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EP1910580A2 - Coulage direct utilisant la filtration par piles - Google Patents

Coulage direct utilisant la filtration par piles

Info

Publication number
EP1910580A2
EP1910580A2 EP06788060A EP06788060A EP1910580A2 EP 1910580 A2 EP1910580 A2 EP 1910580A2 EP 06788060 A EP06788060 A EP 06788060A EP 06788060 A EP06788060 A EP 06788060A EP 1910580 A2 EP1910580 A2 EP 1910580A2
Authority
EP
European Patent Office
Prior art keywords
filter
molten material
vessel
filters
heating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06788060A
Other languages
German (de)
English (en)
Inventor
Thomas J. Todaro
David O. Warren
David A. Lazor
Karl J. Schwenk
Michael W. Kohler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ajax Tocco Magnethermic Corp
Original Assignee
Ajax Tocco Magnethermic Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ajax Tocco Magnethermic Corp filed Critical Ajax Tocco Magnethermic Corp
Publication of EP1910580A2 publication Critical patent/EP1910580A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/02—Refining by liquating, filtering, centrifuging, distilling, or supersonic wave action including acoustic waves
    • C22B9/023—By filtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D43/00—Mechanical cleaning, e.g. skimming of molten metals
    • B22D43/001—Retaining slag during pouring molten metal
    • B22D43/004—Retaining slag during pouring molten metal by using filtering means
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the invention relates generally to the casting of molten metals or other molten/liquid materials. More particularly, the invention relates to a filtration system used for such melting and casting. Specifically, the invention relates to a filtration system wherein the filters are preheated to a temperature similar to a pouring temperature of the molten material to prevent breakage of the filters due to thermal shock and frozen metal clogging associated with temperature filtration.
  • master melt alloy is re-melted in a melting vessel and poured directly into an invested shell.
  • a filter is placed in the pour cup or mold cup of the invested shell to help reduce the amount of resultant inclusions in the cast component.
  • the filter is maintained at or close to the shell temperature, which is significantly lower than the alloy pour temperature and thus can negatively effect the pour temperature and if the alloy freezes, the filters can become clogged. Because of the difference in temperatures, thermal shock can occur and cause fragments of the filter to break off and enter the shell of the mold.
  • filter pore size must be relatively large so as not to impede the flow of metal into the shell.
  • ceramic fiber gaskets are used to seal the filter within the pour cup. The fibrous nature of these gaskets can also contribute to inclusions within the cast component. Such problems greatly reduce the overall effectiveness of pour cup filtering.
  • in-line gate filtering can be employed in the casting of equiaxed components. In this method, ceramic filters are placed in the metal feed runners of the mold. This type of system requires that the mold be configured so that a filter can be placed in the gating either during wax set up or after wax removal.
  • the filters are held at shell temperatures and can be thermally shocked when the molten alloy is poured through them.
  • the filters at these shell temperatures can negatively effect the pour temperature and clog the filters if the alloy freezes. Again the filter pore size needs to be large so as not to effect the fill rate.
  • the material used to affix the filter in place may be a contaminant as well.
  • molten metal is poured from a melting vessel into a tundish that filters and funnels the alloy into a fixed solidification mold, tube or pig.
  • the tundishes are typically equipped with coarse filters, in conjunction with alternating dams and weirs, over and under which the molten material respectively flows.
  • the tundish assembly is radiantly preheated off-line from the melt system and often to a temperature lower than the alloy pour temperature, and then moved into a pouring position where the tundish assembly is not further heated. Because the temperature of the tundish is lower than the alloy pour temperature, filtration needs to be coarse.
  • any interruption in pouring may cause the system to freeze prematurely, resulting in the need to replace the tundish or eliminate its use for the remainder of the pour.
  • the tundish assembly is preheated offline and then moved into the pouring position without additional heating, this configuration and method would not allow for the use of fine filters.
  • the present system and method addresses this problem and is particularly useful for large equiaxed castings.
  • the present invention may be employed on directionally solidified castings and master melt production as well as with essentially any type of molten material.
  • the present invention provides a method comprising the steps of preheating at least one filter to a filter temperature which will prevent breakage of the filter due to thermal shock from contact with molten material; and passing molten material through the at least one filter.
  • the present invention further provides a method comprising the steps of passing molten material through at least one filter disposed within a filter vessel; heating the at least one filter with a heat source other than the molten material during the step of passing to facilitate flow of the molten material through the at least one filter; and transferring filtered molten material from the filter vessel into a containing vessel.
  • the present invention provides a filtration system which prevent thermal shock of the filters, prevents the freezing of the molten material within the filters to prevent clogging thereof, minimizes or eliminates negative effects to the pour temperature to thus maintain a desired pour temperature, and removes impurities ranging even to extremely small sizes.
  • Fig. 1 is a sectional view of a first embodiment of the casting and filtration system of the present invention as viewed from the side.
  • Fig. 2 is similar to Fig. 1 and shows molten material being poured into the filter vessel, moving through the filters therein and pouring into the pour cup and sprue system into a pair of molds.
  • Fig. 3 is a view similar to Fig. 1 of a second embodiment of the casting and filtration system of the present invention.
  • Fig. 4 is a view similar to Fig. 1 of a third embodiment of the casting and filtration system of the present invention.
  • a first embodiment of the casting system of the present invention is indicated generally at 100 in Figs. 1-2; a second embodiment is indicated generally at 300 in Fig. 3; and a third embodiment is indicated generally at 400 in Fig. 4.
  • Casting system 100 includes a pouring vessel 102 which is often a melting crucible, a filtration system or assembly 104 disposed below vessel 102, a transferring system or shell or assembly 106 disposed below assembly 104 and first and second containing vessels in the form of molds 108 and 110 disposed below transferring assembly 106.
  • assembly 106 and molds 108 and 110 are a single assembly.
  • Pouring vessel 102 defines a cavity 112 for containing molten material.
  • Vessel 102 is typically either a main melt furnace in which material is melted or a refining hearth which receives molten material from the main melt furnace.
  • Pouring vessel 102 is disposed above filtration assembly 104 for pouring molten material into assembly 104 via any manner known in the art, such as bottom pouring, overflow pouring or tilting.
  • a heat source 113 is positioned for melting material within cavity 112 of vessel 102 or within a melting furnace which pours molten material into cavity 112.
  • Heat source 113 may be any suitable heating mechanism to include, for example, a plasma torch, an arc electrode, an electron beam apparatus, an inductive heating assembly, a resistance heating assembly and so forth.
  • filtration assembly 104 is located outside of assembly 106 and includes first, second and third filters 114, 116 and 118 which are spaced from one another and are heatable to a temperature which will prevent them from breaking due to thermal shock when molten material is poured therethrough.
  • Filters 114, 116 and 118 may be formed of any suitable material which is appropriate to the temperature at which they will be used and the type of molten material which will be poured therethrough, along with other pertinent environmental factors.
  • the material of which the filters are made is typically based on compatibility with the molten material, affinity for the capturing of dross and potentially for chemical cleaning and stabilization.
  • Filters 114, 116 and 118 may, for example, be formed of ceramic materials such as alumina, mullite, silica, zirconia, calcia, titania and yittria. They may also be formed of various metals, graphite, carbon composites, resins, oxides, nitrides and so forth. Where appropriate, the filters may be used as a susceptor, as later explained, in which case the filters may be formed of such materials as graphite, an alumina-graphite mix, a silica-graphite mix, a clay- graphite, a silicon-carbide or other materials suitable to the purpose.
  • first filter 114 has an upper surface 140 and a lower surface 142 defining therebetween a first constant thickness T1.
  • Filter 114 also has an outer perimeter 144.
  • second filter 116 has an upper surface 146 and a lower surface 148 defining therebetween a constant thickness T2.
  • Filter 116 also has an outer perimeter 150.
  • third filter 118 has an upper surface 152 and a lower surface 154 defining therebetween a constant thickness T3.
  • Third filter 118 also has an outer perimeter 156.
  • each of filters 114, 116 and 118 have constant thicknesses T1 , T2 and T3 which are the same as one another. However, this may vary as desired for the purposes for which the filters are used.
  • the thicknesses T1 , T2 and T3 are not necessarily constant, but may vary across the respective filters.
  • the filtration capability of the filters grows increasingly finer from top to bottom so that second filter 116 is finer than first filter 114 and third filter 118 is finer than second filter 116.
  • the size of the pores used with such filters may vary greatly. For example, for rather coarse filtering, pores which are approximately one inch across may be used while on the other end of the scale, filters having pores similar to that of tissue paper may be used.
  • the filtration capacity of a given filter is commonly measured in pores per inch (ppi), which means pores per linear inch. Filters ranging from 5 ppi to 70 ppi are reasonably common.
  • first filter 114 may be approximately 10 ppi
  • second filter 116 may be approximately 20 ppi
  • third filter 118 may range from 30 to 45 ppi.
  • filters which are extremely fine may be used.
  • filters 114, 116 and 118 are disposed within a passage 120 formed in a filter vessel 122.
  • Passage 120 has an entrance opening 124 adjacent an upper end 126 of filter vessel 122 and an exit opening 128 adjacent a lower end 130 of vessel 122.
  • Passage 120 of filter vessel 122 includes an upper reservoir 121 disposed above first filter 114.
  • Filter vessel 122 includes a sidewall 132 having an inner surface 134 and an outer surface 136. Commonly, sidewall 132 is substantially cylindrical but may have any shape which is suitable to the purpose.
  • Adjacent lower end 130, a shelf 138 is disposed adjacent sidewall 132 inwardly thereof. Shelf 138 may be formed integrally with sidewall 132 and preferably extends in a continuous manner all the way around and in abutment with inner surface 134 of sidewall 132.
  • the respective outer perimeters 144, 150 and 156 of filters 114, 116 and 118 are all of a mating configuration with inner surface 134 of sidewall 132.
  • Third filter 118 is seated on shelf 138 with lower surface 154 of filter 118 contacting shelf 138 adjacent outer perimeter 156 of filter 118.
  • Second filter 116 is spaced upwardly from third filter 118 by a distance D1 , which is more particularly defined between upper surface 152 of third filter 118 and lower surface 148 of second filter 116.
  • first filter 114 is spaced upwardly from second filter 116 by a distance D2, which is more particularly defined between upper surface 146 of second filter 116 and lower surface 142 of first filter 114.
  • filtration assembly 104 includes first and second spacers 158 and 160 disposed within passage 120 of filter vessel 122 so that first spacer 158 spaces second and third filters 116 and 118 from one another and second spacer 160 spaces first and second filters 114 and 116 from one another.
  • first spacer 158 has a sidewall 162 having an outer surface 164 and an inner surface 166 defining a passage 168 extending from a top 170 to a bottom 172 of first spacer 158.
  • outer surface 164 of first spacer 158 is of a mating configuration with inner surface 134 of sidewall 132 of filter vessel 122.
  • First spacer 158 at bottom 172 thereof is seated atop third filter 118 along upper surface 152 adjacent outer perimeter 156.
  • Second filter 116 is seated along lower surface 148 adjacent outer perimeter 150 atop first spacer 158 at top 170 thereof.
  • second spacer 160 has a sidewall 174 having an outer surface
  • first spacer 158 has a height equal to distance D1 and second spacer 160 has a height equal to distance D2.
  • Distances D1 and D2 may or may not be the same as one another depending on the desired spacing to be set between the various filters, as will be detailed further below.
  • Filtration assembly 104 further includes a host vessel 186 within which filter vessel 122 is disposed. More particularly, host vessel 186 includes a sidewall 188 having an outer surface 190 and an inner surface 192 defining a passage 194 extending from a top 196 to a bottom 198 of host vessel 186. Inner surface 192 of sidewall 188 of host vessel 186 is of mating configuration with outer surface 136 of sidewall 132 of filter vessel 122 so that filter vessel 122 is disposed within passage 194 of host vessel 186 with said outer surface 136 in abutment with said inner surface 192.
  • Filtration assembly 104 further includes a susceptor 200 including a sidewall 201 having an inner surface 202 which defines a passage 204 extending from a top 206 to a bottom 208 of susceptor 200.
  • Host vessel 186 is disposed within passage 204 of susceptor 200 with outer surface 190 of sidewall 188 in abutment with inner surface 202 of sidewall 201 of susceptor 200.
  • host vessel 186, filter vessel 122, filters 114, 116 and 118 and spacers 158 and 160 form a removable cartridge. The cartridge may be quickly removed or changed out for several purposes, to include a change in the material being melted within system 100, in order to change the flow control of a given set of filters, or when the filters have met their intended service life.
  • Filtration assembly 104 further includes an induction coil 210 surrounding susceptor 200 and a power source 212 in electrical communication with induction coil 210 for powering induction coil 210.
  • element 210 may represent a resistive heating element which is powered by power source 212.
  • a heat source 214 may be used in place of element 210 and power source 212 depending on the environment in which system 100 is used. Heat source 214 may, for example, be a gas-burning heat source.
  • Filtration assembly 104 further includes a cover 216 at least a portion of which is moveable in order to provide access to entrance opening 124 of filter vessel 122 so that molten material may be poured from pouring vessel 102 into passage 120 of filter vessel 122.
  • cover 216 may have a door which is moveable to an open position to allow access to the entrance opening.
  • cover 216 may be moveable between closed and open positions or may be removable entirely in order to provide such access to entrance opening 124.
  • Transferring assembly 106 includes a pour cup or mold cup 218 and a sprue system 220 disposed below pour cup 218.
  • Pour cup 218 defines a cavity 222 which is in fluid communication with passage 120 of filter vessel 122.
  • Pour cup 218 defines a lower exit opening 224 in fluid communication with cavity 222.
  • Sprue system 220 defines a main channel or passage 226 in fluid communication with exit opening 224 of pour cup 218, with main passage 226 dividing into first and second branch passages 228 and 230 having respective exit openings 232 and 234.
  • Containing vessels or molds 108 and 110 define respective cavities 236 and 238 which are respectively disposed below and in fluid communication with exit openings 232 and 234.
  • system 100 may include a heat source 239 for that purpose.
  • Heat source 239 may be any heating mechanism known in the art, to include an inductive or resistance heating assembly or a gas burning source. While containing vessels 108 and 110 are shown as molds, they may also be other types of vessels for containing molten material, such as a tundish/vessel from which semi-conductor crystals may be pulled.
  • Heat source 113 is operated to melt material to form molten material 240 and to heat molten material 240 to a pouring temperature.
  • molten material 240 is poured or otherwise transferred through preheated filters 114, 116 and 118 in order to filter molten material 240 to whatever degree is suitable for the particular purpose. More particularly, cover 216 is moved or removed from above filter vessel 122 and molten material 240 is poured from pouring vessel 102 into passage 120 of filter vessel 122 via entrance opening 124.
  • molten material 240 such as molten metal or a metal alloy, is poured into upper reservoir 121 and then passes from reservoir 121 through first filter 114 into passage 180 of second spacer 160 as indicated by Arrows A. Molten material 240 then flows from passage 180 through second filter 116 and into passage 168 of first spacer 158 as indicated by Arrows B. Molten material 240 then flows from passage 168 through third filter 118 and out of passage 120 via exit opening 128 into cavity 222 of pour cup 218 as indicated at Arrows C. Molten material then flows from cavity 222 into main passage 226 and branch passages 228 and 230 of sprue system 220 and into respective molds 108 and 110 as indicated by Arrows D and E.
  • molten material 240 such as molten metal or a metal alloy
  • power source 212 is operated to pass an electrical current through induction coil 210 which then electromagnetically couples with susceptor 206 to inductively heat susceptor 206. Heat created within susceptor 206 is then transferred via host vessel 186 and filter vessel 122 to filters 114, 116 and 118. This is most preferably done while cover 216 is in the closed position covering filter vessel 122, as shown in Fig. 1. Alternately, where filters 114, 116 and 118 are of a suitable material to act as susceptors themselves, induction coil 210 may electromagnetically couple directly with the filters in order to heat them inductively in a direct manner.
  • element 210 may also be a resistive heating element so that power source 212 may send an electrical current through the resistive heating element 210 in order to produce heat which may be transferred to filters 114, 116 and 118.
  • susceptor 206 would not be needed.
  • alternate heat source 214 may be used in order to heat filters 114, 116 and 118.
  • the filters 114, 116 and 118 are heated to a temperature which will prevent them from breaking due to thermal shock when molten material 240 is poured onto and through said filters.
  • Molten material 240 is melted and heated to its pouring temperature via heat source 113 independently of the preheating of filters 114, 116 and 118.
  • cover 216 is moved to its open position to allow the pouring of molten material 240.
  • the temperature to which filters 114, 116 and 118 are heated is approximately the same as the pouring temperature of molten material 240.
  • the preheated temperatures of said filters may vary to some degree while allowing them to avoid breakage due to thermal shock.
  • the range of the preheated temperature of the filters may be fairly narrow or somewhat broader.
  • the filters will be heated to within 75°F above or below the pouring temperature of molten material 240. More preferably, the preheated temperature will be within 5O 0 F of the pouring temperature and even more preferably within 25 0 F of the pouring temperature of the molten material.
  • any suitable temperature above the pouring temperature may be used, especially with regard to maintaining fluidity of molten material 240.
  • system 100 is configured so that filters 114, 116 and 118 may be heated independently of the temperature of the molds 108 and 110, which are typically heated via heat source 239 to desired temperatures as well.
  • the preheated temperature of molds 108 and 110 will vary, as previously discussed in part in the Background section of the present application.
  • said filters are also heated throughout the melting process in order to maintain fluidity of molten material 240 through the filters. This is especially important to allow for the use of finer filters.
  • filtration assembly 104 Another advantage of filtration assembly 104 is the ability to produce a head 242 of molten material 240 within filter vessel 122.
  • head 242 of molten material 240 is disposed within reservoir 121 of passage 120 of filter vessel 122.
  • Head 242 may be formed using a single filter by selecting a filter having a suitable pore size to appropriately control the flow rate.
  • filters 114, 116 and 118 are spaced at suitable distances D1 and D2 from one another and specific pore sizes are chosen for each of said filters in order to control the flow rate in a desired manner.
  • the molten material 240 which is disposed between first and second filters 114 and 116 and between second and third filters 116 and 118 it will preferably fill the respective spaces between said filters. That is, passage 168 of first spacer 158 and passage 180 of second spacer 160 is preferably completely filled with molten material 240 during the pouring process. However, heads of molten material 240 similar to head 242 may also be formed between first and second filters 114 and 116 and/or between second and third filters 116 and 118 so that multiple heads may be formed. Head 242 is disposed above first filter 114 so as to allow dross 244 and other like contaminants to flow out of the alloy or other molten material atop head 242.
  • Maintaining head 242 throughout the melting process thus allows the dross to remain on the top and then at the end of the pour to be captured before it enters molds 108 and 110. More particularly, dross 244 will ultimately remain in structure above said molds, more particularly within pour cup 218 or sprue system 220. Thus, dross 244 does not contaminate the molded bodies produced by molds 108 and 110.
  • Filters 114, 116 and 118 may be used with a pressurized system if desired. As is well known, filtering surface area, pressure and degree of filtration determine flow rate and these may be tailored to a particular application of system 100. A variety of advantages are readily noted with the use of system 100. It reduces the number of inclusions and castings as compared to conventional systems. It eliminates the need for fixing agents such as glues in order to hold filters in place, and thus eliminates contamination from such fixing agents. The use of filtration assembly 104 allows pour cup 218 and sprue system 220 to be free of filters and eliminates the need for filters elsewhere within system 100.
  • filtration assembly 104 may be used with another such filtration assembly or a plurality of other such filtration assemblies wherein each assembly 104 may be stacked on top of another in order to provide additional filtration during the pouring process.
  • filtration assembly 104 may be adapted for use with a centrifugal apparatus so that the molten material is not necessarily gravity fed nor fed by a pressurized atmosphere. Thus, the molten material does not necessarily flow downwardly through the filters although this would be the case in the embodiments as shown.
  • filters may be chosen which are suited to the removal of microscopic particles. For instance, filters having a high surface area and a high affinity for gases or other constituents may be used to remove said gases or other constituents from the molten material as it flows through the filters.
  • System 300 (Fig. 3) is similar to system 100 except for the configuration of the filter vessel and the filters and the elimination of spacers between filters.
  • the pouring vessel and heat sources for the pouring vessel and molds are also not shown for simplicity.
  • system 300 includes a filtration assembly 304 which includes first, second and third filters 314, 316 and 318 and a filter vessel 322.
  • First filter 314 has an upper surface 340, a lower surface 342 and an outer perimeter 344.
  • First filter 314 has a width W1 which is equivalent to a diameter thereof when first filter 314 is circular when viewed from above.
  • second filter 316 has an upper surface 346, a lower surface 348 and an outer perimeter 350.
  • Second filter 316 also has a width W2 which is smaller than width W1 of first filter 314 and corresponds to a diameter when second filter 316 is circular when viewed from above.
  • Third filter 318 has an upper surface 352, a lower surface 354 and an outer perimeter 356 and a width W3 which is smaller than width W2. Width W3 also corresponds to a diameter when third filter 318 is circular when viewed from above.
  • Filter vessel 322 defines a passage 320 analogous to passage 120 of filter vessel 122 except that it is a stepped passage. More particularly, filter vessel 322 defines a passage 320 having an entrance opening 324 at an upper end 326 of filter vessel 322 and an exit opening 328 at a lower end 330 of vessel 322. Filter vessel 322 has a stepped sidewall 332 having a stepped inner surface 334 and an outer surface 336 which is substantially the same as outer surface 136 of filter vessel 122 and bears the same relation with respect to host vessel 186. Sidewall 332 has an upper first section 358 and a second section 360 disposed therebelow with an inwardly extending first shelf 362 therebetween whereby inner surface 334 of sidewall 332 is stepped inwardly.
  • Second section 360 is thicker than first section 358.
  • Sidewall 332 further includes a third section 364 disposed below second section 360 with an inwardly extending second shelf 366 therebetween whereby inner surface 334 is further stepped inwardly.
  • Third section 364 is thicker than second section 360.
  • Sidewall 332 further includes a lowerfourth section 368 disposed below third section 364 with an inwardly extending third shelf 370 disposed therebetween whereby inner surface 334 is stepped further inwardly.
  • passage 320 of filter vessel 322 includes an upper first section 372 disposed above first shelf 362 which has a width which is substantially the same as or slightly larger than width W1 of first filter 314.
  • Passage 320 further includes a second section 374 below first section 372 which is disposed between first shelf 362 and second shelf 366 and has a width which is substantially the same as or slightly larger than width W2 of second filter 316.
  • Passage 320 further includes a third section 376 below second section 374 which is disposed between second shelf 366 and third shelf 370.
  • Third section 376 has a width which is substantially the same as or slightly larger than width W3 of third filter 318.
  • Passage 320 further includes a fourth section 378 disposed below third section 376 or in other words disposed below third shelf 370.
  • Fourth section 378 has a width W4 which is smaller than width W3 of third filter 318.
  • first filter 314 is disposed within first section 372 of passage 320 with lower surface 342 seated atop first shelf 362 of sidewall 332.
  • Outer perimeter 344 of first filter 314 is disposed closely adjacent or in abutment with inner surface 334 just above first shelf 362.
  • Width W1 may be selected so that first shelf 314 may be placed atop first shelf 362 without force or shelf 314 may be press fit into first section 372 of passage 320 so that it is held snugly in place with outer perimeter 344 frictionally engaging inner surface 334 of sidewall 332.
  • second filter 316 is disposed within second section 374 of passage 320 with lower surface 348 thereof seated atop second shelf 366 of sidewall 322.
  • second filter 316 may be placed with or without frictional engagement between outer perimeter 350 thereof and inner surface 344.
  • third filter 318 is disposed in third section 376 of passage 320 with lower surface 354 thereof seated atop third shelf 370 of sidewall 332.
  • third filter 318 may be seated with or without frictional engagement between outer perimeter 356 of third filter 318 and inner surface 334 of sidewall 332.
  • the operation of system 300 is essentially the same as system 100 and is therefore described only with regard to distinctions from system 100. It is noted, however, that the stepped passage 320 and differing widths of filters 314, 316 and 318 will require different calculations for controlling the flow rate of molten material through filter vessel 322.
  • Casting system 400 (Fig. 4) is similar to system 300 except for the configurations of the filters, the filter vessel and the host vessel, and the elimination of the sprue system whereby the pour cup is seated atop a single cavity.
  • system 400 includes a filtration assembly 404 which includes first, second and third filters 414, 416 and 418 each disposed in a passage 420 of a filter vessel 422.
  • Passage 420 includes an entrance opening 424 adjacent an upper end 426 of vessel 422 and an exit opening 428 adjacent a lower end 430 of vessel 422.
  • Vessel 422 includes a frustoconical sidewall 432 having a frustoconical inner surface 434 defining passage 420 and a frustoconical outer surface 436.
  • Sidewall 432 tapers inwardly and downwardly, as do inner and outer surfaces 434 and 436.
  • First filter 414 has an upper surface 440, a lower surface 442 and an outer perimeter 444 which tapers inwardly and downwardly in mating relation to tapered inner surface 434 of sidewall 432.
  • second filter 436 has an upper surface 446, a lower surface 448 and an outer perimeter 450 which tapers inwardly and downwardly in mating configuration with inner surface 434 of sidewall 432.
  • Second filter 416 is spaced downwardly from first filter 414.
  • third filter 418 has an upper surface 452, a lower surface 454 and an outer perimeter 456 which tapers inwardly and downwardly in mating relation to inner surface 434 of sidewall 432.
  • Third filter 418 is spaced downwardly from second filter 416.
  • system 400 thus provides a plurality of filters which are seated on a sidewall of or otherwise disposed within a passage of a filter vessel without the need of any glue or fixing agents to secure the filters therein. While systems 100, 300 and 400 may use glues or other such materials, it is preferred not to do so in order to eliminate any additional contaminants to the molten material.
  • Filtration assembly 404 further includes a host vessel 486 having a inwardly and downwardly tapering frustoconical inner surface 488 and an outer surface 490 which is substantially the same as the outer surface of host vessel 186 and has the same relation with regard to susceptor 206.
  • Inner surface 488 of host vessel 486 is in mating relation with outer surface 436 of sidewall 432 of filter vessel 422.
  • system 400 includes a single mold 402 defining a cavity 404. Pour cup 218 is seated atop mold 402 with cavity 222 thereof in fluid communication with cavity 404 of mold 402.
  • system 400 works in substantially the same manner as described with regard to systems 100 and 300.
  • system 400 shows the use of filtration assembly 404 with a single mold 402, thereby eliminating the use of the sprue system.
  • molten material is poured directly from pour cup 218 into cavity 404 of mold 402.
  • system 400 provides a filtration system in which pour cup 218 is free of filters as is the remainder of the system aside from the filters within assembly 404.
  • systems 100, 300 and 400 provide a filtration system for molten material wherein the filters are preheated to prevent breakage thereof due to thermal shock upon contact by molten material being poured through the filters.
  • these systems provide assemblies which allow for the continued heating of the filters throughout the pouring process in order to maintain the fluidity of the molten material as it passes through the filters to provide a desirable flow rate and to prevent the clogging of the filters.
  • the use of the filtration assemblies disclosed herein are useful in directional solidification and single crystal casting because it allows for the elimination of bottom feed runners and filters therein, which permits the use of tighter baffles and internal chill systems while maintaining good filtration of the re-melt alloy.
  • the filters and filter vessels can be of a variety of shapes, including those shown as well as cubic, hourglass-shaped, torroidal, oval and so forth.
  • the shapes of the host vessel, the susceptor and the induction coil may vary as well.
  • each of the host, susceptor and induction coil could be configured in a substantially frustoconical shape or the like which more closely mimic the shape of the filter vessel and thus reduce the thickness of the host vessel walls adjacent the lower end thereof to allow for more efficient transfer of heat from the susceptor to the filters.
  • the overall size of the filtration assembly can easily be as small as one foot in width and one foot in height, thus illustrating the adaptability of the invention for small spaces and the ease with which such assemblies may be stacked as previously discussed.
  • the size of the filtration assembly varies with the application.
  • the present invention is useful over a very wide range of melting temperatures and pouring temperatures.
  • the melting temperatures of various materials which can be used with the present invention range anywhere from room temperature to upward of 4000 0 F.
  • the temperature range is roughly 2400 0 F to 3200 0 F.
  • the pouring temperature is established by the melting temperature of the given material.

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  • Manufacture And Refinement Of Metals (AREA)

Abstract

L'invention concerne un système de coulage comprenant un ensemble de filtration avec un bac filtrant logeant des filtres espacés préchauffés à une température proche d'une température de versement de matériau fondu à filtrer pour empêcher toute fracture du filtre du fait d'un choc thermique résultant d'un contact avec le matériau fondu. De préférence, une bobine d'induction sert à chauffer par induction un compensateur de dérivation adjacent au bac filtrant ou à chauffer par induction des filtres servant eux-mêmes de compensateurs de dérivation. Typiquement, le bac filtrant est disposé au-dessous d'un bac de versement et au-dessus d'un moule, d'une coupelle de versement et de tout système de coulée utilisé et chauffé indépendamment de celui-ci. Les filtres sont chauffés pendant le versement pour faciliter l'écoulement du matériau fondu à travers ceux-ci et ainsi on peut employer des filtres très fins. L'espacement des filtres augmente le contrôle d'écoulement et permet la formation d'une tête de matériau fondu grâce à quoi les déchets flottent vers le haut de la tête pour empêcher leur entrée dans le moule.
EP06788060A 2005-07-29 2006-07-21 Coulage direct utilisant la filtration par piles Withdrawn EP1910580A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US70383105P 2005-07-29 2005-07-29
US11/359,032 US20070022841A1 (en) 2005-07-29 2006-02-21 Direct casting utilizing stack filtration
PCT/US2006/028308 WO2007015956A2 (fr) 2005-07-29 2006-07-21 Coulage direct utilisant la filtration par piles

Publications (1)

Publication Number Publication Date
EP1910580A2 true EP1910580A2 (fr) 2008-04-16

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EP06788060A Withdrawn EP1910580A2 (fr) 2005-07-29 2006-07-21 Coulage direct utilisant la filtration par piles

Country Status (3)

Country Link
US (1) US20070022841A1 (fr)
EP (1) EP1910580A2 (fr)
WO (1) WO2007015956A2 (fr)

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CN1320139C (zh) * 2005-07-28 2007-06-06 上海交通大学 金属液多级电磁净化方法
CN102615248A (zh) * 2012-04-26 2012-08-01 苏州科羽电子技术服务有限公司 一种铸件的生产工艺
CN104334758B (zh) * 2012-04-27 2016-12-28 挪威科技大学 用于灌注熔融金属过滤器的装置和方法
WO2018050751A1 (fr) 2016-09-16 2018-03-22 Technische Universität Bergakademie Freiberg Procédé de purification d'un métal en fusion dans un four à induction
JP6471815B1 (ja) * 2018-01-25 2019-02-20 不二製油株式会社 ストレーナ装置
US20190252509A1 (en) * 2018-02-09 2019-08-15 Semiconductor Components Industries, Llc Electronic device including a conductive layer including a ta-si compound and a process of forming the same
US12059643B2 (en) * 2018-09-21 2024-08-13 Pyrotek, Inc. Electromagnetic priming of molten metal filters
CN113770342A (zh) * 2021-08-12 2021-12-10 芜湖泓鹄材料技术有限公司 浇注用铁水过滤装置
CN114082920A (zh) * 2021-11-17 2022-02-25 江西中鼎金属工艺有限公司 一种金属工艺品的铸熔成型设备
CN114941943A (zh) * 2022-05-27 2022-08-26 张子豪 一种用于铜合金的真空感应熔炼炉

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Also Published As

Publication number Publication date
WO2007015956A3 (fr) 2007-09-20
WO2007015956A2 (fr) 2007-02-08
US20070022841A1 (en) 2007-02-01

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