JPH0448033A - Vertical type bright annealing furnace and annealing method for stainless steel band plate - Google Patents

Abstract

PURPOSE:To allow a steel band plate to travel without contact and without meandering in the annealing furnace by using gas supporting devices having gas pad surfaces, V-shaped slits, sealing plates and guide nozzles on projecting arc surfaces for switching the direction of the steel band plate. CONSTITUTION:The gas supporting devices 26, 27 for switching the direction are disposed in a heating zone 20 and cooling zone 21 of the vertical type bright annealing furnace. The gas supporting devices 26, 27 have the projecting arc surfaces and have the gas pad surfaces 2 in the peak parts of the projections. The devices have a pair of the V-shaped slits 3, 3' disposed on the outer side at both ends of the width of the stainless steel strip 1 and a pair of the sealing plates 4, 4' disposed in parallel with the traveling direction of the band plate 1 on the outer side of the slits 3, 3' and approximately perpendicularly to the arc surfaces. Further, the devices has the horizontal slit-shaped guide nozzles 5, 5' on the gas pad surfaces 2 on the inlet side and outlet side of the band plate 1. The stainless steel band plate 1 is annealed without contact while the meandering is prevented in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vertical bright annealing furnace for stainless steel strips, which is used in producing bright annealed stainless steel.

[Prior Art] Bright annealed stainless steel sheets are characterized by having extremely few surface defects because they are used, for example, as decorative members for reflective mirrors, automobile moldings, etc., without subsequent surface polishing. Therefore, a bright annealing furnace for stainless steel strips is used, which is particularly designed to prevent surface flaws from occurring.

FIG. 8(A) is an example of a normal vertical bright annealing furnace for stainless steel strips (hereinafter abbreviated as strips).

20 is a heating zone and 21 is a cooling zone. The strip 1 is supported by an upper roll 22 and hangs down. Therefore, the strip 1 is kept in contact with itself while traveling through the heating zone 20 and the cooling zone 21. The strip 1 that has left the cooling zone 21 comes into contact with the upper roll 22, but the strip that has left the cooling zone 21 has a hard surface because it has been sufficiently cooled, and even if it comes into contact with the upper roll 22, it will not cause scratches or the like. is difficult to occur. However, Fig. 8 (A)
The bright annealing furnace has the problem that the heating zone 20 and the cooling zone 21 are arranged vertically in the direction in which the strip 1 rises, so the bright annealing furnace becomes taller and the equipment becomes larger. .

For example, in FIG. 8(B), a roll 23 for changing the running direction of the strip 1 is arranged in the heating zone 20, and a cooling zone 2
When the heating zone 20 and the cooling zone 21 are arranged side by side by disposing the roll 25 inside the annealing furnace 1, a bright annealing furnace with a low height is obtained. However, in FIG. 8(B), the rolls 23 and 24 are in a high temperature state or not sufficiently cooled.
and 25.

That is, a strip that has not been cooled sufficiently has a soft surface, and when it comes into contact with the rolls 23, 24, and 25, there is a problem in that this contact causes scratches and the like on the surface of the strip 1.

JP-A-62-139832 and JP-A-62-202031 disclose a floating support device for changing the direction of a running steel strip, which can be used in a continuous annealing furnace for steel plates. Therefore, it is conceivable to use this floating support device for direction change in place of the rolls 23, 24, and 25 shown in FIG. 8(B). Since the floating support device for changing the direction of the crab does not have a means to prevent the strip 1 from meandering, if this device is used, the moving strip 1 may meander and become detached from the floating support device for changing the direction. , there is a problem that threading becomes difficult.

JP-A No. 63-176435 is not a device specified for direction change in an annealing furnace, but is a strip flotation device for conveying the strip in a non-contact manner. Although details are not described in this publication, as shown in FIGS. 7(A) and 7(B), side plates 40, 40' are provided to prevent the strip plate 1 from meandering. However, as mentioned later, the side plate 40.40
If ' is provided, there is a problem that the strip 1 comes into contact with the side plate, making it difficult for the strip to run, or that the side plates 40, 40' cause surface flaws on the strip.

JP-A-60-138019 is not a device for changing direction, but relates to a floater nozzle for conveying strips in a non-contact manner. In this method, a figure 7-shaped slit is provided in the width direction in order to float the "l" end of the strip. As shown in Figure 7 (C), the V-shaped slit in the crab is a slit with the bottom facing toward the center of the width of the strip, so it can be used to change the running direction of the strip. , as will be described later, it is not possible to prevent the strip from meandering.

In addition, although it is not mentioned in the prior art, 1. For example, in a vertical heat treatment furnace for steel strips, the rolled steel strips are passed through a steel strip that has not been straightened in shape. Conventional gas support devices for changing direction have a problem in that the gas support device comes into contact with the ear waves and mid-stretches, causing flaws.

[Problem M to be solved by the invention] The present invention is a bright annealing furnace for stainless steel strips that is lower in height than conventional ones, and that allows the stainless steel strips to run without contact so as not to generate surface flaws. The object of the present invention is to provide a vertical bright annealing furnace for stainless steel strips and an annealing method thereof, in which the running path of the stainless steel strips does not meander.

[Means and effects for solving am] The present invention is a vertical bright annealing method for stainless steel strips in which a high temperature stainless steel strip is heat-treated by changing the running direction in a non-contact manner using a gas support device. It is a furnace.

First, the gas support device of the present invention will be explained.

FIG. 1 shows an example of the gas support device of the present invention, in which (A) is a perspective explanatory view and (B) is a developed view of the gas pad surface. This is a gas support device for changing the traveling direction of the strip l that travels downward. The gas support device w7 is a semicylindrical gas box having a convex arcuate gas pad surface 2, and high-pressure gas is introduced into the gas support device 7 from, for example, a gas introduction hole 8 provided at the bottom, and the gas pad surface 2 The floating gas is blown onto the strip l from the levitation gas ejection slit 9 provided in the. The strip plate 1 is exposed to the gas pad surface 2 via the gas pad by the gas jetted out from the floating gas jetting slit 9.
is supported by.

The gas pad surface 2 of the present invention is provided with a V-shaped slit 3.3' at the top of the convexity. The V-shaped slits 3, 3' are ■Bottom 3-
1.3'-1 are arranged outside both ends of the width of the strip 1, and the bottom 3-1.3'-1 is formed facing outward of the width of the strip 1. ■The distance from the bottom 3-1 (3'-1) to the edge of the width of the strip plate l is not particularly limited, but the strip should be approximately 1/3 to 1/2 of the length of each side of the V-shape. It is preferable to provide it so as to deviate from the width direction of the plate l.

In FIG. 1, the floating gas jetting slit 9 is shown as an example of a rectangular shaped slit, but the shape and arrangement of the floating gas jetting slit 9 may be other known shapes.

A pair of seal plates 4, 4' are further provided on the top of the gas pad surface 2 of the present invention. The sealing plates 4, 4' are provided parallel to the running direction 6 of the strip plate l, substantially perpendicular to the arc surface, and on the outside of the V-bottom 3-1.3'-1 of the V-shaped slit. Seal plate 4, 4
' is provided at the top of the arc surface in an elevation angle range of 30 to 70''. When the seal plates 4, 4' are provided over the entire length of the arc surface, as will be described later, the end of the width of the strip l will be the seal plate. 4 and 4', the smooth running of the strip plate 1 is prevented, and scratches occur on the strip plate L.The height of the seal plate 4°4'' is not particularly limited, but It can be 30 to 501 shoes. Further, it is desirable that the distance between the seal plates 4 and 4' be 20 to 60 mm wider than the width of the strip l.

The gas pad surface of the present invention is further provided with horizontal slit-shaped guide nozzles 5, 5' near the lower end of the convex arc surface of the gas pad surface at the inlet and outlet ends of the strip plate 1. Guide nozzle 5, 5'
Although the length is not particularly limited, a length approximately the same as the width of the strip plate 1 can be used.

In FIG. 1(C), in the present invention, the amount of gas ejected from the guide nozzles 5, 5' is adjusted in accordance with the degree of wave and middle elongation of the strip, as will be described later. Therefore, in the present invention, the V-shaped slits 3, 3
' and the gas ejected from the levitation gas ejection slit 9,
Although a common gas introduction hole 8-1 can be used, the gas ejected from the guide nozzles 5, 5' is introduced from a separately provided gas introduction hole 8-2, and the partition wall 10 is inserted into the gas support device. The structure shall be such that it can be set up and controlled independently.

In the present invention, the V-shaped slit prevents the strip l from running in a meandering manner. Figure 2 is an explanatory diagram of its action, (A) is a plan explanatory diagram;
(B-1) is a side explanatory view of the V-shaped slit 3 side, (B-2
) is an explanatory side view of the V-shaped slit 3' side, and (C) is an explanatory front view. An example in which the band plate 1 deviates (meanders) in the direction of the arrow 11 in FIG. 2(A) due to, for example, non-uniform plate thickness or curling will be described. When the strip plate 1 shifts in the direction of the arrow 11, the entire V-shaped nozzle 3, including the V-bottom 3-1, is covered by the strip plate l. On the other hand, the V-shaped nozzle 3' is detached from the strip plate 1, and only the V end 3''-2 of the ■-shaped nozzle is covered by the strip plate 1. Therefore, the strip plate 1 on the V-shaped nozzle 3 side is
As shown in 1), the gas flow blown upward from 3-1 lifts it up significantly. On the other hand, as shown in Figure 2 (B-2), the strip plate on the V-shaped nozzle 3p side swells slightly laterally due to the gas flow blown out from 3'-2, but is not lifted upward. 1 is inclined on the gas pad surface 2 as shown in FIG.
Move in two directions.

As described above, if the strip 1 falls over and deviates in the direction of the arrow 11 due to uneven thickness or curling, the strip 1 will naturally return to the direction of the arrow 12. Therefore ■Groove 3 and 3°
This naturally prevents the strip plate 1 from meandering.

In the present invention, the seal plate prevents the strip from meandering. For example, due to non-uniform thickness or curling of the strip l, the third
An example of deviation in the direction of arrow 11 in FIG. Band plate 1
deviates in the direction of arrow 11, gap 1 between seal plate 4 and band plate 1
3 becomes smaller, and the gap 13' between the seal plate 4' and the strip plate 1 becomes larger. Gas is ejected from the floating gas ejection slit 9, and a gas pad is formed between the strip plate 1 and the gas pad surface 2. However, since gas is difficult to flow out from the small gap 13, the gas is ejected from the sealing plate 4 side. The internal pressure of the gas pad increases and lifts the strip 1 upward. On the other hand, gas easily flows out from the seal plate 4'' side, so the internal pressure of the gas pad is small and the strip plate 1
Therefore, the strip 1 is not lifted upward.
As shown in Figure (B), although it is inclined on the gas pad surface 2, the strip l moves in the direction of the arrow 12 due to the component force P' of the gravity P acting on the strip l. Thus, even if the strip 1 is shifted in the direction of the arrow 11 due to, for example, uneven thickness or curling, the strip 1 will naturally be returned to the direction of the arrow 12. The sealing plates 4 and 4' thus naturally prevent the strip l from meandering.

FIG. 3 (C-1) is a comparative example in which seal plates 4, 4' are provided over the entire length of the arc surface. At this time, since the gap 13 is small and the strip plate 1 is inclined, the end of the width of the strip plate 1 comes into contact with the seal plate 4 at point Q. This contact impedes the smooth running of the strip 1, and scratches occur on the width edges of the strip 1. In the present invention, the seal plates 4, 4' are
The gas pad is placed only on the top of the gas pad surface 2 as shown in FIG. 3 (C-2). According to the knowledge of the present inventors, the elevation angle θ is 3
0 to 70° is preferred. If it is less than 30@, the force for inclining the strip plate 1 is weak.

Moreover, even if it exceeds 70'', the strip plate l will only swell laterally, the increase in the force for tilting it will be small, and the problems already mentioned will become more serious.

In the present invention, the V-shaped slit and the seal plate can prevent the strip plate 1 from meandering even when used alone, but according to the findings of the present inventors, by using the V-shaped slit and the seal plate together, the strip plate 1 can be prevented from meandering. The effect of preventing meandering running of the vehicle increases synergistically.

The guide nozzle of the present invention prevents the ear waves and elongation of the strip 1 from coming into contact with the gas support device. Figure 4 shows the guide nozzle 5.
. According to the observations of the present inventors, the running path of strip plate 1 without ) is 14
If it is bent along the gas pad surface 2 above -14', the height of the ear wave etc. will be small at do, but 14-14'
The height of the ear wave etc. is large at d□ when it hangs below 14-14', and since the strip l is not restrained below 14-14', it swings in the direction of arrow 15. Run. Therefore, the strip plate 1 easily comes into contact with the lower ends R, R'' of the gas pad surface 2.

FIG. 4(B) shows an example of the present invention in which guide nozzles 5, 5'' are provided, and gas is further injected from the guide nozzles 5, 5' onto the strip l having ear waves. By the jet of gas, the running path at 14-14' of the strip 1 is pushed further outwards, preventing the ear waves etc. of the strip 1 from coming into contact with the lower end of the gas support device.As already mentioned, The amount of gas injected from the guide nozzles 5, 5' is adjusted depending on the size of the ear waves and the swinging path of the strip 1, so the guide nozzles 5, 5'
The gas ejected from 5' is introduced through a gas introduction hole 8-2 provided separately from the floating nozzle 9 and the square nozzles 3 and 3'.

The action of the gas support device of the present invention has been described with respect to a gas support device for changing the running direction of a strip that moves downward after rising. It is clear from the above description that the same effect can be achieved as a gas support device for changing the traveling direction of a vehicle.

As mentioned above, the conventional gas support device for changing the direction of running is insufficient to prevent the strip from meandering or comes into contact with the side weir, so the high-temperature stainless steel strip is heated in a vertical bright annealing furnace for the stainless steel strip. It is not used as a support device to change the running direction of the steel strip.

The gas support device of the present invention can stably support a stainless steel strip plate in a non-contact manner and prevent it from meandering, and can change the running direction. Therefore, the gas support device of the present invention can change direction of a hot stainless steel strip in a non-contact manner.

An example of a vertical bright annealing furnace for stainless steel strips using the gas support device of the present invention will be described below.

FIG. 5 is an explanatory view of a vertical bright annealing furnace for stainless steel strips according to claim (2) of the present invention.

In FIG. 5(A), the gas support device 26 of the present invention is disposed at the top of the vertical bright annealing furnace and supports the stainless steel strip 1 which moves upward and then changes direction and descends. A heating zone 20 is arranged on the ascending track, and a cooling zone 21 is arranged on the turning track and the descending track. Fifth
In Figure (A), the strip plate 1 is not cooled sufficiently on the course of direction change, so the temperature is high and the surface is soft.
is supported by the gas support device 26 of the present invention in a non-contact manner, so no surface flaws occur on the strip 1, and the gas support device 26 of the present invention naturally prevents the strip 1 from meandering. ing. Therefore, there is no need for a complicated device to prevent the strip 1 from meandering, and the cooling zone 2 is kept airtight with an inert gas.
1 can be easily arranged.

Further, for example, in the conventional bright annealing furnace for stainless steel strips shown in FIG. However, the bright annealing furnace of the present invention shown in FIG. 5(A) can have a heating zone on the ascending track and a cooling zone on the descending track. The height can be approximately 172 mm compared to that of .

FIG. 5(B) is another example of claim (2). Claims (
In 2), the rising running path is the heating zone, but the heating zone can be arranged to extend further in front of the running path of the strip l. In FIG. 5(B), the heating zone 20-1 extended to the front is assumed to be an extended heating zone in which the strip plate 1 descends and travels, then changes direction and ascends to travel.
The heating zone (20
~2O-1), it can be used as a support device for the strip l which descends and travels, then changes direction and ascends to travel. That is, when the gas support device 27 of the present invention is used.

Together with the gas support device 26 of the present invention placed at the top, this prevents the strip 1 from meandering, and since the strip 1 runs without contact, even if the strip 1 is at a high temperature, the surface Does not cause scratches.

FIG. 5(C) shows still another example of the present invention. Claim (2
), the ascending track is a heating zone, but the heating zone can also be arranged in a transverse extension in front of the track of the strip l. In FIG. 5(C), the direction changing devices 28 and 29 of the strip plate 1 that change the traveling path by about 90 degrees are arranged in the heating zone 20-2 extending in the lateral direction. When the support device is used for the direction changing devices 28 and 29, the strip 1 does not meander and runs without contact, so even if the strip 1 is at a high temperature, no surface flaws will occur.

In FIG. 5(C), 30 indicates the direction changing devices 28 and 2 of the strip 1.
This is a gas cushion device for catenary control placed between 9 and 9. Heating zone 20-2 extending horizontally
becomes longer and the distance between the deflection devices 28 and 29 becomes longer, the strip 1 runs between 28 and 29 forming a catenary. However, according to the findings of the present inventors, when the strip plate 1 is run with a catenary formed, if the strip plate l is warped upward or downward in the width direction, creases are likely to occur at the bottom of the catenary. , 28 and 29, if a gas cushion device 30 having a gas pad surface for catenary control is provided, the occurrence of this folding flaw can be prevented.

In FIG. 5(B) and FIG. 5(C), 31 is a support device for the strip l when the running direction of the strip l which is not high temperature is changed without contact; 1 is a gas support device of the present invention. Needless to say, when used as this support device 1i31, the strip plate 1 is further prevented from meandering and has the effect of running in a non-contact manner.

[Example] FIG. 6(A) is a diagram showing an annealing furnace in which the gas support device of FIG. 1 is installed at the top of the annealing furnace. That is, FIG. 6(A) is
The gas support device 26 according to claim (1), wherein the gas support device is disposed at the top of the vertical bright annealing furnace, and supports the stainless steel strip 1 that moves upward and then changes direction and moves downward. This is a vertical bright annealing furnace for stainless steel strips, characterized in that an ascending track 20 is a heating zone, and a direction change track and a descending track are cooling zones 21.

Figure 6 CB) is a diagram showing an annealing furnace in which a heating furnace is installed in the pre-process of (A), the heating zone is extended, and connected by a gas support device 27, making a compact and highly productive furnace possible. It is.

FIG. 6(C) is a diagram showing an embodiment in which the entrance roll 32 of the furnace in FIG. 6(B) is replaced with a gas support device i31.

Figure 6(D) shows the lower gas support W2 of the furnace in Figure 6(B).
1 is a diagram showing an example in which gas support device [28, 29, and 30] are changed. This is because when the additionally connected furnace 20-1 and the heating furnace 20 are connected by the lower device 20-2, which is quite far away, a catenary will become a problem in the lower device 20-2. FIG. 6(E) is a diagram showing an example in which the apparatus 30 is used from below, similar to FIG. 6(D), in which the additionally connected furnace 20-1 and the heating furnace 20 are connected to the lower mounting M which is quite far away.
20-2 is a diagram illustrating an example in which an intermediate pad 30 is used from above to prevent a catenary that becomes a problem in the lower device 20-2 when contact is made with the lower device 20-2. FIG. That is, FIGS. 6(B) and (C).

(D) and (E) are the runway 2 where the stainless steel strip descends.
A heating zone provided in 0-1 and a track 20 or 20 and 20-2 that changes direction and ascends, a track that is connected to the heating zone and that ascends the stainless steel strip, and a track that subsequently changes direction and descends. 21, and a gas support device 27 or 28, 29.30 according to claim (1) is arranged for changing the direction of the stainless steel strip in the heating zone, and the stainless steel strip in the cooling zone is For changing the direction of the steel strip, a vertical bright annealing furnace for stainless steel strips equipped with the gas support device 26 according to claim (1) is used to change the direction of the stainless steel strips in a non-contact and meandering manner. It is a figure explaining the method of preventing and annealing.

Each annealing furnace in Fig. 6 has a size of thickness (0.15 to 0.6
− Garden) x width (700-1000+sm) strip steel plate with a tension of 0.05 to 0.2 kg/ms” and a strip speed of 5 m/m.
It is a device that runs at a speed of 60m/wiin and performs annealing.
Five to 15 strips of material are floated and conveyed from the gas support device, but there is little meandering of the strips and there is no contact between the cloth and the gas pad, making stable operation possible.

[Effects of the Invention] According to the present invention, there is provided a bright annealing furnace for stainless steel strips, which has a lower height than the conventional one, in which the stainless steel strips can be run in a non-contact manner, without causing surface flaws, and in which stainless steel strips can be heated without surface defects. It becomes possible to create a vertical bright annealing furnace for stainless steel strips in which the strip travel path does not meander.

In addition, when modifying an existing bright annealing furnace for stainless steel strips, if the present invention is implemented without changing the height of the bright annealing furnace, the length of the heating zone and cooling zone will approximately double, so the stainless steel strip It is possible to run the plate at a speed approximately twice as high as in the past, and the equipment capacity of the bright annealing furnace can be greatly increased.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the gas support device of the present invention, Fig. 2 is an explanatory diagram of the action of the V-shaped slit of the invention, Fig. 3 is an explanatory diagram of the action of the seal plate of the invention, and Fig. 4 is an explanatory diagram of the action of the seal plate of the invention. An explanatory diagram of the action of the guide nozzle of the invention, FIG. 5 is an explanatory diagram of an example of a vertical bright annealing furnace for stainless steel e+i plates of the invention, FIG. 6 is a diagram showing an embodiment of the invention, and FIG. 7 is a conventional one. FIG. 8 is an explanatory diagram of an ordinary vertical bright annealing furnace for stainless steel strips. 1. Stainless steel strip, 2. Gas pad surface, 3.3'
: V-shaped slit, 3-1 (3'-1) : V bottom, 4.4' : Seal plate, 5.5' : Guide nozzle,
6: Stainless steel strip running direction, 7: Gas support device, 8 (8-1, 8-2): Gas introduction hole, 9: Floating gas jetting slit, 10: Partition wall, 20 (20
-1,202): heating zone, 21: cooling zone, 2
6,27°28.29,30,31: Gas support device. Patent applicant Nippon Steel Corporation

Claims (3)

[Claims] (1) In a vertical bright annealing furnace for stainless steel strips, in which a high-temperature stainless steel strip is heat-treated by changing its traveling direction without contact using a gas support device, the gas support device has a convex arc surface. It has a gas pad surface 2, and the gas pad surface 2 has a pair of V-shaped slits 3 formed at the convex top and V-shaped bottoms facing outward, which are arranged on the outside of both ends of the width of the stainless steel strip plate 1.
, 3', and a pair of seal plates 4, 4' on the outside of the V-shaped slits 3, 3', which are parallel to the running direction of the stainless steel strip plate 1 and substantially perpendicular to the arc surface, and further have a gas pad surface 2. Horizontal slit-shaped guide nozzles 5 are installed on the inlet and outlet sides of the stainless steel strip plate 1.
, 5', characterized in that it is a gas support device provided with
Vertical bright annealing furnace for stainless steel strips (2) The gas support device according to claim (1), wherein the gas support device is disposed at the top of the vertical bright annealing furnace to support the stainless steel strip that moves upward and then changes direction and descends and moves. 26. The vertical bright annealing furnace for stainless steel strips according to claim 1, wherein the ascending track is a heating zone, and the direction change track and the descending track are cooling zones. (3) A heating zone provided on a track where the stainless steel strip descends and a track where the stainless steel strip then changes direction and ascends, and a track connected to the heating zone where the stainless steel strip ascends and then changes direction and descends. The gas support device according to claim (1) is provided for changing the direction of the stainless steel strip in the heating zone and for changing the direction of the stainless steel strip in the cooling zone, respectively. A bright annealing method for a stainless steel strip, characterized in that the stainless steel strip is annealed in a non-contact manner and with meandering prevented using a vertical bright annealing furnace for the stainless steel strip.