CN1047547C - Countergravity casting using particulate supported thin walled investment shell mold - Google Patents
Countergravity casting using particulate supported thin walled investment shell mold Download PDFInfo
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- CN1047547C CN1047547C CN91108800A CN91108800A CN1047547C CN 1047547 C CN1047547 C CN 1047547C CN 91108800 A CN91108800 A CN 91108800A CN 91108800 A CN91108800 A CN 91108800A CN 1047547 C CN1047547 C CN 1047547C
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- support media
- shell
- die cavity
- apperance
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D18/00—Pressure casting; Vacuum casting
- B22D18/06—Vacuum casting, i.e. making use of vacuum to fill the mould
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
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Abstract
An expendable pattern of an article to be cast comprises a meltable material that expands upon heating (e.g., a wax pattern). The pattern is invested with particulate mold material to form a thin, layered shell having a wall thickness not exceeding about 0.12 inch. The thin shell wall thickness unexpectedly reduces damage and distortion to the shell during removal of the pattern therefrom by steam autoclaving. After firing, the thin gas permeable shell mold is surrounded by a refractory particulate support media in a vacuum housing. The vacuum housing is then evacuated to evacuate the mold cavity defined by the thin shell and concurrently a pressure is applied to the support media so as to compress the support media about the thin shell to support the shell against casting stresses when molten metal is countergravity cast into the evacuated mold cavity.
Description
The present invention relates to a kind of method and apparatus of antigravity casting molten metal, more specifically say, the present invention relates to a kind of molten metal antigravity casting that adopts ventilative plycast, this shell mould is provided with thin die wall, can bear well, and in casting process, be supported in the fine and close granular support media except that mould stress.
U.S. Pat-A-3,900,064, US-A-4,340,108, US-A-4,532,976, US-A-4,589,466 and US-A-4,791,977 disclose the various vacuum aided Countergravity casting methods that use ventilative plycast.
EP-B-0 019 971 discloses about the thin-shell type of multilayer and be plugged on technology in the granular refractory support media after disposable use apperance is removed.
When manufacturing is applied to the high temperature bonding refractory material plycast of breathing freely of these Countergravity casting methods, at first make a plurality of disposable use apperances (for example meltable apperance) of waiting to cast goods, then they are assembled into a module or mould tree with suitable ingate mould etc.(it includes refractory powder and suitable bonding agent liquation then module to be immersed plastic refractory, can be under environmental condition dry and sclerosis) and spread with refractory material powder than coarse grain, soak hanging material and stucco and hocket, so that on module, be coated with granular refractory material.The operation of soaking hanging material and stucco repeats, and promptly forms the refractory shell mould of multilayer, and it has enough thickness, can bear and remove the stress that is applied in apperance, roasting and the metal casting process on the shell mould thereafter.
Specifically, remove modulo operation and generally undertaken, wherein, the fusible pattern module is placed on temperature range is about 135 ℃ (275 °F) to the steam autoclave of 177 ℃ (350), apperance is melted from refractory shell mould by steam hot pressing.In the past, prior art workman runs into the destruction (crackle for example occurring) of fire-resistant shell mould often carrying out the steam heat-press step, and this is because the thermal expansion of the fire-resistant relatively shell mould of apperance (for example wax-pattern) causes.Be devoted to minimizing or reducing in the process of fire-resistant shell mould appearance destruction (crackle for example occurring) in the steam heat-press step as far as possible, prior art workman once strengthens the shell mould wall thickness so that meet with stresses better.Unfortunately, cause the weight of plycast to increase fire-resistant shell mould thickening, and consume a large amount of refractory materials, increase the casting expense.In addition, fire-resistant shell mould wall is former bigger, also requires to prolong the time of steam hot pressing, so that apperance is removed from the fusible pattern module effectively.Therefore, each patented method of application of aforementioned is come antigravity casting iron-based and the employed plycast of other alloy, and its wall thickness generally makes and is at least about 0.64mm (1/4 inch).
Aforesaid U.S. Pat-A-4,791,977 have illustrated when molten metal during the vacuum aided antigravity casting, have stress to be applied on this fire-resistant shell mould in fire-resistant shell mould.This patent especially recognizes, is applied to static pressure in the metal on the shell mould and acts on the result that the extraneous vacuum around the shell mould combines in casting process because cause the cast metal in shell mould, is applied with harmful stress on shell mould.This patent recognizes, this stress when with shell mould in the high temperature bond of metal when getting up, can cause that shell wall moves, metal penetration in wall, the thorough destruction of metal leakage and shell mould, particularly all the more so when having any structure defective in the shell mould.Although this patent provides a kind of device (for example using the differential pressure technology in mould between the vacuum chamber outside filling passage and the shell mould) that reduces this stress in the plycast, the employed plycast of this patent still requires to have traditional shell mould wall thickness and intensity, with opposing at apperance is removed and molten metal causes when casting stress.
The object of the present invention is to provide a kind of improved, economic Countergravity casting method and equipment, its employed fire-resistant plycast has the wall thickness that significantly reduces, but seldom is damaged (crackle for example occurring) in coming except that operations such as moulds by steam hot pressing.
For achieving the above object, the invention provides a kind of method of antigravity casting molten metal, comprise the steps: to make a disposable apperance of waiting to cast goods, the fusible material that expands when described apperance is included in heating; With apperance coated with the granular refractory Modeling Material; The apperance that is capped is heated,, stay next die cavity from shell so that apperance is removed; Die cavity is vacuumized; It is characterized in that above-mentioned apperance covers step, comprise that with apperance coated with the fire-resistant moulding material of multilayer granular, control forms the thin fire-resistant shell that its wall thickness is no more than about 3mm; Fire-resistant granular support media is configured in around the thin-shell type, die cavity and a substrate liquid inlet that is configured in the support media outside are connected; With molten metal inlet with when following molten metal source is connected, molten metal is made progress antigravity casting in the die cavity that is evacuated; When die cavity is evacuated, support media is exerted pressure, so that make support media center on the extruding thin-shell type, support described shell mould opposing casting stress.
The present invention also provides a kind of equipment of antigravity casting molten metal, comprises the device that die cavity is vacuumized, and it is characterized in that described equipment also comprises: be placed on the fire-resistant granular support media in the case; Be placed on the fire-resistant plycast in the support media, described shell mould has a die cavity that shell wall defined that is no more than about 3mm by thickness; Be configured in the substrate liquid inlet of support media outside, be used for die cavity is connected with following molten metal source; When being evacuated, die cavity is used for device that molten metal inlet is connected with described source, so that make the molten metal pressure upwards enter the die cavity that is evacuated; And when die cavity is evacuated, be used for pressure is applied to device on the support media, so that make support media center on the shell mould extruding, supporting shell mould opposing casting stress.
A kind of improved, economic Countergravity casting method and the equipment of providing is provided, it can significantly reduce the amount of bonding refractory material required when making plycast.
Another advantage of the present invention has been to provide a kind of improved, economic Countergravity casting method and equipment, and it can significantly increase the foundry goods quantity that single plycast can cast out.
Another advantage of the present invention is to provide a kind of improved Countergravity casting method and equipment, it can be reduced in when casting since exist in the metal around the static pressure and shell mould extraneous vacuum state caused is applied to stress on the plycast.
An advantage more of the present invention is to provide a kind of improved Countergravity casting method and equipment, it can support plycast by this way during casting, destruction with the shell mould that prevents to cause by casting stress, allow bigger casting shell, and prevent that molten metal from leaking out from shell mould.
Therefore, the present invention imagines a kind of improved, economic Countergravity casting method and equipment, it comprises: make a disposable apperance of waiting to cast goods, the fusible material that expands when this apperance is included in heating, coated with the fire-resistant Modeling Material of multilayer granular, control forms its wall thickness around apperance and is no more than about 3mm (0.12 inch) with apperance) fire-resistant shell, the apperance that is capped is for example compressed into row by steam heat heats, apperance is removed from shell, stay next die cavity.With the thin-shell type roasting with the mould strength that to require after, fire-resistant granular support media is configured in around the thin-shell type, the substrate liquid that makes die cavity and one be configured in the support media outside enters the mouth and is connected.
Will approach fire-resistant shell mould with granular support media around after, die cavity is vacuumized, simultaneously support media is exerted pressure, support media is centered on and push fire-resistant shell mould, be connected with the molten metal source and when molten metal carried out antigravity casting in the die cavity that vacuumizes, the supporting shell mould was resisted the effect of casting stress with convenient molten metal inlet.
In the present invention practice, adopt wall thickness to be no more than about 3mm (0.12 inch)) fire-resistant shell mould, it is according to being to have found that this shell wall energy is born better in removing mold process to apply thereon stress because apperance expands, and this discovery is with confessed different during prior art is put into practice.More particularly, the present invention relates to a kind of discovery, promptly the gas permeability of thin-shell type is not with thick the reducing and increase of shell wall in direct ratioly, but increases by beyond thought mode.For example, the air penetrability that has been found that this shell wall (promptly being no more than about 3mm (0.12 inch) wall thickness) goes out greatly more than the twice than the air penetrability of the similar shell mould with double wall thickness, will go out three times greatly usually.
The shell gas permeability that has been found that this increase is applied to the stress on the shell in the time of can eliminating and remove mould by steam hot pressing, this is to be penetrated in the fusion epidermis that apperance initially melts by expansions to realize.In addition, the shell mould gas permeability of increase can shorten except that the mould time by promoting the intrusion apperance surface of steam.
Adopt the fire-resistant shell mould of this thin-walled (promptly being no more than about 3mm (0.12 inch)) in the embodiment of this invention, also based on such discovery, promptly shell mould is reinforced or extruding by granular support media is centered on when die cavity is evacuated, this thin-walled shell mould can suitably be supported, and applies thereon stress when the differential pressure antigravity casting with opposing.
For instance, in an embodiment of the present invention; the thin-walled shell mould is placed in the loose granular support media (for example loose foundry sand) in the vacuum tank; when vacuum tank is evacuated so that when casting mold cavity vacuumized; a pressure transfer device relative vacuum case and support media are moved, make support media center on the shell mould extruding.Pressure transfer device can comprise a removable wall of vacuum tank, and environmental pressure is born in the outside of this wall, and the relative vacuum effect is born in the inboard, and support media around the shell mould extruding, is resisted casting stress with the supporting shell mould.On the other hand, pressure transfer device can comprise a pressure air ring, contacts with support media, for same purpose is pushed support media around thin-shell type.
From hereinafter detailed description and accompanying drawing, it is clearer that above-mentioned purpose of the present invention and advantage will become.
Fig. 1 is the side view of a module;
Fig. 2 is that this module covers with the sectional view after the granular founding materials;
Fig. 3 is the sectional view of the thin-shell type after by steam hot pressing module being removed;
Fig. 4 is the sectional view of counter-gravity casting equipment of the present invention, and wherein, shell mould is placed among the granular support media of reinforcing of a vacuum tank, and the external metallization liquid of shell mould inlet be immersed in metal reservoir below;
Fig. 5 is the sectional view of the counter-gravity casting equipment of another embodiment of the present invention;
Fig. 6 is the sectional view of the counter-gravity casting equipment of another embodiment of the present invention.
Now please referring to accompanying drawing, a disposable module or mould tree 10 has been shown among Fig. 1, it comprises cylindrical rising head shaped portion 12 and a plurality of die cavity shaped portion 14 at a middle part, and each die cavity shaped portion 14 is linked to each other with rising head shaped portion 12 by corresponding ingate shaped portion 16 respectively.As shown in the figure, die cavity shaped portion 14 is made the shape of waiting to cast goods or part, and around rising head shaped portion 12 along the alternate configuration of its length direction.In general, each die cavity shaped portion 14 and corresponding ingate shaped portion thereof 16 are formed by injection moulding, connect (for example weld with wax or bonding) then by hand to rising head shaped portion 12.Rising head shaped portion 12 is made single part by injection moulding.
The fire-resistant truncated cone shape collar 18 is connected (for example with wax weldering or bonding) to the bottom of rising head shaped portion 12.
Implementing when of the present invention, do not needing to make the each several part 12,14,16 of module 10 to be made by identical model material, as long as module 10 can heat by steam hot pressing etc. and removes thereafter, this illustrates hereinafter.
Now please referring to Fig. 2.Module 10 by coated with multiple layer refractory 22 around it, to form a shell 30.Module repeated to immerse in the plastic refractory (not shown) soak extension.Plastic refractory comprises refractory material powder (for example zircon, alumina, fused silica or the like) suspension in the adhesive solution that is suspended in such as silester or colloidal state Ludox, and a spot of organic film forms thing, wetting agent and defoamer.Soak after the extension at every turn, excessive slurry is discharged, and on the slurry layer on the module, spread refractory particles with drying.The refractory material that suitable stucco is used has: granular zircon, fused silica, silica, comprise the various aluminium silica groups of mullite, consolidation alumina and similar material.
After each road soaks extension and stucco operation, use and force air dryer or other device, on the flame retardant coating of module 10 or formation formerly, to form a flame retardant coating with the slurry coating sclerosis.These soak hanging material, stucco and dry processes repeat, until forming around the die cavity shaped portion 14 one have the multilayer shell mould 30 of requirement wall thickness t till.
According to the present invention, control shell mould forming process (promptly soaking extension, stucco and oven dry), around die cavity shaped portion 14, to form multiple layer refractory shell mould 30 that its thickest t is no more than about 3mm (0.12 inch), hereinafter will illustrate, have been found that, this wall thickness presents surprising ability, can adapt to the stress that is applied to when removing mould by steam hot pressing on the shell mould.In general, the shell mould wall that is no more than about 3mm (0.12 inch) thickness is to be piled into by four to five layers of flame retardant coating that soaks extension, stucco and baking operation by above-mentioned repeating and form.
Fig. 3 illustrates a fire-resistant shell mould 30 after by steam hot pressing module 10 being removed.Specifically, fire-resistant shell mould 30 shown in the figure is placed on a universal steam autoclave 34 (just schematically illustrating), for example in the 286PT type steam autoclave that can have been bought by Leeds and Bradford company.Can see significantly that remove and stayed a thin fire-resistant shell mould 30 behind the module 10, its each die cavity 36 interconnects with middle part rising head 37 by corresponding laterally ingate 38.In this stage of process, the bottom and the upper end of rising head 37 are opened wide.
In the steam hot pressing, the module that is capped 40 shown in Figure 2 will stand the steam that temperature is about 135 ℃ (275) to 177 ℃ (350) heating of (steam pressure is about 5.62 to 7.73 crust (80 to 110psi)), should be enough to heat time heating time module 20 is melted fire-resistant shell 30.
Specifically, in the starting stage of steam hot pressing, because steam is invaded by ventilative fire-resistant shell mould 30, module 10 melts a surface melting film.Will illustrate that below thin fire-resistant shell mould 30 can be shockingly and unexpectedly absorbed the initial molten film in this surface, thereby has eliminated the apperance expansive force that will be applied in other cases on the shell mould 30.After crossing certain hour, the fusing of the remainder of module 10, its major part is discharged by the perforate 18a in the collar 18 by fire-resistant shell mould 30.
As described above, the wall thickness of fire-resistant shell 30 is controlled according to the present invention, make it to be no more than about 3mm (0.12 inch).Have been found that, this shell wall is thick (for example to present beyond thought highly-breathable, when the known nitrogen air penetrability test of using model casting association to be continued to use is measured under 1038 ℃ (1900 °F)), in order to absorb the initial molten film in the surface of model material during steam hot pressing.For instance, fire-resistant shell mould 30 about 982 ℃ (1800) roastings, have wall thickness and be about 3mm (0.12 inch) (4 flame retardant coatings), through measuring (by above-mentioned nitrogen air penetrability test), present its air penetrability and go out more than the twice greatly than the air penetrability of similar shell mould with double thickness (be that wall thickness is 6mm (0.25 inch), comprise 8 flame retardant coatings).More particularly, wall thickness is the baked fire-resistant shell mould of 3mm (0.12 inch)
30 air penetrabilities of measuring are per minute 316-468cc nitrogen, and wall thickness is that the air penetrability of similar shell mould of 6mm (0.25 inch) is only for per minute 80-120cc nitrogen.
Baked fire-resistant shell mould 30 is preferably made by the present invention, makes its air penetrability that presents be roughly three times of air penetrability of the similar shell mould with double wall thickness at least.
The front is mentioned, this beyond thought highly-breathable of thin fire-resistant shell mould 30 (wall thickness is no more than 3mm (0.12 inch)) enlarges the ability of fire-resistant shell mould, make it to absorb the initial molten film in surface that forms when module 10 is taken in steam hot pressing, from eliminating owing under normal circumstances will be applied to any stress on the shell mould during fire-resistant relatively shell mould 30 thermal expansions of module 10.With different in the prior art practice by increasing the thick situation of resisting this stress that except that mould the time, produces of shell wall, the present invention has found that hot pressing provides significantly improved characteristic to steam in thick the reducing of shell wall (attenuation), can reduce shell deflection and damage as crackle and so on.Because steam can see through the Fast Heating that module 10 was invaded and caused to highly-breathable shell mould 30 well, therefore not only can reduce shell deflection and damage, also can significantly reduce by steam hot pressing and remove the required time of mould.
In addition, can find out significantly in the listed example from following table 1 that owing to adopted thin shell wall thick, the quantity of the refractory particles that fire-resistant shell mould 30 is required has been greatly reduced.Thereby the casting cost is significantly reduced, for example, on the basis of saving the refractory material amount of using, can reduce cost 40% to 75%.
In addition, adopt the thin-walled shell mould that the interval between each die cavity shaped portion 14 and the ingate 16 is reduced, so that significantly increase the foundry goods quantity that each casting mold can cast out.Total growth also increases under low cost with the same manner (except wall thickness).
After the steam hot pressing, shell mould is descended roasting 90 minutes at about 982 ℃ (1800 °F).
Table 1 has been listed given part (for example automobile rocker, window bar and chock) when adopting heavy wall shell mould (being the thick 6mm of shell wall (0.25 inch)) and thin-walled shell mould 30 of the present invention, the comparing data of its so-called load factor (being the part number that each shell mould can cast out).Heavy wall shell mould (9 soaking paste/stuccos) and thin-walled shell mould (4-5 soaking paste/stucco) are all pressed the same manner preparation, use identical slurry and stucco, for example, initially soak the hanging material package and contain 200 purpose fused silicas (15.2 percetage by weight) and 325 purpose zircons (56.9 weight %), colloidal state Ludox bonding agent (17.8 weight %) and water (10.1 weight %), thereafter the hanging material package of soaking contains the mullite that registration mark is Mulgrain M-47 (15.1 weight %), 200 purpose fused silicas (25.2 weight %) and 600 purpose zircons (35.3 weight %), silester bonding agent (15.6 weight %) and isopropyl alcohol (8.8 weight %), and carrying out stucco with about 100 purpose zircons and 60 purpose MulgrainM-47 mullites one after another, the amount of money carries out stucco with about 25 order Mulgrain M-47 mullites.Shell mould is by the top described steam hot pressing roasting then of carrying out.
The weight of the heavy wall shell mould that is applied to various parts in addition in the past that compares in the table (being 6mm (0.25 inch) wall thickness) and the weight of thin-walled shell mould of the present invention (promptly about 2.5mm (0.10 inch) wall thickness).
The load factor of table 1 shell mould and final refractory material weight
Standard shell mould thin-walled shell mould standard shell mould thin-walled shell mould
Load factor load factor weight weight part (number of packages/shell mould) (number of packages/shell mould) changes %g (OZ)/part g (OZ)/part variation % and shakes wall 8ar * 13hi 12ar * 16hi 178 (6.3) 42.5 (1.5) 76
104/ shell mould, 192/ shell mould, 85 window bars 12ar * 8hi 14ar * 10hi 190 (6.7) 42.5 (1.5) 63
96/ shell mould, 140/ shell mould, 46 chocks 10ar * 24hi 12ar * 26hi 79.4 (2.8) 36.8 (1.3) 54
240/ shell mould, 312/ shell mould 30
Note: " ar " is the die cavity number around rising head
" hi " is the die cavity number of plies along riser height
" g (OZ)/part " is " gram (ounce)/part "
Clearly visible from table 1, the thin shell mould of the present invention significantly increases load factor (being the part number that each shell mould can cast out), and significantly reduces the needed refractory material amount of roasting shell mould of making.All these is not produce under the situation of quality of shell mould deflection and damage to obtain in obtaining identical or better steam hot pressing.
According to an embodiment of the present, molten metal antigravity under differential pressure is cast in the thin-walled shell mould 30 (this shell mould is by after about 982 ℃ (1800) roastings), as shown in Figure 4.Specifically, thin-walled shell mould 30 is bearing among the loose refractory particles medium 60 that is contained in the vacuum tank 70.Sidewall 73 and movable roof 74 that this vacuum tank 70 has base support wall 72, erects define a vacuum chamber 76 between base.Base support wall 72 and the sidewall of erectting 73 are made by the gas impermeable material of metal and so on, and movable roof 74 comprises ventilative (porose) plate 75 is connected with vacuum (-tight) housing 77 on it, and (outside) forms a vacuum chamber 78 above air permeable plate 75.This vacuum chamber 78 is connected by the vacuum source of pipe 82 with vavuum pump 80 and so on.Movable roof 74 has the peripheral sealing ring 84 that the inboard with upright side walls 73 fits, and makes roof 74 can keep vacuum seal between the two when opposing sidewalls 73 moves.
When each the parts assembling shown in Fig. 4 is formed Casting Equipment 100, ceramic filling pipe 90 is configured on the vacuum tank 70 so that provide a substrate liquid inlet by rising head 37 and 38 pairs of die cavities 36 of corresponding ingate, when shell mould is placed on it, this filling pipe and the truncated cone shape collar 18 are tightly connected.Shell mould is placed with fire-resistant lid 20 on the top, and rising head 37 tops are clogged.Loose fire-resistant granular support media 60 (the loose casting silica sand of for example about 60 purposes) is put into vacuum chamber 70 round baked shell mould 30, with support media 70 jolt rammings around shell mould 30 of advancing to make in the vacuum tank 70 vibration help vacuum chambers 76.Then movable roof 74 is inserted the opened upper end end of vacuum tank 70, perimeter seal 84 and the sidewall of erectting 73 is tightly connected, and the inboard that makes air permeable plate 75 towards with contact support media 60, as shown in Figure 4.
After the assembling, Casting Equipment 100 is placed on supply source 102 (for example liquid pool) top for the treatment of ingot metal liquid 104.Molten metal 104 generally is contained in the casting jar 106.Start vavuum pump 80 then, the vacuum chamber 78 of vacuum (-tight) housing 77 is vacuumized again vacuum chamber 76 is vacuumized by air permeable plate 75.Vacuum chamber 76 is vacuumized, equally also die cavity 36 is vacuumized by ventilative shell wall.The selection of vacuum is enough in the time of should be in molten metal 104 that filling pipe 90 is submerged as shown in Figure 4 molten metal 104 from upwards suction of liquid pool 102.
When vacuum chamber 76,78 vacuumized, a side that is positioned at perimeter seal 84 outsides of roof 74 was subjected to atmosphere (or environment) pressure, and the inboard of plate 75 is subjected to the effect of relative vacuum.Pressure official post roof 74 opposing sidewalls 73 of roof 74 both sides move down, and make 75 pairs of support media 60 of plate apply enough pressure, so that support media 60 is pushed or is reinforced around shell mould 30, and supporting shell mould opposing casting stress.Like this, when die cavity 36 be evacuated with molten metal when liquid pool 102 is upwards taken out, plate 75 applies a pressure simultaneously, with support media around shell mould 30 extruding, supporting shell mould opposing stress.The pressure size of the extruding support media 60 that is applied by plate 75 can be controlled by the vacuum of setting up in the control vacuum chamber 76.
Clearly visible from Fig. 4, molten metal 104 will upwards be aspirated by filling pipe 90 and rising head 37, enter die cavity 36 by horizontal ingate 38 then.Molten metal 104 thus in die cavity 36 the vacuum antigravity cast out.
When vacuum chamber 76,78 was set up relative vacuum, obviously the epimere of rising head 37 will be near the maximum vacuum in the chamber 78.In addition, very clear, support media 60 will play the effect of the vacuum that reduces shell mould 30 outside close its bottoms.Its result, according to US4,791,977 principle, be reduced the reducing and together of this stress by support media 60 supporting shell moulds 30 by the two stress that is applied on shell mould 30 bottoms that causes that combines of outer vacuum action around interior static pressure head and the shell mould 30, make high-temperature liquid metal 104 can be in thin-shell type 30 (wall thickness is no more than about 3mm (0.12 inch)) antigravity casting, the shell wall that can occur being harmful to does not move in the infiltration shell wall with molten metal.
Have any microstome or similar defective in shell-shaped 30, support media 60 on every side assists also to prevent that molten metal 104 from leaking from fault location, prevents the damage to Casting Equipment, and vacuum is kept, until casting solidification.
In case molten metal 104 solidifies in die cavity 36, will move on the Casting Equipment 100, will make filling pipe 90 leave metal reservoir.Unload the roof 74 of vacuum tank 70 then in the breakdown station (not shown), so as with support media 60 and the shell mould 30 of added metal from vacuum chamber 76, take out.After the cooling, support media 60 can reclaim, and reuses in other shell mould 30.After vacuum chamber took out, the shell mould 30 of added metal can be cooled to room temperature.Owing to be thin-walled, can easily shell mould 30 be removed from the foundry goods that solidifies.For example, the cooling of the shell mould 30 of added metal often makes the quick-fried simply foundry goods that takes off of shell mould 30, and this is because cooling the time has thermal stress to be applied on the shell mould.As a rule, remove thin-shell type 30 and remove comparing of using in the past, only need the very short time than the heavy wall shell mould.
Please referring to Fig. 5, there is shown the Casting Equipment 100 of another embodiment of the present invention '.In Fig. 5, the part similar to Fig. 4 represented with the same numeral of band apostrophe.Casting Equipment 100 among Fig. 5 ' the be different from Casting Equipment 100 among Fig. 4 be it adopted one around case 70 ' donut 110 ', and seal arrangement case 70 ' on airtight diaphragm 112 ' (the playing the active box roof) of flexibility on we at beginning, in order to when case 70 ' when being evacuated to support media 60 ' exert pressure.One of vacuum (-tight) housing 110 ' define around case 70 ' vacuum chamber 76 ' toroidal vacuum chamber 114 ', and ventilative (porose) sidewall sections 116 by an annular ' with vacuum chamber 76 ' interconnect.
Obviously as seen, when vacuum chamber 114 ' be evacuated (by manage 118 ') time, vacuum chamber 76 ' with shell mould 30 ' die cavity 36 ' also be evacuated.
When vacuum chamber 76 ' be evacuated, flexible airtight diaphragm 112 ' outer surface 112a ' be subjected to atmospheric pressure, inner surface 112b ' is subjected to the relative vacuum effect, cause diaphragm 112 ' around the loose fire-resistant granular support media 60 of thin-shell type 30 ' extruding ', when molten metal by from following liquid pool by filling pipe 90 ' and rising head 37 ' upwards press and by ingate 38 ' when entering die cavity, support media 60 ' just according to above just the described mode supporting thin shell of Fig. 4 type to resist stress.The effect of the others of embodiment shown in Figure 5 and advantage, with top to embodiment illustrated in fig. 4 described identical.
Please referring to Fig. 6, the Casting Equipment 100 of another embodiment of the present invention shown in the figure ", wherein similar to Fig. 4 part is represented with the same numeral of the two apostrophes of band.The difference of embodiment among embodiment shown in Fig. 6 and Fig. 4 is that it has adopted the air ring that pressurizes 120 of one or more annulars " (only illustrating one among the figure); be configured in contact with it in the case 70 " in fire-resistant granular support media 60 "; when antigravity casting die cavity 36 " when being evacuated, air ring 120 " is exerted pressure " extruding around thin-shell type 30 with support media to support media.Case 70 " has inactive roof 74 ", the air permeable plate 75 on this roof 74 " comprise be enclosed in case 70 by seal 84 " top " with one with plate 75 " vacuum (-tight) housing 77 that is connected ".Vacuum (-tight) housing 77 " in vacuum chamber 78 " covers air permeable plate 75 " ventilative part 75a ", so that by a vacuum pump apparatus 80 that is connected by pipe 82 " with vacuum chamber 78 " ", case 70 " vacuum chamber 76 " is vacuumized.
After roof 74 " is enclosed in case 70 " goes up and vacuum chamber 76 " and 78 " vacuumized, air ring 120 " by the suitable source of the gas 121 of compressed air and so on " " is pressurizeed by suitable air supply pipe 122.Air ring 120 " pressurization to fire-resistant granular support media 60 " is exerted pressure, and makes it around shell mould 30 " extruding, by above to the described same way as supporting of other embodiment shell mould with the opposing casting stress.In others, the embodiment of Fig. 6 is identical with the effect of the previous embodiment of Fig. 4 and Fig. 5.
Though above the present invention will be described according to some specific embodiments of the present invention, the present invention is not limited thereto, and the present invention only is subjected to the restriction of the scope that claims put down in writing.
Claims (19)
1. the method for an antigravity casting molten metal comprises the steps:
Make a disposable apperance of waiting to cast goods, the fusible material that expands when described apperance is included in heating;
With apperance coated with the granular refractory Modeling Material;
The apperance that is capped is heated,, stay next die cavity from shell so that apperance is removed;
Die cavity is vacuumized;
It is characterized in that,
Above-mentioned apperance covers step, comprises that with apperance coated with the fire-resistant Modeling Material of multilayer granular, control forms the thin fire-resistant shell that its wall thickness is no more than about 3mm;
Fire-resistant granular support media is configured in around the thin-shell type, die cavity and a substrate liquid inlet that is configured in the support media outside are connected;
With molten metal inlet with when following molten metal source is connected, molten metal is made progress antigravity casting in the die cavity that is evacuated;
When die cavity is evacuated, support media is exerted pressure, so that make support media center on the extruding thin-shell type, support described shell mould opposing casting stress.
2. method according to claim 1 is characterized in that making the air penetrability of the thin layer shell mould of formation to go out more than the twice greatly than the air penetrability of the similar shell mould with double wall thickness.
3. method according to claim 2, the air penetrability that it is characterized in that making the described thin layer shell mould of formation are at least three times of air penetrability of described similar shell mould.
4. method according to claim 1 is characterized in that heating in the apperance that will be capped, and so that apperance is removed from shell, stays in the step of next die cavity, and the apperance that is capped is carried out steam hot pressing so that apperance is removed.
5. method according to claim 1, it is characterized in that in the step around fire-resistant granular support media being configured in thin-shell type, shell mould is bearing in the support media in the vacuum tank, when vacuum tank is evacuated, pressure transfer device relative vacuum case and support media are moved, described pressure is applied on the support media.
6. method according to claim 5 is characterized in that pressure transfer device comprises the removable wall of this vacuum tank, is pressed on this support media.
7. method according to claim 6 it is characterized in that making the medial surface of this removable wall to be subjected to the relative vacuum effect, and lateral surface is subjected to the environmental pressure effect.
8. method according to claim 5, it is characterized in that pressure transfer device comprise in the support media that is configured in vacuum tank, with the contacted air ring of support media, when die cavity is evacuated, with the air ring pressurization so that the extruding support media.
9. method according to claim 1 is characterized in that disposable use apperance comprises wax.
10. method according to claim 1 is characterized in that disposable use apperance comprises urea.
11. method according to claim 1 is characterized in that,
The described step that the apperance that is capped is heated comprises that the apperance that will be capped carries out steam hot pressing, and apperance is removed from shell, stays next die cavity;
Describedly fire-resistant granular support media is configured in step around the thin-shell type comprises thin-shell type is enclosed in the fire-resistant granular support media that is contained in the vacuum chamber, described die cavity and a substrate liquid inlet that is configured in described vacuum chamber outside are connected;
Vacuum chamber is vacuumized so that die cavity is vacuumized.
12. the equipment of antigravity casting molten metal comprises the device that die cavity is vacuumized, and it is characterized in that described equipment also comprises:
Be placed on the fire-resistant granular support media in the case;
Be placed on the fire-resistant plycast in the support media, described shell mould has a die cavity that shell wall defined that is no more than about 3mm by thickness;
Be configured in the substrate liquid inlet of support media outside, be used for die cavity is connected with following molten metal source;
When being evacuated, die cavity is used for device that molten metal inlet is connected with described source, so that make the molten metal pressure upwards enter the die cavity that is evacuated; And
When die cavity is evacuated, be used for pressure is applied to device on the support media, so that make support media center on the shell mould extruding, supporting shell mould opposing casting stress.
13. equipment according to claim 12 is characterized in that described molten metal inlet comprises a filling pipe that extends from shell mould outside support media.
14. equipment according to claim 12, it is characterized in that being used for pressure is applied to the removable wall that device on the medium comprises described vacuum tank, when vacuum chamber is evacuated, the effect that it is poor that described removable wall is under pressure, cause described removable wall relative vacuum case and support media to move, make support media center on the shell mould extruding.
15. equipment according to claim 14, it is characterized in that removable wall comprises an air permeable plate of this case, described air permeable plate has medial surface and vacuum (-tight) housing that covers on its lateral surface of a contact support media, the inboard of described vacuum (-tight) housing can be evacuated, by air permeable plate vacuum chamber is vacuumized, the outside of vacuum (-tight) housing is subjected to environmental pressure, when described vacuum chamber is evacuated, described removable wall is moved relative to case, be pressed on the support media.
16. equipment according to claim 14 is characterized in that removable wall comprises an air-locked flexible box end wall.
17. equipment according to claim 12 is characterized in that being used for the device that support media is exerted pressure is comprised an air ring that pressurizes that contacts configuration with the support media in the vacuum chamber.
18. equipment according to claim 12 is characterized in that fire-resistant granular support media comprises loose foundry sand.
19. equipment according to claim 12 is characterized in that:
Described case has a vacuum chamber;
In vacuum chamber, be placed with loose fire-resistant granular support media;
Be provided with and vacuum chamber vacuumized so that the device that die cavity is vacuumized.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US57931990A | 1990-09-06 | 1990-09-06 | |
| US579,319 | 1990-09-06 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1059485A CN1059485A (en) | 1992-03-18 |
| CN1047547C true CN1047547C (en) | 1999-12-22 |
Family
ID=24316424
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN91108800A Expired - Lifetime CN1047547C (en) | 1990-09-06 | 1991-09-05 | Countergravity casting using particulate supported thin walled investment shell mold |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0474078B1 (en) |
| JP (1) | JPH07110404B2 (en) |
| CN (1) | CN1047547C (en) |
| AU (1) | AU635858B2 (en) |
| BR (1) | BR9103830A (en) |
| CA (1) | CA2049228C (en) |
| DE (1) | DE69114954T2 (en) |
| MX (1) | MX173895B (en) |
| RU (1) | RU2039629C1 (en) |
| YU (1) | YU47814B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104399891A (en) * | 2014-11-27 | 2015-03-11 | 温州兰理工科技园有限公司 | Casting method combining investment precise shell-making process with vacuum suction molding technology |
| CN105102149A (en) * | 2013-03-15 | 2015-11-25 | 金属铸造技术股份有限公司 | Refractory mold |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5303762A (en) * | 1992-07-17 | 1994-04-19 | Hitchiner Manufacturing Co., Inc. | Countergravity casting apparatus and method |
| JPH0818122B2 (en) * | 1993-02-02 | 1996-02-28 | 第一鋳造株式会社 | Vacuum shell mold casting method |
| EP0640420B1 (en) * | 1993-03-12 | 2000-06-07 | Hitachi Metals, Ltd. | Vacuum suction casting apparatus |
| GB9724568D0 (en) * | 1997-11-19 | 1998-01-21 | Castings Dev Centre The | Investment casting |
| DE112006000461T5 (en) | 2005-02-22 | 2008-03-13 | Milwaukee School Of Engineering, Milwaukee | casting process |
| CN101386066B (en) * | 2008-10-27 | 2010-06-09 | 秦中林 | Method for casting the iron and steel casting on extrusion machine |
| CN101850401A (en) * | 2010-05-31 | 2010-10-06 | 上虞新达精密铸造有限公司 | Fired mold and precision casting process utilizing same |
| CN102806314A (en) * | 2012-09-03 | 2012-12-05 | 贵州安吉航空精密铸造有限责任公司 | Casting method for aluminum alloy thin-wall fine-hole casting |
| US9486852B2 (en) | 2013-03-14 | 2016-11-08 | Hitchiner Manufacturing Co., Inc. | Radial pattern assembly |
| US9498819B2 (en) | 2013-03-14 | 2016-11-22 | Hitchiner Manufacturing Co., Inc. | Refractory mold and method of making |
| US9481029B2 (en) | 2013-03-14 | 2016-11-01 | Hitchiner Manufacturing Co., Inc. | Method of making a radial pattern assembly |
| KR101367200B1 (en) * | 2013-05-08 | 2014-02-26 | 지정욱 | Process for duplex casting and process for duplex casting apparatus thereof |
| CN104972066A (en) * | 2015-06-15 | 2015-10-14 | 江苏万恒铸业有限公司 | Thin-shell sand culturing casting simple technology |
| CN106513635B (en) * | 2016-12-16 | 2019-02-05 | 上海华培动力科技股份有限公司 | Double-layer hollow cylinder fusible pattern formwork structure for high-temperature alloy process for suction casting |
| CN109719277A (en) * | 2017-10-30 | 2019-05-07 | 科华控股股份有限公司 | The anti-gravity feeding shell structure of heat resisting steel volute process for suction casting |
| CN109465399B (en) * | 2018-12-26 | 2023-11-21 | 广东富华铸锻有限公司 | Gating system with speed reducer shell sand core structure |
| JP6915206B2 (en) * | 2019-08-26 | 2021-08-04 | 呉政寛 | Molten forging method for thin-walled shell molds |
| CN114309474A (en) * | 2022-03-14 | 2022-04-12 | 成都航宇超合金技术有限公司 | Investment casting process of small and medium-sized single crystal turbine blades |
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| US3900064A (en) * | 1972-12-04 | 1975-08-19 | Hitchiner Manufacturing Co | Metal casting |
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| US4340108A (en) * | 1979-09-12 | 1982-07-20 | Hitchiner Manufacturing Co., Inc. | Method of casting metal in sand mold using reduced pressure |
| US4589466A (en) * | 1984-02-27 | 1986-05-20 | Hitchiner Manufacturing Co., Inc. | Metal casting |
| IN170880B (en) * | 1987-05-07 | 1992-06-06 | Metal Casting Tech |
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- 1991-08-15 CA CA 2049228 patent/CA2049228C/en not_active Expired - Lifetime
- 1991-08-16 AU AU82495/91A patent/AU635858B2/en not_active Expired
- 1991-08-24 EP EP19910114237 patent/EP0474078B1/en not_active Expired - Lifetime
- 1991-08-24 DE DE1991614954 patent/DE69114954T2/en not_active Expired - Lifetime
- 1991-09-04 BR BR9103830A patent/BR9103830A/en not_active IP Right Cessation
- 1991-09-05 YU YU149191A patent/YU47814B/en unknown
- 1991-09-05 RU SU5001482 patent/RU2039629C1/en active
- 1991-09-05 MX MX9100964A patent/MX173895B/en unknown
- 1991-09-05 JP JP25280891A patent/JPH07110404B2/en not_active Expired - Lifetime
- 1991-09-05 CN CN91108800A patent/CN1047547C/en not_active Expired - Lifetime
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|---|---|---|---|---|
| CN105102149A (en) * | 2013-03-15 | 2015-11-25 | 金属铸造技术股份有限公司 | Refractory mold |
| CN104399891A (en) * | 2014-11-27 | 2015-03-11 | 温州兰理工科技园有限公司 | Casting method combining investment precise shell-making process with vacuum suction molding technology |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1059485A (en) | 1992-03-18 |
| DE69114954D1 (en) | 1996-01-11 |
| EP0474078B1 (en) | 1995-11-29 |
| JPH07110404B2 (en) | 1995-11-29 |
| BR9103830A (en) | 1992-05-19 |
| CA2049228C (en) | 1996-10-15 |
| YU47814B (en) | 1996-01-09 |
| RU2039629C1 (en) | 1995-07-20 |
| JPH04270024A (en) | 1992-09-25 |
| AU8249591A (en) | 1992-03-12 |
| AU635858B2 (en) | 1993-04-01 |
| YU149191A (en) | 1994-06-24 |
| DE69114954T2 (en) | 1996-07-18 |
| EP0474078A1 (en) | 1992-03-11 |
| MX173895B (en) | 1994-04-07 |
| CA2049228A1 (en) | 1992-03-07 |
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| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
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Expiration termination date: 20110905 Granted publication date: 19991222 |