JPS58218348A - Continuous casting device of thin steel plate - Google Patents

Abstract

PURPOSE:To retard solidification on a short side and to produce a thin steel plate at a high speed by using a refractory material in constituting the inside surfaces of the stationary wall in both side edge parts of a pair of circulating bodies which are disposed so as to face each other, and providing a protective plate for retarding solidification on each of said inside surfaces freely attachably and detachably. CONSTITUTION:The inside surface of a stationary side wall 3 is constituted of an approximately triangular refractory material 11 having an upward divergent and downward convergent shape. A protective plate 14 for retarding solidification is fixed to the free end of an arm 15 which is supported above the wall 3 and is movable vertically and oscillatable. Said plate is attached or detached to or from the inside surface of the material 11 according to the movement of the arm 15. The plate 14 is kept attached to the inside surface of the material 11 until the drawing of an ingot is started after the charging of molten steel is begun to retard the solidification on the short surface side.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuous casting of thin steel plates, and in particular to a fixed side wall of the apparatus for producing thin steel plates of 30 to 50 mm directly from molten steel without going through the steps of ingot making or rough rolling. This paper proposes the structure of the department.

Conventionally, in order to manufacture thin steel sheets, a steel ingot is first created through ingot processing, then it is partially rolled into a slab with a thickness of 100 to 800 mm, and then further rolled, called rough rolling, to a thickness of 80 mm. It was made into a thin steel plate about the size of a gate, and then hot-striped into a thin copper strip with a thickness of 1.0+am or less.

On the other hand, there is a conventional technique as shown in FIG. 1 in which a thin slab is directly cast by a continuous casting method and then rolled into a thin steel plate. This technique involves injecting molten metal (molten m') into a water-cooled mold 102 through an injection nozzle 101 to generate a solidified shell 1()3 along the casting wall.
This is a method in which a thick slab of 08 is continuously drawn out through guide rolls 104, etc., and then rough rolled to form a thin steel plate, but it has the following problems. That is, in this method, the thickness of the slab is determined by the injection nozzle 101.
It is determined by the size of the nozzle diameter, so the smaller the nozzle diameter, the better. However, in order to prevent the molten metal from solidifying inside during injection, the nozzle diameter needs to be larger than lQO+u+, and is generally 150-170.
I use one that is the thickness of a men's. Therefore, the thickness of slabs that can be cast is at least 130 mm, and usually 2 mm thick.
It will be 00 to 260 fights thick. In this sense, the mold used in the conventional continuous casting method described above has a substantially rectangular parallelepiped shape as shown in FIG. 1, and has a structure that makes it difficult to draw out thin slabs.

On the other hand, as a further improvement to the above-mentioned continuous H new device, a pair of circulating metal belts (circulating bodies) are placed opposite each other in the shape of a concave area with a wide bottom. There is a technology that creates a space so that the thin steel plate can be pulled out directly from the bottom, but even this device had the following drawbacks:
°'1 Ogawaa1,1□. , D-work, ah, good. Even if you can say that you can get a smaller downward-shaped space than the second one, the extent is small. For example, a large amount (800t/
, Hr or more) In order to supply hot water using the injection nozzle 1, at least the inner diameter cross-sectional area + 100/2) -1 It is necessary to supply hot water of more than aoot/Hr using a nozzle like this from Taiyo Co., Ltd. and have a thickness of 10
In order to continuously cast thin steel plates with a thickness of 0 mm or less, it is necessary to taper the fixed side walls that constitute the short sides of the casting space to a degree greater than that of natural solidification shrinkage stitching. In this regard, conventional thin steel plate continuous casting equipment has a structure in which all four sides forming the S casting space are water-cooled, so even the fixed side wall side, which corresponds to the short side, has a similar structure to the long side. In order to create a solidified shell at high speed, it is impossible to sew if the concave shape of the short side is made smaller than the amount of natural shrinkage due to solidification.
. In short, for fixed side walls used in such devices:
Amount of squeezing waste to form a downward concave shape: The ratio of the width difference between the + part and the bottom of the height of the casting space to the length of the fixed side wall is limited to a maximum of 1i5% of original M and q waste. This made it difficult to directly manufacture extremely thin steel sheets.

This invention was developed with the aim of overcoming the above-mentioned drawbacks of the conventional fixed side walls for casting thin steel plates, and enables the direct casting of thin steel plates with l'x as high as 80 mm. This paper proposes a fixed side wall for regulating the short side of a steel plate. The details of its construction will be explained below with reference to the drawings, and FIG. 2 of the drawings shows a preferred embodiment of the continuous casting apparatus of the present invention. It is a circulating body (corresponding to the long side wall) that is arranged opposite to each other and performs endless symmetrical movement (circulation) while maintaining the gap [' (pool part)] to hold the cast metal. ,
3 in the figure is a fixed side wall for regulating the short side wall of the slab (W4), which is located at the side edge between the two facing ring bodies 1 and 2, and has a wide upper shape and a concave lower shape. It is approximately triangular. A casting space is formed by both fixed side plates 8 and the pair of circulating bodies 1 and 2. □ Such a casting space: In other words, the molten metal holding area 4a located in the upper part that corresponds to the molten metal pool has a cross section and shape on the side that corresponds to the plate thickness surface, and has a concave shape with the fixed side wall 3 at the bottom of a substantially triangular JFe. A pair of thickness adjusting rolls 5, 5' are arranged at the narrowest portion of the smallest cross-sectional area. The distance between the thickness adjusting rolls 5, 5' is approximately equal to the thickness of the product plate.

The part continuing below the molten metal holding area 4a is a solidified shell growth area 4b, where the solidified shell 6 that has grown and formed along the inner surface of the circulating body 1.2 is rapidly cooled and becomes a thin steel plate 7, which is then circulated. As the body 1.2 moves, it is extracted sequentially from the bottom.

Water-cooled cooling plates 8 and 9 are provided on the back surfaces of the circulation bodies 1 and 2 corresponding to the molten metal holding area 4a and the solidified shell growth area 4b, respectively.
is installed to cool the circulating body 1.2. 10 shown
is an injection nozzle.0 In the case of the device described above, the fixed side wall 8 corresponding to the molten metal holding area 4a has a casting space in the form of an inverted triangle, so the drawbacks of using a slit-type nozzle, which were conventional problems, are resolved. However, in such a continuous casting device, in order for the generated solidified shell 6 to be smoothly continuously cast without breaking or nocluding, it is necessary to The growth is
Said thickness l! It is desirable to start at a position immediately after the 1st and Ath numbers, which is immediately before the minimum gap of the 1st roll 5.5' installation. For example, 1. If the solidification completion point occurs far before the minimum gap, breakage is likely to occur due to the force of the solidification shell, and the load on the thickness adjustment rolls 5 and 5' increases, resulting in stable continuity. Casting becomes difficult.

On the other hand, if the solidification of the surface in contact with the fixed side wall 8 occurs far below the thickness regulating rolls 5, 5', the formation of a solidified shell will be significantly delayed, so there is a risk of steel leakage. Therefore, when considering the structure in the molten metal holding area 4a of the fixed side wall 8 of the device according to the present invention, it was found that the formation of the solidified shell 6 on the side in contact with the short side surface of the steel plate is at least in the molten metal holding area. 4a, the circulating body 1 ('
In response to this request, the 1.1
．． :: It has been found that it is effective to make the fixed side wall 8ejF a refractory material suitable for cooling.

Based on the above-mentioned findings, the structure of the fixed side wall of the present invention, as shown in FIG. On the other hand, the part that continues directly below the refractory part 11, that is, the part below the molten metal holding area 4a that is in contact with the poured molten metal in the casting space, has a cast slab thickness width. quenching plates 12 are arranged in series at intervals equal to , and the solidified shell 6 that has reached the position where a predetermined slab width can be obtained is rapidly cooled and made into a strong slab 1
A material that is compatible with high-speed manufacturing and thinning is adopted.

In addition to the above-mentioned configuration, the present invention has a configuration of the fixed side wall 8 section, in order to further suppress heat dissipation promoted by the influence of the water-cooled backup frame 18 installed on the back side of the fixed side wall 8. A thin slow-solidifying protection plate 14 is supported on the inner surface of the side wall 3 at least from the start of pouring into the casting space until the steel plate is pulled out. This retainer is for 4-o! ,, Yo. Hey there. .

Yo. Oh yeah.

::.

This is to delay.

FIG. 4 shows a drive mechanism for attaching the slow solidifying protective plate 14 to the inner surface of the fixed side wall 3. As shown in drawing 0', the slow solidifying protective plate 14 is attached to the fixed side wall 8 The slow-solidifying protection plate '14 is fixed to the free end of an arm 15 supported upwardly and capable of moving up and down and moving a, and comes into contact with and leaves the inner surface of the refractory 11 according to the movement of the arm 15.
The movement a of the arm 15, which attaches the arm 15 to the inner surface of the refractory 11 in a detachable manner, is caused by the movement of the swinging piece 1, which is rotated by the operation of the swinging cylinder 16 hinged to the backup frame 13.
7 and the lifting cylinder 18 mounted on the swinging piece 17, the movement is performed as shown in FIG. 4.

In addition, in order to delay the solidification 1 on the short side surface than on the long side surface, the deep plate 1 for slow solidification is used to cover the surface of the refractory 11.
4-stitched paper, thick paper such as thin cardboard, wood, other refractory materials, or heat-resistant materials such as water glass or asbestos on the surface.
A material coated with is preferably used.

Further, the time for attaching the slow solidification protection plate 14 to the inner surface of the refractory 11 is from the start of injection of molten steel until at least the start of drawing of the slab (tS plate),
In this sense, it is necessary that the slow-solidifying deep protective layer 14 covers the surface of the refractory 11 for a period of one hour. Note that once drawing starts, the growth of the short side solidified shell 6 does not cause much problem because the contact time between the surface of the refractory 11 and the molten steel is short.

As explained above, according to the fixed side wall of the present invention, solidification on the short side side can be delayed, so that smooth high-speed manufacturing of thin steel plates is possible. Moreover, the life of the fixed side wall refractory itself can be extended.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of a conventional continuous casting apparatus. FIG. 2 is a partial sectional view of a thin steel plate continuous casting apparatus according to the present invention. FIG. 8 is a perspective view of a fixed side wall according to the present invention. FIG. 2 is a sectional view showing one embodiment of a slow solidification protection plate drive mechanism. 1.2... Circulating body 8... Fixed side wall 4a...
- Molten metal holding area 4b... - Solidified shell growth area 5, 5'... Thickness adjustment roll 6... Solidified shell, 6'...
Molten steel 7... Solidified gold N temporary 8.9... Cooling plate 10... Injection nozzle 11... Refractory
12...Quick cooling plate 18...Backup frame 14...Protection plate for slow solidification 15...Arm 16...
... Swinging cylinder 17 ... Swinging piece 18 ... Elevating cylinder Patent applicant: Yosaki Steel Mashiki Company No. 2 Figure 2 ♂

Claims (1)

[Claims] 1. A pair of circulating bodies disposed opposite each other that circulate while maintaining a gap for holding cast molten steel over a certain distance;
In a continuous thin steel plate casting apparatus in which a casting space is constituted by a pair of fixed side walls arranged on both side edges between the two circulating bodies, the fixed side walls are spread over at least the inner wall surface of the molten metal holding area. 1. A continuous thin steel sheet casting device comprising a substantially triangular refractory having a concave shape, and having a slow-solidifying protection plate removably attached to the inner wall surface of the refractory.