Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/10—Supplying or treating molten metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/08—Accessories for starting the casting procedure
  • B22D11/086—Means for connecting cast ingots of different sizes or compositions

Definitions

• the invention relates to a method for changing the thickness of a strand, in particular a steel strand, from a first thickness to a second thickness during continuous casting using a continuous casting mold having a continuous cavity with at least two first ones delimiting the cavity on opposite sides, by their position Width of the strand defining side walls, and at least two further second side walls adjoining the first side walls, which determine the thickness of the strand due to their position and with a strand guide supporting the cast strand in continuation of the second side surfaces and adaptable to different thicknesses of the strand, as well as a device to carry out the procedure.
• the former is necessary if, as in DE-B 29 03 245, with one in the continuous casting mold
• the transition piece to be used is worked and a short sweet transition section is formed which extends from the first width to a new width, the latter when the narrow side walls are slowly adjusted to the new strand width during casting and a longer strand transition section is created.
• the purpose of the formation is to create a method with which the thickness of a strand can be changed from a first thickness to a second thickness without having to stop the casting of the strand.
• the casting had to be stopped, the strand already cast had to be removed completely from the mold and the subsequent strand guide, then the mold had to be replaced or replaced rebuild the narrow sides and adapt the strand guide to the new casting thickness, whereupon a cold strand had to be introduced into the south inlet or into the mold. Only then could the casting process be started again. This was cumbersome and time consuming, especially due to the long downtime of the plant. This is particularly disadvantageous if casting ladles with melt are continuously supplied from the steelworks to the casting hall.
• the invention aims to avoid these disadvantages and difficulties and has as its object to provide a method of the type described above and a cine device for carrying out the method, which make it possible to change the thickness of a strand without having to interrupt the casting process .
• That a sleeve is attached to the intermediate end of the strand by welding one end thereof to the intermediate end of the strand,
• the strand guide is adapted to the second thickness of the strand after the beginning of a further pulling out of the strand, etc. following the progress of extending the strand transition point from the first thickness to the second thickness and in the longitudinal direction of the strand guide gradually.
• Changing a mold narrow side in a continuous slab caster results in significant cost savings, since such a set of narrow sides costs around 5% of the cost of a mold.
• a change in casting thickness is particularly advantageously carried out when a distributor change must take place.
• the intermediate end of the strand is brought to a level below the continuous casting mold by pulling out the strand.
• the second side walls are expediently brought to a distance which is greater than the second thickness of the strand and are only subsequently placed on the sleeve before the sleeve is attached.
• an intermediate space between the sleeve and the side walls of the continuous casting mold is sealed.
• the first side walls are advantageously exchanged for first side walls which are designed in accordance with the second thickness of the strand.
• first side walls which are adjustable in width, for example to provide side walls with mutually displaceable components, as a result of which the continuous casting mold can also be adjusted from the first thickness to the second thickness in a short time.
• the strand guide advantageously changes in a wedge shape from the first thickness to the second thickness while adapting to the second thickness, and this wedge-shaped transition region migrates over the length of the strand guide in synchronism with the pulling out of the strand With.
• the strand guide is formed from segments which are adjustable in the thickness of the strand, the strand guide is expediently gradually, i.e. gradually adapted in sections to the second thickness of the strand.
• only one side wall of the two second side walls is adjusted to the dimension of the second thickness of the strand, and one of the two second side walls remains in place while the thickness is changed.
• the pull-out speed and / or the instantaneous position of the intermediate end of the strand is advantageously recorded, and the strand guide is adjusted via a control or regulating device as a function of the pull-out speed and / or the position of the intermediate end of the strand.
• a device for carrying out the method with a continuous casting mold which has adjustable side walls, and with a strand guide arranged downstream of the continuous casting mold and supporting the strand on opposite sides in the thickness direction
• Different thicknesses of strands can be adapted, is characterized by side walls which can be adapted to different thicknesses of strands and by a sleeve, one end of which forms a strand cross-sectional format, the thickness of which deviates from the thickness initially set on the continuous casting mold.
• the sleeve corresponds at one end to a first strand cross-sectional format with a first thickness and at the other end to a second strand cross-sectional format with a second thickness different from the first thickness, expedient in the case of an enlargement the thickness of the strand, the end of the sleeve that can be attached to the intermediate end of the strand is slightly smaller in cross-section, preferably less by an average of the thickness of the strand shell at the intermediate end, than the strand cross-section, and further advantageously the End of the strand attachable end of the sleeve is tapered on the outside towards the end.
• the device is characterized by means for detecting the pull-out speed or the instantaneous position of the intermediate end of the strand, a control or regulating unit coupled thereto and adjusting means for adjusting the strand guide, the adjusting means being activatable by means of the control or regulating unit and can be deactivated.
• FIGS. 1 to 4 each illustrating a continuous casting plant in a schematic representation in a side view in various stages during a change from a first thickness Di to a second thickness D.
• FIGS. 5 and 6 each show a detail of FIG. 2 and FIGS. 7 to 14 illustrate variants of the method according to the invention or the devices therefor.
• a continuous casting installation for casting a steel strand 1 with a slab cross section is illustrated in each of the figures.
• the molten steel 2 is allowed to flow from a ladle 3 into an intermediate vessel 4, from which the melt 2 flows into the continuous casting mold 6 via a pouring tube 7 reaching into a cavity 5 of a continuous casting mold 6.
• the continuous casting mold 6 is preferably designed as a plate mold and has two first side walls 8, forming the narrow side walls of the strand 1, and two second side walls 10, 10 'forming the wide side walls 9 of the strand 1, both the first and the second side walls 8 , 10, 10 'by means of actuators 11 for Adaptation to different strand cross sections and adjustment of different conicities adapted to the strand cross sections are adjustable.
• the continuous casting mold 6 is of course provided with internal cooling and with an oscillation device, but these details are not shown for the sake of clarity.
• the first side walls 8 are preferably interchangeable, for example by means of a quick-change device, so that the continuous casting mold 6 can be used for casting strands with different thicknesses.
• these could also be adjustable, for example by means of parts which can be moved relative to one another, so that this also makes it possible to adapt to different thicknesses Di and D 2 of strands 1.
• a further possibility would be to clamp the second side walls 10, 10 'between the first side walls 8, so that the second side walls 10, 10' can be moved towards or from one another and always form a closed cavity with the first side walls 8 circumferentially.
• a strand guide 13 is provided below the continuous casting mold 6, which is formed from mutually opposite and supported in support elements 16, 17 and 18, support rollers 12, which extends over approximately a quarter-circle arc into the horizontal, and which initially supports a thin strand shell 14 and one if necessary, strand 1 comprising liquid core 15 extending into the horizontal is used.
• the first support element of the strand guide 13 directly below the continuous casting mold 6 is designed as a straight guide 16.
• a bending zone 17 adjoins this next support element, in which the strand 1 initially emerging from the continuous casting mold 6 in a straight form is bent into a circular arc shape.
• the bending zone 17 is followed by a circular-arc-shaped strand guide part formed from a plurality of support segments 18 arranged one behind the other, which is followed by a straightening zone (no longer shown) and a horizontal strand guide, as is generally realized in arc continuous casting plants.
• the strand guide 13 is entirely adaptable to different thicknesses of cast strands by means of adjusting devices 19, preferably one side of the two roller conveyors lying opposite one another and forming the strand guide 13, etc.
• the outer or lower of the roller tracks is designed as a fixed side against which the opposite inner or upper roller track can be adjusted.
• the roller conveyor sections which are arranged in the straight guide 16, the bending zone 17 and on the individual segments 18 can be preferably with the formation of a wedge-shaped strand guide piece - as illustrated in FIG. 4 for a segment 18 '- and from this wedge position again in an approximately concentric position to the outer roller conveyor and moved back.
• FIG. 1 to 4 illustrate the method according to the invention for changing over a first thickness Di of strand 1 to a second, larger thickness D 2 of strand 1:
• the casting is interrupted and the intermediate vessel 4 is pivoted to the side, so that the continuous casting mold 6 is easily accessible from above.
• the second side walls 10, 10 ' are then separated from one another, etc. to a distance D 3 , which is greater than the second thickness D 2 of the strand 1 to be cast.
• D 3 is greater than the second thickness D 2 of the strand 1 to be cast.
• only one side wall 10 'of the two side walls 10, 10' is adjusted; the second side wall 10 arranged in alignment with the fixed side of the strand guide 13 remains in its position.
• the strand 1 with the intermediate end 20 formed on it is brought into a position below the continuous casting mold 6, whereupon a sleeve 21 is attached to this intermediate end 20 (cf. FIGS. 2 and 5).
• This sleeve 21 has at its lower end 22 attached to the intermediate end 20 a cross section which is slightly less than the strand cross section with the first thickness Di, so that the walls of the sleeve 21 into the still liquid core 15 of the strand 1 immerse, but on the already solidified side walls of strand 1, ie the strand shell 14, come to the plant.
• the lower end region 23 of the sleeve 21 is beveled in a wedge shape. The lower end region 23 of the sleeve 21 is welded to the intermediate end 20 of the strand 1.
• the upper end 24 of the sleeve 21 has a cross section with a second thickness D 2 , with which the strand 1 is to be cast further.
• a second thickness D 2 Between the lower end 22 of the sleeve 21 and the upper end 24 of the sleeve 21 is one side of the sleeve 21, etc. the side which interacts with the adjustable second side wall 10 'of the continuous casting mold 6 is formed in a projecting manner, an inclined transition surface 25 being provided between the lower sleeve part and the upper sleeve part.
• the sleeve 21 is surrounded by a seal 26 - preferably two seals 26 arranged at different altitudes - which come into operation when the adjustable second side wall 10 ′ is moved against the opposite second side wall 10 and a tight fit of the walls of the sleeve 21 on the first and second side walls 8, 10, 10 'of the continuous casting mold 6, as illustrated in FIG. 6.
• first side walls 8 which were present in the continuous casting mold when casting a strand 1 with the first thickness Di, are replaced, etc. against first side walls 8 ', which are designed in accordance with the second thickness D 2 (shown in broken lines in FIG. 5), so that these first side walls 8' can in turn be clamped between the second side walls 10, 10 '.
• first side walls 8 ′ which are designed in accordance with the second thickness D 2 (shown in broken lines in FIG. 5)
• the continuous casting is continued, the sleeve 21 first being filled with the melt 2 (FIG. 3).
• the sleeve 21 is directly exposed to a coolant, preferably cooling water, on the outside sprayed intensively.
• step by step, etc. proceeded segment-wise, with each of the rollers 12 of a segment 18 initially being brought into the wedge position illustrated in FIG. 4 for the segment 18 'during the transition from the first thickness Di to the second thickness D 2 .
• both roller tracks of the strand guide 13 are adjusted symmetrically to the strand center line 27 to the new thickness dimension D 2 , with both second side walls 10, 10 ′ of the continuous casting mold 6 likewise being adjusted here must be set symmetrically to the central axis of the continuous casting mold 6 to the new thickness dimension D.
• the adjusting devices 19 are used, as mentioned above, which can preferably be activated and deactivated via a regulating or control device 28.
• the regulating or control device 28 is coupled to a device for detecting the pull-out speed according to FIG. 1 with the drive rollers 29 detecting the strands on both sides of its broad sides 9, which makes it possible for the individual elements 16, 17 and 18 to be dependent on the position of the strand transition piece from the first thickness Di to the second thickness D.
• the strand 1 is supported over almost its entire length by the strand guide 13 over the section at which it still has the first thickness Di and only directly on the strand transition piece from the first thickness Di to the second thickness D 2 , that is to say only over one short piece, not in direct contact with the rollers 12.
• a new design of the mold is of particular importance for realizing the method according to the invention.
• the broad sides of a continuous slab casting mold were clamped against the narrow sides by means of prestressed disc springs, it being possible to release the clamping by means of a pressure medium cylinder.
• the broad sides could only be moved over extremely short adjustment paths, namely those travel paths that are necessary to free the narrow sides for the purpose of exchanging them for intact ones.
• This prior art is described in documents AT-B - 366.607, AT-B - 343.304 and AT-B - 344.929.
• the broad side walls of a slab mold can be adjusted to a very small extent by means of a pressure medium cylinder for setting different gaps between a broad side and a narrow side, but the narrow sides, which are always of equal width, are also clamped by means of spring assemblies by means of the broad sides .
• the disadvantage associated with these known molds is that when changing the casting thickness, the entire mold always had to be removed and replaced by another mold, which is designed for the other casting thickness. Although it was possible to exchange the narrow sides for a different casting thickness on a mold, this has so far, if at all, only been possible in the maintenance workshop, since complex conversion work is required in such a case.
• a new construction of the mold according to the invention has a hydraulic clamping device 30 for clamping the narrow sides 8, 8 'between the broad sides 10, 10', the broad sides 10, 10 ', in this case the second side walls 10, 10', by means of the Hydraulics are adjustable over a defined casting thickness range 31.
• FIG. 9 shows a section parallel to the vertical longitudinal axis 32 of a mold through the hydraulic cylinders 30, which are used to adjust the wide side walls 10, 10 ', i.e. serve the second side walls 10, 10 'of a slab mold.
• 10 shows a side view of the second side walls 10, 10 ', so that the arrangement of the hydraulic cylinders 30 on the second side walls 10, 10' can be seen.
• FIG. 12 shows a further variant of a continuous casting mold for carrying out the method according to the invention, wherein a second side wall 10 'is flat, but the opposite second side wall 10 is U-shaped.
• the first side walls 8, 8 ' are clamped between the two second side walls 10, 10'.
• the second side walls 10, 10 ' are moved apart, which is also done hydraulically, whereupon the first side walls 8, 8' are placed on the mutually parallel legs of the second side wall 10, which is U-shaped in plan how to do this with dashed lines in Fig. 12 is illustrated schematically.
• the first side walls 8, 8 'are then clamped between the second side walls 10, 10', and the continuous casting can be continued.
• FIG. 13 and 14 illustrate the change in the thickness of the strand 1 from a first thickness Di to a second thickness D 2 which is less than the first thickness Di: in this case, a sleeve 21 has a lower end region, which corresponds to the first larger thickness Di of the strand 1, and its upper end region is designed in accordance with the second smaller thickness D 2 .
• the first side walls 8, 8 ' that is to say the narrow side walls, can then be exchanged for narrower ones, and after the narrower narrow side walls have been clamped, the casting can be continued.
• the strand guide rollers 12 of the strand guide consisting of the parts 13, 16, 17, are adapted to the new strand thickness D 2 in accordance with the progressive extension of the strand 1.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Metal Rolling (AREA)
• Moulding By Coating Moulds (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3522818

Family Applications (1)

Country Status (7)

Families Citing this family (1)

Citations (2)

Family Cites Families (1)

• 1998
  • 1998-11-10 AT AT0187198A patent/AT406745B/de not_active IP Right Cessation
• 1999
  • 1999-10-12 WO PCT/AT1999/000244 patent/WO2000027564A1/de not_active Application Discontinuation
  • 1999-10-12 KR KR1020017005909A patent/KR20010080985A/ko not_active Application Discontinuation
  • 1999-10-12 JP JP2000580780A patent/JP2004500243A/ja not_active Withdrawn
  • 1999-10-12 CN CN99815289A patent/CN1332659A/zh active Pending
  • 1999-10-21 DE DE19950830A patent/DE19950830A1/de not_active Withdrawn
  • 1999-10-29 IT IT1999MI002266A patent/IT1313981B1/it active

Patent Citations (2)

Also Published As

Similar Documents

Legal Events