EP0124688B1 - Casting in a low density atmosphere - Google Patents
Casting in a low density atmosphere Download PDFInfo
- Publication number
- EP0124688B1 EP0124688B1 EP19840101360 EP84101360A EP0124688B1 EP 0124688 B1 EP0124688 B1 EP 0124688B1 EP 19840101360 EP19840101360 EP 19840101360 EP 84101360 A EP84101360 A EP 84101360A EP 0124688 B1 EP0124688 B1 EP 0124688B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- gas
- strip
- atmosphere
- reducing
- quench surface
- 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.)
- Expired
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Images
Classifications
-
- 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
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/0697—Accessories therefor for casting in a protected atmosphere
-
- 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 invention relates to the casting of metal strip directly from a melt, and more particularly to the rapid solidification of metal directly from a melt to form substantially continuous metal strip.
- US-A-4,142,571 discloses a conventional apparatus and method for rapidly quenching a stream of molten metal to form continuous metal strip.
- the metal can be cast in an inert atmosphere or a partial vacuum.
- US ⁇ A ⁇ 3,862,658 and US-A-4,202,404 disclose flexible belts employed to prolong contact of cast metal filament with a quench surface.
- US ⁇ A ⁇ 4,154,283 discloses that vacuum casting of metal strip reduces the formation of gas pocket defects.
- the vacuum casting system requires specialized chambers and pumps to produce a low pressure casting atmosphere.
- auxiliary means are required to continuously transport the cast strip out of the vacuum chamber.
- the strip tends to weld excessively to the quench surface instead of breaking away as typically happens when casting in an ambient atmosphere.
- US-A-4,301,855 discloses an apparatus for casting metal ribbon wherein the molten metal is poured from a heated nozzle onto the outer peripheral surface of a rotary roll.
- a cover encloses the roll surface upstream of the nozzle to provide a chamber, the atmosphere of which is evacuated by a vacuum pump.
- a heater in the cover heats the roll surface upstream from the nozzle to remove dew droplets and gases from the roll surface.
- the vacuum chamber lowers the density of the moving gas layer next to the casting roll surface, thereby increasing formation of air pocket depressions in the cast ribbon. The heater helps drive off moisture and adhered gases from the roll surface to further decrease formation of air pocket depressions.
- Said apparatus does not pour metal onto the casting surface until that surface has exited the vacuum chamber. By this procedure, complications involved in removing a rapidly advancing ribbon from the vacuum chamber are avoided. The ribbon is actually cast in the open atmosphere, offsetting any potential improvement in ribbon quality.
- US-A-3,861,450 discloses a method and apparatus for making metal filament.
- a disk-like, heat-extracting member rotates to dip an edge surface thereof into a molten pool, and a non-oxidizing gas is introduced at a critical process region where the moving surface enters the melt.
- This non-oxidizing gas can be a reducing gas, the combustion of which in the atmosphere yields reducing or non-oxidizing combustion products at the critical process region.
- a cover composed of carbon or graphite encloses a portion of the disk and reacts with the oxygen adjacent the cover to produce non-oxidizing carbon monoxide and carbon dioxide gases which can then surround the disk portion and the entry region of the melt.
- non-oxidizing gas disrupts and replaces an adherent layer of oxidizing gas with the non-oxidizing gas.
- the controlled introduction of non-oxidizing gas also provides a barrier to prevent particulate solid materials on the melt surface from collecting at the critical process region where the rotating disk would drag the impurities into the melt to the point of initial filament solidification.
- the exclusion of oxidizing gas and floating contaminants from the critical region increases the stability of the filament release point from the rotating disk by decreasing the adhesion therebetween and promoting spontaneous release.
- Said patent addresses only the problem of oxidation at the disk surface and in the melt.
- the flowing stream of non-oxidizing gas is still drawn into the molten pool by the viscous drag of the rotating wheel and can separate the melt from the disk edge to momentarily disturb filament formation.
- the particular advantage is that the non-oxidizing gas decreases the oxidation at the actual point of filament formation within the melt pool.
- said patent fails to minimize the entrainment of gas that could separate and insulate the disk surface from the melt.
- US ⁇ A ⁇ 4,282,921 and US-A-4,262,734 disclose an apparatus and method in which coaxial gas jets are employed to reduce edge defects in rapidly quenched amorphous strips.
- US-A-4,177,856 and US-A-4,144,926 disclose a method and apparatus in which a Reynolds number parameter is controlled to reduce edge defects in rapidly quenched amorphous strip. Gas densities and thus Reynolds numbers, are regulated -by the use of vacuum and by employing lower-, molecular weight gases.
- the objcet of the invention is to provide an apparatus and method for efficiently casting smooth metal strip and substantially preventing the formation of gas pocket defects therein.
- the inventive apparatus for casting metal strip comprising a moving chill body having a quench surface, and nozzle means for depositing a stream of a molten metal on a quenching region of said surface to form said strip is characterized in that it further comprises depletion means consisting of a gas nozzle (8), a gas heater (10), a gas supply (12) and an ignition means (30) for continuously supplying a heated gas that creates a low density atmosphere at a depletion region located adjacent to and upstream of said quenching region throughout the whole casting time.
- depletion means consisting of a gas nozzle (8), a gas heater (10), a gas supply (12) and an ignition means (30) for continuously supplying a heated gas that creates a low density atmosphere at a depletion region located adjacent to and upstream of said quenching region throughout the whole casting time.
- the method according to the invention comprises the step of moving a chill body having a quench surface at a selected speed, depositing a stream of molten metal on a quenching region of said quench surface to form said strip heating said quench surface, supplying throughout the whole casting time a heated gas creating a low density atmosphere to a depletion region located adjacent to and upstream of said quenching region and heating said quench surface to a temperature that substantially prevents precipitation of condensed or solidified constituents from said atmosphere onto said depletion region.
- the used gas is a reducing gas capable of causing a chemical reduction reaction, thereby providing a reducing atmosphere.
- ignition means for igniting said reducing gas to produce a reducing flame atmosphere.
- means for providing at least one additional low density atmosphere composed of a low density gas, located along a portion of said strip and/or a flexible hugger belt which entrains said strip against said quench surface to prolong contact therewith and/ or nozzle heating means for heating the nozzle exit portion with a reducing flame to minimize clogging of said nozzle orifice.
- the method and apparatus of the invention advantageously minimize the formation and entrapment of gas pockets against the quenched surface during the casting of the strip.
- the invention avoids the needs for complex vacuum casting apparatus and can be practiced in an ambient atmosphere.
- the heating of the quench surface surprisingly provided better and more uniform cooling and quenching of the molten metal.
- the low-density atmosphere and heated quench surface reduce the formation of gas pockets operating to decrease contact between the molten metal and the quench surface.
- the more uniform quenching provides improved physical properites in the cast strip.
- the reduction of surface defects on the quenched surface side of the strip increases the packing factor of the material and reduces localized stress concentrations that can cause premature fatigue failure.
- the smoothness of the free surface side of the cast strip is also improved by the method and apparatus of the invention. This increased smoothness further increases the packing factor of the material.
- the more uniform quenching afforded by the heated quench surface and low density atmosphere provide a more consistent and uniform formation of the amorphous state.
- the number and size of strip surface discontinuities is reduced, improving the magnetic properties of the strip.
- the present invention effectively minimizes gas pocket defects on the strip surface which contacts the quench surface, and produces strip having a smooth surface finish and uniform physical properties.
- Complex equipment and procedures associated with vacuum casting are eliminated.
- the invention efficiently casts ultra thin as well as extra thick metal strip directly from the melt at lower cost and with higher yield. Such ultra thin and extra thick strips are especially suited for use in such applications as magnetic devices, and can be substituted for conventional materials with greater effectiveness and economy.
- a strip is a slender body the transverse dimensions of which are much smaller than its length.
- a strip includes wire, ribbon, sheet and the like of regular or irregular cross-section.
- the invention is suitable for casting metal strip composed of crystalline or amorphous metal and is particularly suited for producing metal strip which is rapidly solidified and quenched at a rate of at least about 10"°C/sec from a melt of molten metal.
- Such rapidly solidified strip has improved physical properties, such as improved tensile strength, ductility and magnetic properties.
- Fig. 1 shows a representative prior art device for rapidly casting continuous metal strip.
- Molten metal alloy contained in crucible 2 is heated by a heating element 3.
- Pressurization of the crucible with an inert gas forces a molten stream through a nozzle 4 at the base of the crucible and deposits the molten metal onto a moving chill body, such as rotatable casting wheel 1.
- Solidified moving strip 6, after its break-away point from the quench wheel is then routed onto a suitable winding means.
- Quench surface 5 is preferably a material having high thermal conductivity. Suitable materials include carbon steel, stainless steel and copper based alloys such as beryllium copper. To achieve the quench rates of at least about 10 40 C per second, wheel 1 is internally cooled and rotated to provide a quench surface that advances at a speed ranging from about 100-4000 meters per minute. Preferably, the quench surface speed ranges from about 200-3000 meters per minute. Typically, the thickness of the cast strip ranges from 25-100 microns (micrometers).
- Fig. 2 shows a representative apparatus of the invention.
- a moving chill body such as endless casting belt 7, has a chilled casting quench surface 5.
- Nozzle means such as nozzle 4, deposits a stream of molten metal onto a quenching surface 14 of quench surface 5 to form strip 6.
- Nozzle 4 has an orifice 22 located at exit portion 26.
- a depletion means is comprised of gas nozzle delivery means 8, heater means 10, and gas supply 12. The depletion means supplies a gas 24 from gas supply 12 to produce a low density atmosphere and directs the gas with gas nozzle 8 to a depletion region 13 located ajdacent to and upstream of quenching region 14.
- Nozzle 8 is suitably located to direct gas 24 at and around the depletion region 13 so that the gas 24 substantially floods the depletion region 13, providing a low density atmosphere therewithin. Said gas heats the quench surface 5 to a temperature that substantially prevents precipitation of condensed or solidified constituents from the atmosphere onto the depletion region 13. Valve 16 regulates the volume and velocity through nozzle 8. As shown in Fig. 2, gas nozzle 8 is located upstream of quenching region 14 and is directed along the direction of movement of the quench surface. Optionally, gas nozzle 8 can be located coaxial with casting nozzle 4 as representatively shown in Fig. 3.
- low density atmosphere means an atmosphere having a gas density less than 1 gram per liter and preferably, having a gas density of less than about 0.5 grams per liter.
- gas 24 is heated to at least about 527°C and more preferably, is heated to at least about 1027°C.
- hotter gases are preferred because they will have lower densities and will better minimize the formation and entrapment of gas pockets between quench surface 5 and the deposited molten metal.
- Entrapped gas pockets are undesirable because they produce ribbon surface defects that degrade the surface smoothness. In extreme cases, the gas pockets will cause perforations through strip 6.
- a very smooth surface finish is particularly important when winding magnetic metal strip to form magnetic cores because surface defects reduce the packing factor of the material.
- the packing factor is the volume fraction of the actual magnetic material in the wound core (the volume of magnetic material divided by the total core volume) and is often expressed in percent.
- a smooth surface without defects is also important in optimizing the magnetic properties of strip 6 and in minimizing localized stress concentrations that would otherwise reduce the mechanical strength of the strip.
- Gas pockets also insulate the deposit molten metal from quench surface 5 and reduce the quench rate in localized areas.
- the resultant, non-uniform quenching produces non-uniform physical properties in strip 6, such as non-uniform strength, ductility and magnetic properties.
- gas pockets can allow undesired crystallization in localized portions of the strip.
- the gas pockets and the local crystallizations produce discontinuities which inhibit movement of magnetic domain walls, thereby degrading the magnetic properties of the material.
- the invention produces high quality metal strip with improved surface finish and improved physical properties.
- metal strip has been produced with packing factors of at least about 80%, and up to about 95%.
- the mechanism by which gas pockets are reduced can be more readily explained with reference to Fig. 6.
- the gas boundary layer velocity profile near quench surface 5 and upstream of melt puddle 18 is shown schematically at 20.
- the maximum gas boundary layer velocity occurs immediately adjacent to quench surface 5 (substrate) and is equal to the velocity of the moving quench surface.
- moving quench surface 5 ordinarily draws cool air from the ambient atmosphere into upstream region 13 and into quenching region 14, the region of the quench surface upon which molten metal is deposited. Because of the drafting of relatively cool air into the quenching region, the presence of the hot casting nozzle and the molten metal do not sufficiently heat the local atmosphere to significantly reduce the density thereof.
- Melt puddle 18 wets the substrate surface to an extent determined by various factors including the metal alloy composition, the substrate composition, and the presence of surface films.
- the pressure exerted by the gas boundary layer at the melt-substrate interface acts to locally separate the melt from the substrate and form entrained gas pockets which will appear as "lift-off" areas 44 on the ribbon underside.
- the stagnation pressure of the gas boundary layer pressure if the layer hit a rigid wall
- a low density gas in the boundary layer could be employed.
- the selection of a low molecular weight gas is one way to reduce boundary layer gas density.
- the variety of low molecular weight gases which can be used in this fashion is quite limited.
- a preferred manner in which to reduce the boundary layer gas density is to use a heated gas; the density of the gas will diminish as the inverse of the absolute temperature.
- the heating of the quench surface does not degrade the quenching of the molten metal.
- the heating of the quench substrate and the low density atmosphere actually improve the uniformity of the quench rate by minimizing the presence of insulating, entrapped gas pockets, and thereby improve the quality of the cast strip.
- gas 24 is a reducing gas; i.e. it is capable of causing a chemical reduction-type reaction. Accordingly, the gas itself is capable of undergoing chemical oxidation, preferably by combining with oxygen. Suitable reducing gases include carbon monoxide and gas mixtures thereof.
- a reducing atmosphere minimizes the oxidation of strip 6.
- the reducing atmosphere starves quench surface 5 of oxygen and minimizes the oxidation thereof.
- the reduced oxidation improves the wettability of the quench surface and allows molten metal to be more uniformly deposited on quench surface 5.
- the reduced oxidation renders the quench surface much more resistant to thermally induced fatigue crack nucleation and growth.
- the reducing atmosphere also depletes oxygen from the region of nozzle 4 thereby reducing the clogging of nozzle orifice 22, particularly clogging due to oxide particulates.
- additional gas nozzle 32 may be employed to provide additional reducing gas atmospheres along selected portions of strip 6, as representatively shown in Fig. 2.
- Fig. 4 shows an embodiment of the invention wherein the reducing gas is capable of being ignited and burned to form a reducing flame atmosphere.
- Nozzle 4 deposits molten metal onto quench surface 5 of rotating casting wheel 1 to form strip 6.
- the depletion means in this embodiment is comprised of gas supply 12, gas nozzle 8 and ignition means 30.
- Valve 16 regulates the volume and velocity of gas delivered through gas nozzle 8, and a wiper brush 42 conditions quench surface 5 to help reduce oxidation thereon.
- ignition means 30 ignites the gas to produce a heated, low-density reducing atmosphere around upstream region 13 and around quench surface region 14 where molten metal is deposited.
- Suitable ignition means include spark ignition, hot filament, hot plates and the like.
- the hot casting nozzle serves as a suitable ignition means which automatically ignites the reducing gas upon contact therewith.
- the resultant flame atmosphere forms a flame plume 28 which begins upstream of quenching region 14 and consumes oxygen therefrom.
- unburned reducing gas within the plume reacts to reduce the oxides on quench surface 5, nozzle 4 and strip 6.
- the visibility of flame 28 allows easy optimization and control of the gas flow, and plume 28 is effectively drawn around the contour of wheel 1 by the wheel rotation to provide an extended reducing flame atmosphere.
- a hot reducing atmosphere is located around quenching surface 14 and for a discrete distant thereafter.
- the extended flame plume advantageously provides a non-oxidizing, protective atmosphere around strip 6 while it is cooling.
- additional gas nozzles 32 and ignition means 34 can be employed to provide additional reducing flame plumes 36 along selected portions of the strip 6 to further protect the strip from oxidation.
- a further advantage provided by the hot, reducing flame plume is that the smoothness of the free surface side of the strip (the side not in contact with the quench surface) is significantly improved. Experiments have shown that the mean roughness of the rapidly solidified metal strip, as measured by standard techniques such as pack factor, is significantly reduced when the strip is produced in the reducing flame plume of the invention.
- the reducing gas 24 is preferably a gas that will not only burn and consume oxygen in a strongly exothermic reaction, but will also produce combustion products that will remain gaseous at quench surface temperatures ranging from 527°C to 1027°C.
- Gases of this type comprise practically any gas or gas mixture which when heated or combusted produces a thermally-induced, low density atmosphere.
- gases include hydrogen, carbon monoxide, methane, propane and the like, and mixtures thereof.
- reducing gases that provide an anhydrous, reducing atmosphere.
- the temperature to which quench surface 5 is heated during casting depends upon the composition of the strip, the composition of the low density atmosphere present within depletion region 13 and the composition of the quench surface 5.
- the quench surface is heated to a temperature of at least about 50°C and preferably to a temperature of about 50°C to 300°C.
- Quench surface temperatures of at least about 100°C and, most preferably of about 146°C to 246°C substantially prevent precipitation of condensed or solidified constituents from most anhydrous reducing atmospheres onto depletion region 13.
- a reducing flame atmosphere provides an efficient means for heating the atmosphere located proximate to melt puddle 18 to very high temperatures, in the order of 1027 1127°C. Such temperatures provide very low gas densities around the melt puddle 18. The high temperatures also increase the kinetics of the reduction reaction to further minimize the oxidation of quench surface 5, nozzle 4 and strip 6. The presence of a hot reducing flame at nozzle 4 also reduces thermal gradients therein which might crack the nozzle.
- the embodiment of the invention employing a reducing flame atmosphere more efficiently produces a heated, low-density reducing atmosphere around quench surface 5 which improves the smoothness of both sides of the cast strip and more effectively prevents oxidation of quench surface 5, strip 6 and casting nozzle 4.
- the invention may optionally include a flexible hugger belt 38 which entrains strip 6 against quench surface 5 to prolong cooling contact therewith.
- the prolonged contact improves the quenching of strip 6 by providing a more uniform and prolonged cooling period for the strip.
- Guide wheels 40 position belt 38 in the desired hugging position along quench surface 5, and a drive means moves belt 38 such that the belt portion in hugging relation to quench surface 5 moves at a velocity substantially equal to the velocity of the quench surface.
- belt 38 overlaps the marginal portions of strip 6 to directly contact and frictionally engage quench surface 5. This frictional engagement provides the required driving means to move the belt.
- a further atNantage of thin strip is that the strip experiences less bending stresses when wound to a given diameter. Excessive bending stresses will degrade the magnetic properties through the phenomenon of magnetostriction.
- the apparatus and method of the invention are particularly useful for forming very thin metal strip. Since the invention significantly reduces the size and depth of gas pocket defects, there is less chance that such a defect will be large enough to perforate the cast strip. As a result, very thin strip can be cast because there is less probability that a defect large enough to perforate the strip will form.
- the invention can be adapted to cast very thin metal strip, which as-cast, is less than about 15 micrometers thick.
- the strip has a thickness of 12 micrometers or less. More preferably, the strip thickness ranges from 7 to 12 micrometers.
- the thin metal strip has a width dimension which measures at least about 1.5 millimeters, and preferably measures at least about 10 mm.
- a forced-convection-cooled, plain carbon steel substrate wheel used in the present investigation was 38 cm (15 in.) in diameter, 5 cm (2 in.) wide.
- nickel-base ribbons of composition Ni 68 Cr 7 Fe 3 B 14 Si 18 (subscripts in atomic percent) were produced on the steel wheel with low circumferential surface speed (about 10 m/s or 2,000 fpm) to avoid excessive ribbon-substrate adhesion.
- the substrate wheel was conditioned continuously during the run by an idling brush wheel inclined about 10° out of the casting direction.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US48347583A | 1983-04-11 | 1983-04-11 | |
US483475 | 1983-04-11 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0124688A1 EP0124688A1 (en) | 1984-11-14 |
EP0124688B1 true EP0124688B1 (en) | 1988-08-10 |
Family
ID=23920190
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19840101360 Expired EP0124688B1 (en) | 1983-04-11 | 1984-02-10 | Casting in a low density atmosphere |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0124688B1 (ja) |
JP (1) | JPS59209460A (ja) |
AU (1) | AU2453284A (ja) |
CA (1) | CA1213120A (ja) |
DE (1) | DE3473240D1 (ja) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4588015A (en) * | 1984-10-17 | 1986-05-13 | Allied Corporation | Casting in an exothermic reducing flame atmosphere |
JPS62114747A (ja) * | 1985-11-15 | 1987-05-26 | O C C:Kk | 結晶が鋳造方向に長く伸びた一方向凝固組織を有する金属条の連続鋳造法 |
BE1000490A4 (fr) * | 1987-04-22 | 1988-12-27 | O C C Company Ltd | Procede de coulee continue d'un ruban metallique. |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3861450A (en) * | 1973-04-06 | 1975-01-21 | Battelle Development Corp | An improved method of formation of filament directly from molten material |
US3862658A (en) * | 1973-05-16 | 1975-01-28 | Allied Chem | Extended retention of melt spun ribbon on quenching wheel |
CA1068470A (en) * | 1975-02-24 | 1979-12-25 | Allied Chemical Corporation | Production of improved metal alloy filaments |
JPS5474698A (en) * | 1977-11-28 | 1979-06-14 | Univ Tohoku | Superconductive thin band and method of fabricating same |
JPS6038226B2 (ja) * | 1978-06-23 | 1985-08-30 | 株式会社日立製作所 | 金属薄帯の製造装置 |
US4177856A (en) * | 1978-08-28 | 1979-12-11 | General Electric Company | Critical gas boundary layer Reynolds number for enhanced processing of wide glassy alloy ribbons |
US4202404A (en) * | 1979-01-02 | 1980-05-13 | Allied Chemical Corporation | Chill roll casting of amorphous metal strip |
JPS5911164B2 (ja) * | 1979-05-31 | 1984-03-14 | 東北大学長 | 超伝導体薄帯の製造方法および装置 |
US4282921A (en) * | 1979-09-17 | 1981-08-11 | General Electric Company | Method for melt puddle control and quench rate improvement in melt-spinning of metallic ribbons |
US4262734A (en) * | 1979-09-17 | 1981-04-21 | General Electric Company | Apparatus for melt puddle control and quench rate improvement in melt-spinning of metallic ribbons |
DE3165502D1 (en) * | 1980-04-21 | 1984-09-20 | Bbc Brown Boveri & Cie | Multi-layered-solder and method of producing such solder |
EP0040488A1 (en) * | 1980-05-15 | 1981-11-25 | International Business Machines Corporation | Method of fabricating a ribbon structure |
JPS57116356U (ja) * | 1981-01-09 | 1982-07-19 |
-
1984
- 1984-02-10 EP EP19840101360 patent/EP0124688B1/en not_active Expired
- 1984-02-10 DE DE8484101360T patent/DE3473240D1/de not_active Expired
- 1984-02-13 AU AU24532/84A patent/AU2453284A/en not_active Abandoned
- 1984-03-27 CA CA000450620A patent/CA1213120A/en not_active Expired
- 1984-04-11 JP JP7260184A patent/JPS59209460A/ja active Granted
Also Published As
Publication number | Publication date |
---|---|
EP0124688A1 (en) | 1984-11-14 |
JPS59209460A (ja) | 1984-11-28 |
JPH0328254B2 (ja) | 1991-04-18 |
CA1213120A (en) | 1986-10-28 |
AU2453284A (en) | 1984-10-18 |
DE3473240D1 (en) | 1988-09-15 |
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