JPS6021157A - Continuous casting device for thin plate - Google Patents

Abstract

PURPOSE:To avert the deterioration in the characteristic of the edge part and surface of a thin plate with a titled device which forms the surface of the mold on the broad side with moving surfaces by providing passages for supplying a specific sealing material communicating with the opening at the bottom edge of stationary walls for regulating the width of the billet to said walls. CONSTITUTION:A thin billet 2 is continuously produced by pouring a molten metal from a tundish 4 into the space formed of the mold surfaces on the broad sides of, for example, a pair of casting rolls 1a, 1b and a pair of stationary walls for regulating the width of the billet within the width of said mold. A vessel 3 for a molten metal wall consisting of, for example, the side wall 5 and side wall 6 of the stationary walls is provided above the revolving roll mold. Slit-shaped apertures 9 are provided to the bases of the walls 5, 6 and a liquid or quasi-liquid sealing material supplied from supply sources 11 is discharged from said apertures through the passages 10 is the walls 5, 6. The passages 10 have restricting parts 13 so that the uniform sealing is accomplished even if the spacing delta between the vessel 3 and the roll pair 1 fluctuates. The penetration of the molten metal into said spacing is thus effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides continuous thin plate casting for directly casting thin plates from molten metal using a continuous moving mold in which a wide mold surface is formed by the surfaces of a pair of casting rolls or casting belts that rotate in opposite directions. Concerning improvements in casting equipment.

In continuous casting of molten steel, proposals have been made to directly cast thin plates instead of conventional thick slabs.

For example, in JP-A-55-75862, a large diameter roll was used. A direct thin plate rolling method from molten steel is shown. There are various problems inherent in this case, but in particular, as mentioned in this publication, one of the problems is the control of the edges of the thin sheet to be cast, and the surface quality of the thin sheet to be cast. Another major problem is that it is difficult to maintain it in good condition. This is because, in order to rotate the mold without frictional resistance, it is absolutely necessary to provide a gap between the movable mold and the fixed wall (non-rotating part) that regulates the width of the slab. This is because pouring of hot water occurs and both edges of the slab to be cast become uneven. In addition, when a molten metal reservoir is formed by a fixed wall that regulates the width of the slab and a fixed wall perpendicular to the fixed wall, there is a gap between this fixed wall and the surface of the rotary mold that is about to be used for hematopoiesis. However, there is a risk that hot water may pour in, which may roughen the surface of the mold or cause the solidified material to deteriorate the quality of the surface of the slab.

In order to deal with this, Japanese Patent Laid-Open No. 58-32548 proposes supplying powder additives on the surface of the rotary mold, such as those used in conventional continuous casting slabs of molten steel. ing. The supply of this powder additive will provide good lubrication between the sheet slab and the mold surface, but will not compensate for the uniform distribution of this solid powder by gravity over the entire area of the gap. It seems that there is no complete protection against hot water being inserted.

The present invention is aimed at solving such problems, and provides a moving mold formed by the surfaces of a pair of casting rolls or casting belts that are arranged facing each other with a predetermined gap corresponding to the thickness of the slab. and.

A pair of fixed walls located within the width of this movable mold and facing each other with a gap corresponding to the width of the slab (in the illustrations described later, they are called side walls forming part of the sump container). and,
An opening provided at the lower edge of this fixed wall (referred to as a slit-shaped seal material outlet in the illustrations below), a fluid passage in the fixed wall connected to this opening, and a liquid passage connected to this fluid passage. Alternatively, the present invention provides a thin plate continuous casting apparatus including a supply source of a quasi-liquid sealing substance and a constriction structure (an orifice in the later-described illustrations) provided within the fluid passage.

The liquid sealing material that can be used in the present invention is typically lubricating oil such as rapeseed oil, and the semi-liquid sealing material typically includes grease such as silicone grease or finely powdered graphite. There are graphite greases, etc.

Rapeseed oil has excellent oil properties, has little viscosity change due to temperature and pressure, and is effective in preventing the casting slab from seizing on moving molds and uniformly cooling the slab.It also combines with oxygen to form a rubber-like substance. This effectively prevents molten metal from entering the gap. Also.

Silicone grease or graphite grease that contains excess finely powdered graphite has excellent heat resistance and high viscosity, so it not only prevents molten metal from entering the gap, but also generates heat at both edges of the slab due to the heat generated by the grease itself. can prevent overcooling.

The device of the present invention is characterized in that it uses such a sealing material, and even when the size of the gap varies depending on the location or changes over time, it can be used under a constant pressure. This makes it possible to effectively supply this liquid or semi-liquid sealing substance to the gap.

9 The details of the thin plate continuous casting apparatus of the present invention will be explained below with reference to the drawings.

FIG. 1 shows a thin plate continuous casting apparatus using a continuous rotary mold in which a wide mold surface is formed by the surfaces of a pair of casting rolls la and lb that rotate in opposite directions.

A pair of rolls la and lb forming the mold surface are placed horizontally with their rotational axes parallel to each other with a gap between them, and each roll la and lb is equipped with two cooling equipment (not shown) that continuously cools the roll surface. It is installed inside it. The gap between the rolls Ia and lb becomes a movable mold that determines the thickness of the slab, and the thin slab 2 is continuously produced by this and fixed walls (side walls 6a and 6b described later) that regulate the width of the slab. be done.

Above this rotary roll mold, a tundish container 3 formed by a fixed wall is installed, and further above this tundish container 3 is a tundish 4 for supplying molten metal to this tundish container 3. will be installed.

The continuous thin plate casting apparatus of the present invention is characterized by a sealing structure between the movable mold and the sump container 3 formed by the fixed wall. First, to explain the structure of this tundish container 3, it is made of refractory material and is fixed along the direction of the rotation axis of the mold rolls la and lb, as shown in the overall view in Fig. 2. side walls 5a, 5b and mold roll l
The side walls 6a and 6b, which are fixed along the direction perpendicular to the rotating shafts a and lb, and which determine the slab width, form a container that forms a pool space above the movable mold. Side walls 5a, 5b
Below is.

The mold rolls la, lb are connected to a bottom surface having curved surfaces 7a, 7b shaped along the circumferential surfaces of the mold rolls la, lb;

The side walls 6a, 6b extend below the side walls 5a, 5b while gradually tapering on both sides along the curved surfaces 7a, 7b. The inner distance between the lower portions 8a and 8b of the side walls 6a and 6b, which extend downward and protrude from the side walls 5a and 5b, corresponds to the width of the plate to be cast, and this limits the width of the slab. be done. Note that the side walls 5a and 5b do not necessarily need to be provided, and the water reservoir container 3 can be formed only by the side walls 6a and 6b and the movable wall surface.
can sometimes be formed.

In the present invention, among the fixed walls forming the tundish container 3, at least the fixed wall on the side that regulates the slab width, that is, the gap between the side walls 6a, '6b and the movable mold, is filled with liquid or quasi. Seal by a flow of liquid sealing material. As shown in the figure, the water reservoir 3 has side walls 6a, 6b.
If the gap is formed by providing side walls 5a, 5b in addition to the side walls 5a, 5b, the gap between these side walls 5a, 5b and the moving mold is preferably also sealed by a flow of liquid or semi-liquid sealing material.

In this illustrated example, a slit-shaped sealing material outlet 9 is provided on the bottom surface facing the surface of the movable mold, and a sealing material fluid passage 10 leading to the slit-shaped sealing material outlet 9 is connected to this sump. A fluid passageway 10 for this sealing material is provided inside the container 3 and connected to a source 11 of the sealing material.
(preferably through a hesogou 12), the fluid passage 10 in the water reservoir 3 is connected to the constriction part 1.
3, even if the gap δ (FIG. 1) fluctuates, uniform sealing can be achieved.

In the illustrated example, the slit-shaped sealing material outlet 9 provided at the lower edge of the fixed wall has slits 98 in the curved bottom surfaces 7a, 7b in the direction along the side walls 5a, 5b, as shown in FIG. It consists of a slit 9B extending along the side walls 6a, 6b, and in both cases, a constriction part 13 is provided in the fluid passage 10 in the wall of the water reservoir container that communicates with the slit 9B. Also, although it is not visible in the figure, the lowermost bottom surfaces of the side walls 6a and 6b (
The bottoms of the protruding parts 8a and 8b) also have side walls 6a and 6b.
It is preferable to provide a slit-shaped sealing material outlet in the direction along the direction, but a constriction part is also provided in the portion leading to this outlet.

This diaphragm is shown diagrammatically in FIG.

Fluid passage 10 formed inside the refractory layer of the sump container
It is convenient to form the orifice 17 by attaching it to the orifice 17. An orifice 17 is formed in the fluid passage 10 before reaching the seal material outlet 9 by partially constricting the passage cross section to a small size. Seal material outlet 9
If is a slit.

This orifice 17 is also shaped like a slit. It is preferable that the aperture cross section of the orifice 17 be made uniform regardless of the location.

Such a constriction part 13 (orifice 17) is used for fluid communication b8
10, pressure fluctuations do not occur on the liquid or semi-liquid supply side (-next side) even if the gap δ changes.

The sealing material can be uniformly flowed out into the gap δ with stable wood flow. The reason for this can be explained as follows.

What is the relationship between the supply pressure and the discharge amount when liquid or semi-liquid sealing material is discharged from the sealing material outlet 9?

P = K Q2...+11 It is expressed as

However, P: Liquid supply pressure (kg/c) K: Resistance coefficient Q: Liquid discharge amount (n?/min) Also, the liquid supply pressure P is.

P=Pl 10P2 +p3 It is expressed as however.

Pl ;-Pressure loss P2 from the next piping to just before the orifice
, pressure loss at the orifice portion P3 , pressure loss after the orifice Here, regarding P3, the pressure loss in the fluid passage 10 after the orifice is so small that it can be ignored.

P3 = KIX (Q/δ×A)2 It is expressed as however.

K1 ; Resistance coefficient δ at the discharge part; Gap A between the fixed wall (sump container) and the movable mold; Total circumferential length of the gap δ Therefore, if the orifice part is narrowed down so that P2 >> pH 10p3 , P=P2, and in the end the above (11
ceremony.

P2=KQ2 It is expressed as

In other words, even if the gap δ changes, the -order pressure remains the same,
This allows for uniform outflow at a stable flow rate.

In this way, the sealing material is uniformly flowed out from the sealing material outlet 9 into the gap between the fixed wall and the movable mold, but the sealing material blown out from the direction of the slit 9 is now transferred to the sister hematopoiesis. Rotating roll about to head
a, spilled onto the surface of lb.

While blocking the flow of hot water trying to be inserted onto this surface, the sealing material flowing out from the slits (not shown) provided at the bottom of the slit 1-9B and the protruding parts 8a and 8b is prevented from flowing in the width direction of the slab. Prevent hot water from entering. That is,
The gap formed between the pair of rotary mold rolls la, lb and the sump container 3 is surrounded by a uniform seal, effectively preventing molten metal from entering this gap. As a result, deterioration of the surface properties of the slab can be prevented, and the occurrence of irregularly shaped flashing at both edges of the slab can also be prevented.

Here is an example of the specifications for obtaining this effect.

Gap δ formed between mold rolls la, lb and sump container 3; 0.3 to 2 mm Direction B of casting rolls ta, ib; Body length i of 1000 mm casting rolls la, lb; 900 mm rotation speed; 5 ~2
0rpm Oil supply pressure; 140kg/an! (max 210
kg/cJ) Oil supply kr; It is preferable to set it to about 5 to 50 cc/mtn.

The example in Figure 4 is a moving caster J! :! 1, except that a pair of casting bells (15a, 15b) rotating in opposite directions were used instead of the rolls (la, lb) in FIG.
This shows a device similar to the thin plate continuous casting device shown in the figure. In this case as well, by installing a sealing material supply means similar to that explained in FIGS.
It is possible to prevent hot water from being poured in as described above.

As explained above, one aspect of the present invention is to reduce the gap between the movable mold and the fixed wall, especially in the case where molten steel is directly manufactured into a thin plate using a continuous casting apparatus using synchronously movable molds.

By forming a uniform seal using a liquid or i% liquid liquid sealing substance, such as lubricating oil or grease, the problems of deterioration of the properties of thin sheet edges and surface quality can be effectively avoided. This will contribute to the successful implementation of the system.

[Brief explanation of drawings]

Fig. 1 is a schematic concave view showing an example of the thin plate continuous casting apparatus of the present invention, Fig. 2 is an overall perspective view of a tundish container consisting of a fixed wall, and Fig. 3 is a partial perspective view showing an example of the internal structure of the fixed wall. , and FIG. 4 is a schematic cross-sectional view showing another example of the continuous thin plate casting apparatus of the present invention. ■...Rotary mold roll, 2...Thin slab. 3. Hot water container, 4. Tandesoshu. 5. Side wall of the hot water container, 6. Side wall of the same. 7. Curved surface (bottom of water reservoir). 9. Slit-shaped seal material outflow port (opening at the lower edge of the fixed wall). 10...Fluid passage of sealing material within the fixed wall. 11. Seal material supply source, 12. Header 113.
- Squeezed part, 16... Refractory layer. 17... Orifice. Applicant Nisshin Steel Co., Ltd.

Claims (3)

[Claims] (1) A moving mold formed by the surfaces of a pair of casting rolls or casting belts that are placed opposite each other with a predetermined gap corresponding to the thickness of the slab; A pair of fixed walls facing each other with a gap corresponding to the width, an opening numbered on the lower edge of the fixed wall, a fluid passage in the fixed wall connected to this opening, and this fluid passage. A thin sheet continuous casting apparatus comprising: a source of liquid or semi-liquid sealing material connected to the fluid passageway; and a constriction structure provided within the fluid passageway. (2) The thin plate continuous casting apparatus according to claim 1, wherein the liquid sealing substance is a lubricating oil. (3) The thin plate continuous casting apparatus according to claim 1, wherein the semi-liquid sealing substance is grease.