CA1304562C - Tube having filter therein for use in the casting of metals - Google Patents
Tube having filter therein for use in the casting of metalsInfo
- Publication number
- CA1304562C CA1304562C CA000605809A CA605809A CA1304562C CA 1304562 C CA1304562 C CA 1304562C CA 000605809 A CA000605809 A CA 000605809A CA 605809 A CA605809 A CA 605809A CA 1304562 C CA1304562 C CA 1304562C
- Authority
- CA
- Canada
- Prior art keywords
- tube
- filter
- mould
- refractory material
- sprue
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000005058 metal casting Methods 0.000 title claims abstract description 6
- 229910052751 metal Inorganic materials 0.000 claims abstract description 22
- 239000002184 metal Substances 0.000 claims abstract description 22
- 239000011819 refractory material Substances 0.000 claims abstract description 21
- 239000011230 binding agent Substances 0.000 claims abstract description 13
- 239000006260 foam Substances 0.000 claims abstract description 12
- 239000000919 ceramic Substances 0.000 claims abstract description 8
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 239000004576 sand Substances 0.000 claims description 7
- 238000010438 heat treatment Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- 238000005266 casting Methods 0.000 abstract description 14
- 150000002739 metals Chemical class 0.000 abstract description 2
- 238000004512 die casting Methods 0.000 description 8
- 230000005484 gravity Effects 0.000 description 6
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- -1 ferrous metals Chemical class 0.000 description 2
- 238000003780 insertion Methods 0.000 description 2
- 230000037431 insertion Effects 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229920005830 Polyurethane Foam Polymers 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011496 polyurethane foam Substances 0.000 description 1
- 238000007528 sand casting Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Landscapes
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
- Filtering Materials (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
ABSTRACT
TUBE HAVING FILTER THEREIN
FOR USE IN THE CASTING OF METALS
A tube of refractory material having a filter therein for use in the casting of molten metals is made by forming a tube of fibrous refractory material, a binder and optionally particulate refractory material, inserting a filter into the tube, deforming the wall of the tube around the filter so as to hold the filter in place and causing or allowing the binder to harden. The filter may be a honeycomb type of structure having cells which extend from one face to an opposite face, or a structure having interconnecting cells such as a ceramic foam. In use the tube is inserted in a mould sprue which communicates directly with the mould cavity.
TUBE HAVING FILTER THEREIN
FOR USE IN THE CASTING OF METALS
A tube of refractory material having a filter therein for use in the casting of molten metals is made by forming a tube of fibrous refractory material, a binder and optionally particulate refractory material, inserting a filter into the tube, deforming the wall of the tube around the filter so as to hold the filter in place and causing or allowing the binder to harden. The filter may be a honeycomb type of structure having cells which extend from one face to an opposite face, or a structure having interconnecting cells such as a ceramic foam. In use the tube is inserted in a mould sprue which communicates directly with the mould cavity.
Description
--`` 1.3~ 562 TUBE HA~ING FILTER THEREIN
FOR USE IN THE CASTING
OF METALS
This invention relates to a tube of refractory material having a filter therein for use in the casting of metals, a method of making the tube and a mould containing the tube.
Our copending Canadian Patent Application No. 588962 describes a method of casting molten metal in which a tube of refractory material having a filter therein is located in the sprue (defined as a passage which provides the sole means of entry of molten metal) of a mould and the molten metal is poured through the filter into the mould cavity.
The method is particularly useful in the gravity die-casting or low pressure diecasting of non--ferrous metals in permanent moulds such as metal dies.
It has now been found that the tube containing the filter may be conveniently formed by inserting the filter in the tube during manufa--cture of the tube and deforming the wall of the tube around the filter so that the filter is held firmly in position.
According to the invention there is provided a tube of refractory material having a filter therein formed by inserting the filter in 3~
.3~ t~
FOR USE IN THE CASTING
OF METALS
This invention relates to a tube of refractory material having a filter therein for use in the casting of metals, a method of making the tube and a mould containing the tube.
Our copending Canadian Patent Application No. 588962 describes a method of casting molten metal in which a tube of refractory material having a filter therein is located in the sprue (defined as a passage which provides the sole means of entry of molten metal) of a mould and the molten metal is poured through the filter into the mould cavity.
The method is particularly useful in the gravity die-casting or low pressure diecasting of non--ferrous metals in permanent moulds such as metal dies.
It has now been found that the tube containing the filter may be conveniently formed by inserting the filter in the tube during manufa--cture of the tube and deforming the wall of the tube around the filter so that the filter is held firmly in position.
According to the invention there is provided a tube of refractory material having a filter therein formed by inserting the filter in 3~
.3~ t~
the tube during manufacture of the tube and deforming the wall of the tube around the filter to hold the filter in place.
According to a further feature of the invention there is provided a method of making a tube of refractory material having a filter therein comprising forming a tube of fibrous refractory material, a binder and optionally particulate refractory material, inserting a filter into the tube, deforming the wall of the tube around the filter so as to hold the filter in place and causing or allowing the binder to harden.
According to yet a further feature of the invention there is provided a mould for the casting of metal, the mould having a cavity and a sprue communicating directly with the cavity and having located in the sprue, a tube of refractory material having a filter therein as described above.
The filter is preferably located adjacent one end of the tube and the tube is located in the sprue of the mould so that that end of the tube is nearer to the mould cavity.
According to a further feature of the invention there is provided a method of making a tube of refractory material having a filter therein comprising forming a tube of fibrous refractory material, a binder and optionally particulate refractory material, inserting a filter into the tube, deforming the wall of the tube around the filter so as to hold the filter in place and causing or allowing the binder to harden.
According to yet a further feature of the invention there is provided a mould for the casting of metal, the mould having a cavity and a sprue communicating directly with the cavity and having located in the sprue, a tube of refractory material having a filter therein as described above.
The filter is preferably located adjacent one end of the tube and the tube is located in the sprue of the mould so that that end of the tube is nearer to the mould cavity.
For ease of manufacture the tube is preferably of circular horizontal cross-section but the horizontal cross-section of the tube may be for example oval, square or rectangular.
If desired to aid filling of the tube with molten metal, the top end of the tube may be flared in the shape of a funnel.
The material from which the tube is made must be sufficiently refractory to withstand the temperature of the metal to be cast into the mould which is to contain the tube.
The preferred tubes are made by dewater--ing on to a former an aqueous slurry containing fibrous refractory material, a binder and optionally a particulate refractory material, stripping the tube so-formed from the former, inserting a filter in one end of the tube so that the filter is located adjacent that end of the tube, deforming the wall of the tube e.g. by squeezing around the filter so that the filter is held in place and heating the tube so as to harden the binder.
Such tubes can be manufactured accurately to close tolerances. This is important because the outer surface must be such that the tube fits snugly in the sprue of a die or sand mould without being crushed and without floating of the tube occurring when metal is cast into the die or-sand mould.
If desired to aid filling of the tube with molten metal, the top end of the tube may be flared in the shape of a funnel.
The material from which the tube is made must be sufficiently refractory to withstand the temperature of the metal to be cast into the mould which is to contain the tube.
The preferred tubes are made by dewater--ing on to a former an aqueous slurry containing fibrous refractory material, a binder and optionally a particulate refractory material, stripping the tube so-formed from the former, inserting a filter in one end of the tube so that the filter is located adjacent that end of the tube, deforming the wall of the tube e.g. by squeezing around the filter so that the filter is held in place and heating the tube so as to harden the binder.
Such tubes can be manufactured accurately to close tolerances. This is important because the outer surface must be such that the tube fits snugly in the sprue of a die or sand mould without being crushed and without floating of the tube occurring when metal is cast into the die or-sand mould.
The filter may be a honeycomb type of structure having pores which extend from one face to an opposite face, or a structure having inter--connecting pores such as a ceramic foam.
Ceramic foam filters are preferred because molten metal flows through such filters much less turbulently than it does through other types of filter. Ceramic foam filters may be made using a known method of making a ceramic foam, in which an organic foam, usually polyurethane foam, is ir,lpregnated with an aqueous slurry of ceramic material containing a binder, the impregnated foam is dried to remove water and the dried impregnated foam is fired to burn off the organic foam to produce a ceramic foam.
As used herein the term sprue means any passage which is used to provide the sole means of entry of molten metal ~nto a mould.
The mould of the invention has no running system, apart from the sprue. In addition to the mould cavity and the sprue the mould may also have one or more feeder cavities.
The mould of the invention may be used for the casting of a variety of non-ferrous metals, for example, aluminium and aluminium alloys, aluminium bronze, magnesium and its alloys, zinc and its alloys and lead and its alloys, or for the casting of ferrous metals such as iron and steel.
~3~9tStjZ
Ceramic foam filters are preferred because molten metal flows through such filters much less turbulently than it does through other types of filter. Ceramic foam filters may be made using a known method of making a ceramic foam, in which an organic foam, usually polyurethane foam, is ir,lpregnated with an aqueous slurry of ceramic material containing a binder, the impregnated foam is dried to remove water and the dried impregnated foam is fired to burn off the organic foam to produce a ceramic foam.
As used herein the term sprue means any passage which is used to provide the sole means of entry of molten metal ~nto a mould.
The mould of the invention has no running system, apart from the sprue. In addition to the mould cavity and the sprue the mould may also have one or more feeder cavities.
The mould of the invention may be used for the casting of a variety of non-ferrous metals, for example, aluminium and aluminium alloys, aluminium bronze, magnesium and its alloys, zinc and its alloys and lead and its alloys, or for the casting of ferrous metals such as iron and steel.
~3~9tStjZ
The mould may be a sand mould prepared to conventional foundry practice or a permanent mould, such as a metal die, for producing castings by gravity diecasting or by low pressure die-casting.
The preferred application of the mould of the invention is the gravity diecasting of aluminium or aluminium alloys.
In order to insert and locate the tube in the sprue of the mould it is preferred that the outer surface of the tube tapers from one end of the tube to the other end and that the sprue has a corresponding taper, the direction of taper depending on whether the tube is to be inserted in the sprue from above or below. The outer surface of the tube or the mould surface surrounding the sprue may have means for holding the tube firmly in position once it has been inserted in the sprue.
The means may be for example protrusions such as ribs on the lateral surface of the tube or protrusions such as ribs formed on the sprue of a sand mould by the use of a recessed former during mould production or in the case of a metal mould or die protrusions such as ribs machined on the mould or die surface surrounding the sprue.
:13~;~456Z
The preferred application of the mould of the invention is the gravity diecasting of aluminium or aluminium alloys.
In order to insert and locate the tube in the sprue of the mould it is preferred that the outer surface of the tube tapers from one end of the tube to the other end and that the sprue has a corresponding taper, the direction of taper depending on whether the tube is to be inserted in the sprue from above or below. The outer surface of the tube or the mould surface surrounding the sprue may have means for holding the tube firmly in position once it has been inserted in the sprue.
The means may be for example protrusions such as ribs on the lateral surface of the tube or protrusions such as ribs formed on the sprue of a sand mould by the use of a recessed former during mould production or in the case of a metal mould or die protrusions such as ribs machined on the mould or die surface surrounding the sprue.
:13~;~456Z
The refractory tube is preferably located in the sprue such that the lower end of the tube and the filter are not in contact with the casting.
This can be achieved for example by incorporating a ledge above the base of the sprue and seating tube on the ledge.
When a casting requiring a feeder is produced using the tube and mould of the invention it is possible to locate the tube containing the filter in the feeder cavity and to utilise the feeder as the sprue. In such..applications it will be usual to use a tube which has exothermic and/or heat-insulating properties as well as being refractory in order to achieve satisfactory feeding of the casting.
After pouring and as the metal in the mould cavity solidifies and contracts, molten metal is fed from the tube cavity through the filter to compensate for the contraction and to produce a sound casting. After solidification the casting is removed from the mould and the sprue/
feeder is removed.
In order to make it easy to remove the sprue/feeder a breaker core may be located between the lower end of the tube and the mould cavity in accordance with normal practice. The breaker core may be fixed to the base of the tube if desired, for example by means of an adhesive or by shaping .
-.
3~
This can be achieved for example by incorporating a ledge above the base of the sprue and seating tube on the ledge.
When a casting requiring a feeder is produced using the tube and mould of the invention it is possible to locate the tube containing the filter in the feeder cavity and to utilise the feeder as the sprue. In such..applications it will be usual to use a tube which has exothermic and/or heat-insulating properties as well as being refractory in order to achieve satisfactory feeding of the casting.
After pouring and as the metal in the mould cavity solidifies and contracts, molten metal is fed from the tube cavity through the filter to compensate for the contraction and to produce a sound casting. After solidification the casting is removed from the mould and the sprue/
feeder is removed.
In order to make it easy to remove the sprue/feeder a breaker core may be located between the lower end of the tube and the mould cavity in accordance with normal practice. The breaker core may be fixed to the base of the tube if desired, for example by means of an adhesive or by shaping .
-.
3~
the breaker core so that part of the breaker core can be push fitted into the tube. Alternatively the breaker core may be formed integrally with the tube.
By the use of a tube of refractory material having a filter therein and a mould according to the invention, having no running system, apart from the sprue, it is possible to produce castings more economically compared with conventional practices of sand casting or gravity diecasting metals because elimination of the running system significantly reduces the weight of metal which must be cast to produce a particular casting and less fettling of the casting is needed.
The construction of a sand mould or the design of a die for gravity diecasting is simplified andboth can be made smaller compared to conventional sand moulds or dies. An existing die may be modified to produce a mould according to the invention by blocking off its running system and if necessary, machining the sprue of the die to allow insertion of the tube.
Furthermore,...metal can be cast at lower melt temperatures and in the case of gravity die--casting, at lower die tem?eratures.
45t~Z
By the use of a tube of refractory material having a filter therein and a mould according to the invention, having no running system, apart from the sprue, it is possible to produce castings more economically compared with conventional practices of sand casting or gravity diecasting metals because elimination of the running system significantly reduces the weight of metal which must be cast to produce a particular casting and less fettling of the casting is needed.
The construction of a sand mould or the design of a die for gravity diecasting is simplified andboth can be made smaller compared to conventional sand moulds or dies. An existing die may be modified to produce a mould according to the invention by blocking off its running system and if necessary, machining the sprue of the die to allow insertion of the tube.
Furthermore,...metal can be cast at lower melt temperatures and in the case of gravity die--casting, at lower die tem?eratures.
45t~Z
Castings produced in moulds according to the invention have improved directional solidifi--cation characteristics and are substantially free from porosity and inclusions and as a result, have good mechanical properties such as elongation and good machinability and are pressure tight.
The invention is illustrated with reference to the accompanying drawing which is a vertical cross-section of a tube of refractory material having a filter therein according to the invention.
Referring to the drawing a tube 1 of circular horizontal cross-section and made from a composition consisting of fibrous refractory material, particulate refractory material and a binder has a ceramic foam filter 2 located adjacent its lower end 3. During manufacture of the tube 1, after insertion of the filter 2 and before the binder is hardened, the wall 4 of the tube at the lower end 3 is deformed by a squeezing tool so as to hold the filter 2 in the desired place.
Manufacture of the tube 1 is then completed,by heating the tube to harden the binder.
In use the tube 1 is inserted into the sprue of a mould so that the lower end 3 is adjacent the mould cavity and molten non-ferrous metal is poured into the top of the tube 1 and ~ passes through the filter 2 into the mould cavity.
':
The invention is illustrated with reference to the accompanying drawing which is a vertical cross-section of a tube of refractory material having a filter therein according to the invention.
Referring to the drawing a tube 1 of circular horizontal cross-section and made from a composition consisting of fibrous refractory material, particulate refractory material and a binder has a ceramic foam filter 2 located adjacent its lower end 3. During manufacture of the tube 1, after insertion of the filter 2 and before the binder is hardened, the wall 4 of the tube at the lower end 3 is deformed by a squeezing tool so as to hold the filter 2 in the desired place.
Manufacture of the tube 1 is then completed,by heating the tube to harden the binder.
In use the tube 1 is inserted into the sprue of a mould so that the lower end 3 is adjacent the mould cavity and molten non-ferrous metal is poured into the top of the tube 1 and ~ passes through the filter 2 into the mould cavity.
':
Claims (12)
1. A tube of refractory material having a filter fixed therein formed by inserting the filter in the tube during manufacture of the tube and deforming the wall of the tube around the filter to hold the filter in place.
2. A tube according to Claim 1 having an outer surface which tapers from one end of the tube to the other end.
3. A tube according to Claim 1 wherein the tube has protrusions on its outer surface.
4. A tube according to Claim 1 wherein the top of the tube is flared.
5. A tube according to Claim 1 wherein the filter has cells which extend from one face to an opposite face.
6. A tube according to Claim 1 wherein the filter is a ceramic foam.
7. A method of making a tube of refractory material having a filter therein according to Claim 1 comprising forming a tube of fibrous refractory material, a binder and optionally particulate refractory material, inserting a filter into the tube, deforming the wall of the tube around the filter so as to hold the filter in place and causing or allowing the binder to harden.
8. A method according to Claim 7 wherein the binder is hardened by heating the tube.
9. A mould for metal casting comprising a mould cavity and a sprue communicating directly with the cavity and having located in the sprue a tube of refractory material having a filter fixed therein according to Claim 1.
10. A mould according to Claim 9 formed of sand.
11. A mould according to Claim 9 wherein the mould is a metal die.
12. A mould according to Claim 9 wherein the mould surface surrounding the sprue has protrusions for holding the tube in position.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8818186 | 1988-07-30 | ||
| GB888818186A GB8818186D0 (en) | 1988-07-30 | 1988-07-30 | Tube having filter therein for use in casting of non-ferrous metals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1304562C true CA1304562C (en) | 1992-07-07 |
Family
ID=10641375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000605809A Expired - Lifetime CA1304562C (en) | 1988-07-30 | 1989-07-17 | Tube having filter therein for use in the casting of metals |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1304562C (en) |
| GB (1) | GB8818186D0 (en) |
-
1988
- 1988-07-30 GB GB888818186A patent/GB8818186D0/en active Pending
-
1989
- 1989-07-17 CA CA000605809A patent/CA1304562C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| GB8818186D0 (en) | 1988-09-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |