CA1304559C - Moulds for metal casting and sleeves containing filters for use therein - Google Patents
Moulds for metal casting and sleeves containing filters for use thereinInfo
- Publication number
- CA1304559C CA1304559C CA000588962A CA588962A CA1304559C CA 1304559 C CA1304559 C CA 1304559C CA 000588962 A CA000588962 A CA 000588962A CA 588962 A CA588962 A CA 588962A CA 1304559 C CA1304559 C CA 1304559C
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- mould
- filter
- sprue
- casting
- 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
Abstract
ABSTRACT
A mould for metal casting has a mould cavity and a sprue communicating directly with the mould cavity and located in the sprue a sleeve of refractory material having a cellular ceramic filter fixed therein. The mould, which has no running system apart from the sprue, may be a sand mould or a metal die for producing castings by gravity or low pressure diecasting. The cellular ceramic filter may be a honeycomb type of structure having cells which extend between two outer surfaces of the filter or a structure having interconnecting cells such as a ceramic foam.
A mould for metal casting has a mould cavity and a sprue communicating directly with the mould cavity and located in the sprue a sleeve of refractory material having a cellular ceramic filter fixed therein. The mould, which has no running system apart from the sprue, may be a sand mould or a metal die for producing castings by gravity or low pressure diecasting. The cellular ceramic filter may be a honeycomb type of structure having cells which extend between two outer surfaces of the filter or a structure having interconnecting cells such as a ceramic foam.
Description
13~t~ 9 ` - 1 - FS 139 MOULDS FOR METAL CASTING AND SEEEVES
CONTAINING fILTERS FOR USE THEREIN
This invention relates to moulds for metal casting and sleeves containing filters for use therein.
Moulds such as sand moulds or metal dies for casting molten metal, usually have a mould cavity for producing the desired casting and a running system, usually consisting of a sprue, one or more runner bars and one or more ingates,and possibly one or more feeder cavities located above or at the side of the mould cavity.
During solidification cast metals undergo a reduction in their volume. For this reason, in the casting of molten metals into moulds it is usually necessary to employ feeder heads located above or at the side of the castings in order to compensate for the shrinkage which occurs when the castings solidify. It is common practice to surround a feeder head with an exothermic and/or thermally ~nsulated feeder sleeve in order to reta~n the feeder head metal in the molten state for as long as possible and thereby to ~mprove the feeding effect and to enable the feeder head volume to be reduced to a m~n1mum.
The running system connects the point of entry of molten metal ~nto the mould w~th the mould cavity and ensures not only that the mould cav~y ~s filled w~th mo7ten metal sat~sfactor~ly ~.
.
' 13045'i9 but also that the molten metal flows into the mould cavity without turbulence. If molten metal flows into a mould in a turbulent manner, splash-ing can occur, air can be entrapped in the metal thus leading to porosity in the casting and when casting readily oxidisable metals such as aluminium to oxidation of the metal and the production of oxide inclusions in the casting. Use of a running system entails casting more metal than is needed for producing a particùlar casting itself and it is not uncommon for the total weight of a casting running system to be up to about 50X of the total weight of the metal casting.
It has now been found that the need to use a running system can be substantially or com-pletely eliminated by inserting in a mould at the point of entry of molten metal into the mould cavity, a sleeve of refractory material having a ceramic foam fi1ter fixed inside the sleeve.
According to the present invention there is provided a mould for metal casting comprising a mould cavity and a sprue communicating directly with the mould cavity and having located in the sprue a sleeve of refractory material hav1ng a cellular ceramic fllter fixed thereln.
Accordlng to a further feature of the lnventlon there ls provlded for use in a mould for castlng metal as descrlbed above, a sleeve of refractory materlal having a cellular ceramic fllter flxed therein.
: !
~ I
........ ,., . .~
13~4S~9 - 3 - FS 139~
As used herein the term sprue means any passage which is used to provide the sole means of entry of molten metal into the mould cavity.
The mould of the invention has no running system apart from the sprue, but in addi-tion to the mould cavity and the sprue the mould may also have one or more feeder cavities.
The mould and the sleeve 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.
The mould may be a sand mould pre-pared to conventional foundry practice or a perma-nent mould, such as a metal die, for producing castings by gravity diecasting or by low pressure diecasting.
The material from which the sleeve is made must be sufficiently refractory to with-stand the temperature of the metal to be cast in the mould. Suitable materials include metals, ceramic materials, bonded particulate refractory materials such as silica sand and bonded refractory heat-insulating materials contatning refractory fibres. For some applications the sleeve may also contain exothermic materJals. I
Preferably the sleeve is made 13~45S9 4 - FS 13~T ~
in bonded refractory heat-insulating ~aterial and is made by dewatering on to a suitable former an aqueous slurry containing fibrous material and a binder and optionally particulate ~aterial removing the sleeve from the former and then heating the sleeve to remove water and to harden or cure the binder. Such sleeves can be manufactured accurately to close tolerances on both their inner and outer surfaces. This is important because the outer surface must be such that the sleeve fits snugly in the sprue of a die or sand ould without being crushed and without floating of the sleeve occuring when metal is cast into the die or sand mould. Accuracy in the size of the inner surface is important in order to guarantee insertion and location of the filter. Such sleeves are also erosion resistant and this ensures that particles and fibres are not washed from the surface by metal poured into the sleeve and through the filter into the mould cavity.
For ease of manufacture the sleeve will usually be of circular horizontal cross-section but the horizontal cross-section of the sleeve may be for example, oval, oblong or square.
The cellular ceramic filter may be for example a honeycomb type of structure hav~ng cells which extend between two outer surfaces of the filter or a structure having interconnecting pores such as a ceram~c foam.
Ceramlc foam f~lters are preferred and such filters may be made us~ng a known method of - \
13~d~SS~
CONTAINING fILTERS FOR USE THEREIN
This invention relates to moulds for metal casting and sleeves containing filters for use therein.
Moulds such as sand moulds or metal dies for casting molten metal, usually have a mould cavity for producing the desired casting and a running system, usually consisting of a sprue, one or more runner bars and one or more ingates,and possibly one or more feeder cavities located above or at the side of the mould cavity.
During solidification cast metals undergo a reduction in their volume. For this reason, in the casting of molten metals into moulds it is usually necessary to employ feeder heads located above or at the side of the castings in order to compensate for the shrinkage which occurs when the castings solidify. It is common practice to surround a feeder head with an exothermic and/or thermally ~nsulated feeder sleeve in order to reta~n the feeder head metal in the molten state for as long as possible and thereby to ~mprove the feeding effect and to enable the feeder head volume to be reduced to a m~n1mum.
The running system connects the point of entry of molten metal ~nto the mould w~th the mould cavity and ensures not only that the mould cav~y ~s filled w~th mo7ten metal sat~sfactor~ly ~.
.
' 13045'i9 but also that the molten metal flows into the mould cavity without turbulence. If molten metal flows into a mould in a turbulent manner, splash-ing can occur, air can be entrapped in the metal thus leading to porosity in the casting and when casting readily oxidisable metals such as aluminium to oxidation of the metal and the production of oxide inclusions in the casting. Use of a running system entails casting more metal than is needed for producing a particùlar casting itself and it is not uncommon for the total weight of a casting running system to be up to about 50X of the total weight of the metal casting.
It has now been found that the need to use a running system can be substantially or com-pletely eliminated by inserting in a mould at the point of entry of molten metal into the mould cavity, a sleeve of refractory material having a ceramic foam fi1ter fixed inside the sleeve.
According to the present invention there is provided a mould for metal casting comprising a mould cavity and a sprue communicating directly with the mould cavity and having located in the sprue a sleeve of refractory material hav1ng a cellular ceramic fllter fixed thereln.
Accordlng to a further feature of the lnventlon there ls provlded for use in a mould for castlng metal as descrlbed above, a sleeve of refractory materlal having a cellular ceramic fllter flxed therein.
: !
~ I
........ ,., . .~
13~4S~9 - 3 - FS 139~
As used herein the term sprue means any passage which is used to provide the sole means of entry of molten metal into the mould cavity.
The mould of the invention has no running system apart from the sprue, but in addi-tion to the mould cavity and the sprue the mould may also have one or more feeder cavities.
The mould and the sleeve 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.
The mould may be a sand mould pre-pared to conventional foundry practice or a perma-nent mould, such as a metal die, for producing castings by gravity diecasting or by low pressure diecasting.
The material from which the sleeve is made must be sufficiently refractory to with-stand the temperature of the metal to be cast in the mould. Suitable materials include metals, ceramic materials, bonded particulate refractory materials such as silica sand and bonded refractory heat-insulating materials contatning refractory fibres. For some applications the sleeve may also contain exothermic materJals. I
Preferably the sleeve is made 13~45S9 4 - FS 13~T ~
in bonded refractory heat-insulating ~aterial and is made by dewatering on to a suitable former an aqueous slurry containing fibrous material and a binder and optionally particulate ~aterial removing the sleeve from the former and then heating the sleeve to remove water and to harden or cure the binder. Such sleeves can be manufactured accurately to close tolerances on both their inner and outer surfaces. This is important because the outer surface must be such that the sleeve fits snugly in the sprue of a die or sand ould without being crushed and without floating of the sleeve occuring when metal is cast into the die or sand mould. Accuracy in the size of the inner surface is important in order to guarantee insertion and location of the filter. Such sleeves are also erosion resistant and this ensures that particles and fibres are not washed from the surface by metal poured into the sleeve and through the filter into the mould cavity.
For ease of manufacture the sleeve will usually be of circular horizontal cross-section but the horizontal cross-section of the sleeve may be for example, oval, oblong or square.
The cellular ceramic filter may be for example a honeycomb type of structure hav~ng cells which extend between two outer surfaces of the filter or a structure having interconnecting pores such as a ceram~c foam.
Ceramlc foam f~lters are preferred and such filters may be made us~ng a known method of - \
13~d~SS~
making a ceramic form, in which an organic foam, usually polyurethane foam, is impregnated 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.
The filter is preferably located at or adjacent to the lower end of the sleeve. The filter may be fixed inside the sleeve by means of an adhesive.
The refractory sleeve may be formed integrally with the filt~r by forming it around the lateral surface of the filter. During forming it is desirable to cover the open faces of the filter to prevent the material from which the sleeve is formed from entering the pores of the filter and blocking them. When the sleeve and filter are to be used for casting aluminium the cover may conveniently be aluminium foil which in use is immediately melted by molten aluminium poured into the sleeve.
The sleeve may also be formed in two parts and one end of each of the two parts may be fixed to a face of the filter, for example, by means of an adhesive and the lateral surface of the filter sealed to prevent leakage of molten metal in use.
13(~4SS9 The sleeve may have one or more ledges or shoulder on its inner sur~ace for locating the filter in the desired position.
The length of the sleeve may be the same as or similar to the thickness of the filter so that the sleeve is in the form of a ring around the filter. However, it is preferred that the length of the sleeve is appreciably larger than the thickness of the filter, so that the molten metal can be poured into the sleeve, thus avoiding the possibility of metal leaking into the mould cavity around the outside of the sleeve. If desired, to aid filling of the sleeve, the upper end of the sleeve may be flared in the shape of a funnel.
In order to insert and locate the sleeve in the sprue of the mould it is preferred that the outer surface of the sleeve is tapered and that the sprue has a corresponding taper, the direction of taper depending on whether the sleeve is to be inserted in the sprue from above or below.
It is also preferred that the outer surface of the sleeve or the mould surface surrounding the sprue has means for holding the sleeve 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 sleeve 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 protrusion such as ribs ma~chined on the mould or die surface surrounding the sprue.
~3Q`~559 The refractory sleeve is preferably located in the sprue such that the lower end of the sleeve 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 the sleeve on the ledge.
When a casting requiring a feeder is produced using the mould and sleeve of the invention it is possible to locate the sleeve 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 sleeve which has exothermic and/
or heat-insulating properties as well as being refractory in order to achieve satisfactory feeding Of the casting.
By the use of a sleeve 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 wh;ch 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 and both 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 ~ ~\
13~4SS~
The filter is preferably located at or adjacent to the lower end of the sleeve. The filter may be fixed inside the sleeve by means of an adhesive.
The refractory sleeve may be formed integrally with the filt~r by forming it around the lateral surface of the filter. During forming it is desirable to cover the open faces of the filter to prevent the material from which the sleeve is formed from entering the pores of the filter and blocking them. When the sleeve and filter are to be used for casting aluminium the cover may conveniently be aluminium foil which in use is immediately melted by molten aluminium poured into the sleeve.
The sleeve may also be formed in two parts and one end of each of the two parts may be fixed to a face of the filter, for example, by means of an adhesive and the lateral surface of the filter sealed to prevent leakage of molten metal in use.
13(~4SS9 The sleeve may have one or more ledges or shoulder on its inner sur~ace for locating the filter in the desired position.
The length of the sleeve may be the same as or similar to the thickness of the filter so that the sleeve is in the form of a ring around the filter. However, it is preferred that the length of the sleeve is appreciably larger than the thickness of the filter, so that the molten metal can be poured into the sleeve, thus avoiding the possibility of metal leaking into the mould cavity around the outside of the sleeve. If desired, to aid filling of the sleeve, the upper end of the sleeve may be flared in the shape of a funnel.
In order to insert and locate the sleeve in the sprue of the mould it is preferred that the outer surface of the sleeve is tapered and that the sprue has a corresponding taper, the direction of taper depending on whether the sleeve is to be inserted in the sprue from above or below.
It is also preferred that the outer surface of the sleeve or the mould surface surrounding the sprue has means for holding the sleeve 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 sleeve 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 protrusion such as ribs ma~chined on the mould or die surface surrounding the sprue.
~3Q`~559 The refractory sleeve is preferably located in the sprue such that the lower end of the sleeve 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 the sleeve on the ledge.
When a casting requiring a feeder is produced using the mould and sleeve of the invention it is possible to locate the sleeve 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 sleeve which has exothermic and/
or heat-insulating properties as well as being refractory in order to achieve satisfactory feeding Of the casting.
By the use of a sleeve 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 wh;ch 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 and both 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 ~ ~\
13~4SS~
necessary, machining the sprue of the die to allow insertion of the sleeve.
Furthermore, metal can be cast at lower melt temperatures and in the case of gravity diecasting, at lower die temperatures.
Castings produced in moulds according to the invention have improved directional solidification 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 drawings in which Figure 1 is a vertical cross-section of a sleeve according to the invention Figure 2 is a vertical cross-section of a conventional sand mould for producing an aluminium plate casting Figure 3 is a vertical cross-section of a sand mould according to the invention for producing the aluminium plate casting of Figure 2 Figure 4 is a vertical cross-section of a further embodiment of a mould according to the invention I
13~45~
Furthermore, metal can be cast at lower melt temperatures and in the case of gravity diecasting, at lower die temperatures.
Castings produced in moulds according to the invention have improved directional solidification 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 drawings in which Figure 1 is a vertical cross-section of a sleeve according to the invention Figure 2 is a vertical cross-section of a conventional sand mould for producing an aluminium plate casting Figure 3 is a vertical cross-section of a sand mould according to the invention for producing the aluminium plate casting of Figure 2 Figure 4 is a vertical cross-section of a further embodiment of a mould according to the invention I
13~45~
Figure 5 is a diagrammatic top plan of an aluminium cylinder head casting produced in a conventional metal die by gravity diecasting and Figure 6 is a diagrammatic top plan of the aluminium cylinder head casting of Figure 5 produced in a mould according to the invention by gravity diecasting.
Referring to Figure 1 a sleeve 1 made in refractory heat-insulating material has an outer surface 2 which tapers from the bottom 3 of the sleeve to the top 4. The inside of the sleeve 1 has a ledge 5 at the bottom 3 of the sleeve 1 on which there is fixed a ceramic foam filter 6. In use the sleeve 1 is inserted into a mould sprue having a taper corresponding to that of the outer lateral surface 2 of the sleeve 1.
Referring to Figure 2 a sand mould 11 having a mould cavity 12 for producing an aluminium plate casting has a pouring bush 13, a running system comprising a sprue 14, a well 15, a runner bar 16 and an ingate 17 and a feeder cavity 18.
The feeder cavity 18 is lined with a cylindrical heat-insulating feeder sleeve 19 made in bonded fibrous and non-fibrous particulate refractory material.
In use molten metal is poured into the pouring bush 13 and flows through the running system and into the mould cavity 12 and the feeder ca~ity 18.
13~45S~
lo - FS 1391 Referring to Figure 3 a sand mould 21 for producing an aluminium plate casting identical to that to be produced in Figure 2 has a mould cavity 22 and a sprue 23. The mould has no pouring bush and no running system. The sprue 23 is lined with a refractory heat-insulating sleeve 24 made in bonded fibrous and non-fibrous particulate refractory material and the sleeve 24 has a ceramic foam filter 25 located adjacent its lower end 26.
In use molten metal is poured into the sprue 23 and flows through the ceramic foam f;lter 25 into the mould cavity 22. Pouring ceases when the sprue 23 is full of molten metal.
Moulds of the type shown in Figure 2 1s and Figure 3 were used to produce aluminium plate castings measuring 26 cm x 26 cm x 2 cm. The total weight of metal cast using the Figure 2 mould was 5 kg and t~e total.weight of metal cast using the Figure - 3 mould was 3 kg. Using a mould according to the invention therefore gave a saving of 2 kg in the total weight of metal cast.
Referring to Figure 4 a sand mould 31 for producing a plate casting has a mould cavity 32 and a sprue 33 having an upper part 34 and a lower part 35. The lower part 34 is formed by a tapered former which has longitudinally extending recesses in its lateral surface and the recesses form ribs 36 on the surface of the mould material surrouoding the lower part 35. A sleeve 37 having a ceramic foam filter 38 fixed therein as shown in Figurel is inserted into the lower part 35 of the sprue 33 i3~45S9 ~ FS 1391 and is held firmly in place by the ribs 36. In use molten metal is poured into the upper part 34 of the sprue 33 and the metal passes through the ceramic foam filter 38 into the mould cavity 32.
Referring to Figure 5 an aluminium cylinder head casting 41 produced in a gravity die having four cylinders 42 and two valve ports 43 per cylinder has a running system consisting of a sprue 44 connected via runner bars 45 and ingates 46 to the cylinder head and three cylindrical feeders 47 and an elongate feeder 48. The casting 41 is produced by pouring molten aluminium into the sprue 44 so that it flows through the running system into the die cavity and the feeder cavities.
~eferring to Figure 6 an identical aluminium cylinder head casting 51 to that shown in Figure 5 having four cylinders 52 and two valve ports 53 per cylinder has three cylindrical feeders 54A, 54B, 54C and an elongate feeder 55 but no running system. Prior to production of the casting a refractory sleeve made in bonded fibrous and non-fibrous particulate refractory material and having a ceramic foam filter fixed inside the sleeve at one end was inserted into the cavity of the gravity die for producing the central feeder 54B of the three cylindrical feeders so that the bottom end of the sleeve containing the ceramic foam filter was just above the top of the die cavity. The casting 51 was produced by pouring molten a1uminium into the cavity for feeder 54B so that it passed through the sleeve and the filter into the die .
,-' '' : .
" , ' ' , ' - ' ~3045iS~
CdVity and the other feeder cavities. The total weight of the casting shown in Figure 5 was 19.0 kg made up of 10.5 kg for the cylinder head itself, 6.0 kg for the feeders and 2.5 kg for the running system. The total weight of the casting shown in Figure 6 was 16.5 kg thus resulting in a saving of cast metal of 2.5 kg compared with the Figure 5 casting.
Referring to Figure 1 a sleeve 1 made in refractory heat-insulating material has an outer surface 2 which tapers from the bottom 3 of the sleeve to the top 4. The inside of the sleeve 1 has a ledge 5 at the bottom 3 of the sleeve 1 on which there is fixed a ceramic foam filter 6. In use the sleeve 1 is inserted into a mould sprue having a taper corresponding to that of the outer lateral surface 2 of the sleeve 1.
Referring to Figure 2 a sand mould 11 having a mould cavity 12 for producing an aluminium plate casting has a pouring bush 13, a running system comprising a sprue 14, a well 15, a runner bar 16 and an ingate 17 and a feeder cavity 18.
The feeder cavity 18 is lined with a cylindrical heat-insulating feeder sleeve 19 made in bonded fibrous and non-fibrous particulate refractory material.
In use molten metal is poured into the pouring bush 13 and flows through the running system and into the mould cavity 12 and the feeder ca~ity 18.
13~45S~
lo - FS 1391 Referring to Figure 3 a sand mould 21 for producing an aluminium plate casting identical to that to be produced in Figure 2 has a mould cavity 22 and a sprue 23. The mould has no pouring bush and no running system. The sprue 23 is lined with a refractory heat-insulating sleeve 24 made in bonded fibrous and non-fibrous particulate refractory material and the sleeve 24 has a ceramic foam filter 25 located adjacent its lower end 26.
In use molten metal is poured into the sprue 23 and flows through the ceramic foam f;lter 25 into the mould cavity 22. Pouring ceases when the sprue 23 is full of molten metal.
Moulds of the type shown in Figure 2 1s and Figure 3 were used to produce aluminium plate castings measuring 26 cm x 26 cm x 2 cm. The total weight of metal cast using the Figure 2 mould was 5 kg and t~e total.weight of metal cast using the Figure - 3 mould was 3 kg. Using a mould according to the invention therefore gave a saving of 2 kg in the total weight of metal cast.
Referring to Figure 4 a sand mould 31 for producing a plate casting has a mould cavity 32 and a sprue 33 having an upper part 34 and a lower part 35. The lower part 34 is formed by a tapered former which has longitudinally extending recesses in its lateral surface and the recesses form ribs 36 on the surface of the mould material surrouoding the lower part 35. A sleeve 37 having a ceramic foam filter 38 fixed therein as shown in Figurel is inserted into the lower part 35 of the sprue 33 i3~45S9 ~ FS 1391 and is held firmly in place by the ribs 36. In use molten metal is poured into the upper part 34 of the sprue 33 and the metal passes through the ceramic foam filter 38 into the mould cavity 32.
Referring to Figure 5 an aluminium cylinder head casting 41 produced in a gravity die having four cylinders 42 and two valve ports 43 per cylinder has a running system consisting of a sprue 44 connected via runner bars 45 and ingates 46 to the cylinder head and three cylindrical feeders 47 and an elongate feeder 48. The casting 41 is produced by pouring molten aluminium into the sprue 44 so that it flows through the running system into the die cavity and the feeder cavities.
~eferring to Figure 6 an identical aluminium cylinder head casting 51 to that shown in Figure 5 having four cylinders 52 and two valve ports 53 per cylinder has three cylindrical feeders 54A, 54B, 54C and an elongate feeder 55 but no running system. Prior to production of the casting a refractory sleeve made in bonded fibrous and non-fibrous particulate refractory material and having a ceramic foam filter fixed inside the sleeve at one end was inserted into the cavity of the gravity die for producing the central feeder 54B of the three cylindrical feeders so that the bottom end of the sleeve containing the ceramic foam filter was just above the top of the die cavity. The casting 51 was produced by pouring molten a1uminium into the cavity for feeder 54B so that it passed through the sleeve and the filter into the die .
,-' '' : .
" , ' ' , ' - ' ~3045iS~
CdVity and the other feeder cavities. The total weight of the casting shown in Figure 5 was 19.0 kg made up of 10.5 kg for the cylinder head itself, 6.0 kg for the feeders and 2.5 kg for the running system. The total weight of the casting shown in Figure 6 was 16.5 kg thus resulting in a saving of cast metal of 2.5 kg compared with the Figure 5 casting.
Claims (14)
1. A mould for metal casting comprising a mould cavity and a sprue communicating directly with the mould cavity and having located in the sprue a sleeve of refractory material having a cellular ceramic filter fixed therein.
2. A mould according to Claim 1 formed of sand.
3. A mould according to Claim 1 wherein the mould is a metal die.
4. A mould according to Claim 1 wherein the sprue has protrusions for holding the sleeve in position.
5. A sleeve of refractory material for use in a mould for casting metal according to Claim 1 having a cellular ceramic filter fixed therein.
6. A sleeve according to Claim S wherein the filter has cells which extend between two outer surfaces of the filter.
7. A sleeve according to Claim 5 wherein the filter is a ceramic foam.
8. A sleeve according to Claim 5 wherein the filter is located at or adjacent the lower end of the sleeve.
9. A sleeve according to Claim 5 wherein the sleeve has one or more ledges on its inner surface for locating the filter.
10. A sleeve according to Claim 5 wherein the filter is fixed inside the sleeve by means of an adhesive.
11. A sleeve according to Claim 5 wherein the sleeve is formed integrally with the filter by forming the sleeve around the lateral surface of the filter.
12 A sleeve according to Claim 5 wherein the sleeve is formed in two parts, one end of each part is fixed to a face of the filter and the lateral surface of the filter is sealed.
13. A sleeve according to Claim 5 wherein the upper end of the sleeve is flared.
14. A sleeve according to Claim 5 wherein the sleeve has protrusions on its outer surface for holding the sleeve in position in a mould sprue.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8802083 | 1988-01-30 | ||
| GB888802083A GB8802083D0 (en) | 1988-01-30 | 1988-01-30 | Mould & method of casting nonferrous metals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1304559C true CA1304559C (en) | 1992-07-07 |
Family
ID=10630788
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000588962A Expired - Lifetime CA1304559C (en) | 1988-01-30 | 1989-01-24 | Moulds for metal casting and sleeves containing filters for use therein |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1304559C (en) |
| GB (1) | GB8802083D0 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107127297A (en) * | 2017-06-27 | 2017-09-05 | 河南省登封市光大耐火材料有限公司 | A kind of casting and pouring facility |
-
1988
- 1988-01-30 GB GB888802083A patent/GB8802083D0/en active Pending
-
1989
- 1989-01-24 CA CA000588962A patent/CA1304559C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| GB8802083D0 (en) | 1988-02-24 |
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