Field of Invention
The present invention relates to an arrangement for aligning tundish nozzles for multi-strand billet casters in continuous casting shop. More particularly, the invention relates to a arrangement comprising hydraulic power pack for controlling the movement of the alignment templates and providing a precise, fast and accurate alignment of the nozzles the tundish nozzles for multi-strand billet casters in continuous casting shop.
Background Art
In the earlier arrangement, the tundishes were kept on one of the six tundish alignment stands for relining and maneuvered by the overhead crane in the available gap of approximately 20 mm to achieve and approximate alignment of the nozzle seat holes with respect of fixed template. The nozzles are placed in the nozzle seats.
US 4148351 describes a device for aligning the mould tube of the caster. The mould tube is a part of the casting machine into which the molten steel is poured through the tundish nozzles for casting and is implemented in the mould tube and is about the alignment of the mould tube. There is no component for aligning the nozzles and placing them perfectly in the tundish in alignment with the template.
Generally the continuous casting shop has two 6 strand billet casters where the molten steel is brought in ladles and is poured into tundish. Each tundish has six nozzles from where the molten steel is poured into the moulds or casting billed of section 100x100 - 150x150 sq. mm The nozzles in the tundish need to be accurately aligned with respect to the moulds for such defined section sizes For this purpose the continuous casting shop has six tundish alignment stands for tundish preparation. In each of the tundishes six nozzles are placed during relining. The alignment of tundish nozzles with respect to the fixed nozzles setting template, which matches the moulds in the casters, is important for smooth casting. Any misalignment results in off centering of the nozzles with respect to mould and thereby strand stoppage or eventual breakout of casting
The main disadvantage with the existing arrangement is that there is no dedicated arrangement for movement of the tundish with respect to the template or vice-versa in any of the 6 stands
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Another disadvantage is that the relining and maneuvering of the tundish in the alignment stands being done by the overhead crane, controlled movement of tundish is not possible
The other disadvantage is that the alignment of the tundish with respect to the template take a lot of time due to uncontrolled and inaccurate movement of tundish by the overhead crane.
Thus there is a need to provide a simple, operator friendly arrangement with all the controls conveniently available to the operator for controlling the movement of the alignment template very precisely for fast and accurate alignment of the nozzles thereby reducing loss in production time and increasing production by eliminating misalignment of the tundish
nozzles.
Objects Of The Invention
The basic object of the present invention is to impart inching motion (high precision movement) of the template with respect to the nozzles of the tundish.
Another object of the present invention is to increase the casters strand availability or average availability of number of strands for casting from 5.5 to 5.6.
Another object is accurate placement of nozzles in the tundish.
The other object is to reduce the overhead crane engagement time from about 1 hour to 15 minutes.
Summary Of Invention
Thus according to the main aspect of the present invention there is provided an arrangement for controlling the movement of the templates to align it with respect to the holes of the tundish thereby providing a precise, fast and accurate alignment of the nozzles for multi-strand billet casters for continuous casting, said arrangement comprising:
(i) tundish with nozzles;
(ii) tundish hole alignment checking template adapted for aligning tundish
holes;
(iii) means in contact with the said template for providing guided motion to it; (iv) nozzle setting blocks with stepped hole adapted for final alignment of
nozzles;
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(v) at least one alignment fixture placed on the said template and adapted for initial alignment of the tundish nozzles with said blocks on template;
(vi) at least one nozzle setting rod adapted for final alignment of the tundish nozzles with said blocks on template and;
(vii) means for providing power for the said controlled motion.
Detail Description Of The Invention
The arrangement for aligning tundish nozzles of the present invention comprises tundish holes alignment checking template, PLC controlled hydraulic power pack, alignment mechanism, plurality of alignment fixtures and nozzle setting rods.
The tundish holes alignment checking template is used prior to nozzles alignment for checking the straightness of the tundish holes of diameter 100 mm. The nozzles are required to be aligned in the tundish for proper casting in the six strand casters where the six moulds are kept at a center distance of 1100 mm accurately. The diameter of tundish holes 100 mm and the tundish nozzles outer diameter is about 94 mm, so that the nozzles can be disposed accurately in the holes maintaining 6 mm clearance. The movable template on the tundish alignment stand imparted with inching motion is adapted for accurately aligning it with the tundish holes. The nozzles are then placed in the tundish at an exact distance of 1100 mm.
In the present invention the mechanism for alignment of tundish nozzles with template comprises a fabricated beam, fabricate template, sliding joints and guides adapted to provide guided translatory motion to the template in the horizontal XY plane and the longitudinal X axis, transverse Y axis and rotary motion in XY plane. The sliding joints are provided with sliding plates to minimise friction. The material of the sliding plate is copper, tin, zinc and lead. The sliding plates are provided with grooves for effective lubrication of its total bearing area and port for lubrication. The mechanism is simply supported by fabricated structural bracket on the tundish alignment stands.
The alignment mechanism comprises a fabricated template adapted for checking the geometrical correctness of the nozzle seating holes in the tundish.
The arrangement comprises six alignment fixtures with outer diameter of 99 5 mm and length 400 mm, which are fabricated from seamless pipe with appropriate tolerance to it and is
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adapted to check the initial alignment of the template with respect to tundish The seamless pipe has internal diameter of 50 mm and outer diameter of 80 mm.
The PLC controlled hydraulic power pack comprises hydraulic oil reservoir of capacity 200 liters, motor, pump and air cooled oil cooler, double acting cylinders with a maximum working pressure of 210 kg/cm2, solenoid operated directional valves, flow control valves, pilot operated check valves, pressure regulator, pressure line filter, return line filter, accumulated and impulse tubing and fitting.
The PLC controlled hydraulic power pack is adapted for providing controlled continuous as well as inching movement alignment mechanism to the template in two axes i e. X axis and Y axis and rotational motion in the XY plane i.e. the horizontal plane, to align the tundish nozzle with respect to the template. The PLC controlled hydraulic power pack provides inching movement to the template for accurately aligning the template with tundish. The PLC provides signal accordingly to the valves for appropriate movement of the cylinders and is capable of providing motions in X direction, Y direction and XY direction with a displacement of 1 mm per momentary push button operation The speed of the actuator is controlled by adjustment of the flow control valves in the hydraulic cylinders to achieve the inching motion of 1 mm per momentary push and release operation of push buttons.
The hydraulic cylinders of the hydraulic power pack are adapted for providing desired motion to the mechanism for accurate alignment One double acting cylinder of the hydraulic power pack is adapted to impart linear motion of the beam and the template in X direction. Two hydraulic cylinders are mounted on the said beam and is adapted to impart linear motion in Y direction and rotational motion in XY plane to the template The beams are provided with counterweights adapted to counter the dead weight of the cylinders and their mounting brackets. The sliding plate and the guide provided in the template is adapted for constraining motion of the mechanism in the X direction The template comprises a center guide and a pin arrangement adapted to constrain the translatory motion of the template along Y direction and rotational motion in the XY plane
The hydraulic power pack and its main control panel, which houses the PLC and electrical components is installed in brick work and roof enclosure comprising an exhaust fan, rolling shutter and louvered window and having proper illumination
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The main control panel is mounted on the floor in the enclosure. The main control panel is adapted for housing the PLC and all the power and control circuit elements including DC power pack of 24 Volts DC, 10 Amps.
The hydraulic power pack is operated by push button control on the local control panel and the pendant control panel through the PLC. The PLC is Siemens S7-200 with a Programming Software STEP7-Micro/WIN32 and communication cable PC-PPI Cable. The PLC runs software logic developed in STEP7-Micro/WIN32 software adapted for operating the hydraulic power pack. The control push button when pushed to ON position, the PLC provides signals in predetermined sequence to the solenoid operated direction control bar for moving the template in different directions. Depending on the sequence of valve operation as per command given through the control panel push buttons, the template moves in X direction, Y direction or XY direction in the XY plane thus aligning the template with respect to the Tundish
Nozzle setting rods are of diameters 12 mm, 13 mm, 15 mm and 16 mm having appropriate tolerance adapted for the final alignment of the nozzles with nozzle setting blocks in the template The nozzle setting blocks in the template are provided with corresponding stepped hole having diameter of decreasing dimension. The stepped hole is of 16 mm, 15 mm, 13 mm and 12 mm diameter, each step length being 20 mm with appropriate tolerance adapted for accurate and precised alignment of the nozzles in the tundish.
A local control arrangement installed on the tundish alignment stand platform is adapted for control and indications of the operation in the arrangement. A pendant type operator panel comprising all push button controls is adapted to operate the arrangement in a user-friendly manner A selection switch provided in the local control station is adapted to select between local control panel and pendant control panel for operating the arrangement from either one of these panels
The process for alignment of nozzles comprises checking the tundish with the tundish hole alignment checking template for geometrical correctness of the tundish nozzle holes, placing the tundishes which are found alright and the rectified tundishes on the tundish alignment stand for alignment of tundish nozzle, aligning the template by inching motion provided by the hydraulic cylinder and finally aligning the tundish nozzle by means of nozzle setting rods.
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Brief Description Of Accompanying Figures
Figure 1 illustrates the elevation view of the alignment mechanism of the present invention along with the tundish.
Figure 2 illustrates the plan view of the alignment mechanism of the present invention. Figure 3 illustrates the tundish hole alignment-checking template along with tundish turned upside down.
Figure 4 illustrates the alignment fixture of the alignment mechanism of the present invention
Figure 5 illustrates the sectional view of the tundish nozzle and nozzle setting blocks.
Figure 6 illustrates the nozzle setting rods.
Figures 7(a) and 7 (b) illustrate the misalignments in the X-direction.
Figures 8 (a) and 8 (b) illustrate the misalignments in the Y-direction
Figures 9 (a) and 9 (b) illustrate the angular misalignments.
Figure 10 illustrates the alignment mechanism of the present invention along with alignment
fixtures.
Figure 11 illustrates the final placement of nozzles.
Detail Description Of Accompanying Figures
In figure 1 the elevation view of the alignment mechanism of the present invention is illustrated As shown in figure 1 the mechanism for alignment of tundish nozzles (15) of the tundish (27), shown in figure 5 with tundish holes alignment checking template (1) (also shown in figure 3) which are fabricated and comprises a fabricated beam (2), sliding joints (3) and guides (4). The fabricated beam (2), sliding joints (3), guides (4), central guide (9) and pin arrangement (10) provide guided translatory motion to the template (1) in the horizontal XY plane and the longitudinal X-axis, transverse Y-axis and rotary motion in XY plane The sliding joints (3) and guides (4) are provided with sliding plates (5) (shown in figure 2) to minimise friction The material of the sliding plate (5) is copper, tin, zinc and lead alloy. The sliding plates (5) (shown in figure 2) are provided with grooves (6) for effective lubrication of its total bearing area and port for lubrication The mechanism is simply supported by fabricated structural bracket (7) on the tundish alignment stands (8). The sliding plate (5) and the guide (4) provided in the mechanism is adapted for constraining motion of
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the mechanism in the X direction. The mechanism comprises a center guide (9) and a pin arrangement (10) adapted to constrain the translatory motion of the mechanism along Y direction and rotational motion in the XY plane
In figure 2 the plan view of the alignment mechanism of the present invention is illustrated. In the figure two hydraulic cylinders (11) are mounted on the said fabricated beam (2) and is adapted to impart linear motion in Y direction and rotational motion in XY plane to the fabricated template (1) The fabricated beam (2) is provided with counterweights (12) adapted to counter the dead weight of the hydraulic cylinders (11) and their mounting brackets (13).
In figure 4 the alignment fixture of the alignment mechanism of the present invention is illustrated. In the figure the alignment fixture (14) fabricated from seamless pipe (26) with appropriate tolerance to it is adapted to check the initial alignment of the template (1) with respect to tundish nozzle (15).
In figure 5 the sectional views of the tundish nozzle (15) and nozzle setting blocks (16) are illustrated. The nozzle setting rods (17) (shown in figure 6) having appropriate tolerance are adapted for the final alignment of the tundish nozzles (15) with nozzle setting blocks (16) in the template (1) The nozzle setting blocks (16) in the template (1) are provided with corresponding stepped holes (18) adapted for accurate alignment of the nozzles in the tundish.
In Figures 7(a) and 7 (b) the misalignments in the X-direction are illustrated In figure (7a) the misalignment (19) of the tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown. The hydraulic cylinder (11) moves the fabricated beam (2) along with the template (1) to the left position (20) by movement in the X-direction to the left. In figure (7b) the misalignment (21) of the tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown. The hydraulic cylinder (11) moves the fabricated beam (2) along with the template (1) to the right position (20) by movement in the X-direction to the right.
In Figures 8(a) and 8(b) the misalignments in the Y-direction are illustrated. In figure (8a) the misalignment (22) of the tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown. The hydraulic cylinder (11) moves the fabricated beam (2) along with the template (1) inward by movement in the Y-direction. In figure (8b) the misalignment (23) of the Tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown The hydraulic
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cylinder (11) moves the fabricated beam (2) along with the template (1) to the outward position by movement in the Y-direction
In Figures 9(a) and 9(b) the angular misalignments are illustrated. In figure (9a) the angular misalignment (24) of the tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown. The hydraulic cylinder (11) rotates the template (1) in anti-clockwise direction. In figure (9b) the misalignment (25) of the tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown. The hydraulic cylinder (11) rotates the template (1) in clockwise direction.
In figure 10 the alignment mechanism of the present invention along with alignment fixtures (14) is illustrated for checking the alignment of template with respect to the tundish.
In figure 11 the final placement of nozzles is illustrated The nozzle setting rods (17) for final alignment of the tundish nozzles (15) with respect to the nozzle setting blocks (16) is shown.
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We claim:
1 An arrangement for controlling the movement of the templates to align it with respect
to the holes of the tundish thereby providing a precise, fast and accurate alignment of the nozzles for multi-strand billet casters for continuous casting, said arrangement comprising:
(i) tundish with nozzles;
(ii) tundish hole alignment checking template adapted for aligning tundish
holes,
(iii) means in contact with the said template for providing guided motion to it; (iv) nozzle setting blocks with stepped hole adapted for final alignment of
nozzles; (v) at least one alignment fixture placed on the said template and adapted for
initial alignment of the tundish nozzles with said blocks on template, (vi) at least one nozzle setting rod adapted for final alignment of the tundish
nozzles with said blocks on template and; (vii) means for providing power for the said controlled motion.
2. An arrangement as claimed in claim 1, wherein the said blocks on the said fabricated
template are nozzle setting blocks comprising stepped holes having diameter of
decreasing dimension adapted for accurate and precised alignment.
3. An arrangement as claimed in claim 1 wherein the said template is adapted for
translatory motion of the template along Y direction and rotational motion in the XY
plane.
4. An arrangement as claimed in claim 1, wherein means in contact with the said
template for providing guided motion comprises
(i) fabricated beam for directing motion of the template on it; (ii) sliding joints on the said beam and (iii) guides on the said beam
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5 An arrangement as claimed in any preceding claim, wherein the sliding joints comprising grooved sliding plates are adapted for effective lubrication with minimization of friction during movement of template on the fabricated beam.
6. An arrangement as claimed in claims 4 and 5, wherein the guides are adapted for
providing the translatory motion to the template on the said fabricated beam.
7. An arrangement as claimed in claim 1, additionally comprising means adapted for
constraining the translatory motion of the template along Y direction and rotational
motion in the XY plane.
8. An arrangement as claimed in claim 7, wherein said means for constraining
translatory and rotational motion comprises center guide and a pin.
9. An arrangement as claimed in claim 1, wherein the said means for providing power
comprise hydraulic power pack comprising hydraulic cylinders for controlling
translatory motion of the template in X-direction and Y-direction and rotational
motion in the XY-direction with a momentary displacement of 1 mm of the template
10. A process for alignment of the tundish nozzles comprising
(i) aligning tundish hole by means of tundish holes alignment checking
template;
(ii) placing the Tundishes on the tundish alignment stand;
(iii) switching on the hydraulic unit;
(iv) alignment of the tundish by way of inching motion;
(v) further alignment by means of alignment fixtures and
(vi) final alignment of the tundish nozzles by means of nozzle setting rods.
Dated this the 18th day of February, 2005.

An arrangement for controlling the movement of the template (1) to align it with respect to the holes of the tundish (27) thereby providing a precise, fast and accurate alignment of the nozzles for multi-strand billet casters for continuous casting, said arrangement comprising tundish (27) with nozzles (15), tundish hole alignment checking template (1), means in contact with the said template (1) for providing guided motion to it, nozzle setting blocks (16) with stepped hole (18), at least one alignment fixture (14) placed on the said template (1) adapted for initial alignment of the tundish nozzles (15) with said blocks (16) on template (1), at least one nozzle setting rod (17) adapted for final alignment of the tundish nozzles (15) with said blocks (16) on template (1) and means (11) for providing power for the said controlled motion.