JPS61284535A - Continuous annealing furnace for steel strip providing multistep floating transfer treating zone - Google Patents

Abstract

PURPOSE:To anneal steel strip continuously while preventing generations of flaw, drawing, etc., using equipment of a small setting area, by providing continuously treating zone having vertical multiplex pass transferring means by rolls, to a heating zone and a soaking zone having multisteps floating transfer. CONSTITUTION:In the first treating zone 1 composed of the heating zone A, the soaking zone B and the first cooling zone C, multisteps float transferring means in which float supporting apparatus by a statical pressure pad 2 are provided by plural steps in vertical direction, further a turning over apparatus 3 for transferring the strip in vertical direction is provided to the end part, is set. To the zone 1, the second treating zone 10 composed of an overage treating zone D and the second cooling zone E is provided continuously, to provide vertical multiplex pass transferring by a roll transferring means 11. A steel strip treating material W is transferred through the zones 1, 10 by respective transferring means, to anneal it continuously and efficiently without causing flaw, drawing, etc. In the constitution, setting area of annealing furnace can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention particularly relates to a continuous annealing furnace for steel strip suitable for continuous annealing treatment of tin plate blanks.

(Prior Art) Conventionally, the furnace types of continuous annealing furnaces for smoothed strips are broadly classified into horizontal furnaces and next-type furnaces. The furnace type varies depending on the throughput, the purpose of processing El, etc. Multilayer furnace 5L type furnace, tilting furnace. Either a [horizontal ten vertical type] type furnace or a full vertical type furnace is selected.

On the other hand, as means for conveying the steel strip during continuous annealing, there are a roll conveyance method, a catenary conveyance method, and a floating conveyance method.

By the way, generally speaking, the capacity of steel strip is 20,000 ~
When performing continuous annealing treatment at a rate of 40,000 tons/month, as disclosed in Japanese Patent Publication No. 59-42732, etc., a heating zone, a soaking zone, a first cooling zone (overaging treatment zone) and a final cooling zone are A vertical furnace with all vertical belts is used.

In some cases, as described in Japanese Patent Publication No. 56-18053, there are furnaces in which the direct heating zone is horizontal and the subsequent zones are vertical, or as described in Japanese Patent Publication No. 58-53052. Continuous annealing furnaces that are a combination of a horizontal furnace and a vertical furnace are also used, such as a furnace in which the overaging treatment zone after quenching is horizontal and consists of multiple passes.

The continuous annealing furnaces described in each of the above publications perform annealing treatment while supporting the steel strip with rolls and passing it through the furnace.

(Problems with conventional technology) Adopting a vertical furnace type for a continuous annealing furnace is! This furnace type is effective in securing a production capacity of 20,000 to 40,000 tons/month in the basic furnace and reducing the installation space. In order to ensure stable conveyance, it is necessary to apply a tension of 0.5 to 1,000 kg/mm'' in the heating zone and soaking zone.

Therefore, in order to prevent shrinkage (heat buckling or tension buckling) from occurring in the treated material, there is a limit to the thickness or width of the treated material, and that limit is:
The plate thickness is approximately 0.15+u, and the plate width is 9
20+u! There is a limit to the continuous annealing treatment of thinner steel strips and wider steel strips. Furthermore, since rolls are used as the transport means, measures must be taken to eliminate the temperature difference between the rolls located in the heating zone and soaking zone and the processed material in order to prevent the occurrence of squeezing of the waste strip. The problem is that it requires

On the other hand, in a furnace type that combines a horizontal furnace and a vertical furnace, the tension in the horizontal furnace is smaller than that in the vertical furnace.
Compared to the case where all the furnaces are vertical, the occurrence of squeezing can be somewhat reduced, but there are problems in that not only a large number of conveying rolls are required, but also scratches are caused by the rolls.

The present invention is characterized in that the occurrence of shrinkage in the treated material is caused by the tension applied in the heating zone and the soaking zone and the uniform heating properties of the treated material. The amount of tension applied in the heating zone and soaking zone is required to stably convey the material, and heat buckling or tension buckling tends to occur when the temperature of the processed material rises and during the soaking process. This was done with a focus on

(Means for Solving the Problems) In order to solve the problems of the conventional continuous annealing furnace for rope strips, the present invention provides a floating support device for rope strips in which annealing furnaces are arranged in a plurality of stages in the vertical direction. and a reversing device located near the end of the flotation support device for transferring the steel strip from the upper stage to the lower stage, and
If a second processing zone equipped with roll conveyance means is provided in series with a first processing zone that includes at least a heating zone and a soaking zone, then at least the last zone of the second treatment zone is configured to be conveyed by a vertical multiple bus. The steel strip is annealed by being passed through a second treatment zone following the first treatment zone in which the steel strip is conveyed in multistage flotation.

(Example) FIG. 1 shows a continuous annealing furnace for soft tin plate, which is an embodiment of the continuous annealing furnace for steel strip, equipped with a multi-stage floating conveyance treatment zone according to the present invention. l and second
It consists of a treatment zone 10.

The first treatment zone 1 is provided with a levitation conveying means consisting of a levitation support device 2 for levitating and supporting the treatment material W made of steel strips and a reversing device 3 for transferring the steel strips from the upper stage to the lower stage.

This floating support device 2 is, for example,
The processing material W, which is known from Japanese Patent No. 51, is composed of a plurality of static pressure pads disposed vertically facing each other with respect to the pass line, and high-temperature pressure is ejected inward from a jet nozzle (not shown) onto the front and back surfaces of the processing material W. The processing material W is suspended and supported by the static pressure generated by the gas, and is also heated.

Further, the reversing device 3 provided at the end of each pass line p is disclosed in Japanese Patent Publication No. 39-20785 or Japanese Patent Publication No. 54-38.
As disclosed in Japanese Patent No. 782, the steel strip is transferred from the upper stage to the lower stage by blowing out gas to transfer the treated material W from the upper stage to the lower stage in a non-contact state, but this may also be a roll.

Floating support device 2 and reversing device 3 arranged in multiple stages in the vertical direction
The first processing zone l having multiple horizontal paths is divided into a heating zone A, a soaking zone B, and a first cooling zone C by a partition wall 5.6. It supplies gas at a temperature appropriate to the relevant zone.

In the above embodiment, the first treatment zone l was divided into three zones by the partition wall 5.6, but it is sufficient if there is at least a heating zone A and a soaking zone B in which the pass line p is arranged in multiple stages in the vertical direction. .

The second treatment zone 10 is provided adjacent to the first treatment zone 1 and consists of an overaging treatment zone and a second cooling zone E. In each zone E, the processing material W is conveyed vertically in multiple buses by being wound alternately around rolls +1.11, which are conveying means provided at a predetermined interval above and below.

Also, each band.

E is provided with heating means or cooling means (not shown).

In addition, in the embodiment, the processing material W is conveyed vertically in multiple passes in each zone E, but at least in the final zone (
In the embodiment, only the second cooling zone E) may be of the vertical multiplex bus transport system.

In addition, +2, 13, and 14 are priddle roll devices for controlling the tension of the processing material W.

Next, heat treatment in the continuous annealing furnace configured as described above will be explained.

The soft tin plate that is the treated material is heated to the annealing temperature in heating zone A, as shown in heat curve a in Figure 2.
Subsequently, after being held in the soaking zone B for a predetermined time, the first
It is rapidly cooled to the overaging temperature in the cooling zone C, and then subjected to an overaging treatment, and then cooled to around room temperature in the second cooling zone E.

The shape of the treated material is 0.05 to 0.5 mm.
Plate thickness, 600-1500mm plate width 500-70
When processing at a conveyance speed of 0 m/min, continuous annealing can be performed without causing throttling by setting the tension applied in heating zone A, soaking zone B, and first cooling zone C to approximately 0.3 kg/mm. It turns out that it can be treated.

In addition, if the first cooling zone C and the overaging treatment zone are provided with a slow cooling function, continuous annealing treatment of hard tin plate blanks can be performed in the same furnace, as shown in heat curve b in Fig. 2. It is possible.

The continuous annealing furnace of the present application can also be applied to other steel strips.

(Effects) As is clear from the above explanation, according to the continuous annealing furnace for steel strip equipped with a multi-stage floating conveyance treatment zone according to the present invention, floating conveyance is adopted at least in the heating zone and the soaking zone. The material to be processed can be transported with low tension, and annealing can be performed without causing scratches or drawing. Also, the low tension transport allows continuous annealing of thinner steel strips or wider steel strips. becomes.

It should be noted that the most preferable reversing device is a non-contact type reversing device as shown in the above embodiment, but since the number of rolls used is small, the above effects are not significantly impaired. Furthermore, the flotation support device serves as a heating means for the material to be treated;
The treated material is heated by forced convection, which not only improves thermal efficiency and shortens the furnace length, but also allows the pass line of the first treatment zone to be arranged in multiple stages in the vertical direction. The installation area of the treatment zone can be reduced,
The above effects can be improved.

Note that in the first treatment zone, a floating support device that also serves as a heating means is disposed within one furnace shell, so thermal efficiency is also good. Also,
Uniform heating properties in the width direction of treated materials can also be achieved by forced convection heating,
That is, the blowing of hot air from both sides is improved by heating.

Further, since the processing material is conveyed in at least the final zone of the second treatment zone by vertical multi-pass conveyance, the installation space can be reduced compared to an all-horizontal furnace.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a continuous annealing furnace for steel strip equipped with a multi-stage floating conveyor treatment zone according to the present invention, and FIG. 2 is a heat curve. 1-first treatment zone, 2-flotation support device, 3-inversion device, l
O - second treatment zone, 11 - roll (conveying means), A - heating zone, B - soaking zone, C - first cooling zone, D - overaging treatment zone, E - second cooling zone, W - treatment Material, p ~ pass line.

Claims (4)

[Claims] (1) A floating conveyance means consisting of a steel strip flotation support device arranged in multiple stages in the vertical direction, and a reversing device located near the end of the flotation support device to transfer the steel strip from the upper stage to the lower stage. and a second treatment zone equipped with a roll conveying means is provided in series with the first treatment zone having at least a heating zone and a soaking zone, and at least the final zone of the second treatment zone is subjected to vertical multiple passes. 1. A continuous annealing furnace for steel strip, comprising a multi-stage flotation conveyance treatment zone, wherein the steel strip is annealed by passing through a second treatment zone subsequent to the first treatment zone in which the steel strip is conveyed in multi-stage flotation conveyance. (2) A continuous steel strip comprising a multi-stage flotation conveyance processing zone according to claim 1, wherein the flotation support device is a static pressure pad placed oppositely across the steel strip. Annealing furnace. (3) A continuous annealing furnace for steel strip comprising a multistage floating conveyance treatment zone according to claim 1 or 2, wherein the reversing device is a non-contact type reversing device. (4) The multi-stage type according to any one of claims 1 to 3, wherein the first treatment zone includes a heating zone, a soaking zone, and a first cooling zone. Continuous annealing furnace for steel strip with floating conveyor treatment zone.