JPS61284534A - Continuous annealing furnace for steel strip - Google Patents

Abstract

PURPOSE:To anneal wide steel strip continuously while preventing generations of flaws, drawing, etc., thereof using equipment having a small space, by providing continuous treating zone in which vertical multiplex pass transfer is adopted to at least the final zone, to a heating zone and a soaking zone adopting floating transfer. CONSTITUTION:A treating material W is passed through the first treating zone 1 divided to the heating zone A, the soaking zone B and the first cooling zone C by partition walls 4, 5, by a floating transfer means 2 composed of a static pressure pad 3 and a turning over apparatus 6, then passed through the second treating zone 10 adopting vertical multiplex pass transfer, using many rolls 11 composed of an average treating zone D and the second treating zone 10 provided continuously thereto and annealing treated. In this way, setting space of continuous annealing furnace is decreased and thin and wide steel strip is annealing treated continuously and efficiently without generating flaws and drawing.

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 steel strip are broadly classified into horizontal furnaces and vertical furnaces. The furnace type has a different throughput. Depending on the type of steel to be treated, the purpose of treatment, etc., all horizontal type furnaces are available. Either a multilayer furnace, a vertical furnace, a tilting furnace, a horizontal + 1/2 vertical furnace, or an all-vertical 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, soaking zone, first cooling zone (overaging treatment zone) and final cooling zone are required. A vertical furnace with all vertical belts is used.

In addition, in some cases, continuous annealing furnaces consisting of a combination of a horizontal furnace and a vertical furnace are also used, as described in Japanese Patent Publication No. 56-18053 or Japanese Patent Publication No. 58-53052.

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 the Prior Art) Adopting a vertical type continuous annealing furnace means that one furnace requires 20,000 to 400,000 mm. This furnace type is effective in securing production capacity of 1/2 month and reducing the installation space. is 0.5 to 1. in the heating zone and soaking zone. It is necessary to apply a tension of o&g/mm'.

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 0.15xi, and the plate width is 9
20J11, and there is a limit to the continuous annealing treatment of steel strips with a thinner plate thickness and standard strips with a wider plate width. Furthermore, since rolls are used as a conveying 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 shrinkage of the steel strip. The problem is that you need it.

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 a 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 squeezing of 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. We focused on the fact that the amount of tension applied in the heating zone and soaking zone is regulated to ensure stable conveyance, and that heat buckling or tension buckling tends to occur during soaking treatment due to temperature rise of the processed material. It was done by

(Means for Solving the Problems) In order to solve the problems of the conventional continuous annealing furnace for steel strip, the present invention provides an annealing furnace equipped with a floating conveyance means and at least a heating zone and a soaking zone. A second processing zone having a roll conveying means is connected to the first processing zone, and at least the last zone of the second treatment zone is conveyed by vertical multiple buses, and the steel strip is transferred to the first treatment zone. Subsequently, it passes through a second treatment zone and is annealed.

(Example) Fig. 1 shows a continuous annealing furnace for soft tinplate blanks, which is an embodiment of the continuous annealing furnace for steel strip according to the present invention, and is roughly composed of a first treatment zone I and a second treatment zone IO. Become.

The first treatment zone I is provided with a floating conveyance means 2 that floats and conveys a treatment material W made of steel strip. This floating conveyance means 2 is, for example,
It consists of a plurality of static pressure pads 3 that are arranged vertically facing each other with respect to the bus line p, and the treatment material W known in Japanese Patent No. 1451 is ejected inward from a jetting nozzle (not shown) onto the front and back surfaces of the treatment material W. Static pressure created by high temperature pressure gas,
This is for floating and supporting the processing material W and heating it.

In the embodiment, the floating conveyance means 2 are arranged in a plurality of stages in the vertical direction, and the partition walls 4°5
f The treatment zone 1 is divided into a heating zone A, a soaking zone B, and a first cooling zone C, and gas at a temperature corresponding to the zone is supplied to the static pressure pad 3 of each zone.

It is supposed to be paid.

6 is a reversing device provided at the end of each bus line p, and this reversing device 6 blows out gas as disclosed in Japanese Patent Publication No. 39-20785 or Japanese Patent Publication No. 54-38782. , which guides the processing material W in a non-contact manner, but this may also be a roll.

In addition, in the example described in @, the first treatment zone l is connected to the partition walls 4 and 5.
Although the zone is divided into three zones, it is sufficient to have at least a heating zone A and a soaking zone B. Further, the bus line p is not limited to being provided in multiple stages.

The second treatment zone 1O 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 11 and 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 transported by vertical multiple buses in each zone E, but at least the final zone (
In the embodiment, only the second cooling zone E) may be of the vertical multiplex bus transport system.

Additionally, reference numerals 12, 13, and 14 are priddle roll devices for controlling the tension of the processing material W.

Next, continuous annealing treatment in the 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 the heating zone, as shown in heat curve a in Figure 2.
After being held for a predetermined time in the soaking zone B, it is rapidly cooled to the overaging temperature in the first cooling zone C, and after that, it is cooled to around room temperature in the second cooling zone E through an overaging treatment. The shape of the treated material is 0.05 to 0.5 mm.
Plate thickness, 600-1500mm temporary width, 500-7
When processing at a conveying speed of 0.00 m/min, the tension applied in heating zone A, soaking zone B, and first cooling zone C is approximately 0.3 kg/mm', so that continuous annealing can be performed without causing throttling. It turned out that it can be done.

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

Moreover, Honcho's continuous annealing furnace 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 according to the present invention, floating conveyance is adopted at least in the heating zone and the soaking zone, so the treated material can be conveyed with low tension. , it is possible to perform annealing treatment without the occurrence of scratches, and without the occurrence of squeezing, and the continuous annealing treatment of thinner leap strips or wider steel strips is possible due to the low tension conveyance. Furthermore, the floating conveyance means essentially serves as a heating means for the material to be treated, and the material to be treated is heated by forced convection, so that the thermal efficiency is improved accordingly and the furnace length can be shortened.

In addition, uniform heating properties in the width direction of the treated material as well as forced convection heating, that is, the blowing of hot air from the front and back sides, are improved by heating.

Further, since the processing material is transported in at least the last zone of the second processing zone by vertical multiple bus transportation, the installation space can be reduced compared to an all-horizontal furnace.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a continuous annealing furnace for steel strip according to the present invention, and FIG. 2 is a heat curve. 1-first treatment zone, 2-flotation conveyance means, 3-static pressure pad,
6 - Reversing device, IO - Second treatment zone, 11 - Roll (conveying means), A - Heating zone, B - Soaking zone, C - First cooling zone, D - Overaging treatment zone, E - Second cooling Band, W ~ treated material, p ~ bus line.

Claims (2)

[Claims] (1) A second treatment zone equipped with a roll conveyance means is connected to a first treatment zone which is equipped with a floating conveyance means and has at least a heating zone and a soaking zone, and at least A continuous annealing furnace for steel strip, characterized in that the final zone is conveyed by vertical multiple buses, and the steel strip is annealed by passing through a second treatment zone following the first treatment zone. (2) The continuous annealing furnace for steel strip according to claim 1, wherein the first treatment zone comprises a heating zone, a soaking zone, and a first cooling zone.