DE1095999B - Process for continuous casting, especially of difficult-to-melt metals - Google Patents

Description

GERMAN

It is known that the melt, which is still liquid or in the process of solidification, is mechanical, magnetic or subject to electrical vibrations. The frequency of the oscillation is 10 Hz in some cases and in other cases it reaches up to a few 1000 Hz. By influencing the melt, a Structural improvement achieved and counteracted segregation.

When pouring the melt by the continuous casting process, the melt can also be in the Mold are set in rotation in order to improve the strand structure. This rotation gives the As a result of the centrifugal force, the melting surface has the shape of a paraboloid of revolution. The melting mirror well has their lowest point in the strand axis, which shifts downwards when the rotational speed is increased. The specifically lighter slag collects in this trough, which is intermittently or continuously with it the continuously sinking strand is drawn into the solidification zone. The frozen strand shows therefore often slag inclusions in the strand axis or in its vicinity.

Another disadvantage of the rotary movement is that the melt due to the centrifugal force on the Mold wall rises and pushes back the oil film flowing downwards along this wall. By the resulting lack of lubrication solidifies the melt on the wall and the strand remains hang. In order to avoid this disadvantage, one has the action of the rotary movement on the melt shifted in the direction of strand movement. Through this shift and the associated Relocation of the center of movement of the circular movement of the melt to a different solidification axis, however, increasingly occurs. Of the With this deep setting of the center of movement, the melting mirror takes on a shape in which the Slag can accumulate in the angle between the melting surface and the mold wall. The slag solidifies on the mold wall and is lowered with the strand. This gives the strand a slag jacket, which gives it a wavy look. Because of this slag jacket, the strand must be peeled will. The experiences with this type of application of a rotating field in continuous casting plants were therefore unfavorable.

In order to achieve a fine-grain strand structure, a circular movement of the melt is desirable, but this must not reach such a level that the melt on the mold wall in hikes up at an acute angle. However, this rotating movement must not be so small that the slag introduced into the mold with the melt reaches the mold wall.

Process for continuous casting, especially those that are difficult to melt

Metals

Applicant:

Gebr. Böhler & Co. Aktiengesellschaft,
Vienna,

acting through the branch,
Stuttgart-Untertürkheim, Benzstr. 19th

Claimed priority:

Austria from July 30, 1953

Dipl.-Ing. Bruno Tarmann, Kapfenberg (Austria),
has been named as the inventor.

According to the invention, it is therefore proposed to set the melt in a circular motion and here to choose the speed of the movement or the position of the center of movement so that the mat of the melt introduced into the mold or the slag that accumulates on the melt surface Slag layer is kept away from the mold wall with security, but without the melt can climb up the mold wall.

The subject matter of the invention is explained using a drawing.

Fig. 1 shows the shape of a melting mirror, in which the resulting from the circular movement The trough is so deep that the steadily sinking strand in the strand axis takes parts of the slag with it and the melt rises as a result of the high speed on the mold wall, the oil film on the The mold wall is pushed back, solidified there and thereby the strand sticking to the Mold wall caused.

Fig. 2 shows a melt level in which the slag is at an angle between the melt and the mold wall collects, solidifies there and surrounds the strand in the form of a slag jacket.

3 shows the enamel mirror shape to be striven for according to the invention, the melt mirror being through the rotating movement of the melt has a shallow trough, but the centrifugal force is not so great, that the melt creeps up the mold wall at an acute angle; the melting level lets

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rather, see a downward curvature (meniscus) on the mold wall.

Appropriately, the trough z. B. with slag be covered, but this cover must not reach the mold wall.

The required shape of the melt mirror is best achieved by a rotating field that is variable in height and frequency achieved, with which the speed and the position of the rotating field to the melting level is regulated can be that a melting mirror shape corresponding to FIG. 3 is established. For this purpose, the Continuous casting mold equipped with one or more coils, their position in relation to the melting level is optional can be changed.

Claims (2)

PATENT CLAIMS: 1. Process for continuous casting, especially of difficult-to-melt metals, the melt poured into the mold in a circular motion by means of a rotating field is offset, characterized in that by regulating the speed of the melt or the position of the center of movement with the help of one or more, if necessary, height and / or variable-frequency rotating fields a melting level is maintained in the Has a trough in the middle and the edge of which forms an angle with the mold wall which is approximately corresponds to the contact angle that is present when the melt is at rest. 2. The method according to claim 1, characterized in that the melting mirror trough with a the melt covering substance, e.g. B. slag is filled. Considered publications:
German patent specification No. 307 225. 1 sheet of drawings I 009 680/434 12. SO