Start-up billet head for a continuous casting machine for metal, in particular, steel

Abstract

A start-up billet head for a continuous casting machine for metal closes off an outlet of the casting die before start-up of the casting process. The start-up billet head has a coupling part facing an interior of the casting die and forms together with a billet cast in the casting die a positive-locking, hook-shaped connection. The connection can be decoupled after leaving the casting die by performing a tilting movement of the start-up billet head about a joint of the start-up billet. The coupling part has a recess with a first side active in a billet removal direction and a second side facing the first side. The first and second sides have oppositely oriented arc shapes. The coupling part has the shape of a preliminary billet profile with at least one undercut located in the area of at least one flange or angled joint of the preliminary billet profile.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a start-up billet head for a continuous casting machine for casting metal, in particular, steel. The start-up billet head closes off the outlet of the continuous casting die before starting up the casting process. The start-up billet head comprises a coupling part facing the interior of the casting die which together with the cast billet forms a positive-locking, hook-shaped connection which, after leaving the continuous casting die, can be decoupled by a tilting movement of the start-up billet head about a joint of the start-up billet wherein the hook-shaped coupling part on the side that is active (i.e., acts on the billet to be removed) in the billet removal direction is undercut with an arc shape and on the opposite side has an arc shape that is oriented opposite to the arc shape of the undercut.

[0003] 2. Description of the Related Art

[0004] Such a start-up billet head is known from DE 38 10 304 C1. Such start-up billet heads serve to convey at the beginning of the casting process the steel solidified within the continuous casting die in the area of the coupling part by means of a start-up billet and a driving device. The start-up billet head forms thus a detachable coupling between the leading end of the cast billet and the start-up billet. As soon as the start-up billet head has passed through the driving device, the driving device can thus transmit the removal forces onto the cast billet itself and the start-up billet must be decoupled via the start-up billet head. The phase of transmission of the removal forces onto the start-up billet head and from it onto the casting strand depends on to which degree the coupling can already receive forces. The take-up of the removal forces depends on the configuration of the start-up billet head. The configuration of the start-up billet head, however, depends also on the cast billet profile. It is therefore not possible to employ the known start-up billet head in connection with all cast cross-sections and all dimensions of the cast billet.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide a start-up billet head which can be employed in connection with especially complex billet cross-sections and thus continuous casting die cross-sections such that at the beginning of the casting process sufficiently high removal forces can be transmitted onto the cast billet.

[0006] In accordance with the present invention, this is achieved in that for a continuous casting die for a preliminary billet profile the coupling part has at least one undercut in the area of a flange or an angled joint of a preliminary billet profile. This makes it possible to engage complex billet cross-sections with weak stay parts such that a sufficiently high removal force during start-up can be transmitted onto the billet profile in that the flange part or the angled joint take on as much as possible of the removal force.

[0007] The principle of the invention can be applied according to further features, for example, such that for a double-T billet profile in both flanges of the preliminary billet profile undercuts are symmetrically arranged. The cross-sections and dimensional widths available within the flanges make it possible to transmit the required magnitude of removal force onto the solidifying cast billet.

[0008] According to other features, it is provided that the undercut extends, beginning parallel at the stay of the preliminary billet profile and then following the transition between the stay and the flange, with a certain proportion of the thickness of the flange within the flange. The flange thickness can thus be used in a beneficial way for the removal force transmission.

[0009] According to another embodiment it is suggested that on the active side of the hook-shaped coupling part a flange wall is formed whose wall surface extends to the area of the undercut. The cast metal fills thus the space at the location of the large cross-section of the flange so that in the case of preliminary billet profiles considerably greater removal forces can be transmitted.

[0010] In this connection, it is advantageous that the flange wall has a thickness which corresponds approximately to half the thickness of the flange in the preliminary billet profile. By using half the thickness it is possible to utilize as much as possible the cross-section available for the removal force transmission.

[0011] Moreover, it is possible to advantageously use the principle that with reduced thickness of the stay of the billet profile the undercut or undercuts are limited to the flange or the flanges of the preliminary billet profile. In this way, it is thus also possible to cast preliminary billet profiles with thinner stays without the removal force transmission suffering thereby.

BRIEF DESCRIPTION OF THE DRAWING

[0012] In the drawing:

[0013] FIG. 1 is a longitudinal section of the continuous casting die with start-up billet head; and

[0014] FIG. 2 is a front view of the start-up billet head viewed in the removal direction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] According to FIG. 1, the start-up billet head is to be used for a continuous casting machine for metal, in particular, steel. The start-up billet head closes off the outlet 1a of the continuous casting die 1 before the beginning of the casting process by means of the coupling part 2 facing the interior 1b of the casting die which coupling part is arranged so as to seal the die. The coupling part 2 forms together with the cast liquid metal, which quickly solidifies, the positive-locking hook-shaped connection 3 which, after the cast billet has left the die, can be decoupled, i.e., released, at a location downstream of a removal device by a tilting movement of the start-up billet head about a joint 4 of the start-up billet 5. For this process, the hook-shaped coupling part 2 has a recess with an arc shape at the side 7 which is active in the billet removal direction 6 (acts on the billet to be removed, i.e., transmits removal forces). The opposite side 8 of the recess is provided with an oppositely oriented arc shape.

[0016] For applying this principle on a so-called continuous casting die for preliminary billet profiles in which preliminary billet profiles, for example, double-T sections, angled sections or U-sections are cast, it is advantageous that the coupling part 2 has at least one undercut 9 in the area of a flange 10 or an angled joint of a billet profile 11 (FIG. 2). In the illustrated double-T billet profile 11a the two flanges 10 of the billet profile 11 have undercuts 9 schematically arranged therein (FIG. 2). Accordingly, higher removal forces can be transmitted at these locations, even when thinner stays 12 are present.

[0017] The undercut 9 begins at the stay 12 of the billet profile 11 and extends parallel to the stay and then follows the transition 13 between the stay 12 and the flange 10 with a certain preset proportion 14 of the thickness 10a of the flange 10, respectively. On the active side 7 of the hook-shaped coupling part 2 a flange wall 15 is formed whose wall surface 15a continues into the area of the undercut 9. As an example, it is shown that the flange wall 15 has a thickness 15b which corresponds approximately to half the thickness 10a of the flange 10 the billet profile 11. In principle, with decreasing thickness 12a of the stay 12 of any suitable billet profile, the undercut 9 or the undercuts 9 can be limited to the flange 10 or the flanges 10 of the preliminary billet profile.

[0018] While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A start-up billet head for a continuous casting machine for metal, wherein the start-up billet head is configured to close off an outlet of a continuous casting die before start-up of the casting process; the start-up billet head comprising: a coupling part facing an interior of the casting die configured to form together with a billet, that is cast in the casting die, a positive-locking, hook-shaped connection, wherein the connection is configured to be decoupled after leaving the casting die by performing a tilting movement of the start-up billet head about a joint of the start-up billet; the hook-shaped coupling part having a recess with a first side active in a billet removal direction and a second side facing the first side; the first side of the hook-shaped coupling part having an arc shape and the second side having an arc shape oriented opposite to the arc-shape of the first side; the coupling part having a shape of a preliminary billet profile and comprising at least one undercut configured to be located in the area of at least one flange or at least one angled joint of the preliminary billet profile.

2. A start-up billet head according to claim 1, wherein the preliminary billet profile is a double-T profile having two flanges and a stay connecting the flanges, wherein the two flanges of the billet profile are provided with one of the undercuts, respectively, and wherein the undercuts are symmetrically arranged.

3. A start-up billet head according to claim 1, wherein the at least one undercut begins parallel to a stay of the preliminary billet profile and then follows a transition between the stay and the flange of the preliminary billet profile end extends within the flange with a certain proportion of the thickness of the flange.

4. A start-up billet head according to claim 1, wherein on the active side of the hook-shaped coupling part a flange wall is formed whose wall surface extends into the area of the undercut.

5. A start-up billet head according to claim 4, wherein the flange wall has a thickness which corresponds approximately to half the thickness of the flange.

6. A start-up billet head according to claim 1, wherein the preliminary billet profile has a stay connected to the flange and wherein, with decreasing thickness of the stay of the billet profile, the at least one undercut is limited to the at least one flange or angled joint of the preliminary billet profile.