The present disclosure relates to a system, apparatus, and method for aligning a continuous casting mold and a starter block, and more particularly, to alignment of a mold starter block alignment with a continuous casting mold whereby the starter block or the continuous casting mold is movable relative to the mold during alignment, and locked down upon alignment between the mold and the starter block.
Metal products may be formed in a variety of ways; however numerous forming methods first require an ingot, billet, or other cast part that can serve as the raw material from which a metal end product can be manufactured, such as through rolling or machining, for example. One method of manufacturing an ingot or billet is through a continuous casting process known as direct chill casting, whereby a vertically oriented mold cavity is situated above a platform that translates vertically down a casting pit. A starter block may be situated on the platform and form a bottom of the mold cavity, at least initially, to begin the casting process. Molten metal is poured into the mold cavity whereupon the molten metal cools, typically using a cooling fluid. The platform with the starter block thereon may descend into the casting pit at a predefined speed to allow the metal exiting the mold cavity and descending with the starter block to solidify. The platform continues to be lowered as more molten metal enters the mold cavity, and solid metal exits the mold cavity. This continuous casting process allows metal ingots and billets to be formed according to the profile of the mold cavity and having a length limited only by the casting pit depth and the hydraulically actuated platform moving therein.
Alignment between the starter block and the mold cavity is important to reduce molten metal leaks during the initial casting start up phase and to minimize damage to either the mold cavity walls or the starter block when the two are brought together ahead of the casting process.
The present disclosure relates to a system, apparatus, and method for aligning a continuous casting mold and a starter block, and more particularly, to alignment of a mold starter block alignment with a continuous casting mold whereby the starter block or the continuous casting mold is movable relative to the mold during alignment, and locked down upon alignment between the mold and the starter block. Embodiments described herein may provide a continuous casting mold alignment system including: a continuous casting mold; a mold frame supporting the continuous casting mold; a starter block; and at least one bearing assembly. The at least one bearing assembly is movable between a lowered position and a raised position, where the at least one bearing assembly, in the raised position, engages and supports one of the continuous casting mold or the starter block. The at least one bearing assembly, in the raised position, enables the one of the continuous casting mold or the starter block to be moved into alignment with the other of the continuous casting mold or the starter block by a force below a predefined threshold. In the lowered position, the at least one bearing assembly disengages the one of the continuous casting mold and the starter block, where in response to the at least one bearing assembly being in the lowered position, the one of the continuous casting mold or the starter block cannot be moved by a force below the predefined threshold.
According to some embodiments, the system may include at least one pneumatic cylinder, where the at least one bearing assembly is moved between the raised position and the lowered position by the at least on pneumatic cylinder. Systems may include an alignment guide arranged between the starter block and the continuous casting mold, where the alignment guide causes movement of the one of the starter block or the continuous casting mold relative to the other of the starter block or the continuous casting mold in response to the one of the starter block or the continuous casting mold being supported by the at least one bearing assembly and the starter block engaging the continuous casting mold. The alignment guide may include a tapered pin and a receiver, where the movement of the starter block may be performed as the tapered pin engages the receiver.
According to an example embodiment in which the at least one of the continuous casting mold and the starter block being the starter block, embodiments of the system may include a platform defining a support surface, where in response to the at least one bearing assembly being in the lowered position, the starter block is supported by the support surface, and where in response to the at least one bearing assembly being in the raised position, the starter block is supported by the at least one bearing assembly. In response to the at least one bearing assembly being disposed in the raised position, the starter block supported by the bearing assembly is movable in two orthogonal directions relative to the platform in response to forces along either direction of a first vale, where in response to the at least one bearing assembly being disposed in the lowered position, the starter block is supported by the starter block support surface and is not movable in the two orthogonal directions relative to the platform in response to forces along either direction of the first value. Embodiments may include a clamp to engage the starter block, where in response to the at least one bearing assembly being moved to the lowered position, the clamp applies a force to the starter block. In response to application of force from the clamp, a force of the starter block against the support surface is greater than a weight of the starter block.
According to an example embodiment in which the at least one of the continuous casting mold and the starter block being the continuous casting mold, the bearing assembly may be supported by the mold frame. The at least one bearing assembly, in the raised position, engages and supports the mold, where the mold is movable relative to the starter block for alignment of the mold with the starter block. The bearing assembly may include a clamping block, where in response to the bearing assembly moving from the raised position to the lowered position, the clamping block secures the continuous casting mold to the mold frame. In response to the bearing assembly being in the raised position, the continuous casting mold may be movable in two orthogonal directions in response to forces in the two orthogonal directions of a first value, where in response to the bearing assembly being in the lowered position, the continuous casting mold is not movable in the two orthogonal directions in response to forces in the two orthogonal directions of the first value.
Embodiments described herein may provide a method of aligning a continuous casting mold with a starter block including: advancing at least one bearing assembly to a raised position, where the at least one bearing assembly, in the raised position, engages and supports one of the continuous casting mold or the starter block; aligning the one of the continuous casting mold or the starter block with the other of the continuous casting mold or the starter block; and retracting the at least one bearing assembly to a lowered position, where the at least one bearing assembly, in the lowered position, is disengaged from the one of the continuous casting mold or the starter block. In response to the one of the continuous casting mold or the starter block being engaged by and supported by the at least one bearing assembly, forces along two orthogonal directions below a first value move the one of the continuous casting mold or the starter block relative to the at least one bearing assembly. In response to the one of the continuous casting mold or the starter block being disengaged by the at least one bearing assembly, forces along two orthogonal directions below the first value do not move the one of the continuous casting mold or the starter block relative to the at least one bearing assembly.
The aligning of the continuous casting mold or the starter block with the other of the continuous casting mold or the starter block may include moving the one of the continuous casting mold or the starter block along two orthogonal directions relative to the other of the continuous casting mold or the starter block. Moving the one of the continuous casting mold or the starter block along two orthogonal directions relative to the other of the continuous casting mold or the starter block may be performed by an alignment guide arranged between the starter block and the continuous casting mold. Methods may include clamping the one of the continuous casting mold or the starter block in a secured position in response to retracting the at least one bearing assembly to the lowered position.
In an example embodiment in which the one of the continuous casting mold or the starter block is the continuous casting mold, clamping the continuous casting mold in the secured position in response to retracting the at least one bearing assembly to the lowered position may include clamping the continuous casting mold to a mold frame. In an example embodiment in which the one of the continuous casting mold or the starter block is the starter block, clamping the starter block in the secured position in response to retracting the at least one bearing assembly to the lowered position includes clamping the starter block to a platform in a casting pit of a continuous casting mold system.
Embodiments described herein may include an alignment system for aligning a starter block with a continuous casting mold. The alignment system may include: a bearing assembly including at least one bearing having a bearing surface; a lifting mechanism where the lifting mechanism is configured to move the bearing assembly between a lowered position in which the bearing surface is recessed below a support surface and a raised position in which the bearing surface is proud of the support surface; and a clamping mechanism to secure one of a starter block or a continuous casting mold to a starter block support surface or a mold frame, respectively. The lifting mechanism may include a pneumatic cylinder. The bearing assembly, in the raised position, may be configured to support the starter block and enable the starter block to be moved relative to the continuous casting mold with a force substantially lower than a force required with the bearing assembly in the lowered position. The bearing assembly, in the raised position, may be configured to support the continuous casting mold and enable the continuous casting mold to be moved relative to the starter block with a force substantially lower than a force required with the bearing assembly in the lowered position.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Example embodiments of the present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. Indeed, embodiments may take many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
Embodiments of the present disclosure generally relate to a system, apparatus, and method to align a starter block of a direct chill mold system, also referred to as a continuous casting mold system, with a mold cavity of the system to substantially fill the mold cavity, and setting the optimum clearance between the starter block and the mold walls. Embodiments align the starter block with the mold thereby reducing molten metal leakage and reducing the likelihood of damage to one or both of the starter block or the mold walls.
Vertical direct chill casting or continuous casting is a process used to produce ingots or billets that may have a variety of cross-sections shapes and sizes for use in a variety of manufacturing applications. The process of direct chill casting begins with a horizontal mold table or mold frame containing one or more vertically-oriented molds disposed therein. Each of the molds defines a mold cavity, where the mold cavities are initially closed at the bottom with a starter block to seal the bottom of the mold cavity. Molten metal is introduced to each mold cavity through a metal distribution system to fill the mold cavities. As the molten metal proximate the bottom of the mold, adjacent to the starter block solidifies, the starter block is moved vertically downward along a linear path into a casting pit. The movement of the starter block may be caused by a hydraulically-lowered platform to which the starter block is attached. The movement of the starter block vertically downward draws the solidified metal from the mold cavity while additional molten metal is introduced into the mold cavities. Once started, this process moves at a relatively steady-state for a continuous casting process that forms a metal ingot having a profile defined by the mold cavity, and a height defined by the depth to which the platform and starter block are moved.
During the casting process, the mold itself is cooled to encourage solidification of the metal prior to the metal exiting the mold cavity as the starter block is advanced downwardly, and a cooling fluid is introduced to the surface of the metal proximate the exit of the mold cavity as the metal is cast to draw heat from the cast metal ingot and to solidify the molten metal within the now-solidified shell of the ingot. As the starter block is advanced downward, the cooling fluid may be sprayed directly on the ingot to cool the surface and to draw heat from within the core of the ingot.
In order for the casting process to begin properly, the starter block 115 has to be aligned with the mold cavity 107 of the continuous casting mold 105. Any misalignment may result in molten metal escaping from the mold cavity before it has had the chance to solidify. Molten metal escaping from the mold cavity between the mold and the starter block before it has a chance to solidify will spill into the pit into which the platform 120 descends, which results not only in a lost cast part, but requires substantial cleaning of the pit and any affected components within the pit before casting may resume or start again. Further, continuous casting molds and starter blocks are precisely machined and somewhat susceptible to damage, such that if a starter block is brought into engagement with a mold and the two components are not properly aligned, one or both of the starter block and the mold may be damaged which can adversely affect the ability of the parts to generate a satisfactory casting.
Embodiments described herein provide a mechanism by which the starter block can be repeatably and accurately aligned with a continuous casting mold such that the mold cavity is sealed at a bottom of the mold cavity with the starter block. Embodiments include a system that is at least partially automated to reduce the manual, human interaction needed for alignment between the starter block and the mold. Example embodiments provided herein include embodiments in which the starter block is moved relative to the continuous casting mold for alignment, while other embodiments permit movement of the continuous casting mold relative to the starter block for alignment.
An example embodiment of a system to facilitate alignment between the starter block and the mold is illustrated in
The continuous casting mold 105 and the starter block 115 may be aligned with one another when bringing the two components together. The alignment may be performed when lowering the mold frame 109 into position bringing the continuous casting mold 105 into alignment with the starter block 115. Optionally, the platform may be displaced to a lower position than when casting is started to position the starter block 115 below the continuous casting mold 105, and the platform 120 may be raised for alignment of the starter block with the mold. In either scenario, the continuous casting mold 105 and starter block 115 begin the alignment process displaced from one another to allow for alignment before or while the mold and starter block are brought into contact with one another.
Also shown in
The starter block 115 may be aligned with a respective continuous casting mold 105 when the mold frame 109 shown in
Referring back to
During alignment, the bearing assemblies 164 may be raised relative to the starter block support plates 117 such that bearing surfaces of the bearing assemblies stand proud of the starter block support plates.
While some embodiments of the bearing assembly may not require lubrication, the illustrated embodiment includes a grease zerk fitting 174 to receive lubricant for the bearing assembly. The illustrated bearing assembly 164 further includes a pneumatic cylinder 176 and pneumatic cylinder assembly 180 whereby the bearing plate 182 can be raised and lowered relative to the pneumatic cylinder body 180 by virtue of pressure and/or vacuum applied to the pneumatic connectors 178.
This pneumatic cylinder enables the bearings 172 to be raised into contact with the starter block 115 and to support the weight of the starter block 115 on the bearings 172. The pneumatic cylinder operates in cooperation with the other pneumatic cylinder assemblies shown in
Embodiments described herein provide a system for alignment of a starter block with a mold where the system operates between three states. A first state includes raised bearing assemblies 164 as shown in
While example embodiments described and illustrated herein disclose a pneumatic cylinder used as a lifting mechanism to raise the bearing assemblies into contact with the starter block, other lifting mechanisms may be employed to move the bearing assemblies between a raised position in which the bearing surface is proud of the starter block support surface and a lowered position in which the bearing surface is recessed below the starter block support surface. For example, the bearing assemblies 164 may be moved from the lowered position to the raised position using a cam mechanism whereby rotation of the cam lifts the bearing assemblies. Other mechanisms may include hydraulic cylinders, electric servo motors, electric solenoids, or the like. As such, the lifting of the bearing assemblies may be accomplished by a variety of different lifting mechanisms.
While embodiments of the figures illustrate bearing assemblies 164 used to enable the starter block to be moved for alignment, embodiments may use other mechanisms by which the starter block can be relatively easily moved relative to the platform and the mold to bring the starter block into alignment with the mold. Some mechanisms to achieve this may include compressed air bearings to create a layer of air on which the starter block floats to some degree, low friction coatings or liners on which the starter block may translate, lubricants such as greases or oils, flowing water bearing floatation, compressed air and oil mixture, compressed air and water mixture, or electro magnets to repel the starter block from the platform to “float” the starter block, for example.
While the starter block is in a low-friction state relative to the platform, using the bearing assemblies 164 of the figures or any of the aforementioned techniques, alignment of the starter block to the mold may be accomplished in a variety of ways. An alignment jig including spacers or shims placed on either the mold or the starter block may guide the starter block into alignment with the mold as they are brought together—either through the lowering of a mold frame or the raising of the platform to meet the mold. Optionally, pins or guides with alignment lugs that engage and force the starter block into alignment with the mold as they are brought together may be used. According to some embodiments, physical parts that move into or out of position, such as cylinders (pneumatic or hydraulic) or mechanical equipment may move into place the starter block with the mold. Analog sensors may be used to measure distances needed for alignment and actuators may be used in combination with these sensors to sense alignment and move the starter block accordingly.
Once alignment is complete, the starter block may be lowered onto the starter block support plates which may include a high or relatively-high friction surface such that the starter block no longer moves relative to the platform. The high friction surface may include a metal surface which may be textured or a surface with an added texture such as a high-friction liner or coating that includes a high friction finish.
One or more clamps can be actuated to clamp the starter block in place once alignment is complete. Clamping of the starter block in place further precludes movement of the starter block which may damage the mold or the casting part or process. Each starter block supported by a platform may have an individual system for alignment, or in some embodiments where the molds are at fixed positions relative to one another, starter blocks may be joined with the same fixed positions relative to one another requiring alignment of the plurality of starter blocks at the same time.
As described above with respect to
The example embodiments described above involve movement of the starter block 115 relative to the continuous casting mold 105 for alignment. However, embodiments may include a continuous casting mold 105 that is movable relative to a stationary starter block 115 for alignment.
The bearing assemblies 202 of the illustrated embodiment include a shaft 204 that extends from the bearing assembly and travels with the bearing assembly between the raised position and the lowered position. The shaft 204 extends through a hole of the continuous casting mold 105, such that the bearings 206, in the raised position, engage the continuous casting mold around this hole.
The shaft 204 receives thereon a clamp member 214 as shown in
Once the alignment of the continuous casting mold 105 with the starter block 115 is complete, the bearing assemblies 202 may be moved to a lowered, retracted position where they are lowered into the mold frame 109 and the bearings 206 disengage from the continuous casting mold 105. This may be accomplished using cylinders 220 as described above with respect to the aforementioned embodiment. Also as noted above, the pneumatic cylinders may include quick exhaust valves that allow the bearing assemblies 202 to be lowered at a relatively rapid pace such that alignment is not lost during retraction. Once the bearing assemblies 202 are lowered, the continuous casting mold 105 rests on the mold frame 109 with a relatively high degree of friction between the mold frame and the continuous casting mold. In this position, forces below the threshold force that would be sufficient to move the continuous casting mold while supported by the bearings are not sufficient to move the continuous casting mold relative to the mold frame.
As the bearing assemblies are lowered, the clamp member 214, which is larger than the hole 210 of the continuous casting mold, clamps the continuous casting mold between the clamp member 214 and the mold frame 109. This clamping force drives the continuous casting mold 105 into engagement with the mold frame with a force greater than the weight of the continuous casting mold alone, thereby further securing the aligned position of the continuous casting mold.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Number | Name | Date | Kind |
---|---|---|---|
3957105 | Foye | May 1976 | A |
5634511 | Steen | Jun 1997 | A |
5647427 | Collins | Jul 1997 | A |
20110315339 | Naess, Jr. | Dec 2011 | A1 |