JPS6410306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for the continuous casting of metals, in particular steel, in which molten metal is introduced into a fixed continuous casting mold through a reservoir and a nozzle. This invention relates to a method in which a cast body is drawn out according to the pressure of the molten metal.

BACKGROUND OF THE INVENTION Methods and devices of this type are used for casting thin castings at relatively high casting speeds, where surfaces without longitudinal and transverse cracks and without casting marks are required. The current state of the art is divided into the following methods, each of which has an independent meaning in principle. Continuous casting of metals is thus carried out in vertical and horizontal mode with vibrating molds or relative movements between the casting body and a horizontal continuous casting mold. A moving mold is then used, consisting of pairs of belts, rollers, chains, etc.

Problems to be Solved by the Invention According to the conventional configuration as described above, movement marks are generated on the surface of the cast body due to vibration or relative motion, and the cast body is also reoxidized.

Means for Solving the Problems In order to solve the above problems, the continuous casting method for metals, particularly steel, of the present invention is such that molten metal is introduced into a fixed continuous casting mold through a storage tank and a nozzle, and the cast body is A method in which the material is pulled out according to pressure,
The molten metal is guided to the outlet of a nozzle connected to the spout of the continuous casting mold, and the molten metal forms a fixed meniscus at the exit of the nozzle, maintaining dynamic equilibrium and being guided into the continuous casting mold. Also, during the casting, a metal foil is continuously entrained in each case on at least two opposite cross-sectional sides at the drawing speed of the casting.

Effect According to the method of the present invention, the metal foil located between the fixed continuous casting mold and the cast body moves integrally with the cast body, and is substantially free from the surface of the cast body. No movement occurs.

Embodiment An embodiment of the present invention will be described below based on the drawings.

Molten metal (for example, molten steel) 1 flows from a storage tank 2 through a nozzle 3 into a casting chamber 4a of a continuous casting mold 4 that is water-cooled and fixed in position. The flow relationships illustrated for this inflow are maintained during casting while maintaining the hydraulic pressure ΔP. At the same time, in order to avoid vibrations of the continuous casting mold 4, the metal foil 5 is continuously fed between the continuous casting mold 4 and the casting body 7 at a withdrawal speed 6 of the casting body 7 corresponding to the casting speed.

The supply of molten metal 1 is as in the first embodiment (Fig. 1).
According to , this is done by utilizing the flow relationship in a fixed meniscus 8, and the fixed meniscus 8 is constructed by taking into consideration the molten metal pressure ΔP, temperature T, surface tension Σ, and casting speed Vg. This also determines the form and extension 9 of the fixed meniscus 8. The fixed meniscus 8 in dynamic equilibrium further follows the nozzle exit cross-sectional area d. Other criteria for proper formation of the flow are:
These are the shape of the nozzle 3 and the immersion depth of the continuous casting mold 4 in the casting chamber 4a.

The molten metal 1 is supplied according to the second embodiment (Fig. 2).
According to the same method, stable flow relationships are used with a fixed meniscus 8 in dynamic equilibrium.

The fixed-position continuous casting molds 4 each have a guide 10 for the metal foil 5 on the casting side 4b, which consists of a casting side roller 4c (FIG. 1) or a casting side radius 4d (FIG. 2). has been done.
In the case of FIG. 1, the guide 10 is also the confluence guide 11.
This is supplemented by
e to create the necessary metal contact between this water-cooled mold wall 4e and the metal foil 5. This contact is broken off again outside the continuous casting mold 4, since the metal foil 5 has lubricating properties on one side 12A facing the water-cooled mold wall 4e in the casting chamber 4a and therefore slips;
However, the other side 12B facing the casting body 7 has adhesion properties and can therefore be transported together with the casting body 7.

The nozzle 3 can protrude into the continuous casting mold 4 without contact (FIG. 1) or sealed with an external part 3a (FIG. 2), this sealing being assisted by a metal foil 5. .

Usually, the metal foil 5 is stored in a bundle 13,
Continuously withdrawing speed from the roller core (casting speed) 6
It is rolled out. Metal foil 5 returns 14 (Figure 1)
It can also be supplied for reuse. Furthermore, it is suitable to introduce an inert gas 15 into the area of the nozzle 3 protruding into the continuous casting mold 4 in a contactless manner to prevent reoxidation of the molten metal 1.

The principle according to the invention can be used not only for horizontally arranged continuous casting molds 4 as shown in the embodiment, but also for vertically arranged continuous casting molds, simply by using a storage tank 2.
All you have to do is adapt the configuration accordingly. The use of metal foils 5 on at least two opposing cross-sectional sides of the casting body 7 is also carried out in accordance with the cooling conditions, with the exception of very thin casting bodies, i.e. casting bodies with a thickness of not more than 100 mm, where the casting cross-section is narrow. metal foil to the side 5
It is also possible to abandon the introduction of

In the redevelopment of the method according to the invention, the dynamic equilibrium of the molten metal 1 is determined by the molten metal temperature, the molten metal composition,
It is configured in relation to the molten metal pressure at the nozzle exit, and also in relation to the nozzle exit cross-sectional area or nozzle form, the dimensions of the cast body, and the casting speed.

The apparatus for carrying out the method comprises placing a metal foil 5 on a fixed continuous casting mold 4 on the casting side 4b.
The drive for the metal foil 5 is provided by the casting 7 itself, and the metal foil 5 consists of an aluminum tape or a steel tape. This configuration makes it possible to avoid any wear of the continuous casting mold 4. Further, the cast body 7 simply touches the metal foil 5. Furthermore, the metal foil 5 consisting of an aluminum tape or a steel tape allows a controlled oxidation, an advantageous migration and thus a cooling structure of the casting material which is formed evenly on both sides of the casting body 7.

The redevelopment of the device according to the invention consists in that the nozzle 3 projects into the continuous casting mold 4 without contact. This arrangement avoids wear and heat problems at the molten metal supply point.

The redevelopment of the invention consists in that the nozzle 3 protrudes into the continuous casting mold 4 in a sealed manner by means of the outer part 3a and the metal foil 5. Oxidation can thereby be avoided in a simple manner and, moreover, cannot have a detrimental effect on the precise introduction of the metal foil along the inner wall of the casting chamber 4a of the continuous casting mold 4.

Another improvement of the invention consists in that the metal foil 5 is provided with a nickel coating. The nickel coating will reduce heat transfer and thus the rate of solidification in the casting body 7 can be influenced depending on the desired cooling curve of each casting material chosen.

Effects of the Invention According to the present invention having the above configuration, since it is a fixed mold system, it is possible to avoid vibration marks that occur when using a moving mold system, thereby achieving high surface quality and reducing mechanical engineering costs. , and also provides high safety against cracking. Furthermore, the metal foil can avoid reoxidation of the molten metal, and the properties of the metal foil can significantly influence the cooling of the molten metal in a favorable direction. Furthermore, the molten metal forms a fixed meniscus at the exit of the nozzle and is introduced into the continuous casting mold while maintaining dynamic equilibrium, which greatly simplifies the pouring situation, and the continuity of the cross section and flow rate makes it possible to The transition from nozzle to continuous casting mold can be guaranteed. It should be noted that the method according to the invention can be used both for vertical continuous casting molds and for horizontal continuous casting molds.

Instead of the lubricating properties of a graphite mold with deposited graphite for exfoliation, another refinement of the invention provides that the metal foil has lubricating properties on the side facing the casting wall of the casting chamber and on the side facing the casting body. It has adhesive properties. This allows the parts of the metal foil that adhere to the casting to remain smooth and relatively metallically pure in the cooled state, since they can be easily released by rapid cooling or similar shock-producing methods, as long as they are not oxidized. It is possible to produce a cast body with a surface.

[Brief explanation of drawings]

FIG. 1 shows an axial longitudinal section through a horizontal continuous casting mold during molten metal casting in accordance with an embodiment of the invention, and FIG. 2 shows the same longitudinal section through a horizontal continuous casting apparatus as a selected embodiment. 1... Molten metal (molten steel), 2... Storage tank, 3... Nozzle, 4... Continuous casting mold, 4a... Casting chamber, 5... Metal foil, 7... Cast body, 8... Fixed meniscus, 10...
Guide, 12A...inner surface, 12B...outer surface.

Claims (1)

[Claims] 1. A method for continuous casting of metal, especially steel, in which molten metal is introduced into a fixed continuous casting mold through a storage tank and a nozzle, and the cast body is withdrawn according to the pressure of the molten metal. The molten metal is guided to the outlet of a nozzle connected to the pouring port of the continuous casting mold, the molten metal forms a fixed meniscus at the outlet of the nozzle, maintains dynamic equilibrium, and flows into the continuous casting mold. During casting as well as being guided by
Continuous casting process for metals, in particular steel, characterized in that one metal foil is successively followed on at least two opposite cross-sectional sides at the drawing speed of the casting body. 2. Claim 1, characterized in that the metal foil has lubricating properties in the casting chamber on the side facing the mold wall and adhesive properties on the side facing the cast body. Continuous casting method for metals, especially steels, as described in .