Bow-type continuous casting plant for billets.

The invention relates to a bow-type according to the preamble of Claim first

In order to achieve a low profile in steel casting, molds are used with curved mold cavity. By reducing the arc radii of such molds, the height could be reduced further. With decreasing Kokillenradien but elongation increases during straightening of the strand in the strand crust in the leveler. It has therefore been proposed to combine Kreisbogenkokillen with oval-arcuate strand guides. Such plants require for casting a flexible dummy bar, which is usually of articulated limbs.

For smaller formats, namely metal billets plants, are at Kreisbogenstranggiessanlagen instead of flexible starter bars advantageously so-called rigid, arcuate starter bars verwendet.In Offenlegungsschrift 2'629'453, which forms the preamble is, a curved continuous billet or Vorblockstränge with a rigid dummy described. The length of the dummy bar is such that simultaneously the head end is inserted into the curved mold and the foot end is on the blowing leveler engaged. In Tangentpunkt a pair of driving rollers of the traction leveler is arranged. A straightening roller, the same strand, a decoupling between Anfahr and cast strand performs, directs the arc-shaped strand in Tangentpunkt after the one-point straightening method. After uncoupling the rigid starting bar is brought by a drive in a parking device above the horizontal Ausförderstrecke. With correspondingly large circular arc, for example, between 4 and 8 m radius, such, they are also susceptible to cracking steels or larger strand formats, because the strain is smaller when straightening with increasing radius of the arc. If a radius of the arc of 3 m or less is provided, so the strain increased during straightening in Tangentpunkt. The distance between the pair of driving rollers in Tangentpunkt and the disconnection and straightening roller is shorter. This leads to structural and / or surface defects on the cast strands.

The invention has for its object to provide a curved continuous with a rigid dummy bar, on the one hand has a low profile with a radius of curvature of, for example, R ≦ 3 m and at the same structural and / or surface defects such as cracks etc. avoids the cast strand.

To achieve this object the invention proposes a curved continuous front according to the sum of the features of claim. 1

The inventive curved continuous allows to pass out a rigid, circular dummy by an oval-arcuate strand guide member without radial bending forces act on the dummy. In further enables the inventive basic concept, to replace a portion of the arcuate strand guideway through the oval-arcuate straightening path, whereby early, for example before reaching the Tangentpunktes, the cast arcuate strand into two or more sub-stages can be gently bent. The bending reaction roller (s) shall ensure that the train, regardless of any irregular temperature, especially during Angiessperiode, well-defined strain changes along the straightening section is exposed. In contrast to the inventive concept of straightening strand uncontrollably directed at one stage in the known Einpunktrichten. In this case, the strand is not directed along a curve, but in accordance with its instantaneous local resistance to bending. According to the invention therefore can be with rigid dummy first time without detriment to the cast strand in its structure significantly reduced, which has a positive effect on both the height of the plant as well as the length of the parking facility for the rigid starting bar bulky Bogenstranggiessanlagen.

The oval-arcuate straightening path can start seen in strand direction eg when a vertical radii beam and subsequent to the Richtstreecke Ausförderstrecke for cast strands may rise slightly or be arranged horizontally. An advantageous embodiment is obtained when the pair of driving rollers arranged on a radius beam which is in train running direction before the vertical radii beam and between two radii beams an angle to 30 degrees, preferably between 5-20 degrees, is provided. is proposed as a further alternative solution, to be located on the vertical beam radii bending reaction roller of the oval-arcuate straightening path.

The start of the bending process along the strand guide can be freely selected by a placement of the traction roller pair according to the size of the intended Giessformates, steel quality etc.. The design principle also allows free design of the indicative number of stages between the pair of driving rollers and straightening rollers. According to another proposed solution, the disposed in the strand conveying direction after the vertical radii beam straightening roller separate the cast strand at the same time uncoupling from dummy and lead straight from the arc via an oval arc in an at least two directional stages. Between the pair of driving rollers and the leveling roll any number of bending reaction rollers can be arranged along the outside of the oval-arcuate straightening path.

At the discretion of the skilled artisan, the format and quality steel specific expansions to the strand surface to bend pipes in front of and shared in the vertical radii beam. For the purpose of an additional alternative solution is proposed, that is arranged on the vertical radii beam bending reaction roller is fixed in position so that the straightening section is divided into two part straightening distances with substantially equal part strain on the strand surface. The change in elongation along the straightening section of the strand surface with a strand thickness of, for example, 100 mm can be adjusted advantageously to a maximum of 0.002% / mm.

The dummy bar with the coupling member of the cast strand can be attached directly to the rigid starting bar. There are also known variants, which provide between the dummy bar and the rigid starting bar an additional coupling element, which ensures a separation between the cast strand and the dummy at each casting cycle. In a particularly advantageous embodiment of the rigid starting bar has a pivotal Anfahrkopfglied with a pivot axis parallel to the pivot axis of the dummy bar. The role for uncoupling of the dummy bar from the cast strand exerts a radially directed substantially to the arcuate tracts force on this Anfahrkopfglied. This uncoupling is initiated before the cast strand reaches the target and Entkupplungsrolle. Such a dummy can be smoothly inserted into the mold in addition, even if the dummy or the strand guide having by wear certain dimensional tolerances for nominal dimensions. The dummy bar can easily pivoted during retraction by the mold and thereby be centered. Modern sealing methods simultaneously to pinch when entering a seal, such as described in EP Patent No. 0'114'309, are also applicable to such investments.

The precision of the introduction of the dummy bar can be further increased when the dummy bar is guided at its opposite end to the dummy bar by means of an articulated in an arc center of the pivot lever.

In the following the invention will be described with reference to figures of exemplary embodiments.

Show it:<ul><li>FIG. 1 is a side view of a curved continuous schematically illustrated and</li><li>FIG. 2 is a side view of an oval-arcuate straightening path.</li></ul>

In Fig. 1 is a bow-type with a curved mold 3, an oscillating means 4 and a secondary cooling device 5 is shown. The center of the circular arc is denoted by the ninth A blowing leveler is made of a pair of driving rollers 6, 6 ', a straightening roller 7 and a bending reaction roller 8 constructed. A circular arc-shaped rigid starting bar 10, which is held and guided by an articulated in an arc center 9 pivot lever 11 during the movement is shown in an uncoupling position of a cast strand 12th A stop short 13 represents a portion of a parking device. The pivot lever 11, which may be connected to the dummy bar 10 fixed or detachable, has a not shown, per se known rotary actuator.

He can the dummy pivot about the arc center 9 and insert it into the drive roller pair 6, 6 'or lead out of this. An arrow 15 points to an uncoupling, in which the straightening roller 7 separates the cast strand 12 and disengaged from the dummy bar 10th Below the guide track 17 of the arc-shaped dummy 10 a oval-arcuate straightening section 18 is provided with the bending reaction roller 8 for the cast strand between the pair of driving rollers 6, 6 'and the uncoupling 15th The Teibrollenpaar 6, 6 'is on the circular arc, for example, has a radius of 2.5 m. The bending reaction roller 8 is positioned such that a first example of Aufbiegeradius yields 4.5 m. A following roller 20 is already arranged in the horizontal plane of a cooling bed. With 7 'is shown in a 7 position to the disengagement dash-dotted lines the role. She has in this position the function of straightening roller.

The rollers 20 are Ausförderstrecke, which can be arranged horizontally or slightly inclined. The pair of driving rollers 6, 6 'is located on a radius ray 21 of the guide track 17 of the arc-shaped dummy bar 10 begins at the center of the ninth This radii beam 21 is in strand direction 22 in front of a vertical beam radii 23. Between two radii beams 21, 23 is an angle alpha, for example, to 30 degrees, preferably between 5-20 degrees provided.

On the vertical radii beam 23 and the bending reaction roller 8 of oval-arcuate straightening section 18 is arranged. It is located below the guide track 17 of the arcuate starter bar 10, approximately in the middle of the oval-arcuate straightening section 18. Between the rollers 6, 6 'and the bending reaction roller 8, the strand is bent in a first step. In the strand conveying direction 22 after the vertical radii beam 23 separates at Ent clutch stelle 15 the straightening roller 7 the cast strand from the dummy and bends the cast strand in the said two directional stairs from the arc via an Oval arc into a straight line. The position of the bending reaction roller 8 or the radius of the first bending step can be calculated so that arise along the straightening section 18 two part straightening distances with substantially equal strain on the strand surface. It can be easily implemented for example in a 100 mm thick strand, an arc radius of 2500 mm, a length of the straightening section of at least 1000 mm strain changes Epsilon in% / mm at the strand surface of 0.002.

In FIG. 2, the same reference numerals as in Fig. 1 are used for the same parts. The rigid dummy bar 10 is provided with a pivotable Anfahrkopfglied 25 with a pivot axis 26 parallel to the pivot axis in the arc center 9 (Fig. 1) of the dummy bar 10 is provided. The roller 7 to disengage the starter bar 10 from the cast strand 12 exerts a radially directed substantially to the arcuate tracts force on the Anfahrkopfglied 25th The uncoupling, in this example, initiated earlier and the foot end of the strand 12 can be better directed. The Anfahrkopfglied 25 is provided with means to ensure a return of the tilting member 25 in the arcuate shape of the dummy bar 10th

In addition to the roller 8 is in this example a further bending reaction roller 8 'included, which results in an additional straightening stage. The cast strand 12 is directed in this example by means of the roller 7 at the same time in three directional stages. Dot-dash line, the arc-shaped guide track 17 of the dummy bar 10 is shown.