US3926248A - Orifice structure for extruding molten metal to form fine diameter wire - Google Patents

Orifice structure for extruding molten metal to form fine diameter wire Download PDF

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Publication number
US3926248A
US3926248A US405388A US40538873A US3926248A US 3926248 A US3926248 A US 3926248A US 405388 A US405388 A US 405388A US 40538873 A US40538873 A US 40538873A US 3926248 A US3926248 A US 3926248A
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United States
Prior art keywords
orifice
molten metal
polycrystalline
density
diameter wire
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US405388A
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English (en)
Inventor
Jerome J English
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.)
Monsanto Co
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Monsanto Co
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 Monsanto Co filed Critical Monsanto Co
Priority to US405388A priority Critical patent/US3926248A/en
Priority to ZA00746443A priority patent/ZA746443B/xx
Priority to SE747412723A priority patent/SE406428B/sv
Priority to FR7434131A priority patent/FR2247297B1/fr
Priority to GB4388574A priority patent/GB1458460A/en
Priority to BE149391A priority patent/BE820909A/xx
Priority to AU74180/74A priority patent/AU7418074A/en
Priority to CA211,210A priority patent/CA1005793A/en
Priority to IT28271/74A priority patent/IT1022755B/it
Priority to DE19742448434 priority patent/DE2448434A1/de
Priority to JP49116239A priority patent/JPS5066430A/ja
Application granted granted Critical
Publication of US3926248A publication Critical patent/US3926248A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/51—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on compounds of actinides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/005—Continuous casting of metals, i.e. casting in indefinite lengths of wire

Definitions

  • the apparatus employed in the practice of these methods is comprised essentially of a crucible having an orifice element in its base, either as a part of the base, or preferably, as an orifice insert.
  • the crucible is further provided with heating means to melt the charge and maintain it in the molten condition.
  • means are provided for applying a positive head pressure to the molten charge to force it through an extrusion orifice at appropriate jet velocities.
  • the materials which comprise the orifice must be highly resistant to thermal shock and have sufficient high temperature strength to withstand the mechanical stresses imparted throughout the course of extrusion.
  • the orifice material must be chemically compatible with the molten charge being extruded. That is, the orifice material should be corrosion and erosion resistant to chemically reactive melts at high temperatures in order to assure dimensional stability of the orifice during operations.
  • an object of this invention to provide an apparatus for extruding molten metals and alloys thereof with an orifice member which can withstand the thermal, mechanical and chemical stresses imposed by the extrusion operation without change in the structural integrity of the orifice.
  • an extrusion apparatus for forming fine diameter wire from molten metal contains an orifice structure which is composed of polycrystalline thorium oxide (ThO having a density of from 9.5 to 10.0 gm/cm and a purity of at least 99.5 percent.
  • the thoria may be in the completely pure form or contain up to 0.5 percent by weight of a sintering agent.
  • the sintering agent or densification aid may be selected from any one of a large number of compounds known to perform this function.
  • FIGURE represents a schematic cross-sectional view of a typical extrusion apparatus wherein molten metals are extruded as filamentary jets to form fine diameter wire.
  • the molten metal charge is contained in crucible 2, having a base plate 3, with the crucible and base plate being supported by pedestal 4.
  • Insulating cylinder 5 and susceptor 6 enclose the crucible 2 and its base plate 3.
  • the heat required for conducting the process is provided by induction heating coils 7.
  • An extrusion head pressure is provided by a pressurized inert gas (source not shown) supplied through gas line 8, which communicates with the interior of the unit through the unit head 9. Sealing rings 10 serve to maintain the pressure within the enclosure and prevent leakage past base plate 3.
  • the molten metal 1 is forced through orifice 11 in orifice plate 12 by the applied head pressure to form a filamentary shaped molten jet.
  • the nascent jet Upon emerging from orifice 11, the nascent jet passes through a film-forming atmosphere contained within cavity 14 of pedestal 4.
  • the film-stabilized molten jet then passes through a cooling column (not shown) where sufficient heat is removed for conversion to the solid state.
  • thoria can be densified to the levels required in the practice of this invention.
  • hot-pressing is fully described at pages 183-230 of the volume titled, High Temperature Oxides, edited by Allen M. Alper and published by the Academic Press of New York and London. Briefly stated, powder-like particles of the ceramic are pressed together and compacted at high pressures and temperatures.
  • the pressures normally employed are in the order of l000l0,000 p.s.i. with the temperatures being generally in the 1500-2000C. range.
  • Another suitable process is disclosed in U.S. Pat. No. 3,574,645.
  • a quantity of fine grained thorium oxide having a particle size of about 0.05 to 2.0 microns is first die pressed at about 10,000 p.s.i. to yield a compacted green body having a density of about 40 to 50 percent of the theoretical density.
  • the green body is then sintered to substantially theoretical density at a temperature of at least about 2000C. in a hydrogen-water vapor atmosphere having a dew point between about 25C. to +25C.
  • the sintering operation is conducted over a time span of about 7 hours.
  • the thoria orifice may consist of 100 percent pure thoria or a composition consisting of thoria and up to 0.5 weight percent of a sintering agent, for example, calcium oxide (CaO).
  • a sintering agent for example, calcium oxide (CaO).
  • the optional densifying aid it may be blended with the thoria particles prior to the pressing operation.
  • Plates or discs of high density, polycrystalline thoria can readily be machined to desired shapes and sizes by methods known to the art. Fine diameter orifices are usually produced by machining a countersink in the feed face of the orifice plate and thereafter drilling and polishing an orifice of the desired diameter concentric with the countersink. The orifice may also be radiused if desired. There may be more than one orifice in any given plate or disc.
  • the orifice defining members may also serve as the base plate for the crucible.
  • the orifice plate insert is generally of a circular configuration and may, if desired, be secured in the base plate by using a clamp or hold-down ring. Multiple orifice insert discs may, of course, be employed in the base plate of the crucible.
  • the orifice should have an aspect ratio of between 1 and 20, preferably less than 10, exclusive of the countersink.
  • EXAMPLE I An extrusion apparatus of the type illustrated in the FIGURE was fitted with an orifice insert disc having a composition consisting of polycrystalline thorium oxide and 0.125 percent by weight of calcium oxide as a densification aid.
  • the orifice capillary entrance was cone-shaped with a vertex angle of about 30.
  • a solid bar of the steel alloy was first placed in the crucible of the apparatus before heating was initiated.
  • the crucible of the apparatus was then heated to a temperature which ranged between about l510-1550C.
  • a second steel alloy bar was slowly fed into the heated crucible through an O-ring seal placed in the head of the pressure chamber (i.e., the bar melted at its tip, with the drippings being directed into the crucible).
  • the chamber was pressurized to about 20 p.s.i.g. This produced a pressure gradient across the thoria orifice insert which forced the molten steel alloy through the capillary orifice.
  • the apparatus continued to stream over a period of 91 hours. This is an exceptionally long spinning run without experiencing orifice failure under such severe conditions.
  • the apparatus was cooled down and the thorium oxide orifice insert was removed for microscopic examination of its microstructure and to take measurements on the extent of dimensional change in the orifice capillary. No cracks or other evidence of structural deterioration from mechanical stress were detected. Moreover, it was found that the diameter of the orifice capillary increased only 0.0007 of an inch over this long spinning run under extreme environmental conditions. This indicated an extraordinary resistance to the highly corrosive effects of molten steel alloys as well as resistance to erosion from the flow of these materials.
  • EXAMPLE II A series of various thoria orifice inserts were tested in the same apparatus and in like manner as described in Example I.
  • the densities of the test orifice discs ranged from between 9.90 to 9.97 gm/cm
  • the diameter of the orifice capillaries in all instances was 0.010 inch.
  • a molten steel alloy charge such as employed in Example I, was streamed through the orifices under the conditions as set forth in Example I for periods of time ranging from between 50 and hours. Following the test runs, measurements were made on the extent of dimensional change in the diameters of the orifice capillaries. It was found that the diameter increases were limited to the range of from 0.0005 inch to 0.003 inch. Upon microscopic examination, there was no indication of structural deterioration as a result of mechanical stress.
  • EXAMPLE III The object of this Example is to provide the test results obtained with an orifice insert of the prior art against which the performance of the high-density thoria inserts of this invention as set forth in Examples 1 and II above were compared.
  • a high density beryllium oxide (BeO) orifice insert was fitted in the crucible plate of the same extrusion apparatus as was employed in Examples I and [1, above.
  • a molten steel alloy charge having a composition as described in the previous Examples was then streamed through the orifice for a period of 3 hours under extrusion conditions corresponding to those as described in Examples I and II.
  • a measurement was made on the dimensional changes in the orifice capillary. It was found that the diameter had increased from an original 0.006 inch to 0.011 inch.
  • samples of high density ceramics of the following compositions were subjected to the test procedure as outlined above: Al- O (single crystal and polycrystalline); BeO; MgO; ZrO 2Al O 'SiO ZrO 'SiO Y O CeS; M081 and BN.
  • an apparatus for extruding molten metal to form fine diameter wire said apparatus being characterized by a crucible assembly for containing a molten metal charge and having an orifice defining element as an essential part thereof, means for forcing molten metal contained in the crucible through an orifice in said orifice defining element and heating means for maintaining said charge in the molten state, the improvement which comprises: an orifice defining element which is composed of polycrystalline thorium oxide having a density of from 9.5 to 10.0 gm/cm and a purity of at least 99.5 percent.
  • said orifice defining element is composed of polycrystalline thorium oxide having a density of from 9.5 to 10.0 gm/cm, and wherein said polycrystalline thorium oxide is percent pure.
  • composition of said orifice defining element consists of polycrystalline thorium oxide having a density of from 9.5 to 10.0 gm/cm and up to 0.5

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Continuous Casting (AREA)
  • Extrusion Of Metal (AREA)
US405388A 1973-10-11 1973-10-11 Orifice structure for extruding molten metal to form fine diameter wire Expired - Lifetime US3926248A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US405388A US3926248A (en) 1973-10-11 1973-10-11 Orifice structure for extruding molten metal to form fine diameter wire
ZA00746443A ZA746443B (en) 1973-10-11 1974-10-09 Improved orifice structure for extruding molten metal to form fine diameter wire
FR7434131A FR2247297B1 (sv) 1973-10-11 1974-10-10
GB4388574A GB1458460A (en) 1973-10-11 1974-10-10 Extrusion orifices
BE149391A BE820909A (fr) 1973-10-11 1974-10-10 Structure a orifice perfectionnee pour extruder un metal fondu pour former un fil de fin diametre
AU74180/74A AU7418074A (en) 1973-10-11 1974-10-10 Orifice structure
SE747412723A SE406428B (sv) 1973-10-11 1974-10-10 Munstycke for strengpressning av smelt metall
CA211,210A CA1005793A (en) 1973-10-11 1974-10-10 Orifice structure for extruding molten metal to form fine diameter wire
IT28271/74A IT1022755B (it) 1973-10-11 1974-10-10 Struttura di crifizio migliorata per l estrusione di metalli fusi per formare fili metallici di diametro fine
DE19742448434 DE2448434A1 (de) 1973-10-11 1974-10-10 Duese zum extrudieren einer metallschmelze zur herstellung feiner draehte
JP49116239A JPS5066430A (sv) 1973-10-11 1974-10-11

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US405388A US3926248A (en) 1973-10-11 1973-10-11 Orifice structure for extruding molten metal to form fine diameter wire

Publications (1)

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US3926248A true US3926248A (en) 1975-12-16

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US405388A Expired - Lifetime US3926248A (en) 1973-10-11 1973-10-11 Orifice structure for extruding molten metal to form fine diameter wire

Country Status (11)

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US (1) US3926248A (sv)
JP (1) JPS5066430A (sv)
AU (1) AU7418074A (sv)
BE (1) BE820909A (sv)
CA (1) CA1005793A (sv)
DE (1) DE2448434A1 (sv)
FR (1) FR2247297B1 (sv)
GB (1) GB1458460A (sv)
IT (1) IT1022755B (sv)
SE (1) SE406428B (sv)
ZA (1) ZA746443B (sv)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4260007A (en) * 1979-03-14 1981-04-07 Allied Chemical Corporation Method and apparatus for casting amorphous filament using a crucible with a boric oxide seal

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3516478A (en) * 1967-12-05 1970-06-23 Monsanto Co Apparatus for separation of impurities from metal melts in a filament spinning device
US3645657A (en) * 1969-07-02 1972-02-29 Monsanto Co Method and apparatus for improved extrusion of essentially inviscid jets
US3658979A (en) * 1965-03-30 1972-04-25 Monsanto Co Method for forming fibers and filaments directly from melts of low viscosities

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3658979A (en) * 1965-03-30 1972-04-25 Monsanto Co Method for forming fibers and filaments directly from melts of low viscosities
US3516478A (en) * 1967-12-05 1970-06-23 Monsanto Co Apparatus for separation of impurities from metal melts in a filament spinning device
US3645657A (en) * 1969-07-02 1972-02-29 Monsanto Co Method and apparatus for improved extrusion of essentially inviscid jets

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4260007A (en) * 1979-03-14 1981-04-07 Allied Chemical Corporation Method and apparatus for casting amorphous filament using a crucible with a boric oxide seal

Also Published As

Publication number Publication date
CA1005793A (en) 1977-02-22
DE2448434A1 (de) 1975-04-24
GB1458460A (en) 1976-12-15
FR2247297A1 (sv) 1975-05-09
AU7418074A (en) 1976-04-15
ZA746443B (en) 1975-11-26
SE406428B (sv) 1979-02-12
FR2247297B1 (sv) 1980-08-01
JPS5066430A (sv) 1975-06-04
IT1022755B (it) 1978-04-20
BE820909A (fr) 1975-04-10
SE7412723L (sv) 1975-04-14

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