EP0021981A1 - Verfahren und Vorrichtung zum Giessen von Stücken aus geschmolzenem keramischem Material - Google Patents

Verfahren und Vorrichtung zum Giessen von Stücken aus geschmolzenem keramischem Material Download PDF

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Publication number
EP0021981A1
EP0021981A1 EP80400882A EP80400882A EP0021981A1 EP 0021981 A1 EP0021981 A1 EP 0021981A1 EP 80400882 A EP80400882 A EP 80400882A EP 80400882 A EP80400882 A EP 80400882A EP 0021981 A1 EP0021981 A1 EP 0021981A1
Authority
EP
European Patent Office
Prior art keywords
mold
liquid
bath
supply duct
container
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Withdrawn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
EP80400882A
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English (en)
French (fr)
Inventor
Jacques Le Clerc De Bussy
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.)
CLERC DE BUSSY LE
Original Assignee
CLERC DE BUSSY LE
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 CLERC DE BUSSY LE filed Critical CLERC DE BUSSY LE
Publication of EP0021981A1 publication Critical patent/EP0021981A1/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/54—Producing shaped prefabricated articles from the material specially adapted for producing articles from molten material, e.g. slag refractory ceramic materials

Definitions

  • the present invention relates to a process for molding parts made of ceramic materials melted at high temperature.
  • the invention is particularly applicable to obtaining parts obtained from ceramic materials which are liquid at a temperature above 1500 ° C., which has a limited pasty melting range or a frank melting, and which crystallize during the cooling.
  • mullite formed of 70% by weight of A.1 2 0 3 approximately and 30% of Si0 2 , which melts around 1800-1850 °, and certain refractories based on Si0 2 - A1203-ZrO2 which melt around 1750 ° C.
  • These ceramic materials melted at high temperature based on various oxides such as alumina, silica, magnesia, zirconia, etc. are distinguished by remarkable resistance to pressure and or to abrasion, as well as by their refractory properties.
  • the object of the present invention is to provide a method and a device which allow the industrial production of pieces of ceramic material melted at high temperature, these pieces being of small dimensions and, possibly, of complicated shape.
  • the invention provides a method of molding parts made of molten ceramic materials, from an oxide bath maintained in the liquid state in an oven and permanently covered with a layer of pulverulent raw material.
  • ovens are the only ovens currently used, because the layer of powdery raw material which overhangs the bath limits energy losses.
  • the oven is normally of the "self-filling" type, that is to say that its walls and its bottom, made of cooled metal, are permanently separated from the liquid by an insulating and protective layer of solidified ceramic material. Heating is usually provided by passing an electric current through the bath, this current being supplied by immersion electrodes. In the central part of the furnace, these electrodes being of refractory metal and inert with respect to the bath.
  • the internal vacuum of the mold is connected by its lower part, to a supply duct directed downwards and cooled, the pulverulent material is removed over a limited area of the surface of the bath by expelling it with a gas jet directed from top to bottom, then the supply duct is lowered to this zone devoid of pulverulent material and it is made to penetrate into the liquid bath, then a depression is established in the mold which causes the liquid from the bath to rise in the conduit and in the mold.
  • the gas jet is passed through the supply conduit by creating an overpressure in the mold during the phases of the operation which precede the establishment of the vacuum.
  • the method reconciles the advantages of direct casting, namely a short and straight supply duct, and those of source casting, namely a peaceful arrival of the liquid in the mold without risk for the walls of the mold.
  • the problem posed by the passage of the pulverulent material which overcomes the bath, and which would risk having the entry of unmelted material into the mold, is resolved by the overpressure of compressed air.
  • the supply duct makes its hole in the pulverulent layer, which closes around it during molding, which minimizes heat loss.
  • the process makes it possible, in an extremely simple manner, to obtain hollow bodies, with walls of constant or variable thickness; for this, the vacuum in the mold is interrupted before the liquid is frozen in the channel, so that the liquid is emptied. We can thus obtain pieces in the form of tubes, crucibles, etc.
  • the thickness of the walls can be varied locally.
  • the mold proper 1 is made of silica sand agglomerated with sodium silicate;
  • a sand having a particle size of 50 to 120 micrometers was used, agglomerated with approximately 3% of sodium silicate, to which is added, before implementation, approximately 5 to 6% of an organic hardener. Trade.
  • the molds obtained, after baking at 400-500 ° C, have a porosity of about 35 to 43% by volume. It is clear that the grain size of the sand, the nature, the rate of the binder and the thickness of the mold depend on the refractory raw material used and the material of the product. we want to get.
  • the mold is armed with an external metal mesh so as to allow it to withstand the hydrostatic pressure.
  • a base 2 of the same material, contains a connection part 3 which connects the internal vacuum of the mold 1 to that of the supply channel 4.
  • a mold cover 5 contains a cavity 6, which communicates with the internal vacuum of the mold and which is intended to serve as a flyweight.
  • the assembly is supported by a metal ferrule 7, with the interposition of a thick layer of Kieselguhr 8, intended to serve as thermal insulation and to provide cooling as slow as desired.
  • a spring 9 maintains constant pressure on each other the cover 5, the mold proper 1 and the base 2.
  • the ferrule 7 is placed inside a removable bell 10 constituting a closed and sealed enclosure, connected by a pipe 11 to a source of vacuum and gas pressure, not shown. It has been found that the permeability of the mold is sufficient for the pressure inside the mold to faithfully follow the variations in pressure in the bell 10.
  • FIG. 2 describes in more detail the supply channel or "squeegee" 4.
  • This in its main part, is formed of a copper tube 12, pierced with an axial frustoconical bore which widens upwards.
  • a second concentric tube 13 defines with the tube 12 a water chamber 14 divided into two concentric parts by a cylindrical partition 15 which does not descend to the bottom of the chamber.
  • the two parts of the water chamber are respectively connected to a con supply line 16 and a discharge pipe 17 for the cooling water. All of these parts are made of copper.
  • the “squeegee” is held by a support 18, fixed on the base of the bell 10, by means of springs 19, which press it upwards against the base 2 of the mold, so as to prevent the outflow of liquid.
  • a flexible seal 20 connects the base 2 of the bell with the tube 12, so that the bell and the tube constitute a gas-tight assembly, with no other opening than the tube 11 and the bore of the tube 12 of the nozzle.
  • the nozzle nozzle is an annular piece 21 of molybdenum which screws into the tube 13 to come to bear on the tube 12. It has an internal bore 22 which is frustoconical and widens downwards, its smallest diameter is slightly lower than that of the tube 12 at the point of contact, and the part 21 has an acute edge at this point.
  • the reason for this arrangement is as follows: after the nozzle has left the bath, a solidified mass is formed which includes the material which is in the tube 12 and the nose 21, as well as a certain quantity of material which s flourishes on the lower end of the nose.
  • nozzles were used whose minimum diameter was 20 or 25 mm for mullite and 17 mm for a refractory based on silica-alumina-zirconia.
  • the operating mode is as follows: the mold 1 is prepared with its wire mesh, then placed in the shell 7, with its base 2 and its cover 5. The shell is then placed in the bell 10 in which the supply duct 4 is already in place. The different parts of the mold and the conduit 4 are then clamped against each other by the action of the springs 9 and 19. The bell is then suspended by a chain 23 in which a load cell 24 is inserted, and we send, by the 'intermediate of the.-pipe 11, a slight air flow in the bell. This air passes through the mold and exits through the nozzle 4. The assembly is then lowered towards the bath of molten product 25, which is located in an electric oven of conventional type. The air flow drives out the pulverulent material 26 which overhangs the bath, exposing the surface of the bath over a small area, then the nose enters the bath itself.
  • the depth of insertion of the nozzle nozzle must be sufficient to reach an area where the bath is homogeneous and bubble-free, and to prevent any suction of air during filling of the mold.
  • the squeegee should not be pushed too deep to avoid excessive local cooling of the bath.
  • the final depression must be such that the liquid bath rises at least to the top of the cavity 6, to constitute the flyweight.
  • a lower vacuum would cause imperfect filling, but a higher vacuum, as well as a vacuum introduced too suddenly, can cause the cover 5 to be lifted by the liquid, in opposition to the spring 9.
  • the mold 1 Once the mold 1 is filled, it suffices to hold the assembly in place for a few moments and under vacuum provided the liquid freezes in the supply duct 4. It has in fact been observed that this freezing does not occur as long as the liquid circulates in this conduit to fill the mold, but it solidifies there with a high speed, variable however according to the products, as soon as circulation is interrupted.
  • the filling of the mold is noted appreciably by the load cell 24, which gives the weight of the whole of the bell of the mold and of the product which fills it. It will be noted that the control of the air flow through the pipe 11 would be too imprecise due to the gradual heating of the air which is in the porosity of the mold and of the Kieselguhr.
  • the bell is raised above the bath and then driven away from the oven.
  • This orifice can be provided for this purpose with a calibrated valve.
  • the nose 21 is unscrewed, and the bell 10 is opened.
  • the ferrule 10 which contains the mold 1 is extracted upwards therefrom, to which a frustoconical rod of material which has solidified in the bore of the tube remains attached.
  • the juice is cooled mold - to complete solidification and return to a temperature allowing its removal, however, the bell can be charged with another shell containing another mold for a new operation.
  • the cavity 6 of the cover which is intended to form a counterweight, is no longer necessary and the cover 5 can optionally be removed to facilitate the descent of the liquid.
  • the vacuum is interrupted after filling the mold to the desired height but before the material solidifies in the nozzle. The liquid then flows towards the bath, leaving a solidified layer of a thickness which can be determined with precision by preliminary tests fixing the duration of stay of the liquid in the mold.
  • the liquid must not rise to the cover, if the latter is preserved, because there would then form on the inner surface of the latter a solidified layer, little or not permeable, which would oppose the interruption of depression, and therefore the redascente of the liquid.
  • hollow objects of small thickness are obtained by using a nozzle which operates in the manner of a paint sprayer; this nozzle has a small diameter bore for the liquid and, moreover, preferably, an air inlet, for example nozzles arranged in an annular manner, and of controlled flow.
  • the vacuum is produced very suddenly, and a spray of the liquid is then formed in the form of fine droplets which come to coat the wall of the mold and solidify there in a thin layer.

Landscapes

  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing Of Tubular Articles Or Embedded Moulded Articles (AREA)
  • Mold Materials And Core Materials (AREA)
EP80400882A 1979-06-18 1980-06-17 Verfahren und Vorrichtung zum Giessen von Stücken aus geschmolzenem keramischem Material Withdrawn EP0021981A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7915485A FR2459212A1 (fr) 1979-06-18 1979-06-18 Procede et dispositif de moulage de pieces en matiere ceramique fondue
FR7915485 1979-06-18

Publications (1)

Publication Number Publication Date
EP0021981A1 true EP0021981A1 (de) 1981-01-07

Family

ID=9226715

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80400882A Withdrawn EP0021981A1 (de) 1979-06-18 1980-06-17 Verfahren und Vorrichtung zum Giessen von Stücken aus geschmolzenem keramischem Material

Country Status (3)

Country Link
US (1) US4374799A (de)
EP (1) EP0021981A1 (de)
FR (1) FR2459212A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2625495A1 (fr) * 1987-12-28 1989-07-07 Ppg Industries Inc Traitement prealable de refractaires coules a l'etat fondu

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1332513C (en) * 1987-04-02 1994-10-18 Yoshihiro Nakai Superconductor and method of manufacturing the same
US5042561A (en) * 1988-03-30 1991-08-27 Hitchiner Manufacturing Co., Inc. Apparatus and process for countergravity casting of metal with air exclusion
CN112895070B (zh) * 2021-01-15 2022-11-01 都江堰瑞泰科技有限公司 一种熔融氧化铝砖胚的负压成型工艺、熔融氧化铝砖胚

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE412395C (de) * 1924-04-01 1925-04-21 Eisengiesserei Verfahren zur Herstellung von Formstuecken aus geschmolzenem Gut aller Art
FR752967A (fr) * 1932-07-13 1933-10-04 Saint Gobain Perfectionnement aux procédés et dispositifs de fabrication par fusion des objets creux en matières réfractaires
FR1542536A (fr) * 1967-06-29 1968-10-18 Comp Generale Electricite Procédé de mise en forme de pièces mécaniques et produits ainsi obtenus
LU69059A1 (de) * 1973-04-06 1974-02-22

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1758463A (en) * 1925-01-09 1930-05-13 Petersson Ernst Furnace for casting iron and other difficult fusible metals under pressure
US1953427A (en) * 1933-08-01 1934-04-03 United Glass Bottle Mfg Ltd Method of and means for feeding raw material to glass melting furnaces
US2379401A (en) * 1942-04-16 1945-06-26 American Steel Foundries Method and apparatus for casting metal
US2544598A (en) * 1948-02-28 1951-03-06 Wetherill Engineering Company Metal casting mold
US2828516A (en) * 1955-02-08 1958-04-01 Koppers Co Inc Ladle for casting metal
NL6905546A (de) * 1969-02-28 1970-09-01
US3867132A (en) * 1969-07-11 1975-02-18 Republic Steel Corp Method of deslagging molten metal
US3635791A (en) * 1969-08-04 1972-01-18 Gen Motors Corp Pressure pouring in a vacuum environment
SE364654B (de) * 1971-11-18 1974-03-04 Asea Ab
US3863706A (en) * 1972-12-04 1975-02-04 Hitchiner Manufacturing Co Metal casting
US3862656A (en) * 1973-02-16 1975-01-28 Aurora Metal Corp Method and apparatus for vacuum casting of metal
US3880634A (en) * 1974-04-24 1975-04-29 American Optical Corp Method and apparatus for producing tubing from short glasses
DE2645585C3 (de) * 1976-10-06 1979-08-30 Wolfgang Prof. Dr.-Ing. 1000 Berlin Wuth Verfahren zur kontinuierlichen oder diskontinuierlichen Behandlung von geschmolzenen schwermetalloxidhaltigen Schlacken zur Freisetzung von Wertmetallen und/oder deren Verbindungen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE412395C (de) * 1924-04-01 1925-04-21 Eisengiesserei Verfahren zur Herstellung von Formstuecken aus geschmolzenem Gut aller Art
FR752967A (fr) * 1932-07-13 1933-10-04 Saint Gobain Perfectionnement aux procédés et dispositifs de fabrication par fusion des objets creux en matières réfractaires
FR1542536A (fr) * 1967-06-29 1968-10-18 Comp Generale Electricite Procédé de mise en forme de pièces mécaniques et produits ainsi obtenus
LU69059A1 (de) * 1973-04-06 1974-02-22

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2625495A1 (fr) * 1987-12-28 1989-07-07 Ppg Industries Inc Traitement prealable de refractaires coules a l'etat fondu

Also Published As

Publication number Publication date
FR2459212A1 (fr) 1981-01-09
US4374799A (en) 1983-02-22
FR2459212B1 (de) 1983-05-13

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