METHOD FOR CASTING A MELT BY MEANS OF A MELT CONTAINER IN WHICH A MELT RECEIVING SPACE IS FORMED
20230038351 · 2023-02-09
Assignee
Inventors
- Gerhard SIEGLHUBER (Muehlheim am Inn, AT)
- Harald SEHRSCHOEN (Waldzell, AT)
- Johannes VOITHOFER (Haag am Hausruck, AT)
Cpc classification
B22D35/04
PERFORMING OPERATIONS; TRANSPORTING
B22D11/10
PERFORMING OPERATIONS; TRANSPORTING
B22D35/00
PERFORMING OPERATIONS; TRANSPORTING
B22D41/12
PERFORMING OPERATIONS; TRANSPORTING
B22D17/30
PERFORMING OPERATIONS; TRANSPORTING
International classification
B22D11/10
PERFORMING OPERATIONS; TRANSPORTING
B22D17/30
PERFORMING OPERATIONS; TRANSPORTING
B22D35/04
PERFORMING OPERATIONS; TRANSPORTING
B22D39/06
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method for casting a melt uses a melt container in which a melt receiving space is formed. The melt container has a spout in the form of a lance on the bottom on the melt container. The method includes the following steps: filling the melt container with melt, wherein the melt is introduced into the melt receiving space of the melt container from a crucible using a spout orifice of the lance; casting at least one cast workpiece with melt; filling the melt container with melt again. When filling the melt container with melt, more melt is received in the melt receiving space than is needed for casting the cast workpiece. Directly before the renewed filling of the melt container, a remainder of melt having an oxide skin formed at the melt surface is present in the melt receiving space of the melt container.
Claims
1. A method for casting a melt (2) by means of a melt container (3) in which a melt receiving space (4) is formed, wherein the melt container (3) has a spout (5) in the form of a lance (20) located on the bottom on the melt container (3), wherein the method comprises the following method steps: filling the melt container (3) with melt (2), wherein the melt (2) is introduced into the melt receiving space (4) of the melt container (3) out of a crucible (25) by means of a spout orifice (6) of the lance (20); casting at least one cast workpiece with melt (2) from the melt container (3), wherein the melt (2) received in the melt receiving space (4) is introduced into a mold (29) via the spout orifice (6) of the lance (20); filling the melt container (2) with melt (3) again, wherein during the filling of the melt container (3) with melt (2), so much more melt (2) is received in the melt receiving space (4) than is required for casting the cast workpiece that directly before the renewed filling of the melt container (3), a remainder of melt (2), which has an oxide skin formed at the melt surface (19), is present in the melt receiving space (4) of the melt container (3), wherein the level of the melt surface (19) of the melt remaining in the melt receiving space (4) lies above the lance (20) inside the melt receiving space (4).
2. The method according to claim 1, wherein for filling the melt receiving space (4) of the melt container (3), the lance (20) is immersed in a crucible (25) filled with melt (2) such that the spout orifice (6) of the lance (20) lies below the crucible fill level (27) during the entire filling operation.
3. The method according to claim 2, wherein directly before immersing the lance (20) in the crucible (25), at least a part of the melt (2) remaining in the melt receiving space (4) of the melt container (3) is discharged into the crucible (25).
4. The method according to claim 1, wherein the melt receiving space (4) of the melt container (3) has a non-wettable surface (38), in particular a ceramic surface (38), to which the oxide skin of the melt (2) does not adhere.
5. The method according to claim 1, wherein while filling the melt container (3) with melt (2), between 1% and 30%, in particular between 5% and 20%, preferably between 10% and 15%, more melt (2) is received in the melt receiving space (4) than is required for casting the cast workpiece.
6. The method according to claim 1, wherein the melt receiving space (4) of the melt container (3) is emptied completely in periodic intervals and/or before shutting down the melt container (3), and the oxide skin is blown out of the melt receiving space (4) by means of a gas blast.
7. The method according to claim 1, wherein the oxide skin present in the melt receiving space (4) at the surface of the melt (2) is sucked off in periodic intervals and/or before shutting the melt container (3) down.
8. The method according to claim 1, wherein the oxide skin present in the melt receiving space (4) at the surface of the melt (2) is removed, in particular discharged in periodic intervals and/or before shutting the melt container (3) down by means of an oxide skin discharge orifice formed in the melt container (3).
9. The method according to claim 1, wherein the melt receiving space (4) is designed such that when it is at least partially filled with melt (2), it is closed off in a gas-tight manner, wherein a gas valve (7) is formed, by means of which gas can be fed into or removed from the melt receiving space (4), wherein the gas valve (7) is opened while the melt container (3) is being filled with melt (2), so that the melt (2) can flow out of the crucible (25) and into the melt receiving space (4) via the lance (20), and the gas valve (7) is closed after the melt (2) has flown in, and subsequently, while the gas valve (7) is closed, melt (2) is discharged from the melt receiving space (4) back into the crucible (25) via the lance (20) until a vacuum is generated that is sufficient to keep the remaining melt (2) in the melt receiving space (4).
10. The method according to claim 1, wherein when casting the at least one cast workpiece, the melt (2) is admitted, in a first method step, from the melt container (3a, 3b) into the mold (29a, 29b) at a first inflow speed until the spout orifice (6) is immersed at least partially in the melt (2) introduced into the mold (29a, 29b), and wherein in a second method step, the melt (2) is admitted into the mold (29a, 29b) at a second inflow speed, wherein the second inflow speed is greater than the first inflow speed.
11. The method according to claim 1, wherein while filling the melt container (3a, 3b) with melt (2), in a first method step, the lance (20) is moved, in particular pivoted, at the surface of the crucible (25) such that the oxide skin at the surface is torn open, and in a second method step, the lance (20) is immersed in the melt present in the crucible (25) in the torn region of the oxide skin.
12. (canceled)
Description
[0028] For the purpose of better understanding of the invention, it will be elucidated in more detail by means of the figures below.
[0029] These show in a respectively very simplified schematic representation:
[0030]
[0031]
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038]
[0039]
[0040]
[0041]
[0042] First of all, it is to be noted that in the different embodiments described, equal parts are provided with equal reference numbers and/or equal component designations, where the disclosures contained in the entire description may be analogously transferred to equal parts with equal reference numbers and/or equal component designations. Moreover, the specifications of location, such as at the top, at the bottom, at the side, chosen in the description refer to the directly described and depicted figure and in case of a change of position, these specifications of location are to be analogously transferred to the new position.
[0043]
[0044] The melt transport device 1 has a melt container 3, in which a melt receiving space 4 is formed, which serves to receive the melt 2. On its inner side, the melt receiving space 4 has a surface 38, which is in contact with the melt 2 when the melt receiving space 4 is filled.
[0045] Moreover, the melt transport device 1 comprises a spout 5, which is coupled to the melt container 3. The spout 5 may be designed as an integral component of the melt container 3. Moreover, it is also conceivable that the spout 5 is formed as a separate component which is coupled to the melt container 3. The spout 5 has a spout orifice 6, via which the melt 2 received in the melt container 3 can flow out of the melt transport device 1 into a mold.
[0046] The spout orifice 6 may have a circular cross-section. Furthermore, it is also conceivable that the spout orifice 6 has a square cross-section. Moreover, it is also conceivable that the spout orifice 6 has a rectangular cross-section, wherein in particular a longitudinal extension of the spout orifice 6, which extends normal to the section plane, may have a great extension. For example, the longitudinal extension of the spout orifice 6 may measure up to 2000 mm, in particular up to 500 mm. This is advantageous particularly in elongated cast workpieces, such as cylinder blocks or cylinder heads.
[0047] Of course, this longitudinal extension of the spout orifice 6 may also be advantageous for the other embodiment variants.
[0048] Moreover, a gas valve 7 is formed, which is flow-connected to the melt receiving space 4 and which is designed for regulating the introduction of gas into the otherwise gas-tight melt receiving space 4. The gas valve 7 is arranged above a fill level maximum 8, so that no melt 2 can flow into the gas valve 7. The fill level maximum is selected such that when the melt container 3 is filled to the fill level maximum 8 with melt 2, a gas-filled space still remains in the melt receiving space 4, in which gas-filled space a pressure can be set by means of the gas valve 7.
[0049] Moreover, a pressure determining means 9 may be provided, by means of which an internal pressure in the melt receiving space 4 can be determined. Thus, the gas pressure in the melt receiving space 4 can be adjusted in a targeted manner by the gas valve 7.
[0050] As may further be gathered from the exemplary embodiment according to
[0051] Moreover, a weighing cell 39 may be formed, by means of which the weight and thus the fill level of the melt receiving space 4 can be determined.
[0052] As can further be seen from
[0053]
[0054] For transporting the melt container 3, it may be advantageous if the first melt surface 18 is situated slightly below the overflow level 17, as shown in
[0055] As can further be gathered from
[0056] Moreover, it may of course be provided that the siphon 13 is integrated directly into the lance 20. A siphon 13 integrated into the lance 20 can work according to the same operating principle as described here.
[0057] In the exemplary embodiment according to
[0058] Moreover, it may also be provided that the container 21 that is open towards the top is arranged on the spout 5 in an exchangeable manner.
[0059] As can be further gathered from
[0060] Moreover, it may be provided that the bottom side of the lance 20a, 20b and/or the immersion aid 47 is designed such that they have no protruding surfaces, so that, as far as possible, no oxide skin adheres to the lance 20a, 20b when the lance 20a, 20b is being pulled out of the crucible 25. In particular, it may be provided that all surfaces of the lance 20a, 20b directed upwards are formed to be pointing downwards in a conical and/or oblique manner, so that the oxide skin is repelled when the lance 20a, 20b is being pulled out.
[0061]
[0062]
[0063] As can be seen in
[0064] As can be seen in
[0065] If the gas flowing out of the melt receiving space 4 is able to pass the gas valve 7 without pressure, the actual fill quantity level 11 will adapt to the furnace fill level 27 when the melt container 3 is filled. During the subsequent closing of the gas valve 7 and lifting of the melt container 3, the actual fill quantity level 11 will be lowered until the vacuum in the melt receiving space 4 is great enough to keep the melt 2 at the same level due to the pressure difference between the interior pressure in the melt receiving space 4 and the ambient pressure.
[0066] Once the target fill quantity level 12 in the melt receiving space 4 is reached, the gas valve 7 can be closed again and the melt container 3 can be lifted again, as shown in
[0067] Here, when lifting the melt container 3, melt 2 flows out of the melt receiving space 4 back into the crucible 25 until a pressure lower than the ambient pressure arises in the melt receiving space 4, which pressure keeps the melt in the melt receiving space 4.
[0068] In an advancement, it may be provided that subsequently, by opening the gas valve 7, melt 2 is further discharged from the melt receiving space 4 until a desired fill level of melt 2 is reached in the melt receiving space4. In this regard, the desired fill level of melt 2 can be selected such
[0069] In this regard this desired fill level of melt 2 in the melt receiving space 4 is selected such that after casting the cast workpiece or the cast workpieces, a remainder of melt 2 remains in the melt receiving space 4.
[0070] In a subsequent method step, the melt container 3 can be transported to its casting position.
[0071]
[0072]
[0073] As can be seen in
[0074]
[0075]
[0076]
[0077] As can be gathered from
[0078] In order to then reach the target fill quantity level 12 in the melt receiving space 4, the melt receiving space 4 can be evacuated by means of a vacuum pump 28, whereby the melt 2 is sucked into the melt receiving space 4. Subsequently, the gas valve 7 can be closed in order to keep the actual fill quantity level 11 in the melt receiving space 4 at a constant level during the transport of the melt transport device 1.
[0079] As the melt receiving space 4 is already evacuated by means of the vacuum pump 28 prior to the lifting of the melt container 3, as shown in
[0080]
[0081] As can be gathered from
[0082] In such an embodiment variant, it may additionally be provided that the riser tube 34 of the low-pressure furnace 33 and the spout 5 are coupled to one another by means of a coupling 31.
[0083]
[0084] As is further evident from
[0085] In the exemplary embodiment according to
[0086] In the exemplary embodiment according to
[0087] In the exemplary embodiment according to
[0088] As is evident from
[0089]
[0090]
[0091] As is further evident from
[0092] The second melt container 3b has a second melt receiving space 4b and a second spout 5b in the form of a lance 20b located on the bottom on the second melt container 3b. The spout 5b has a spout orifice 6b.
[0093] The melt transport device 1 may be designed such that both melt containers 3a, 3b can be moved simultaneously and synchronously with one another. In particular, it may be provided that both melt containers 3a, 3b can be moved jointly by means of shared drive devices. Thereby, the structure of the melt transport device 1 can be kept as simple as possible.
[0094] The casting device 37 furthermore comprises a mold 29, which has a mold cavity 30. In particular, a first mold 29a is assigned to the first melt container 3a, and a second mold 29b is assigned to the second melt container 3b. By means of the casting device 37 shown in
[0095] As is further evident from
[0096] Furthermore, it may be provided that the mold 29 can also be pivoted about a horizontal axis. Thus, the mold 29 and the melt container 3 can be pivoted simultaneously.
[0097] As can further be gathered from
[0098] The distance adjusting device 44 can be designed, for example, in the form of a linear adjusting device, as can be seen in
[0099] In a further embodiment, it is also conceivable that the distance adjusting device 44 is designed, for example, in the form of a fastening arm for receiving the melt containers 3a, 3b, wherein a change in the distance 45 can be achieved by pivoting the fastening arm and thus the melt containers 3a, 3b about a vertical axis.
[0100]
[0101] As is evident from
[0102]
[0103] As can be seen in
[0104] The exemplary embodiments show possible embodiment variants, and it should be noted in this respect that the invention is not restricted to these particular illustrated embodiment variants of it, but that rather also various combinations of the individual embodiment variants are possible and that this possibility of variation owing to the technical teaching provided by the present invention lies within the ability of the person skilled in the art in this technical field.
[0105] The scope of protection is determined by the claims. Nevertheless, the description and drawings are to be used for construing the claims. Individual features or feature combinations from the different exemplary embodiments shown and described may represent independent inventive solutions. The object underlying the independent inventive solutions may be gathered from the description.
[0106] All indications regarding ranges of values in the present description are to be understood such that these also comprise random and all partial ranges from it, for example, the indication 1 to 10 is to be understood such that it comprises all partial ranges based on the lower limit 1 and the upper limit 10, i.e. all partial ranges start with a lower limit of 1 or larger and end with an upper limit of 10 or less, for example 1 through 1.7, or 3.2 through 8.1, or 5.5 through 10.
[0107] Finally, as a matter of form, it should be noted that for ease of understanding of the structure, elements are partially not depicted to scale and/or are enlarged and/or are reduced in size.
LIST OF REFERENCE NUMBERS
[0108]
TABLE-US-00001 1 Melt transport device 2 Melt 3 Melt container 4 Melt receiving space 5 Spout 6 Spout orifice 7 Gas valve 8 Fill level maximum 9 Pressure determining means 10 Fill level sensor 11 Actual fill quantity level 12 Target fill quantity level 13 Siphon 14 Reservoir 15 Siphon wall 16 Melt container outer side 17 Overflow level 18 First melt surface 19 Second melt surface 20 Lance 21 Container 22 Strut 23 Spout channel 24 Melt furnace 25 Crucible 26 Filling position 27 Crucible fill level 28 Vacuum pump 29 Mold 30 Mold cavity 31 Coupling 32 Siphon wall bottom edge 33 Low-pressure furnace 34 Riser tube 35 Drain projection 36 Tube end angle 37 Casting device 38 Surface melt receiving space 39 Weighing cell 40 Pivoting device 41 Pivot bearing 42 Horizontal axis of rotation 43 Pivot drive 44 Distance adjusting device 45 Distance 46 Quick-release connector 47 Immersion aid