity θ: Nozzle angle This pressure is generated over half the circumference. The sum of the vertical components of this pressure is balanced by twice the sum of the tension on the plate and its own weight.

A gas jut nozzle having such a structure is called a gas cushion nozzle, and has an effect similar to that of a so-called hovercraft. That is, as can be seen from the equation θ), as the flying height h decreases, the pressure P increases. In other words, this means that the strip 1 is pushed back when it approaches the 70-piece main body 2, and has a very effective effect in preventing contact between the strip 1 and the 70-piece main body 2.

(Example 1) Example 1 is shown in FIGS. 1 and 2. As shown in FIG. 7, the upper nozzle 10 of a continuous annealing furnace is replaced with a floating support device for changing the direction of the present invention. −■It is a cross section.

In Figures 1 and 2, 1 is a strip, 2 is a 7
0 is the floater body, 3 is the pressure receiving surface of the floater, 4 is the gas nozzle,
21 is a gas supply pipe, 22 is a gas discharge pipe, 23 is a float, 24 is a support, 25 is a furnace shell, and 26 is a heat insulating material. As described in FIGS. 5 and 6, a, h, and δ are the pressure generating portion, flying height, and nozzle width, respectively. C1c is a rib provided on the pressure-receiving surface parallel to the traveling direction of the plate and parallel to the plate width direction, and the tip thereof is parallel to the pressure-receiving surface. These are small holes lined up in the width direction of the plate that share the gas header with the gas nozzle 4 at the top of the pressure receiving surface. This need not be a small hole, but may be a slit. In Fig. 2, pressure is generated between the strip 1 and the pressure receiving surface 5 due to the jet flow from the gas nozzle 4, and this pressure supports the strip's own weight and tension, but most of the jet flow from the gas nozzle 4 The flow is reversed along the plate as shown in the figure, but on the floater, gas leaks from the high-pressure part supporting the plate to the atmosphere through the plate edge. It is desirable that the leakage amount of this gas is small, and in order to stop this gas leakage, ribs 6 are provided in the present invention.
Even so, if the area of the opening between the plate edge and the pressure receiving surface of the 70 is extremely large, such as when the flying height is high, the inflow gas from the gas nozzle 4 may leak before reaching the top of the floater. Gas may not reach the top of the floater. In other words, this means that the pressure cannot be maintained and the strip can float, which is dangerous. For this reason, the pressure is maintained by blowing out gas from a small hole provided near the top.

(Example 2) Other embodiments of the invention are shown in FIGS. 3 and 4.

FIG. 4 is a cross section taken along the line ■-■ in FIG. Most of the symbols are the same as those in Figures 1 and 2, but a rib b extending in the circumferential direction and a rib d extending in the perpendicular direction (width direction) are provided between the small holes C. The pressure maintained by the jet flow prevents the rib b from slipping in the direction of the rib b.

In the above embodiments, the case where the strip moves from below and returns downwards is shown, but the present invention is not limited to this, and may conversely be carried out from above and return upwards, or horizontally. It can also be applied to horizontal shapes that come and return to horizontal.

〔Effect of the invention〕

The effects achieved by the present invention are enumerated as follows.

(1) Since there is no slippage between the strip and the roll, the strip will not be scratched.

(2) Since the length of the strip between the rolls is always constant, there is no slack in the strip between the rolls, and the running is stable.

(3) The stripping speed can be rapidly accelerated or decelerated without delay, and schedule-free operation is possible, increasing the economic efficiency of the furnace.

(4) Tracking defects due to thermal crown are eliminated.

(5) Since there is no slippage between the strip and the roll, there is no running resistance due to mating, so the tension can be lowered. Therefore, the priddle equipment becomes inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a schematic view showing an embodiment of a floating support device for changing the direction of a traveling steel strip according to the present invention, FIG. 2 is a sectional view taken along the line I-1 in FIG. 1, and FIG. A schematic diagram showing an embodiment, FIG. 4 is a sectional view taken along the line ■-■ in FIG. 3, and FIG. 5 is a diagram for explaining a conventional technique in which a floater is provided in place of the upper roll of the furnace in a continuous annealing furnace. Figure 6 is a sectional view taken along line A-A in Figure 5;
FIG. 7 is an overall layout diagram of a conventional continuous annealing furnace. Sub-agents 1) Meiji agent Ryo Hagiwara - Multiple agents Atsuo Anzai Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] A floating support device that changes direction by supporting a running steel strip using gas pressure, and has gas jet nozzles that extend in the width direction of the strip near the start and end points of direction change, and whose directions are opposite to each other. In a product with multiple rows of ribs extending in the width direction of the plate protruding from the pressure receiving surface on the arc connecting the
At least one or more rows of gas nozzles are provided on the circumference of the pressure-receiving surface lined up in the width direction of the plate, or at least one or more rows of gas nozzles on the circumference and ribs extending in the width direction of the plate are arranged in parallel between the rows. A floating support device for changing the direction of a traveling steel strip.