JPS58218353A - Stationary side plate of continuous casting device of thin steel plate - Google Patents

Abstract

PURPOSE:To produce a thin steel plate at a high speed and to improve the life of stationary side plates by providing a comosite refractory material wherein a conductive exothermic type core material is enclosed with a non-reaction type external material in a holding part for molten metal formed of circulating bodies and the stationary side plates. CONSTITUTION:A stationary side plate 3 is constituted of a holding part 4a of an approximately a triangular shape of an upward divergent and downward convergent shape for molten metal, and a region 4b for growing a solidified shell thereunder. A composite material of a non-reaction type external material 11b which has non-conductive exothermic characteristic and oxidation resistance and is joined with a core material 11a of condutive exothermic type so as to enclose the same is provided at the center in said part 4a. A quick cooling plate 12 is used for the part 4b, whereby the solidification on the short side of an ingot is made slow with respect to the long side and the leakage is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fixed side plate for a continuous thin steel sheet casting apparatus, and in particular, it can be used without going through the steps of ingot making or rough rolling.
11 Thin steel plates directly from molten steel! This paper proposes a fixed side plate with a composite structure for use in the above-mentioned equipment.

Conventionally, in order to manufacture thin steel sheets, a steel ingot is made by mass ingot processing, which is then bloomed into a slab with a thickness of 100 to 800 mm, and then further rolled for 30 mm, called rough rolling. ◇ In contrast, in the conventional continuous casting method, thin-walled slabs were directly cast using the continuous casting method, and then rolled into thin steel sheets, as shown in Figure 1. There was a technique like this. This technique involves injecting molten metal (molten steel) into a water-cooled mold 102 through an injection nozzle 101 to generate a solidified shell 108 along the casting wall.
The thick slab is continuously pulled out through guide rolls 104 and the like.

This method then performs rough rolling to make a thin steel plate, but it has the following problems. That is, in this method, it is determined by the thickness of the slab or the diameter of the injection nozzle 101, so the smaller the nozzle diameter is, the better. However, in order to prevent the molten metal from solidifying inside the nozzle during injection, it is necessary to set the nozzle diameter to 100 mm or more, and generally a nozzle diameter of 150 to 170 mm is used. are doing. Therefore, the thickness of slabs that can be cast is at least 180 mm thick, and usually has a thickness in the order of 200 to 26 θ. In this sense, the mold used in the conventional continuous casting method described above has a substantially rectangular parallelepiped shape as shown in Figure 1.
The structure made it difficult to pull out thin slabs.

In response to this, as a further improvement to the above-mentioned continuous casting apparatus, a pair of circulating metal belts are disposed facing each other in the shape of a concave area with an upper width lower than the upper part.
A□ゎTodoroki□. 1゜Work:;・ There is a technology that allows thin steel plates to be pulled out directly from the bottom, but even this device had the following drawbacks. □ That is, even if it is possible to obtain a concave-shaped casting space at the lower end of the drawing side that is smaller than the diameter of the injection nozzle, the extent of this is small. For example, in order to supply a large amount of hot water (more than 30 ot/Hr) using the injection nozzle 1, the inner diameter cross-sectional area must be at least (1 (I O/2)! x π (2) or more) (
Therefore, a nozzle with an outer diameter of 130 mm or more is required. Using such a large-volume forged nozzle, T80
In order to supply hot water over 0t/Hr and to continuously cast thin steel plates with a thickness of tooorm or less, the shape of the fixed side plate that has a short side of the casting space fPt must be reduced by more than the natural solidification time (taper). ) must be added. In this regard, conventional continuous channel steel sheet casting equipment has a structure in which all four surfaces forming the casting space are water-cooled, and in particular, the fixed side □ plate side, which corresponds to the short side surface, is also the same as the long side surface. In order to create solidification at such a speed, it is impossible to narrow down the shape of the corner under the short side Llii by more than 1 inch by solidification; in short, the fixed side plate used in such a device In the case of , the amount of squeezing waste to make the bottom J1 shape: casting/
The ratio of the width difference of the upper and lower pieces to the height of the space (the height of the space and the length of the fixed side plate) is limited to a natural shrinkage of 1.5% at most, and direct manufacturing of extremely thin steel plates is not possible internally. Ta.

This invention was developed with the aim of overcoming the drawbacks of the conventional stationary side plates for thin steel plate casting equipment as described above. This relates to the structure of the fixed side plate that regulates the surface.

The details of the construction will be explained below. Figure 2 of the drawings shows a preferred embodiment of the continuous casting apparatus of the present invention. tilt (a circulating body (corresponding to the long side wall) of a pair of opposing arrangements that moves (circulates) symmetrically while maintaining the water pool 5. Also, 8
is a fixed side plate for regulating the short side wall of the slab (steel plate), which is located at the side edge between the two opposing circulating bodies 1.degree.2, and is approximately triangular in shape with an upper wide shape and a lower concave shape. Both fixed side plates 8
A casting space is formed by the above-mentioned pair of circulating bodies 1 and 2.

Such a casting space, that is, the molten metal holding area 4a located in the upper part that corresponds to the molten metal pool, has a cross-sectional shape on the side that corresponds to the plate thickness side, which has a substantially triangular concave shape with the fixed side plate 8, and the narrowest point A pair of thickness adjusting rolls 5 and 5' are arranged in the cross-sectional area. The thickness adjusting roll 5,
The interval 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 sheet. As the circulating bodies 1 and 2 move, they are extracted sequentially from the bottom.

Water-cooled cooling plates 8.
g is installed to cool the circulation bodies 1 and 2. 1 shown
0 is the injection nozzle.

In the case of the apparatus described above, since the stationary side plate 8 corresponding to the molten metal holding area 4a has an inverted triangular casting space, the conventional drawbacks of using a slit-type nozzle are eliminated.

However, in such a continuous casting device, in order to smoothly continuously cast the solidified shell 6 without breaking or bulging, it is necessary to prevent the solidified shell from growing from the fixed side plate 8.4. , it is desirable to start at +Vf immediately before or immediately after the minimum gap for installing the Jv adjustment levers 5, 5'. For example, if the solidification start point tit occurs far before the minimum +141 gap, the solidification shell is likely to break, and the load on the thickness adjusting rolls 5, 5' increases, resulting in a stable Continuous casting becomes difficult.

On the other hand, if the solidification of the part in contact with the fixed side plate 3 occurs at a position far below the thickness regulating roll 5.5', the fixed side plate 8 is of a fixed type without any openings or the like. Seizure between the solidified shell 6 and the fixed side plate 8 is likely to occur, and steel leakage is also likely to occur.

Therefore, we investigated the structure of the molten metal holding area 4& of the fixed side plate 8 of the vinegar fixing side plate 8 according to the present invention.
9 fx <,! : 'ff11f! i*jiAm,
,,8゛°7°'' It is necessary to make it start later as it comes in contact with the circulating bodies 1 and 2 which correspond to the 8 sides, and it is suitable to be constructed of refractory material to meet these requirements. However, in many cases, the formation of the short-side solidified shell 6 cannot be sufficiently suppressed simply by the insulation and thermal effects of the refractory, and in this sense, the approximately triangular fixed side plate a made of the refractory is Based on the above-mentioned findings, the fixed side plate of the present invention has a substantially triangular shape with a concave shape as shown in FIGS. 8 and 4, The inner surface in contact with the molten steel is made of refractory V111 which has excellent heat insulation properties, and the refractory l
The part that continues below: That is, the part below the molten metal holding area 4a that is in contact with the molten metal that is in contact with the casting space, is provided with rapid cooling plates 12 with a spacing (D) equal to the thickness of the slab. We propose a method in which the solidified shell 6, which has reached the position where one width can be obtained, is rapidly cooled to form a strong slab, thereby making it compatible with heavy-speed production and thinning.

Above, Tue, □n. , + , u l! fls G: *
'frl t #6 m'rl! f@,,,...
,,Snow ・A core material 11a preferably made of thermal type 0 or SiO, a non-conductive heat generating pond that is combined to surround it, and a BN-based material with excellent oxidation resistance *Aj, 0. ; −
Non-reactive peripheral material 11 preferably made of SiO□ type material
It is composed of a composite material of 2-3 IN with b. The non-reactive peripheral material 11b is in contact with molten steel, but since it is a non-conductive refractory, there is no risk of electrical leakage, and since it does not contain o or sio, there is little oxidative wear and tear, and a long life can be expected.

On the other hand, the core material 11a generates heat by being energized with I...
This has the effect of delaying the formation of the short side solidified shell 6 in contact with the fixed side plate 8. iM@ is performed via the bus bar 18a and the current-carrying terminal 18b to heat the core material 11a.

In order to further improve the effect of suppressing the formation of solidified shell 6 due to heat generation of the core material 11a, a non-conductive refractory material 11'b was drilled and embedded in the center of the core material 11a. That is, in the case of the present invention, the non-conductive refractory material 11/b is buried in the center of the core material 11a, leaving a small portion (S) at the lower end.With such a structure, the lower end of the fixed side plate 8 The heat generation efficiency increases as it goes to the bottom (lower corner), and the effect of suppressing the formation of the solidified shell 6 improves.In the experimental example, the distance M (S It was found that the relationship is effective when S□〉S.

In addition, 4th. In the figure, a current-carrying terminal 13 is attached to the upper end of the refractory 11.
However, there are current-carrying terminals 1 on the top and bottom of the sides of the refractory] 1.
Even if 8 is arranged and energized, the same effect as 4 above can be obtained.

A backup frame 14 having a water cooling space 16 is installed on the outer wall side (anti-casting space side) of the above-mentioned refractory 11, and this refractory 11 is placed in a state where a heat insulating space 15 is provided in the backup frame 14. It is fixed via a fixing fitting 17.

Now, the backup frame 14 and the refractory 1
1 (underneath the fixed side plate 8 of the molten metal holding area 4a (solidified shell growth area), there is a quenching plate 12 as described above.
This is a water-cooled metal type (copper is preferred) which has a water passage space 18 in its interior. This quenching plate 12 has a protrusion 12a on its upper outer surface facing away from the casting space.
9 supports the fireproof '1111 by fixing it to the lower surface of the backup frame 14.

As mentioned above, the reason why the heat insulating space 15 is provided on the outer surface of the refractory 11 and the backup frame 14 is made to have a water-cooled structure is to prevent the fixed side plate 8 from deforming due to thermal load and leaking molten steel or extracting a deformed steel plate. This is to prevent the stationary side plate 8 from becoming misaligned in order to prevent accidents such as falling.

In addition, when the fixed side plate 8 using the above-mentioned refractory 11 is adopted, the solidification of the so-called short side of the slab proceeds later than that of the long side (the quenching surface in contact with the circulating long side), so the drawing process is difficult. It is possible to make the (a-b) / / shown in Fig. 1 into natural solidification and make it significantly larger than the limit of shrinkage h16.
As the outer peripheral material 11b etc. of No. 1, A/9o, knee 5ioB
, 4 (p, t, o8: 90%.

Sin, : 10%),
MgO-5iO- system (MgO: 9 o
%.

5in2r 1 n%), BN-based material (B≋i:=95% or more) is used, and as the core material 11a, a-si
(3-ht, 08-Sin, system (Q:20
%, 810: 5%.

A10!65%*5ins: tr) and 0-S
The iO-MgO-18 SiO system is used.

Figure 5 shows the effect of the refractory inner peripheral material llb.
Comparative refractories (1
) e (2) and the refractory of the present invention were heated at a temperature of IQ 00°C in an air atmosphere, and the reduction in oxidation length was investigated, and the effect of the present invention is remarkable.・Table 1 As explained above, when the fixed side plate of the present invention is used, it is possible to delay the solidification of the short sides, making it possible to produce thin steel plates at high speed, and also to reduce solidification. It is effective in preventing shell breakage and bulging. Furthermore, such a fixed side plate has no risk of electrical leakage and has excellent oxidation resistance, resulting in a long service life.

[Brief explanation of the drawing]

Fig. 1 is a partial perspective view of a conventional continuous casting device, Fig. 2 is a partial sectional view of a continuous thin steel plate casting device according to the present invention, and Fig. 8 and $4 are both a fixing device according to the present invention. The cross-sectional view of the side plate and FIG. 5 are characteristic diagrams of oxidation loss of refractories. 1.2... Circulating body 8... Fixed side plate 4a...
- Molten metal holding area 4b... Solidified shell growth area 5, 5'... Thickness adjustment roll 6... Solidified shell 6'... Molten steel 7...
- Solidified metal plate 8, 9... Cooling plate lO... Injection nozzle 11... Refractory 11a... Refractory core material 11b... Refractory outer peripheral material 12... Quenching plate
18a... Busnoku - 18b... Current-carrying terminal 14...) (Tuck-up frame
15...Insulated space 16...Water cooling space
17...Fixing metal fittings 18...Water flow space
19...Bolt Figure 1 Figure 9;) Figure 9N4 Figure

Claims (1)

[Scope of Claims] l. A pair of circulating bodies arranged opposite each other, which circulate while maintaining a gap for holding cast molten steel over a certain distance, and located on both side edges between the circulating bodies. In the fixed side plate of a continuous thin steel plate forming device that constitutes a casting space with a pair of fixed side plates, the fixed side plate is connected to a substantially triangular molten metal holding part that forms a corner under the upper width, and a solidified slab thickness that follows the fixed side plate. A composite refractory consisting of a conductive heat-generating core material surrounded by a non-reactive outer peripheral material is provided on the inner surface of the molten metal holding portion, and the solidified shell growth region has a width approximately equal to A fixed side plate for a continuous casting machine for thin steel sheets, characterized in that the shell growth region/acid part is a quenched plate.