CA1206722A - Method and apparatus for pressure diecasting - Google Patents
Method and apparatus for pressure diecastingInfo
- Publication number
- CA1206722A CA1206722A CA000433684A CA433684A CA1206722A CA 1206722 A CA1206722 A CA 1206722A CA 000433684 A CA000433684 A CA 000433684A CA 433684 A CA433684 A CA 433684A CA 1206722 A CA1206722 A CA 1206722A
- Authority
- CA
- Canada
- Prior art keywords
- pressure
- casting die
- casting
- die
- reservoir
- 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
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000004512 die casting Methods 0.000 title claims abstract description 9
- 238000005266 casting Methods 0.000 claims abstract description 106
- 239000000155 melt Substances 0.000 claims abstract description 33
- 229910052751 metal Inorganic materials 0.000 claims abstract description 15
- 239000002184 metal Substances 0.000 claims abstract description 15
- 239000000463 material Substances 0.000 claims description 12
- 238000002425 crystallisation Methods 0.000 claims description 10
- 230000008025 crystallization Effects 0.000 claims description 10
- 208000036366 Sensation of pressure Diseases 0.000 claims 2
- 238000010586 diagram Methods 0.000 description 17
- 239000007789 gas Substances 0.000 description 11
- 239000007792 gaseous phase Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005058 metal casting Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000789 Aluminium-silicon alloy Inorganic materials 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
A pressure die-casting method and apparatus in which the melt from a molten metal reservoir is delivered and fills the casting die under the action of a difference in pressures created in the molten metal reservoir and the casting die and when the melt fills the die it is under the action of vacuum, ambient or increased gas pressure. The method is characterized by that after filling the casting die with melt up to a preset level in the unfilled cavity of the casting die or in one or several unfilled independent cavities of the die an additional gas pressure considerably higher than that acting already in the casting die is created and simultaneously this additional gas pressure is equalized by the counter acting pressure created on the other side of the casting die.
A pressure die-casting method and apparatus in which the melt from a molten metal reservoir is delivered and fills the casting die under the action of a difference in pressures created in the molten metal reservoir and the casting die and when the melt fills the die it is under the action of vacuum, ambient or increased gas pressure. The method is characterized by that after filling the casting die with melt up to a preset level in the unfilled cavity of the casting die or in one or several unfilled independent cavities of the die an additional gas pressure considerably higher than that acting already in the casting die is created and simultaneously this additional gas pressure is equalized by the counter acting pressure created on the other side of the casting die.
Description
The invention relates to a pressure die-casting method and finds application in Eoundries for the production of castings in different materials with high physico-mechanical characteristics.
The invention also relates to an apparatus to carry out the method.
In the known pressure die-casting method the melt from a molten metal reservoir passes via a closed material conduit and fills the casting mould under the action of a difference in pressures existing in the melt reservoir and the casting mould. Filling of the casting mould starts under an ambient pressure and when the mould is filled up to a preset level appropriate vacuum is created in the still unfilled space of the mould over the melt to control the rate of final mould filling. Upon completion of mould filling the melt inside crystallizes and the ready casting is removed there-from.
A drawback of the method is that the melt crystallizes under the effect of the already created vacuum or low pressure and therefore it is impossible to have control over the crystallization process in all sections of the casting and in particular when components oE an intricate design are involved. It results in worsening the physico-mechanical properties of the cast part.
The object of this invention is to create a pressure die-casting method and apparatus (machine) which allows for the control of the die-filling and crystallization processes in any part of the casting die at minimum energy losses and producing cast components with high physico-mechanical properties.
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The invention also relates to an apparatus to carry out the method.
In the known pressure die-casting method the melt from a molten metal reservoir passes via a closed material conduit and fills the casting mould under the action of a difference in pressures existing in the melt reservoir and the casting mould. Filling of the casting mould starts under an ambient pressure and when the mould is filled up to a preset level appropriate vacuum is created in the still unfilled space of the mould over the melt to control the rate of final mould filling. Upon completion of mould filling the melt inside crystallizes and the ready casting is removed there-from.
A drawback of the method is that the melt crystallizes under the effect of the already created vacuum or low pressure and therefore it is impossible to have control over the crystallization process in all sections of the casting and in particular when components oE an intricate design are involved. It results in worsening the physico-mechanical properties of the cast part.
The object of this invention is to create a pressure die-casting method and apparatus (machine) which allows for the control of the die-filling and crystallization processes in any part of the casting die at minimum energy losses and producing cast components with high physico-mechanical properties.
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- 2 --According to the present invention there is provided a pressure die-casting method in which the melt from a molten metal reservoir is delivered and fills the casting die under the action oE a difference in pressures created in the molten metal reservoir and the casting die and when the melt fills the die it is under the action of vacuum, ambient or increased gas pressure, characterized by that after filling the casting die with melt up to a preset level in the unfilled cavity of the casting die or in one or several unfilled independent cavities of the die an additional gas pressure considerably higher than that acting already in the casting die is created and simul~
taneously this additional gas pressure is equalized by the counter acting pressure created on the other side of the casting die.
The abovesaid additional pressure can be maintained at a constant level until the complete crystallization of melt in the casting die or continuously increased for the time from its creation until the completion of crystallization.
The advantages of the method lie in the fact that the additional gas pressure starts acting on the melt at a preset time selected in dependence on the configuration of the concrete casting part and its constructive material and is created in the casting die. Thus the die-filling with melt and crystallization of the latter are influenced at the same time effecting the control over the said two processes at minimum energy consumptions. All this makes possible the production of casting components possessing desired and at same time high physico-mechanical features independent of their configuration.
According to the present invention, there is also provided ''~J~
- 2a -an apparatus for pressure die-casting comprising:
- a reservoir - a casting die made of two-parts and comprising a cavity, said reservoir being connected to said casting-die, and said casting-die having an additional cavity, - a first source of pressure to which said reservoir is connected, - a second source of pressure to which said reservoir is connected, - a rnultiplying cylinder connected to said cast-ind die, said multiplying cylinder being also connected to said additional cavity and to said second source of pressure.
Preferred embodiments will now be described as examples without any limitative manner having reference to the attached drawings, wherein /
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Figure 1 A schematic diagram of the machine for the im-plementation of the method when casting with melt supplied by means of a difference in gas pressures created in the casting die and the molten metal reservoir;
Figure 2 An examplary indicator diagram of the delivery pressure during castin~ as per the diagram on Fig. l;
Figure 3 A schematic diagram of the machine for the im-plementation of the method in casting under an ambient pressure in a casting die and with a delivery pressure produced by a piston;
Figure 4 An indicator diagram of the delivery pressure in casting as per the diagram on Fig.3;
Figure 5 A flow diagram of casting in the presence of vacuum in the casting die and the creation of a delivery pressure in result of a difference in pressures of gaseous phase;
Figure 6 An indicator diagram of delivery pressure in casting as per the diagram shown on Fig. 7;
Figure 7 A schematic diagram of the machine for the im-plementation of the casting method with an increased pressure in the casting die and a delivery pressure created by the difference in pressures of gaseous phase;
Figure 8 An indicator diagram of the delivery pressure in casting as per the diagram on Fig.5.
The machine for the implementation of the method as per Fig. 1 consists of a molten metal (melt) reservoir 1 - ~r :~2~;~67~
connected to the casting die 3 by means of a material feed conduit 2. The castiny die is made in 2 parts - a lower par~
31 and an upper part 32 forming the casting cavity 4, while the additional cavities 5 are formed in the upper part 32.
The melt reservoir is connected to a compressed gas source 6 via a valve 7. The qas pressure in the gas source 6 is Pl which is also the delivery pressure. The melt reservoir 1 is provided with a pressure indicator 8 which is by means of a transducer 9 and a valve 10 connected to a compressed gas tank 13 being under a high pressure - P3. A multiplying cylinder 11 is mounted on the lower part of the die 3 and by means of a control butterfly valve 12 and a conduit is connected to the additional cavities 5 on one side and by means of a conduit via the valve 10 - to the compressed air tank 13.
The casting process as per this examplary flow diagram is performed in the following manner: when the melt is ready for casting a difference between pressures in the melt reservoir 1 and the casting die 3 (31,32) is created and the melt starts filling the casting cavity 4 via the material feed conduit, while in the melt reservoir l - casting die 3 system there could have existed vacuum, ambient or increased pressure. In the filling process the delivery pressure rises in result of overcoming the friction forces, the hydraulic height of melt and the throttling effect of the gaseous phase when coming out of the vents being gradually and unevenly filled by melt. When a preset level of melt is reached as shown with the A-A line and p. "a" of the indicator diagram (Fig. 2), the delivery pressure Pl changes its character for instance as a result of the abrupt change in the cross section of the casting. By means of a signal given by the pressure indicator 8 to the deliver~ pressure the transducer 9 is actuated and opens the valve 10 so that the gaseous phase from the high pressure source 13 is supplied to the unfilled ~ ~, 67~
additional cavities 5 of the casting die 3 and to the multiply-ing cylinder 11 and the high pressure P3 is established in the casting die 3. During the movement of the piston in the multiplying cylinder 11 the molten metal flow from the melt reservoir 1 is interrupted and the casting die 3 is finally filled with melt. After the pressure has been taken off and cooling performed, the ready casting part is removed and the cycle repeated.
The machine for the implementation of the method as per Fig. 3 consists of a material cylinder 1 connected via a riser duct to the casting die 3 comprised of a right part 31 and a left part 32 which define the casting cavity ~ and the additional cavity 5 (dead head). The material cylinder 1 is connected to a pressure source 6 having a pressure Pl through a valve 7, a conduit and a power cylinder 18 with a pressure indicator 8 fitted on it. The power cylinder 18 is connected to the multiplying cylinder 11 one part of which communicates through a tube with the die cavity 4 and via a valve 14 with the compressed air tank 13 being under a high pressure P3. The~pressure indicator 8 is connected to a tranducer 9 which, in its turn, is connected through a valve 10 to the additional cavity 5 and the multiplying cylinder llo The communication between the transducer 9 and the additional cavity 5 is provided with a control gate 12.
According to the diagram shown on Fig. 3 the casting process runs as follows:
Characteristics of the casting part: A car piston in aluminium-silicon alloy having a skirt with a 6 mm thick wall; a reinforcing ring in the lower portion of the skirt;
bosses in the zones of piston bolt seats having a thickness of 20 mm and a bottom wall thickness of 25 mm.
Casting is performed in a two-cavity metal casting die 3 with a split wedge core for the central hole and cores for the radial holes. The air vents, the riser duct and the 672~:
dead heads 5 are formed in the die 3.
The gas passing from the compressed air tank 13 via an opened valve 14 into the multiplying cylinder ll creates a gas pressure of 60 MPa. Then the valve 14 is closed and a portion of melt is poured into the material cylinder 1. In the power cylinder 18 and the multiplying cylinder ll a hydraulic pressure is provided from the tank 6 at an opened valve 7. The piston of the power cylinder 18 moves the melt filling the cavity of the die 3. When filling the additional cavities 5 of the die 3 the delivery pressure Pdel (Fig. 4) read by the pressure indicator 8 changes and after having filled a part of the dead heads 5, it changes its character (p- "a", Fig. 4) and upon a signal by the pressure indicator 8 the transducer 9 is being actuated to open the valve 10 starting the piston of the multiplying cylinder 11 and a pressure of 300 ~Pa is being exerted on the dead heads 5.
Such pressure is maintained until the completion of the crystallization process in the casting part and thereafter it is removed and the part is taken out of the die. The casting part obtained after the appropriate heat treatment has the following characteristics: ~B= 32 - 36.105 N/m2;
S= 27 - 30.105 N/m2; ~ > 3~; ~B = 120 - 140u The machine for the implementation of the method as per Fig. 5 consists of a molten metal (melt) reservoir 1 communicating via a material feed conduit ~ with the casting die 3 that comprises two parts - the lower part 31 and the upper part 32 with the cavity 4 in-between. In the upper part 32 there are additional cavities 5 (dead heads) provided. The melt reservoir 1 is connected with the gas pressure source 6 at a pressure Pl through a valve 7. The melt reservoir 1 and the space of the casting die 3 are connected by a pressure indicator 8 provided with a transducer 9. The transducer 9 via a valve 10 communicates with the high pressure tank 13 at a pressure P3, the latter being connected via the said ~.
~2(~67~
valve 10 to the multiplying cylinder 11 comrnunicating with the lower part 31 of the die. The space of the multiplying cylinder 11 in front of the piston communicates with the additional cavities 5 of the casting die 3 through a control gate 12. The space of the casting die 3 is connected with the vacuum tank 17 by means of a tube and a valve 16.
According to the diagram shown on Fig. 5 the casting process is carried out in the following way:
Charateristics of the casting part: a car sus-pension component in aluminium alloy with a complex combinationof thin and thick walls in the thickness range from 4 to 25 mm. The bosses are concentrated in three places at a distance from the central hole ranging 300 - 400 mm. A
complex ribbed design with a rib relief up to 90 mm.
The casting is performed in a metal casting die of two parts located in a sealed chamber.
The split line of the parts 31, 32 has a complex configuration. The air vents are made in the casting die, while the dead heads are over the bosses of the casting part.
The cavities of the casting part in the space between the ribs are formed by inserts and between them there are also vents.
prior to commencement of casting in the chamber incorporating the casting die 3 there is created vacuum of 0,1 - 0,2 MPa from the source 17 at an opened valve 16. A difference between pressures in the melt reservoir 1 and the casting die 3 is produced to result in the initial filling of the cavity 4 for the casting part. When the melt blocks the vents of the split planes, the delivery pressure changes its character and by means of a signal from the indicator 8 the transducer 9 which opens the valve 10 is actuated.
A high pressure equalized by the piston of the multiplying cylinder 11 is established in the cavity of the casting die 3. Such pressure is maintained until the com-pletion of the crystallization process in the casting part \
6~
and thence it is removed and the casting part is taken out of the die. The vacuum is maintained only until the complete filling of the casting die 3 with melt.
The machine for the implementation of the method as per Fig. 7 consists of a molten metal (melt) reservoir 1 connected via a material feed conduit 2 with the casting die
taneously this additional gas pressure is equalized by the counter acting pressure created on the other side of the casting die.
The abovesaid additional pressure can be maintained at a constant level until the complete crystallization of melt in the casting die or continuously increased for the time from its creation until the completion of crystallization.
The advantages of the method lie in the fact that the additional gas pressure starts acting on the melt at a preset time selected in dependence on the configuration of the concrete casting part and its constructive material and is created in the casting die. Thus the die-filling with melt and crystallization of the latter are influenced at the same time effecting the control over the said two processes at minimum energy consumptions. All this makes possible the production of casting components possessing desired and at same time high physico-mechanical features independent of their configuration.
According to the present invention, there is also provided ''~J~
- 2a -an apparatus for pressure die-casting comprising:
- a reservoir - a casting die made of two-parts and comprising a cavity, said reservoir being connected to said casting-die, and said casting-die having an additional cavity, - a first source of pressure to which said reservoir is connected, - a second source of pressure to which said reservoir is connected, - a rnultiplying cylinder connected to said cast-ind die, said multiplying cylinder being also connected to said additional cavity and to said second source of pressure.
Preferred embodiments will now be described as examples without any limitative manner having reference to the attached drawings, wherein /
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Figure 1 A schematic diagram of the machine for the im-plementation of the method when casting with melt supplied by means of a difference in gas pressures created in the casting die and the molten metal reservoir;
Figure 2 An examplary indicator diagram of the delivery pressure during castin~ as per the diagram on Fig. l;
Figure 3 A schematic diagram of the machine for the im-plementation of the method in casting under an ambient pressure in a casting die and with a delivery pressure produced by a piston;
Figure 4 An indicator diagram of the delivery pressure in casting as per the diagram on Fig.3;
Figure 5 A flow diagram of casting in the presence of vacuum in the casting die and the creation of a delivery pressure in result of a difference in pressures of gaseous phase;
Figure 6 An indicator diagram of delivery pressure in casting as per the diagram shown on Fig. 7;
Figure 7 A schematic diagram of the machine for the im-plementation of the casting method with an increased pressure in the casting die and a delivery pressure created by the difference in pressures of gaseous phase;
Figure 8 An indicator diagram of the delivery pressure in casting as per the diagram on Fig.5.
The machine for the implementation of the method as per Fig. 1 consists of a molten metal (melt) reservoir 1 - ~r :~2~;~67~
connected to the casting die 3 by means of a material feed conduit 2. The castiny die is made in 2 parts - a lower par~
31 and an upper part 32 forming the casting cavity 4, while the additional cavities 5 are formed in the upper part 32.
The melt reservoir is connected to a compressed gas source 6 via a valve 7. The qas pressure in the gas source 6 is Pl which is also the delivery pressure. The melt reservoir 1 is provided with a pressure indicator 8 which is by means of a transducer 9 and a valve 10 connected to a compressed gas tank 13 being under a high pressure - P3. A multiplying cylinder 11 is mounted on the lower part of the die 3 and by means of a control butterfly valve 12 and a conduit is connected to the additional cavities 5 on one side and by means of a conduit via the valve 10 - to the compressed air tank 13.
The casting process as per this examplary flow diagram is performed in the following manner: when the melt is ready for casting a difference between pressures in the melt reservoir 1 and the casting die 3 (31,32) is created and the melt starts filling the casting cavity 4 via the material feed conduit, while in the melt reservoir l - casting die 3 system there could have existed vacuum, ambient or increased pressure. In the filling process the delivery pressure rises in result of overcoming the friction forces, the hydraulic height of melt and the throttling effect of the gaseous phase when coming out of the vents being gradually and unevenly filled by melt. When a preset level of melt is reached as shown with the A-A line and p. "a" of the indicator diagram (Fig. 2), the delivery pressure Pl changes its character for instance as a result of the abrupt change in the cross section of the casting. By means of a signal given by the pressure indicator 8 to the deliver~ pressure the transducer 9 is actuated and opens the valve 10 so that the gaseous phase from the high pressure source 13 is supplied to the unfilled ~ ~, 67~
additional cavities 5 of the casting die 3 and to the multiply-ing cylinder 11 and the high pressure P3 is established in the casting die 3. During the movement of the piston in the multiplying cylinder 11 the molten metal flow from the melt reservoir 1 is interrupted and the casting die 3 is finally filled with melt. After the pressure has been taken off and cooling performed, the ready casting part is removed and the cycle repeated.
The machine for the implementation of the method as per Fig. 3 consists of a material cylinder 1 connected via a riser duct to the casting die 3 comprised of a right part 31 and a left part 32 which define the casting cavity ~ and the additional cavity 5 (dead head). The material cylinder 1 is connected to a pressure source 6 having a pressure Pl through a valve 7, a conduit and a power cylinder 18 with a pressure indicator 8 fitted on it. The power cylinder 18 is connected to the multiplying cylinder 11 one part of which communicates through a tube with the die cavity 4 and via a valve 14 with the compressed air tank 13 being under a high pressure P3. The~pressure indicator 8 is connected to a tranducer 9 which, in its turn, is connected through a valve 10 to the additional cavity 5 and the multiplying cylinder llo The communication between the transducer 9 and the additional cavity 5 is provided with a control gate 12.
According to the diagram shown on Fig. 3 the casting process runs as follows:
Characteristics of the casting part: A car piston in aluminium-silicon alloy having a skirt with a 6 mm thick wall; a reinforcing ring in the lower portion of the skirt;
bosses in the zones of piston bolt seats having a thickness of 20 mm and a bottom wall thickness of 25 mm.
Casting is performed in a two-cavity metal casting die 3 with a split wedge core for the central hole and cores for the radial holes. The air vents, the riser duct and the 672~:
dead heads 5 are formed in the die 3.
The gas passing from the compressed air tank 13 via an opened valve 14 into the multiplying cylinder ll creates a gas pressure of 60 MPa. Then the valve 14 is closed and a portion of melt is poured into the material cylinder 1. In the power cylinder 18 and the multiplying cylinder ll a hydraulic pressure is provided from the tank 6 at an opened valve 7. The piston of the power cylinder 18 moves the melt filling the cavity of the die 3. When filling the additional cavities 5 of the die 3 the delivery pressure Pdel (Fig. 4) read by the pressure indicator 8 changes and after having filled a part of the dead heads 5, it changes its character (p- "a", Fig. 4) and upon a signal by the pressure indicator 8 the transducer 9 is being actuated to open the valve 10 starting the piston of the multiplying cylinder 11 and a pressure of 300 ~Pa is being exerted on the dead heads 5.
Such pressure is maintained until the completion of the crystallization process in the casting part and thereafter it is removed and the part is taken out of the die. The casting part obtained after the appropriate heat treatment has the following characteristics: ~B= 32 - 36.105 N/m2;
S= 27 - 30.105 N/m2; ~ > 3~; ~B = 120 - 140u The machine for the implementation of the method as per Fig. 5 consists of a molten metal (melt) reservoir 1 communicating via a material feed conduit ~ with the casting die 3 that comprises two parts - the lower part 31 and the upper part 32 with the cavity 4 in-between. In the upper part 32 there are additional cavities 5 (dead heads) provided. The melt reservoir 1 is connected with the gas pressure source 6 at a pressure Pl through a valve 7. The melt reservoir 1 and the space of the casting die 3 are connected by a pressure indicator 8 provided with a transducer 9. The transducer 9 via a valve 10 communicates with the high pressure tank 13 at a pressure P3, the latter being connected via the said ~.
~2(~67~
valve 10 to the multiplying cylinder 11 comrnunicating with the lower part 31 of the die. The space of the multiplying cylinder 11 in front of the piston communicates with the additional cavities 5 of the casting die 3 through a control gate 12. The space of the casting die 3 is connected with the vacuum tank 17 by means of a tube and a valve 16.
According to the diagram shown on Fig. 5 the casting process is carried out in the following way:
Charateristics of the casting part: a car sus-pension component in aluminium alloy with a complex combinationof thin and thick walls in the thickness range from 4 to 25 mm. The bosses are concentrated in three places at a distance from the central hole ranging 300 - 400 mm. A
complex ribbed design with a rib relief up to 90 mm.
The casting is performed in a metal casting die of two parts located in a sealed chamber.
The split line of the parts 31, 32 has a complex configuration. The air vents are made in the casting die, while the dead heads are over the bosses of the casting part.
The cavities of the casting part in the space between the ribs are formed by inserts and between them there are also vents.
prior to commencement of casting in the chamber incorporating the casting die 3 there is created vacuum of 0,1 - 0,2 MPa from the source 17 at an opened valve 16. A difference between pressures in the melt reservoir 1 and the casting die 3 is produced to result in the initial filling of the cavity 4 for the casting part. When the melt blocks the vents of the split planes, the delivery pressure changes its character and by means of a signal from the indicator 8 the transducer 9 which opens the valve 10 is actuated.
A high pressure equalized by the piston of the multiplying cylinder 11 is established in the cavity of the casting die 3. Such pressure is maintained until the com-pletion of the crystallization process in the casting part \
6~
and thence it is removed and the casting part is taken out of the die. The vacuum is maintained only until the complete filling of the casting die 3 with melt.
The machine for the implementation of the method as per Fig. 7 consists of a molten metal (melt) reservoir 1 connected via a material feed conduit 2 with the casting die
3 comprising a left part 31 and a right 32 while the casting cavity 4 is formed in-between. The additional cavities (dead head) 5 are formed in the left part 31. The melt reservoir 1 is connected to the pressure source 6 with a pressure Pl by means of a valve 7. The pressure source 6 communicates also with the casting die 3 via a valve 15. To the melt reservoir there is fitted a pressure indicator ~ provided with a transducer 9 9 which via a valve 10 is connected to the high pressure tank 13 having a pressure P3. The high pressure tank 13 is connected with a multiplying cylinder 11 connected to the right part 32. The space in front of the piston of the multiplying cylinder 11 communicates via a pipe conduit and a control gate 12 with the additional cavities 5.
According to the diagram shown on Fig. 7 the casting is performed as follows:
Characteristics of the casting part: A ribbed component designed to operate under the effect of water vapours at 150 and a pressure of 10 MPa at the requirements for ~B= 30 - 32.105 N/m2 and ~S > 20%.
Casting is carried out in a two-cavity metal die with an elastic seal. Between the seal ring and the working cavity of the die there is a deep and wide channel made which communicates with the working cavity of the die by means of vents. The vents and the space for the dead head are formed in the casting die.
The melt being a technically pure grade of Zn is supplied to the melt reservoir 1 where the melt is agitated by means of nitrogen under a pressure of lO.105 N/m and thereafter in the melt reservoir 1 - casting die 3 system a pressure of 10.105 N/m2 is - 7a -established. A pressure diferential is created and the melt fills the casting die 3 up to the line A-A (p. "a"
on Fig.8) and the delivery pressure changes its nature.
Upon a signal from the pressure indicator 8 the trans-ducer 9 is actuated to open the valve 10 and a pressure of 96.105 N/m2 is established in the unfilled cavity 5 of the casting die 3. This pressure is equalized by the pressure in the multiplying cylinder 11. In movement of the piston of the multiplying cylinder 11 the incoming flow of melt from the melt reservoir 1 is shut off and final filling of the casting die 3 is performed at a high pressure. The crystallization of the melt completed, the pressure is removed from the casting die 3 and the latter is cooled and taken out.
According to the diagram shown on Fig. 7 the casting is performed as follows:
Characteristics of the casting part: A ribbed component designed to operate under the effect of water vapours at 150 and a pressure of 10 MPa at the requirements for ~B= 30 - 32.105 N/m2 and ~S > 20%.
Casting is carried out in a two-cavity metal die with an elastic seal. Between the seal ring and the working cavity of the die there is a deep and wide channel made which communicates with the working cavity of the die by means of vents. The vents and the space for the dead head are formed in the casting die.
The melt being a technically pure grade of Zn is supplied to the melt reservoir 1 where the melt is agitated by means of nitrogen under a pressure of lO.105 N/m and thereafter in the melt reservoir 1 - casting die 3 system a pressure of 10.105 N/m2 is - 7a -established. A pressure diferential is created and the melt fills the casting die 3 up to the line A-A (p. "a"
on Fig.8) and the delivery pressure changes its nature.
Upon a signal from the pressure indicator 8 the trans-ducer 9 is actuated to open the valve 10 and a pressure of 96.105 N/m2 is established in the unfilled cavity 5 of the casting die 3. This pressure is equalized by the pressure in the multiplying cylinder 11. In movement of the piston of the multiplying cylinder 11 the incoming flow of melt from the melt reservoir 1 is shut off and final filling of the casting die 3 is performed at a high pressure. The crystallization of the melt completed, the pressure is removed from the casting die 3 and the latter is cooled and taken out.
Claims (8)
1. A pressure die-casting method in which the melt from a molten metal reservoir is delivered and fills the casting die under the action of a difference in pres-sures created in the molten metal reservoir and the casting die and when the melt fills the die it is under the action of vacuum, ambient or increased gas pressure, characterized by that after filling the casting die with melt up to a preset level in the unfilled cavity of the casting die or in one or several unfilled independent cavities of the die an additional gas pressure considerably higher than that acting already in the casting die is created and simul-taneously this additional gas pressure is equalized by the counter acting pressure created on the other side of the casting die.
2. A method according to claim 1 characterized by that the additional gas pressure is maintained constant until the complete crystallization of melt in the casting die.
3. A method according to claim 1 characterized by that the additional gas pressure rises continuously from the moment of its creation until the completion of melt crystallization in the casting die.
4. Apparatus for pressure die-casting, comprising:
- a reservoir, - a casting die made of two-parts and comprising a cavity, said reservoir being connected to said casting-die, and said casting-die having an additional cavity, - a first source of pressure to which said reservoir is connected, - a second source of pressure, to which said reser-voir is connected, - a multiplying cylinder connected to said casting die, said multiplying cylinder being also connected to said additional cavity and to said second source of pressure.
- a reservoir, - a casting die made of two-parts and comprising a cavity, said reservoir being connected to said casting-die, and said casting-die having an additional cavity, - a first source of pressure to which said reservoir is connected, - a second source of pressure, to which said reser-voir is connected, - a multiplying cylinder connected to said casting die, said multiplying cylinder being also connected to said additional cavity and to said second source of pressure.
5. Apparatus according to claim 4, wherein:
- said reservoir which contains molten metal is connected to said casting die by means of a material feed conduit, - said casting die comprises a lower part and an uppper part forming said cavity, said additional cavity being formed in the upper part of said casting die, - said first source of pressure is a delivery pressure P1, and - said second source of pressure is a high pres-sure P3.
- said reservoir which contains molten metal is connected to said casting die by means of a material feed conduit, - said casting die comprises a lower part and an uppper part forming said cavity, said additional cavity being formed in the upper part of said casting die, - said first source of pressure is a delivery pressure P1, and - said second source of pressure is a high pres-sure P3.
6. Apparatus according to claim 4, wherein:
- said reservoir is connected to said casting die by means of a riser duct, - said casting die comprises a right part and a left part forming said cavity and said additional cavity, - said first source of pressure P1 is connected to said reservoir by means of a valve, a conduit and a power cylinder having a pressure indicator, - said second source of pressure is a high pressure P3, said power cylinder is connected to said multiplying cylinder one part of which communicates with said cavity and by means of a valve with said second source of high pressure, - said pressure indicator being connected to a transducer which is connected by means of a valve to said additional cavity and to said multiplying cylinder, - a control gate being provided between said transducer and said additional cavity.
- said reservoir is connected to said casting die by means of a riser duct, - said casting die comprises a right part and a left part forming said cavity and said additional cavity, - said first source of pressure P1 is connected to said reservoir by means of a valve, a conduit and a power cylinder having a pressure indicator, - said second source of pressure is a high pressure P3, said power cylinder is connected to said multiplying cylinder one part of which communicates with said cavity and by means of a valve with said second source of high pressure, - said pressure indicator being connected to a transducer which is connected by means of a valve to said additional cavity and to said multiplying cylinder, - a control gate being provided between said transducer and said additional cavity.
7. Apparatus according to claim 5, wherein:
- said reservoir is connected to said first pressure source by means of a first valve, and to said casting die by means of a pressure indicator provided with a transducer, said transducer communicating with said high pressure source by means of a second valve, - said source of high pressure being connected to said multiplying cylinder by means of said second valve, said multiplying cylinder communicating with the lower part of said casting die, - said multiplying cylinder having a space in front of a piston inside said cylinder, said space com-municating with said additional cavity by means of a control gate, - said casting die being connected with a vacuum tank by means of a tube and a valve.
- said reservoir is connected to said first pressure source by means of a first valve, and to said casting die by means of a pressure indicator provided with a transducer, said transducer communicating with said high pressure source by means of a second valve, - said source of high pressure being connected to said multiplying cylinder by means of said second valve, said multiplying cylinder communicating with the lower part of said casting die, - said multiplying cylinder having a space in front of a piston inside said cylinder, said space com-municating with said additional cavity by means of a control gate, - said casting die being connected with a vacuum tank by means of a tube and a valve.
8. Apparatus according to claim 4, wherein:
- said reservoir which contains molten metal is connected to said casting die by means of a material feed conduit, - said casting die comprises a left part and a right part, said cavity being formed in-between, and said additional cavity being formed in said left part, - said reservoir being connected to said first pressure source by means of a valve, said first pressure source communicating with said casting die by means of a valve, - a pressure indicator provided with a trans-ducer being fitted to said reservoir, said transducer being connected by means of a valve to said high pressure source - said high pressure source is connected with said multiplying cylinder and said a multiplying cylinder is connected to said right part of said casting die, - said multiplying cylinder having a space in front of a piston thereinside, said space communicating with said additional cavity by means of a control gate.
- said reservoir which contains molten metal is connected to said casting die by means of a material feed conduit, - said casting die comprises a left part and a right part, said cavity being formed in-between, and said additional cavity being formed in said left part, - said reservoir being connected to said first pressure source by means of a valve, said first pressure source communicating with said casting die by means of a valve, - a pressure indicator provided with a trans-ducer being fitted to said reservoir, said transducer being connected by means of a valve to said high pressure source - said high pressure source is connected with said multiplying cylinder and said a multiplying cylinder is connected to said right part of said casting die, - said multiplying cylinder having a space in front of a piston thereinside, said space communicating with said additional cavity by means of a control gate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000433684A CA1206722A (en) | 1983-08-02 | 1983-08-02 | Method and apparatus for pressure diecasting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000433684A CA1206722A (en) | 1983-08-02 | 1983-08-02 | Method and apparatus for pressure diecasting |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1206722A true CA1206722A (en) | 1986-07-02 |
Family
ID=4125778
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000433684A Expired CA1206722A (en) | 1983-08-02 | 1983-08-02 | Method and apparatus for pressure diecasting |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1206722A (en) |
-
1983
- 1983-08-02 CA CA000433684A patent/CA1206722A/en not_active Expired
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