KR20060058718A - Flow system for pressure casting - Google Patents

Abstract

A metal flow device, for high pressure die casting of alloys using a method or machine having, or operable to provide, a pressurised source of molten alloy and a mould defining at least one die cavity, defines a metal flow path by which alloy received from the pressurised source is able to flow into the die cavity. A first part of the length of the flow path includes or comprises a runner; while a second part of the length of the flow path from an outlet end of the runner includes a flow-path exit module (FEM). The FEM has a form which controls the alloy flow whereby the alloy flow velocity decreases progressively from the level at the outlet end of the runner whereby, at a location at which the flow path communicates with the die cavity, the alloy flow velocity is at a level significantly below the level at the outlet end of the runner and such that, on filling of the die cavity, the alloy is able to undergo solidification in the die cavity and back along the flow path towards the runner.

Description

FLOW SYSTEM FOR PRESSURE CASTING

The present invention relates to an improved alloy flow system for use in pressure casting of alloys.

In several recent patent applications, the present inventors have disclosed inventions relating to pressure casting of alloys, utilizing what is called a controlled expansion port (or CEP). These applications include PCT / AU98 / 00987 associated with magnesium alloy pressure casting and PCT / 01/01058 associated with aluminum alloy pressure casting. They also include PCT / AU01 / 00595 and PCT / AU01 / 01290, and the Australian interim applications PR7214, PR7215, PR7216, PR7217 and PR7218, filed August 23, 2001, respectively. These other applications relate to various devices and devices for use in pressure casting of magnesium, aluminum and other pressure castable alloys and these alloys.

As mentioned above, CEP is utilized in the invention of the aforementioned patent applications. CEP is a relatively short portion of the alloy flow path that increases in cross-sectional area from the inlet end to the outlet end of the CEP such that the alloy flowing through the CEP has a substantially low flow rate at its outlet end relative to the inlet end. The reduction in flow rate is such that in its flow through the CEP, the alloy undergoes its state change. In other words, by the molten alloy received from the pressurized source of the supply to the inlet end of the CEP, the reduction in the flow rate from that obtained at the inlet end to the outlet end is such that the state of the alloy is in the molten state at the inlet end. From the semi-solid or thixotropic state at the outlet end.

In its flow through the die cavity beyond the outlet end and substantially in communication with the flow path, it is most desirable that the alloy remain in a semisolid or thixotropic state. By solidification of the alloy sufficiently fast in the die cavity and back to or into the CEP from the die cavity, the resulting casting results in a fine, spheroidal form of degenerate dendritic form in the matrix of the secondary phase. It can be characterized by microstructures with spheroidal or rounded major particles.

Applicants' pending application PCT / AU03 / 00195 discloses a method of producing alloy castings using a metal flow system for high pressure die casting and a high pressure die casting machine. The system and method of this application utilizes a flow path that includes a CEP, but also includes a CEP outlet module, called a CEM, through which the alloy from the outlet of the CEP passes into the die cavity in its flow. In CEP, the alloy undergoes a state change from the molten state to the semisolid state as a result of a sufficient reduction in the CEP flow rate from the appropriate flow rate at the CEP inlet end. At the location where the flow path is in communication with the die cavity, the flow rate of the alloy is significantly lower than the outlet end level of the CEP, and the state change occurring in the CEP is substantially maintained through the filling of the die cavity, the alloy being in the die cavity and In order to experience rapid solidification again along the flow path towards the CEP, the alloy has a form that controls the flow of the alloy, which gradually decreases from the level of the CEP outlet end.

Applicants have found that the form of CEM can be utilized for the advantages of other applications. This use in the form of CEM is very surprising in that it is contrary to conventional implementations, systems and apparatus for high pressure die casting.

As mentioned above, “CEM” refers to the exit module for the CEP. The term is not relevant for the present invention where CEP is not used. Rather, the present invention utilizes a flow path with an outlet module through which the alloy flows from the runner to the die cavity. The outlet module of the present invention has a form suitable for CEM, but it is distinguished herein as a flow path outlet module or "FEM".

The present invention provides a metal flow device for high pressure die casting of alloys using a mold forming at least one die cavity and a machine having a pressurized source of molten alloy or operable to provide the source, the device comprising The alloy received from the pressurized source forms a metal flow path through which the alloy can flow into the die cavity, where:

(a) the first portion of the flow path length comprises a runner;

(b) the second portion of the flow path length from the outlet end of the runner comprises a flow path exit module (FEM);

The FEM has a form that controls the flow of the alloy to gradually reduce the flow rate of the alloy from the runner's exit end level, whereby the flow rate of the alloy is significantly greater than the runner's exit end level, where the flow path is in communication with the die cavity. At the level below, upon filling of the die cavity, the alloy is subject to solidification along the flow path from the die cavity and back towards the runner.

Additionally, the present invention provides a pressure casting machine for high pressure die casting of alloys, the machine comprising a pressurized source of molten alloy, mold formation in one or more die cavities and alloys received from the pressurized source flow into the die cavity May provide or provide a metal flow device that forms a metal flow path that may be adapted to

(a) the first portion of the flow path length comprises or includes a runner;

(b) the second portion of the flow path length from the outlet end of the runner comprises a flow-path exit module (FEM),

The FEM controls the flow of the alloy such that the flow of the alloy gradually decreases from the level at the outlet end of the runner, whereby the flow rate of the alloy is at the outlet end of the runner at a location where the flow path is in communication with the die cavity. It is shaped to be at a level significantly below the level, causing the alloy to undergo solidification along the flow path at the die cavity and back towards the runner upon filling the die cavity.

The present invention also provides a method for producing an alloy casting using a high pressure die casting, which can be provided or provided with a pressurized source of molten alloy and a mold forming at least one die cavity, wherein the alloy is a flow path. Flows from the source into the die cavity along

(a) the alloy is allowed to flow along a runner in a first portion of the flow path;

(b) In the second portion of the flow path between the first portion and the die cavity, the flow of the alloy is controlled so that from the level at the outlet end of the runner, the flow path is significantly above the outlet level of the runner. The flow rate is gradually reduced to the flow rate in communication with the die cavity at the lower level.

As mentioned above, the second portion of the flow path reduces the flow rate of the alloy below the flow rate level of the outlet end of the runner. In this specification, the second part of the flow path is more simply referred to as the "flow-path exit module" or "FEM".

The runner has a predetermined cross-sectional area at least at its outlet end, so that at a flow rate of the alloy mass that can be generated by the machine, the runner is approximately 60 m / s up to 180 m / s for magnesium alloys and other than magnesium alloys. For alloys it is desirable to be able to result in an alloy flow rate at the runner exit end that exceeds about 40 m / s up to 120 m / s. In one configuration, the FEM increases the cross sectional area in the direction extending beyond the outlet end of the runner, precluding a change in the state of the alloy from the molten state to the semi-solid state exhibiting thixotropic properties from the molten state. You can. In another configuration, the increase in cross-sectional area is such that the reduction in flow rate can prevent the alloy from undergoing a change of state to enable filling of the die cavity by the molten alloy. Although it is not necessary to provide a shrink, the gate formed at the outlet end of the flow path provides a constriction, through which the flow of the alloy occurs. In one form, the gate is at the exit end of the FEM. In another form, the outlet end of the FEM is spaced apart from the gate by a second runner having a cross-sectional area that is at least equal to that of the outlet end of the FEM.

According to the present invention, filling of the die cavity can be achieved by molten metal. That is, from the pressurized source, the alloy can be received in the flow path in the molten state and remain in this state until it solidifies in the die cavity. This differs from the inventors' previous inventions based on the use of CEP in that the alloy in the molten state changes to a semisolid state that can exhibit thixotropic properties. In this regard, the present invention may be similar to the practice of conventional high pressure die casting. However, the present invention is further and remarkably different from the conventional practice.

In accordance with the inventors' previous inventions based on CEP, conventionally produced semi-solid alloys have a solid content, which can exhibit thixotropic properties. To this end, the alloy has more than about 25 wt% solids, typically at least about 30 wt% solids, for example about 60 to 65 wt% solids. While the present invention allows the filling of the die cavity by molten metal, there are situations in which the alloy accommodated into the die cavity may have a low solids content. However, the low solids content obtainable by the present invention is insufficient to allow the alloy to exhibit thixotropic properties.

By means of a cold chamber pressure die casting machine, primary dendritic particles can be formed in a shot sleeve. These may vary in size up to approximately 60 μm and may not be beneficial for casting. When the present invention is used in a cooling chamber machine, it is maintained that these particles can be formed in the shot sleeve. When this situation occurs, the particles in modified form contain or contribute to the solids content of the alloy flowing into the die cavity.

In addition, with the use of the present invention, low levels of solids can be formed as a result of the flow of the alloy along the flow path. The weight percentage of these solids is insufficient to confer the alloy's properties under overall thixotropic conditions with respect to the alloy. The solids content is at a level below about 25 wt%, for example about 20 or 22 wt%, and more typically below a level of about 17 wt%. This also applies when using a cooling chamber machine when the solids formed as a result of the flow of the alloy along the flow path are combined with the solids produced from the main dendritic particles formed in the shot sleeve.

Solids have a very small particle size in that solids are present in the alloy flowing into the die cavity by use of the present invention. This can be established by the microstructure of the casting which solidifies sufficiently rapidly produced using the present invention. Thus, castings may represent microstructures having rounded main dendritic particles no larger than approximately 50 μm in size, which represent solids produced in the flow of an alloy along a flow path comprising particles of that size.

Solids with small particle sizes represent an alloy that receives very strong shear forces in the flow along the flow path. The shear forces result from the flow rate at the runner and from the significant reduction of the flow rate for the alloy as it passes through the FEM. The strength of the force is evident from flow modeling determinations. Strong shear forces are also evident by the main features of the microstructure that can be achieved in the casting produced using the present invention.

A feature of the first microstructure is the rounded main denticular particles described above, and the fine particle size and uniform distribution of the particles. A feature of the second microstructure is that there are substantially no larger, branched dentritic particles that may form in the shot sleeve when using a cooling chamber machine. Shear forces are thought to be strong enough with respect to breaking these particles. An additional feature by both hot and cold chamber machines is that there are substantially no defects in pressure casting resulting from gas porosity. Rather than exhibiting these defects in the regions separated by the entrained gas, the microstructure of the casting produced by the present invention, for example, is present in a very fine, substantially uniformly distributed form. Any gas resulting from the air entrapment. The fineness of any gas and the uniformity of distribution are such that adverse effects on physical properties are substantially avoided.

The shape of the FEM that causes the alloy to reduce the flow rate is such that the cross sectional area in the alloy flow direction must increase. The flow of the alloy may consist of a flow rate of substantially fixed mass. However, due to the increasing cross-sectional area of the FEM, the alloy undergoes a gradual but substantial decrease in flow rate from the level at the exit end of the runner to the position where the alloy enters the die cavity. In causing a decrease in flow rate, FEM achieves results similar to those achieved in CEP. In spite of this similarity, the reduction is semi-solid from its molten state to the extent that the alloy results in thixotropic properties, even if the flow rate of the alloy in the runner is similar to that required at the inlet end of the CEP for the state change. It doesn't change state. In other words, the flow rate reduction in the FEM is such that at least the state change up to the above amount is excluded.

Due to its FEM's increase in cross-sectional area in the flow direction, the flow device according to the invention is different from the flow system used in conventional die casting practices. In conventional practice, it is common to maintain a substantially constant flow rate except where the flow path is in communication with the die cavity. In the flow system used in the conventional practice, the shrinkage provided at the position referred to as the gate causes the alloy to undergo a sharp increase in flow rate so that the alloy can flow into the die cavity as a thin high speed jet. In the flow path according to the invention, the shrinkage of the gate need not be provided and the alloy may flow into the die cavity as a relatively wide stream. In the metal flow device of the present invention, the flow path may have a predetermined cross section at a position where the flow path communicates with the die cavity larger than the cross sectional area of the runner. In a conventional implementation, the area of the gate is smaller than the cross-sectional area of its runner. However, the flow path according to the invention does not have a gate shrinkage, but this is not essential and at least in some cases a shrinkage gate can be provided. Whether or not a shrink gate is provided, the flow path of the present invention is different from the conventional practice. The first part of the flow path comprising the runner is of significantly smaller cross-sectional area than the conventional runner. In addition, the second portion of the flow path between the outlet end of the runner and the outlet end of the FEM increases in cross-sectional area in the flow direction, causing a desired reduction in alloy flow rate through the FEM. In these respects, the flow path is slightly similar to that of PCT / AU03 / 00195, although there are essential and important differences.

As described herein below, higher runner flow rates are required for use of the present invention as compared to those used in conventional pressure die casting. For a pressure casting machine capable of supplying an alloy at a given mass flow rate, the runner required for the present invention has a smaller cross-sectional area compared to a conventional runner to achieve higher flow rates at the mass flow rate. In this respect, the runner of the present invention may be substantially the same as required by the teachings of PCT / AU03 / 00195. However, in the flow path of the present invention, the flow of the alloy from the outlet end of the runner passes directly into the FEM and directly or indirectly from the outlet of the CEP. Moreover, the present invention limits the amount by which an alloy can be changed in its semisolid form to prevent the development of thixotropic properties. In contrast, the FEM in the configuration of PCT / AU03 / 00195 is intended to facilitate the maintenance of semi-solid alloys that occur in CEP and have thixotropic properties.

The outlet end of the FEM may be in a position where the flow path is in communication with the die cavity. This is desirable, however, the outlet end of the FEM may be spaced from this position by a second runner that does not provide significant shrinkage in the flow of the alloy. Thus, the cross-sectional area of the second runner may be substantially equal to the area of the FEM outlet. As will be appreciated, the second runner of the system of the present invention has a larger cross-sectional area than the runner of the first portion of the flow path, which is the inverse relationship of the relationship between the first runner and the second runner in conventional pressure casting implementations.

The FEM of the device of the present invention may take various forms. In a first aspect, the FEM forms or includes a channel having a width substantially exceeding its depth and a transverse cross-sectional area greater than the exit area of the runner that can accommodate the molten alloy. In the first aspect, the width of the channel, which may exceed its depth by at least a certain degree, is preferably arranged in a plane extending transverse to the runner. The channel is adapted to radially diffuse the alloy flowing from the runner into it to experience a decrease in flow rate. The cross-sectional area of the channel may increase in the flow direction of the alloy, resulting in further reduction of the alloy flow rate.

In the first aspect, the channel may be substantially flat or curved over its width if appropriate for the die cavity for a given casting. Alternatively, however, a sawtooth or corrugated structure may be used to form peaks and troughs over its width, slightly similar to some forms of chill vent. Can have The channel may be increased in cross section by one of the width and depth of the channel being constant along its length and the other gradually increasing, preferably uniformly. However, if desired, each of the width and depth may be increased in the flow direction of the alloy. According to the serrated or corrugated form, this form has the advantage of maximizing the flow length for a given distance between the runner outlet and the position where the flow path communicates with the die cavity, but generally it is more convenient to increase only the width. Do.

According to the first form in which the FEM forms a channel having a width substantially above the depth, the configuration is generally such that the flow path of the alloy is in communication with the die cavity through an opening having a width substantially above the depth. This is particularly well suited for filling die cavities by indirect or edge feed, especially when the die cavities are for producing thin castings.

In a second form, the FEM of the device according to the invention forms or comprises a channel having a width and depth having the same extent and a transverse cross-sectional area which gradually increases in the flow direction of the alloy. This form with a progressively increasing cross section also provides the low flow rate required at the location where the flow path is in communication with the die cavity.

Given the shape of the die cavity at the location where the flow path is in communication with it, the channel of the second type of FEM may be open at its end away from the runner that can accept the molten alloy, the open end being To form the position. However, the location is preferably formed by an elongate opening extending along one side of the channel. In the preferred configuration, the channel may extend substantially linearly from the runner along the side edge of the die cavity, and the elongate opening is along the side of the channel adjacent the edge of the die cavity. However, in order to provide an end of the channel away from the runner extending along the lateral edge of the die cavity, the channel is preferably curved to facilitate it to be of appropriate length. In particular, with this curved form of the channel, the flow path may be bifurcate beyond the runner in the flow direction of the alloy to provide two or more channels each having such an end with such an elongated opening. In a branched configuration, the openings in each channel may provide communication with the die cavity at the common edge or at each edge of the die cavity. If the two curved channels are in communication with the die cavity at the common edge, the end of each channel away from the runner may end at a short distance from each other such that their side openings are longitudinally spaced along the common edge of the die cavity. In an alternative configuration, however, the two channels merge at the ends to form respective arms of the closed loop, in which case the openings are again spaced apart again, or they are common for each arm. A single elongate opening may be formed.

The gradual decrease in alloy flow rate in the FEM of the metal flow system of the present invention, and the gradual increase in cross-sectional area of the second portion causing the decrease may be continuous. In addition, the gradual decrease in speed and the increase in area may be substantially uniform or step-wise along at least a section of the second part. The first and second forms for the FEM described above are well suited to provide a reduction in the continuous velocity produced by the continuous increase in cross-sectional area along at least most of the length of the second portion.

In a third form of providing stepwise reduction of flow rate, the FEM includes a chamber through which an alloy received from the runner flows, and the chamber achieves stepwise reduction of the alloy flow rate. In the third aspect, the FEM comprises channel means having a form that provides communication between the chamber and the die cavity and at least substantially maintains the flow rate level preserved in the chamber. The communication channel means may be of a type similar to the first form of FEM described above, while it may have a substantially uniform or slightly enlarged cross section. Alternatively, the channel means may comprise one or more channels, but preferably two or more channels, if necessary, except that such channels or each of these channels may have a substantially uniform cross section. Similar to the second form of FEM described above.

The third type of chamber may have any suitable shape. In one conventional configuration, it may have the form of an annular disk. This arrangement is suitable for use when the communication means is one or more channels. In the above arrangement, when the communication means includes two or more channels, the channels may be in communication with a common die cavity or each die cavity.

One or more channels of the third form of communication means of the FEM may be open to its die cavity at the end opening of the channel or at the elongate side opening as described with reference to the second form.

In each aspect of the invention, the FEM is disposed parallel to the parting plane of the mold forming the die cavity. The first portion of the flow path may be similarly arranged so that its runner is also parallel to the plane, and the alloy received from the sprue or runner portion extends into the plane through one mold portion. Alternatively, the first portion of the flow path may extend through this mold, with the outlet of the runner in or near the splitting plane.

Flow rates for the use of CEP in achieving a change in alloy form from the molten state to the semisolid state with thixotropic properties are described in detail in the patent applications mentioned above. However, for magnesium alloys, the flow rate at the inlet end of the CEP generally exceeds about 60 m / s, preferably about 140 to 165 m / s. For aluminum alloys, the flow rate at the inlet end is generally above 40 m / s, for example 80 to 120 m / s. For other alloys, such as zinc copper alloys that can be converted to semisolid states with thixotropic properties, the flow rate at the CEP inlet end is generally similar to that for aluminum alloys, but can vary depending on the unique properties of the individual alloys. have. In general, the reduction in flow rate to be achieved in the CEP is intended to achieve a flow rate at the CEP outlet that is approximately 50 to 80% of the flow rate at the inlet end, for example 65 to 75%.

According to the use of the FEM according to the invention, no CEP is used. The alloy may also remain molten in its flow into the die cavity, but the alloy does not undergo state changes up to the amount that results in thixotropic properties even when some solids are formed. Nevertheless, the flow rate of the runner at least at the outlet end of the runner may be similar to that required for the use of the CEP. Thus, the flow rate at the outlet end of the runner or the flow rate at the inlet end of the FEM relative to magnesium is greater than approximately 60 m / s, preferably from about 130 to 160 m / s, but may be in the range up to approximately 180 m / s. have. For aluminum alloys and other alloys such as zinc and copper alloys, the flow rate at the outlet end of the runner or the inlet end of the FEM can be made as described above for the use of CEP.

In general, the reduction in flow rate to be achieved in the FEM is very substantial. Indeed, the reduction may exceed that obtained with the use of CEP. Thus, the reduction in flow rate in the CEP is 50-80%, for example 65-75%, of the flow rate at the inlet end of the CEP, while the FEM can achieve a greater reduction in flow rate. Practical considerations favor FEMs with an effective flow length as short as possible. The length of the FEM varies depending on its average cross sectional area, but may range from approximately 15 to 35 mm. In addition, the FEM preferably has a total length shorter than its effective flow length because it has a wavy, corrugated or serrated structure that increases the back-pressure of the flow system.

As with the CEP, the length of the FEM varies with the cross-sectional area at the outlet end of the runner where it receives the flow of alloy. Since the CEP is intended to cause a change of state of the alloy from the molten state to the semisolid state exhibiting thixotropic properties, it is expected that the FEM will have a shorter length than the CEP for the exit end cross-sectional area of a given runner. Longer lengths, which provide a more gradual increase in cross-sectional area for the FEM from the runner inlet, appear to be necessary to provide conditions suitable to avoid state changes at all or at least to the extent necessary for CEP. However, the inventors have discovered that this is not necessarily the case. Rather, the inventors have found that for a given cross-sectional area at the exit end of the runner, the FEM needs to have a shorter length than required for the CEP provided for the runner.

The foregoing description of the invention forms the basis for a given die cavity or said die cavity. However, it should be understood that the present invention is applicable for multi-cavity molds. In this case, the FEM formed by the system of the present invention may be split or extended to provide separate flow for each of the common die cavities or two or more die cavities. Indeed, as illustrated herein with reference to the drawings, generally providing such separate flows from a common FEM facilitates achieving a reduction in the required alloy flow rate.

BRIEF DESCRIPTION OF DRAWINGS To make the present invention easier to understand, the following detailed description of the accompanying drawings follows.

1 is a schematic diagram of two cavity mold structures taken on a split plane between a fixed mold and a movable mold portion, illustrating a first embodiment of the present invention;

FIG. 2 is a cross-sectional view taken on line II of FIG. 1 and shown in an enlarged scale; FIG.

FIG. 3 is a schematic diagram illustrating a second embodiment of the present invention similar to FIG. 1 but having a single die cavity;

4 is a side view of the configuration of FIG. 3;

FIG. 5 is similar to FIG. 4 but shows a first modification of the second embodiment; FIG.

FIG. 6 is similar to FIG. 4 but shows a second modification of the second embodiment; FIG.

FIG. 7 is similar to FIG. 3 but illustrates a third embodiment of the present invention;

8 is a side view of the configuration of FIG. 7;

9 is a schematic view similar to FIG. 1 but illustrating a fourth embodiment of the present invention;

FIG. 10 is a partial cross-sectional view taken on the line VIII-VIII in FIG. 9; FIG.

FIG. 11 is similar to FIG. 3 but illustrates a fifth embodiment of the present invention;

12 is a partial cross-sectional view taken on line XII-XII in FIG. 1;

FIG. 13 is similar to FIG. 11, but shows a first modification of the fifth embodiment of the present invention; FIG.

FIG. 14 is similar to FIG. 11 but shows a second modification of the fifth embodiment;

FIG. 15 is a partial cross-sectional view taken on line XV-XV in FIG. 14; FIG.

FIG. 16 is similar to FIG. 3, but illustrates a sixth embodiment of the present invention;

17 is a side view of the configuration of FIG. 16;

FIG. 18 is similar to FIG. 17 but illustrates a modification of the sixth embodiment;

19 is a plan view of a casting produced using the seventh embodiment of the present invention;

20 is a schematic plan view of a part of the seventh embodiment;

21 is a side view of the configuration shown in FIG. 20.

1 and 2, formed by a fixed mold half 12 and a movable mold half 13, each used to produce each casting in a high pressure casting machine (not shown). Two die cavities 10 and 11 are shown herein. Each of the cavities 10, 11 is configured to receive an alloy from the pressurized supply of the molten alloy of the machine, the alloy being passed to each cavity by a common alloy feed device 14 according to the first embodiment of the invention. The above embodiment is the invention according to the first aspect as described above.

The alloy feed device 14 is a FEM as previously described herein, which extends between the first portion formed by the nozzle 16 shown in more detail in FIG. 2, and between each cavity and over the outlet end of the nozzle 16. It forms a flow path for the molten alloy with a second portion called it.

In overall form and detail, the nozzle 16 comprises an elongated annular housing 20 in which a first portion of the metal flow path forms a bore comprising a runner 22. The housing 20 has an outlet end neatly received in the insert 26 of the fixed mold binary 12, while its outlet end abuts against the fitting 28 of the platen 29. do. Around the housing 20, there are layers of electrical resistance coil 30, outer coil 30, and insulator 32. In addition, an insulating gap 34 is provided between the insulator 32 and the insert 26 except for a short distance at the outlet end of the housing 20 in metal-to-metal contact with the insert 26. In addition, the gap 34 extends between the insulator 32 and the fitting 28. Coil 30 and insulator 32 are provided for control of the thermal energy level of housing 20 and the alloy temperature flowing through runner 22.

In the configuration of the nozzle 16, the runner 22 is of constant cross section over its length, except for a short distance at the outlet end tapered down to the cross section of the outlet end 22a of the runner 22. From the outlet end 22a of the runner 22, the bore of the housing 20 flares over a very short end 35. This may provide a transition of the metal flow path to the FEM 18 and, like the FEM 18, serves to reduce the flow rate of the alloy relative to the level at the end 22a of the runner 22. Alternatively, the flared end 35 may cooperate with a spreader cone as described with reference to FIGS. 3 and 4, in which case the flared end 35 is more pronounced at the flow rate of the alloy. Reduction may also be provided.

The FEM 18 of the flow path of the alloy is formed by a shallow rectangular channel 36 into the center where the bore of the housing 20 is open. The channel 36 is formed by mold dividing 12, 13 and has a width and length size parallel to the dividing plane P-P between the mold dividing 12, 13. Thus, channel 36 is perpendicular to nozzle 16.

The channel 36 provides alloy flow to each of the die cavities 10 and 11 where the flow rate of the alloy decreases below the prevail level at the outlet end 22a of the runner 22. This is achieved by an alloy spreading radially outwards in the channel 36, from the end 22a, as indicated by the dotted line circles shown in FIG. 1. Thus, the molten alloy can travel from the end 22a onto the expanding front of the channel 36 which is tangential to the radial direction. The expanding flow of the alloy is constrained when it reaches the opposite sides of the channel 36, but each open end 36a of the channel 36 in which the channel 36 is in communication with the die cavities 10, 11, respectively. And 36b) to allow continuous flow at reduced flow rates. Over the portion of the channel 36 leading to the die cavity 10, the opposite sides of the channel 36 are substantially parallel such that the reduced flow rate required for the cavity 10 is shorter in front of the open end 36a. It can be obtained from. However, for the portion of the channel 36 leading to the cavity 11, the opposite sides diverge in the flow direction such that the flow rate is reduced at which the flow rate is required differently at the open end 36b to the cavity 11. It is to be continuously reduced to obtain. The flow of alloy continues to achieve filling of each die cavity 10, 11. The flow of the alloy through each cavity 10, 11 may be made at a sufficiently low flow rate below the flow rate at the runner 22 end 22a, and the back pressure on the flow of the alloy may be maintained at an appropriate level.

The configuration of the mold dividing 12, 13 allows the extraction of thermal energy from the alloy of each die cavity 10, 11 at the completion of the cavity filling in each cavity 10, 11, and again in the channel 36. Along the way to provide rapid solidification of the alloy to the outlet end 22a of the runner 22. The thin cross section of the channel 36 facilitates this. Further, extraction of thermal energy mainly by the die dividing 12 and its insert 26 is due to the metal to metal contact between the insert 26 and the housing 20 around the end 22a. In spite of the heating by, the cooling is allowed to proceed to the end 22a again.

3 and 4 show a second embodiment of a configuration for producing a casting, in which case a single cavity mold of a high pressure casting machine is used. The second embodiment also follows the first aspect of the invention, as described above, but utilizes a sawtooth channel shape rather than a flat channel as in FIGS. 1 and 2. Parts corresponding to parts of FIGS. 1 and 2 have the same reference numerals plus 100. Mold moulds are not shown, however, and only a portion of the housing 120 of the nozzle 116 is illustrated.

3 and 4, the channel 136 end of the FEM 118 has a rounded end flat portion 40 in communication with the runner 122. Also, as described above, the channel 136 has a die cavity 110 having a sawtooth shape that forms a peak 42a and a trough 42b extending transverse to the direction of alloy flow through the portion 42. Has a portion 42 between and portion 40.

Movable die bins are not shown, but the spreader cones 46 of the bins are illustrated. By means of a mold die cavity clamped together, the cone 46 is received in the flared end 135 of the bore of the nozzle housing 120 beyond the outlet end 122a of the runner 122. Thus, the alloy flowing from the runner 122 is frusto-conically spread before entering the channel 136. Depending on the cone angle of the core 46 and the portion 135, the flow rate of the alloy entering the channel 136 is the same as that obtained at the outlet end 122a of the runner 122 although it is usually substantially unchanged. It may be slightly different.

Within the channel 136, the molten alloy received from the runner 122 first diffuses rapidly and the flow rate is reduced. Upon flowing through the portion 42 of the channel 136, due to the opposite sides of the channel 136 branching to the end 136a, the flow rate is further reduced therethrough to the open end 136a. Thus, the alloy that flows into and fills the die cavity 10 can be maintained at an appropriate back pressure. The serrated structure (with one or more teeth) of part 42 of the channel 136 increases the back pressure to the required level. Apart from the detailed differences, the overall performance by the structure of FIGS. 3 and 4 is substantially as described with reference to FIGS. 1 and 2.

5 shows a first modification of the embodiment of FIGS. 3 and 4. 5 is identical in overall form to that of FIGS. 3 and 4 except that the outlet end 122a of the runner 122 is in direct communication with the channel 136. That is, there is no flared portion relative to the bore of the housing 120, so no cone is required.

A partial view of FIG. 6 (die cavity not shown) illustrates a second variant of the embodiment of FIGS. 3 and 4. The variant of FIG. 6 is identical in overall form to FIGS. 3 and 4 except that portion 42 of channel 136 of FEM 118 is wavy or corrugated rather than serrated. However, the structure of FIG. 6 also provides adequate back pressure.

Further, the third embodiment of Figs. 7 and 8 is according to the first aspect of the present invention as described above. In the configurations of FIGS. 7 and 8, portions corresponding to those of FIGS. 1 and 2 have the same reference numerals plus 200.

As in the embodiments of Figures 3 and 4, the third embodiment of Figures 7 and 8 is for producing castings using a single cavity mold. However, in this case, the channel 236 of the FEM 118 does not include part of the sawtooth structure. Rather, channel 236 has flat top and bottom major surfaces. The surfaces also slightly converge in the direction of flow of the alloy through the outlet end 236a and the cavity 210 therethrough, while opposite sides of the channel 236 diverge in that direction. This configuration allows, in the flow direction, the channel 236 to increase its transverse cross-sectional area towards the elongated thin open end 236a such that the flow rate of the alloy is significantly at the flow rate at the outlet end 222a of the runner 222. It is intended to gradually decrease to an appropriate level at the lower end 236a.

In the embodiment of FIGS. 7 and 8, the runner 222 extends in parallel with the split plane PP between the mold dividing 212, 213 and communicates with the end of the channel 236 away from the die cavity 210. To provide. Runner 222 is formed by dividing particles 212 and 213 rather than by nozzles, while runner 222 is aligned with the centerline of the cavity 210 and channel 236 of FEM 218. The supply of the alloy to the inlet end of the runner 222 can be through the bore of the main runner or nozzle, which bore of the main runner or nozzle, for example, is a mold fixed in a direction perpendicular to the plane PP. Extends through the bipartite 212.

Within the channel 236 is an arched wall 50 extending between the top main surface and the bottom main surface of the channel 236. The wall 50 forms a recess 52 that is open toward the outlet end 222a of the runner 222 to capture any solid slug or the like from an existing casting cycle that is carried into the chamber 236 with the alloy. capture and preservation.

In general, operation using the embodiment of FIGS. 7 and 9 will be understood from the description of FIGS. 1 and 2 and 3 and 4.

9 and 10 are similar in many respects to the first embodiment of FIGS. 1 and 2. 9 and 10 are also according to the first aspect of the present invention as described above, and portions corresponding to those of FIGS. 1 and 2 have the same reference numeral plus 300.

In the embodiment of Figures 9 and 10, the configuration is also provided for the production of castings using a high pressure casting machine. The machine has a mold that forms two die cavities 310 and 311 between mold bins 312 and 313. The die dividing also forms an elongated channel 336 extending between the cavities 310 and 311 parallel to the dividing plane P-P. Channel 336 forms FEM 318 of the flow path of the molten alloy in which the first portion is provided by runner 322. The runner 322 is formed by the housing 320 of the nozzle mounted to the mold dividing 312 fixed at right angles to the plane P-P. The runner 322 is in communication with the channel 336 in the middle between the cavities 310, 311 such that the alloy is divided in opposite directions with respect to the respective cavities 310, 311.

From the outlet end 322a of the runner 322, the alloy is spread at the end 335 of the housing 320 bore and then enters the central region 54 of the channel 336. In region 54, the depth of channel 336 is increased such that region 54 provides a circular recess that can help stabilize the flow of the alloy. From region 54, the alloy splits and flows in opposite directions to each open end 336a, 336b of channel 336 and then enters into each die cavity 310, 311.

The alloy received into the runner 322 from the pressurized source of the machine will experience a decrease in flow rate in the FEM 318. The flow path of the alloy is such that the flow rate is reduced at the end 335 from the value of the outlet end 322a of the runner 322, and then thereafter further reduced to each open end 336a, 336b of the channel 336. It is. This further reduction causes the alloy to spread radially from the outlet end of the housing 320 to the amount allowed by the opposing sides of the channel 336 in the region 54. The alloy then flows along the channel 336 to opposite ends 336a and 336b and the flow rate continues due to opposite sides slightly diverging from the region 54 to the opposite ends 336a and 336b. Is reduced. Finally, the ends 336a and 336b are inclined at an angle with respect to the end of each die cavity 310 and 311 where the open ends 336a and 336b respectively provide communication. The silver has a cross-sectional area larger than the transverse cross-sectional area perpendicular to the longitudinal size of the channel 336, thereby enabling further reduction of the alloy flow rate at the ends 336a, 336b.

The configuration is such that the alloy passing through the open ends 336a and 336b has a flow rate substantially lower than the flow rate at the outlet end 322a of the runner 322. The substantially low flow rate is adapted to facilitate the maintenance of sufficient back pressure on the alloy phase during filling of the cavities 310 and 311. The configuration also promotes rapid solidification of the alloy in the cavities 310 and 311 upon completion of filling of the die, such that solidification is from the cavities 310 and 311 along the channel 366 to the end 322a of the runner 322. It's supposed to be a fast way back.

In one embodiment according to FIG. 9, the combined area of the open ends 336a, 336b of the channel 366 is approximately 45% greater than the area at the outlet end 322a of the runner 322, the end 366a. 366b), the corresponding flow rate decreases. In this regard, each open end 336a, 336b has an area smaller than the area at runner end 322a, while each open end 336a, 336b has an end (in the configuration of FIGS. It should be understood that it accommodates approximately half of the total alloy flow (as in the case of 36a, 36b).

In the example above, the open ends 336a and 336b may have a width of 30 mm and a depth of 0.9 mm. The configuration is suitable for a die cavity 310 having a size of 2 mm depth perpendicular to the plane P-P, which cavity 311 has a corresponding size of 1 mm. In each die cavity, the alloy may flow on the front to achieve filling of the die cavity and spread as it moves away from each open end 336a, 336b. Thus, the flow rate of the alloy being further reduced in each cavity 310, 311 can maintain sufficient back pressure.

In the configurations of FIGS. 9 and 10, the inclination of the open ends 336a, 336b is adapted to direct the alloy over the corners of each cavity 310, 311, which proves advantageous. This slope has been found to increase the back pressure on the flow of the alloy. Also adjacent the end 336b, the channel 336 is provided with a short length 336c that is inclined with respect to the plane P-P, which also helps maintain proper back pressure.

11 and 12 illustrate a fifth embodiment of the present invention other than the second aspect of the present invention described above. In FIGS. 11 and 12, the alloy flow device shown extends in parallel with the split plane PP between the mold mould 60 and the movable mold mould 61 fixed to the die cavity 62. Has a path. The flow path includes a runner 63 forming a first portion of the flow path. The second portion of the flow path comprises a FEM in the form of a channel 66 opposite the C-shaped arms 67, 68. Only part of the arm 67 is shown, which is of the same shape as the arm 68 but is opposite.

Each arm 67, 68 of the FEM channel 66 extends laterally outwardly from an enlargement 69 of the outlet end 63a of the runner 63, respectively. Has From the outer end of the portion 68a, the arm 68 has a second portion 68b extending in the same direction as or far from the runner 63. Arm 68 has a third portion 68c that extends laterally inward toward the continuous portion of the runner 63 line beyond the portion 68b. Although not shown, arm 67 also has second and third portions, respectively, beyond portions 67a corresponding to portions 68b and 68c of arm 68. Each arm 67, 68 provides a communication with the die cavity 62 in the U-shaped recess 72 at the end of the cavity 62.

The runner 63 and the FEM channel 66 have a trapezoidal shape in which the transverse cross section is bilaterally symmetrical, as shown for the portion 67a of the arm 67 in FIG. 12. The runner 63 has a uniform cross-sectional area over most of its length, but adjacent the outlet end, it tapers down to the area of the outlet end 63a of the runner 63. From the enlarged portion 69 of the flow path, each arm 67, 68 of the channel 66 increases in cross-sectional area to a maximum adjacent the far end.

One example is based on FIGS. 11 and 12 and is suitable for the production of magnesium alloy casting on a high temperature chamber pressure die casting machine with a single die cavity mold, the runner 63 having a molten magnesium alloy from the machine source having a flow rate of 50 m / sec. It may have a configuration to be supplied under a predetermined pressure up to the inlet end of the). At the taper to the outlet end 63 of the runner 63, the flow rate of the molten alloy is increased to achieve 112.5 m / s. From expansion 69, the alloy is divided evenly for the flow along each arm. For positions A to E shown for arm 68, the flow rate of the alloy is 90 m / sec at A, 80 m / sec at B, 70 m / sec at C, 60 m / sec at D and E Can be gradually reduced to 50 m / sec.

Each arm is provided with an elongate opening in communication with the die cavity 62. For the end and position C, D, E of arm 68, the opening for arm 68 (and similar for arm 67) is 0.5 mm from C to D, 0.6 mm from D to E, And from E to the end may have an average width of 0.8 mm. Thus, the total length of each slot is 35.85 mm, through which the flow rate of the total alloy decreases from 70 m / sec at C to 50 m / sec or less at the end of each arm above E.

FIG. 13 is a modification of the configuration of FIGS. 11 and 12, and corresponding portions have the same reference numerals plus 100. 13 shows the main runner 70 through which the alloy is supplied to the runner 163. In this example, the arms 167, 168 of the FEM channel 166 communicate with the die cavity along the straight end of the cavity. A configuration for using a magnesium alloy may provide a flow rate of molten alloy of 150 m / sec at the outlet end 163a of runner 163. At each arm of channel 166, the flow rate of the alloy is 125 m / sec at A, 110 m / sec at B, 95 m / sec at C, and 80 m / sec at the ends of each arm 167, 168. Can be reduced. The opening from each arm to the die cavity consists from just before each position D to the end of each arm. Operation with this configuration is as described with respect to FIGS. 11 and 12.

Figures 14 and 15 show in greater detail the variant of Figure 13 for the runner 163 and the channel (FEM 166.), with respect to the magnesium alloy as described in detail with respect to Figure 13. Suitable cross-sectional areas and flow rates are as follows.

location Area (mm ² ) 163a 8.5 A 6.0 B 6.8 C 8.0 D 9.6

 As can be appreciated, the area shown for positions A through D is for one arm of the FEM channel 166. However, relating these to the areas for the outlet end of runner 163 needs to take into account the fact that each arm provides about half the flow of alloy flowing through the runner.

16 shows a portion of a flow device for a further embodiment of the present invention, viewed vertically at the split plane. 17 and 18 show alternative examples of the configuration of FIG. 16.

16-18, the flow of molten alloy is shown only at the terminal portion 80 forming the outlet end 80a. However, runner 80 forms the first portion of the flow path of the flow system, while channel 82, chamber 84, and channel 86 form the FEM or second portion of the flow system. The molten alloy flows from runner 80 to channel 82 and into chamber 84, which then flows through each channel 86 to a single or each die cavity (not shown). 82 has a larger cross-sectional area than the outlet end of runner 80, which may be constant or may increase to chamber 84. In either case, it is lower than that obtained at the outlet end of runner 80. Provide the flow rate of the alloy In the chamber 84, the flow of the alloy can be spread, which results in further reduction of the flow rate From the chamber 84, the flow of the alloy is divided, along each channel 86 Each of the channels 86, such as channel 82, provides an additional reduction in the flow rate of the alloy therein or along. Given the division of alloy flow, channel 86 is smaller than channel 82. While having a cross-sectional area, It may generate.

Chamber 84 may be thinner than channels 82 and 86 as shown in FIG. 17, or thicker as shown in FIG. 18. Alternatively it may have a thickness similar to the channel.

In general, operation by the configuration of FIGS. 16 to 18 will be understood from the description with reference to the preceding embodiments.

19 illustrates a casting 90 that can be produced using further embodiments of the present invention. The casting is a pair of laterally adjacent pairs that are coupled in series at adjacent ends by a tie 92 of metal that solidifies in a channel providing a flow of metal between the respective die cavities in which the bar 91 is cast. Tension bar 91. Casting 90 is illustrated as a cast condition, and therefore, it includes metal 93 that solidifies along the portion of the metal flow path through which the alloy is fed into the die cavity. The metal 93 comprises a metal section 94 solidified in the FEM and a metal section 95 solidified in the runner of the metal flow path.

To obtain the tension bar 91, the casting 90 is cut along the connection between each end of the tie 92 and each side of each bar 91, while the metal 93 is the tension to which it is attached. Severe from the side of the bar 91. The shape of the rigid metal 93 is shown in more detail in FIGS. 20 and 21. Of course the metal 93 has the same form as the corresponding section 96 of the metal flow device according to the invention, and further description of the metal 93 in FIGS. 20 and 21 shows the metal as is the case with the corresponding section 96. Reference is made to (93). Accordingly, the metal sections 94 and 95 are understood as representing the runner 98 and the FEM 97 of the corresponding metal flow system, respectively. Shading represents the respective mold dimers 101, 102 that are separable by the dividing line P-P and form a die cavity and metal flow system.

As can be seen from FIGS. 20 and 21, the FEM 97 has an overall rectangular shape, with runners 98 in-line in the longitudinal direction. The outlet end 98a of the runner 98 is in communication with the FEM 97 at the center of one end of the FEM. Thus, the molten alloy flows along the runner 98, and from the runner 98, the alloy flows through the FEM 97 toward its end away from the runner outlet 98a. However, towards the far end, the FEM 97 opens laterally to a short second runner 100 through which the alloy can pass through the first portion of the series die cavity in which the tension bar 91 is cast.

Along the first portion of its length from the runner outlet 98a, the FEM 97 is configured to generate resistance to the flow of the alloy therethrough. This is caused by alternating ribs 101a and 102a formed by the respective mold portions, which extend laterally with respect to the flow of the alloy through the FEM 97 and protrude into a generally rectangular FEM. Is achieved. The width of the FEM 97 and the minimum distance A between successive ribs are calculated to achieve the required flow rate for a given alloy. Thus, for example, the molten magnesium alloy may be reduced to a flow rate from 150 m / s at the inlet 98a of the runner 98 in flow rate through the FEM 97.

In the embodiments illustrated in the figures, the flow rate of the molten alloy in the runner is preferably very substantial as previously described herein. Thus, for magnesium alloys, the flow rate at the runner and at the inlet to the FEM can be a flow rate in excess of 60 m / s, such as up to approximately 180 m / s, but preferably from about 130 m / s to 160 m / s. . For other alloys, such as aluminum, zinc and copper alloys, the flow rate may be a flow rate exceeding 40 m / s, such as a flow rate of approximately up to 160 m / s, but is preferably approximately 80 to 120 m / s. The result of this is that for pressurized sources of molten alloy that can generate a mass flow rate of a given alloy, the runners used in the present invention are those runners needed to accommodate the much smaller flow rates used in conventional pressure die casting. It has a small cross section compared to This facilitates the retraction of the molten metal that follows the runner back from the solid / liquid interface upon completion of the casting cycle, when the interface is close to the exit end of the runner. In addition, temperature control of the molten alloy in the runner is facilitated more rapidly due to the reduced mass of the molten alloy in the runner.

Within the aforementioned ranges, the flow rate of more preferred alloy runners varies depending on the type of FEM used and the type and size of casting produced. The shape of the FEM, in particular its effective flow path length, can vary with the reduction in the flow rate of the alloy to be achieved in the FEM. Typically, the reduction in flow rate to be achieved in the FEM is greater than 20%, but preferably greater than 30% of the runner flow rate, and may exceed 50%. Typically, it is necessary to use higher runner flow rates to achieve higher levels of flow rate reduction. In any case, the reduction of the flow rate must be sufficiently gradual so as to avoid substantial changes in the alloy from the molten state to the semisolid state exhibiting thixotropic properties, at least upon flow to the inlet of the die cavity.

As described above, the FEM achieves a reduction in flow rate by increasing the cross sectional area of the flow path from the area of the outlet end of the runner. Reduction of the flow rate can be achieved up to the level used in conventional die casting. As a result, the increase in cross-sectional area along the FEM can be made up to the area at its exit end, similar to the cross-sectional area of a conventional runner. Nevertheless, the volume of the FEM is substantially smaller than the volume of the corresponding length of the conventional runner. This, in combination with the substantially smaller cross section of the runner required by the present invention, sprues / runners where metal volumes that solidify in the flow system and need to be removed from casting and recycling upon completion of the casting cycle are recycled in conventional practice. To be substantially smaller than metal. Thus, less shot weight is required for each casting cycle in producing a given casting, which means lower recycling costs, faster cycle times, reduced protruding areas, and at least in some cases other, lower die temperatures. It brings advantages. However, it is important to note that in addition to these advantages, the present invention enables the production of successful castings, even if they do not always maintain the essentially low level of porosity resulting from the semi-solid filling achieved by the use of CEP.

Each metal flow device of the embodiments of FIGS. 1-21 will vary depending on the machine in which it is to be used. Thus, the device needs to be operable in the manner required at the machine mass flow rate at which the machine is operable. Therefore, the runner of the first part of the flow path of the device needs to have a cross-sectional area which generates the flow rate of the alloy required here at the mass flow rate. The cross sectional area need not be dominant over the length of the runner, but may be provided only at the outlet end of the runner, for example. Thus, at this end, the runner may be stepped down from a larger cross-sectional area such that the required flow rate at the outlet end is obtained. In addition, the FEM is designed to have a predetermined length and the cross-sectional area along the length increases in the flow direction so that the shear force generated in the alloy does not cause a state change of the alloy into a semisolid state having thixotropic properties. If the shear produces a solid in the alloy, it should be made in an amount less than 25%, preferably in an amount less than about 20 to 22%, for example less than about 17 wt%. However, even in this case, since the excellent microstructure as described above is found to be achieved, even a solid is not necessarily produced at all. That is, strong shear forces appear to force the fully molten alloy, such that this microstructure is obtained upon solidification of the cast alloy. It is apparent that the shear force aids nucleation or nucleation of the dissolved surface.

A range of commercial castings have been produced in two dual series of trials, under conventional practice and working according to the present invention. In the first series, magnesium alloy castings were made on certain (type and capacity) hot chamber machines. In the second series, aluminum alloy castings were made on certain (type and capacity) low temperature chamber machines. For magnesium casting, details common to the conventional practice and practice according to the invention are listed in Table 1, respectively, and the specific features for each mode of execution are listed in Tables 2 and 3, respectively. For aluminum castings, the corresponding data are listed in Tables 4-6. In Tables 2, 3, 5 and 6, respectively, the average piston speed values and the average runner speed values are shown for the rapid filling operating conditions of the second stage.

Each magnesium alloy casting for each of the products detailed in Table 1 was produced under conventional casting conditions detailed in Table 2 and under the conditions according to the invention detailed in Table 3. For each casting made under the conditions detailed in Table 3, a metal flow device corresponding to the embodiment illustrated in FIGS. 14 and 15 was used. Each of the castings whose details are provided in Table 2 or Table 3 proved to be sound. However, those produced according to the present invention exhibit excellent microstructures. This superiority lies in terms of the greater uniformity of the microstructures and the constituent form of the microstructures throughout the casting. Castings produced under conventional conditions exhibited larger individual grains of a nominally branched dendritic pattern, and in some cases porous regions up to levels of 1/5% or more than those produced from air entrapment. In contrast, the castings made according to the present invention exhibited fine, ellipsoidal or rounded individual grains. In addition, the latter castings were substantially free of porous regions and, with respect to the amount by which porosity could be determined, were found to be less than 1.5% and substantially uniform and very finely distributed.

The microstructures of the castings (M1, M2, M3) produced according to the present invention showed filling of the die cavity with alloys having a solids content of less than approximately 20%, which is a relatively low level. This was not the case for the microstructure of the casting M4 because it indicated filling of the cavity with an alloy containing almost no solids. However, in the case of casting M4, the re-dissolution of solids in the die cavity occurred due to the relatively large mass of the transmission case and thus slower cooling.

Each aluminum alloy casting for each of the products detailed in Table 4 was similarly produced under the conditions of Table 5 (conventional) and Table 6 (invention). Under the conditions of Table 6, each of the castings made in trials A1 and A2 used metal flow devices corresponding to the examples of FIGS. 20 and 21. The ones of trials A3 and A5 used devices corresponding to those of FIGS. 14 and 15. Each of Trials A4 and A6 to A10 each used the experimental device described below. Each casting made in accordance with the present invention exhibited superior microstructures as compared to the microstructures of corresponding castings made under conventional conditions. The differences in the microstructures are essentially as described above for the magnesium alloy casting.

It is believed that the microstructures for the brackets of castings A8 and A9 emerge from the filling of the die cavity with molten alloys whose solid content is negligible. This situation is less evident with the microstructures of castings A1 to A7, even if each of them results from the filling of the die cavity with only a very small amount of solids. None of the microstructures for castings A1 to A9 exhibited large isolation grains resulting from the main phase solidification of the shot sleeve. In each case, when these large grains appear to form in the shot sleeve, they break under the strong shearing force prevailing in the FEM, increasing the number of fine grains.

The experimental metal flow device described above used for each of trials A4 and A6 to A10 is formed on each side of each mold portion, which forms a split plane between the portions. That is, both the runner and the FEM extend along the split plane. When viewed perpendicular to the plane, the FEM has side edges that diverge from each other in a distant direction from the outlet end of the runner to an elongate gate that extends laterally with respect to the length of the runner. Thus, the runner ends at the apex of the FEM in the form of a delta or triangle in this respect. Viewed in a side view parallel to the plane of division, the FEM is curved or arched between the exit end of the gate and the runner because the face of one mold is convex and the face of the other mold is concave. The configuration is such that the convex surface portion is curved over the end of the runner so that the alloy flowing from the exit of the runner is deflected by the surface portion so that the alloy passes through the elongated gate to fill the triangular volume of the FEM.

Finally, it should be understood that various modifications, modifications and / or additions may be introduced to the structures and configurations of the above-described parts without departing from the spirit or scope of the present invention.

Claims (27)

A metal flow device for high pressure die casting of alloys using a machine capable of providing or providing a pressurized source of molten alloy and a mold to form one or more die cavities, The device forms a metal flow path through which an alloy received from the pressurized source can flow into the die cavity, (a) the first portion of the length of the flow path comprises or comprises a runner; (b) the second portion of the flow path length from the outlet end of the runner comprises a flow-path exit module (FEM); The FEM has a form that controls the flow of the alloy such that the flow rate of the alloy is gradually reduced from the level at the outlet end of the runner, whereby the flow rate of the alloy is at a location where the flow path is in communication with the die cavity. The level is significantly lower than the level of the outlet end of the runner, and upon filling of the die cavity the alloy is subject to solidification along the flow path from the die cavity and back towards the runner. The method of claim 1, The runner has a predetermined cross-sectional area at least at its outlet end so that at an alloy mass flow rate that can be produced by the machine, the runner is approximately 60 m / s up to 180 m / s for magnesium alloys and other than magnesium alloys. Device for the alloy flow at runner outlet ends exceeding approximately 40 m / s up to a maximum of 120 m / s. The method of claim 2, The FEM is characterized in that the cross sectional area is increased in the direction extending beyond the outlet end of the runner, thereby eliminating the change of state of the alloy from the molten state to the semi-solid state exhibiting thixotropic properties. Device. The method of claim 2, The increase in cross-sectional area is such that the flow rate is reduced such that the alloy does not undergo a change of state to enable filling of the die cavity by the molten alloy. The method of claim 3, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than 25 wt%. The method of claim 3, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than 20 or 22 wt%. The method of claim 3, The increase in cross-sectional area is such that the alloy is adapted to achieve a solids content of less than approximately 17 wt%. The method according to any one of claims 1 to 7, A gate is formed at an outlet end of the flow path to provide a constriction for the flow of alloy through the path. The method according to any one of claims 1 to 7, A gate is formed at an outlet end of the flow path, wherein the gate is not a contraction to the flow of alloy through the path. The method according to claim 8 or 9, And the gate is at the outlet end of the FEM. The method according to claim 8 or 9, The outlet end of the FEM is spaced apart from the gate by a second runner having a cross-sectional area at least equal to that of the outlet end of the FEM. In a pressure casting machine for high pressure die casting of alloys, The machine includes a pressurized source of molten alloy, a mold to form one or more die cavities, and a metal flow device to form a metal flow path allowing the alloy received from the pressurized source to flow into the die cavity. Or can provide, (a) the first portion of the length of the flow path comprises or comprises a runner; (b) the second portion of the flow path length from the outlet end of the runner comprises a flow-path exit module (FEM); The FEM controls the flow of the alloy such that the flow rate of the alloy is gradually reduced from the level of the outlet end of the runner, whereby the flow rate of the alloy is at the outlet where the flow path communicates with the die cavity. A level significantly below the level of the end, wherein the alloy is shaped to undergo solidification along the flow path in the die cavity and back towards the runner. The method of claim 12, The runner has a predetermined cross-sectional area at least at its outlet, so that at an alloy mass flow rate that can be produced by the machine, the runner is approximately 60 m / s up to 180 m / s for magnesium alloys and other than magnesium alloys. A machine, characterized in that it is capable of inducing alloy flow rates at runner outlet ends exceeding approximately 40 m / s up to a maximum of 120 m / s. The method of claim 13, The FEM is characterized in that the cross sectional area is increased in the direction extending beyond the outlet end of the runner, thereby eliminating the change of state of the alloy from the molten state to the semi-solid state exhibiting thixotropic properties. Machine made. The method of claim 13, The increase in cross-sectional area is such that the flow rate is reduced such that the alloy does not undergo a change of state to enable filling of the die cavity by the molten alloy. The method of claim 14, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than 25 wt%. The method of claim 14, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than 20 or 22 wt%. The method of claim 14, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than approximately 17 wt%. A method of producing alloy casting using a high pressure die casting machine having a pressurized source of molten alloy and a mold forming at least one die cavity, The alloy flows from the source to the die cavity along a flow path; (a) the alloy is adapted to flow along a runner in a first portion of the flow path; (b) In the second part of the flow path between the first part and the die cavity and comprising a flow-path exit module (FEM), the flow of the alloy is controlled to be predetermined from the level of the exit end of the runner. And gradually reduce the flow rate to a flow rate such that the flow path is in communication with a die cavity at a level significantly below the outlet level of the runner. The method of claim 19, The runner is provided with a predetermined cross-sectional area at least at its outlet end such that at an alloy mass flow rate that can be produced by the machine, the flow rate of the alloy at the outlet end of the runner is highest at approximately 60 m / s for magnesium alloys. And a flow rate of alloy at the exit end of the runner up to 180 m / s and for alloys other than magnesium alloys up to approximately 40 m / s up to 120 m / s. The method of claim 20, The FEM is characterized in that the cross sectional area is increased in the direction extending beyond the outlet end of the runner, thereby eliminating the change of state of the alloy from the molten state to the semi-solid state exhibiting thixotropic properties. How to. The method of claim 20, The increase in cross-sectional area is characterized in that the decrease in flow rate is such that the alloy does not undergo state changes and the die cavity is filled by the molten alloy. The method of claim 21, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than 25 wt%. The method of claim 21, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than 20 or 22 wt%. The method of claim 21, The increase in cross-sectional area is such that the alloy is capable of achieving a solids content of less than approximately 17 wt%. The method according to any one of claims 19 to 25, The flow of the alloy is restricted by a gate formed at the outlet end of the flow path. The method according to any one of claims 19 to 25, The flow of the alloy is not limited by the gate formed at the outlet end of the flow path.

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