AU616889B2

AU616889B2 - Furnace for making and delivering melts

Info

Publication number: AU616889B2
Application number: AU17142/88A
Authority: AU
Inventors: Jury Kirillovich Krumin; Artur Eduardovich Mikhelson; Ekabs Ekabovich Sheimanis
Original assignee: INSTITUT FIZIKI AKADEMII NAUK LATVIISKOI SSR
Current assignee: Rizhsky Politekhnichesky Institut Imeni Ayapelshe; INSTITUT FIZIKI AKADEMII NAUK LATVIISKOI SSR
Priority date: 1988-02-25
Filing date: 1988-02-25
Publication date: 1991-11-14
Anticipated expiration: 2008-02-25
Also published as: AU1714288A; FR2633708B1; JPH02504065A; WO1989008230A1; FR2633708A1; GB2224339B; GB2224339A; DE3891262T1; GB8923794D0

Description

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~h 8 9.1 OPI DATE 22/09/89 APPLN. ID 171'42 88 PCT NUMBER PCT/SU88/00016 ME) gYH1AP~rLHAIB, AOJP DATE 19/10/89 C (51) MeXujiynaPOAaR aa aceca4mscaIAlls (21) Homep meatynapo~sof ny6auxaim: WO 89/08230 aao6peirenw 4. Al (22) 1a8T8 memyapo~nolk F27B 3/02, 3/08 UY6Auncagan: 8 ceirra~ps 1989 (08.09.89) (21) Homep xe*uyn8PApo 0A oaanIM: PCT/SU88/'00046 COH ApTYP 3AyaPiAOBuq [SU/SU]; JIHenBaP~e 228321, JIaTBHcxax CCP, OFPCCHR pafios, ya. Ox- (22) ,Iara uewvuapo~xofk uzAaqH: 'ro~pa axrex, A. 35, its. 2 (SU) IIMIKHELSON, Artur 4)espajxa 1988 (25.02.88) Eduardavich, Lielvarde IEVIMAHHC Exa6c Exas6osjrq [SU/ SUI; Cwiacnxnc 229021, JIaTmmvcxaa COP, Pii~ccmsg pa&oH, yA. Mliepa, A. 29, XB. 9 (SU) (71) 3aEDH'rean: HHCTHTYT cH3HRH AKAATEMHH [SHEIMANIS, Ekabs Ekabovich, Salaspils HAYK JIATBHflCKR CCP [SU/SU]; Caiiacnzvrc 229021. Jlas~icas COP, PiescxHAi pa&Ho, yA. MHepa, A. 32 (SU) (INSTITUT FIZIK AKADEMII NAUK (74) Areis': TOPPOBO-flPOMLIIIJIEHHAH IIAjIATA LATVII8KOI SSR, Salaspils PHX*CCKHR COOP; Mocxwa 103735, yn. Kygi~mmeaa, A. 5/2 rHOJIHTEXHH'qECKdHf HHCTHTYT HMEHH [THE USSR CHAMBER OF COMMERCE AND fSU/SU]; Pmrs 226355, ya, lesmma, INDUSTRY, Moscow (SUA.

A. 1 (SU) [RIZHSKY POLITEKHNICHESKY INS- TITUT IMNI A.Ya.PELSHE, Riga (81) YiXaaanni-e rocygapcmsa: AU, DE, GB, HU, JP (72) Hao6perareaa: KPYMHHb lOpsii KuHwinoHH-4 (SU/ Ony6MMioBaa SU]; PHI'S 226059, yA. B~xepH~exy, A. 77, nS. 21 (SU) C omtemo o mewynapOiiom noucKe [KRUMIN, Jury Kirillovich, Riga MHKETIb- (54) Title: FURNACE FOR MAKING AND DELIVERING MELTS (54) Haanaime Hao6peTelilU: I'b AIJIR IipHrOTOBJIEHH5I H BbIliA-IH CMIABOB 47 r~J (57) Abstract The furnace comprises a lined working chamber t1) with sheating heaters located under the furnace roof, a metal guide for delivering the metal and a running magnetic field inductor mounted outside the working chamber The metal guide consists of two branches 7) -a lower and an upper one-, which are oriented at an obtuse angle a in relation to each other. Above the upper branch of the metal guide is mounted a partition The inductor consists of two sections (10, 11) located, respectively, under the lower and the upper branches of the metal guide FURNACE FOR PREPARING AND DELIVERING ALLOYS Field of the Invention The invention relates to non-ferrous and ferrous metallurgy, and more particularly it relates to a furnace for preparing and delivering alloys of required compositions.

The present invention can be utilized to the utmost effect in production of aluminium and its alloys, for preparing an alloy of a required composition with the use of electric or gas-fired furnaces of the reverberatory type, where electromagnetic action of magnetic fields onto a conducting medium is employed.

The invention can be also used in production of alloys of copper, zink, magnesium, lead, iron and other metals.

Prior Art The ever-growing requirements put before the quality of articles made of metal alloys are reflected in the ever-stricter demands on the accuracy of the composition of an alloy and its minimized content of unwanted impurities oxides), to say nothing of theability of quickly introducing into the alloy the modifying and alloying additives for intense interaction with the base metal of the alloy, e.g. for reising the maximum temperature in the process of preparing the alloy, for prolonging the service life of articles made therefrom, for obtaining the alloy with required properties. On the other hand, a significant rate of melting losses in the process of preparing an alloy and the presence of oxide inclusions in final articles tend to step up the percentage of rejects.

Furthermore, the equipment generally used nowadays is not sufficiently reliable, wriich manifests itself in considerable downtime taken by maintenance and repair I IL 2 jobs, which affects the productivity of preparing alloys.

There is known a furnace for preparing and delivering liquid liquid or molten metals (DE, A, 1286701), particularly alumihium, comprising a single-sided inductor of a travelling magnetic field, providing for contactless variable dispensing of the melt from -he furnace. A drawback of this known furnace is its narrow field of applicability solely for electromagnetic delivery of the molten metal; moreover, the furnace is not adequately efficient on account of the process of preparing the product involving prolonged residence of the alloy in the furnace.

There is further known a furnace for preparing and delivering alloys (CA, A, 1085613), comprisihg a refractory-lined working chamber enclosed in a metal jacket, heaters arranged under the dome of the furnace, an inclined metal conduit for delivering the molten metal arranged in the bottom part of the working chamber, and an inductor of a travelling magnetic field arranged externally of the working chamber along 'he metal conduit. A partition is mounted above the metal conduit in the working chamber, longitudinally of the conduit. One wall of the chamber, adjoining the inductor, is made slanting, of a non-magnetic material. The fur- Snace is operable in two modes: the mode of agitatirg the molten metal in the furnace and the mode of delivering the molten metal from the furnace.

In operation of the inductor in the agitation mode, the direction of the travelling magnetic field is oriented from the delivery outlet to the control zone of the furnace, the operation ensuring that the temperature differential between the surface layers of the molten metal and the bottom of the furnace is reduced from 1500C to some 100C. When the direction of the travelling magnetic wave is switched over to that 3 from the central zone of the furnace towards the delivery outlet, the furnace operates in the alloy delivery mode.

A drawback of this furnace of the prior art is that when it is operated in the delivery mode, considerable turbulence of the flow of the alloy in the delivery conduit, accompanied by bubbling, results in braking the continuity of the surface fill, thus promoting oxidation of the alloy. Consequently, when the furnace is operated in the delivery mode, the ingots obtained are of relatively poor quality on account of a high content of impurities in the form of oxides, oxide films and other inclusions.

of the Invention 15 It is an aim of the present invention to solve the .problem of creating a furnace for preparing and delivering alloys, wherein the working chamber should be of a structure providing for separating the processes of S•agitation and delivery of the molten metal or alloy, thus significantly reducing the degree of oxidation of the :metal or alloy when it is being delivered from the furnace.

Accordingly the present invention provides a furnace for preparing and delivering alloys, comprising a refractory-lined working chamber enclosed in a jacket, heaters arranged under the dome of the furnace, an inclined molten metal conduit for delivering the molten metal arranged in the bottom part of the working chamber, a partition overlying in a spaced relationship the molten I metal conduit and extending longitudinally thereof, and an inductor of a travelling magnetic field arranged externally of the working chamber along the molten metal conduit, wherein the molten metal conduit forms a lower and an upper run, with the partition overlaying the upper run of the molten metal conduit and arranged to extend to a level below that of the molten metal, the inductor being made of first and second sections separately operable and arranged respectively under the lower and upper runs of 7 the molten metal conduit, wherein activation of the first 8893S/KLS/26.08.91 4 section of the inductor causes agitation of the molten metal within the working chamber and activation of the second chamber induces delivery of the molten metal from the working chamber along the upper run to an outlet.

Thus, the present invention provides for separating the functions of agitating and delivering the molten metal or alloy. This is attached by having the molten metal conduit made of two runs overlying the respective sections of the externally arranged inductor, selectively energised to correspond to the required operating mode.

Furthermore, this also provides for substantially reducing the input of electric power, as only one section of the inductor is energised in either mode.

The invention further provides for enhancing the 15 quality of final articles by reducing the content of oxide inclusions.

n Moreover, as the breaking of the continuity of the protecting surface film is avoided, the loss of the metal .:oooi S"or alloy is reduced.

An additional advantage of the present invention is that it provides for upgrading the accuracy of the S: metering out of the uelt being ,dispensed, owing to elimination of the bubbling of the melt being delivered by the furnace.

In a preferred embodiment of the invention, the lower part of the partition extends at an angle to the upper run of the molten metal conduit, so that the gap therebetween flares out towards the lower run of the conduit.

This provides for enhancing the efficiency of the furnace in the delivery mode by more complete utilisation of the energy of the molten metal stream.

Moreover, with the lower part of the partition being at an angle to the upper run of the metal conduit, the flow of the melt in the delivery mode becomes more laminar.

93S/KLS/26.08.91 It is expedient that the angle of the inclination of the lower part of the partition with respect to the upper arm of the molten metal conduit should be within 5 10°. With the angle selected within this range, the hydraulic resistance in the molten metal conduit is minimized.

According to one embodiment of the invention, the metal jacket of the furnace in the area of the molten metal conduit is made of two electrically insulated liquid-cooled radiators of a non-magnetic material, one radiator being received within the other one, with the plates of the two radiators alternating and the two radiators defining a solid structure.

This design feature of the furnace enhances its reliability by precluding the leaks of the molten metal from the furnace. Furthermore, this feature prolongs the service life of the refractory lining of the furnace in the zone of action of the inductor, and, hence, the service life of the furnace, as a whole. Moreover, this design festure prolongs intervals between routine maintenance periods of the furnace.

Brief Description of the Drawings Other objects and advantages of the present invention will be made apparent in the following description of its embodiment, with reference being made to the accompanying drawings, wherein: Fig. I schematically illustrates a furnace embodying the invention; Fig. 2 shows in more detail a sectional view taken along line II II of Fig. 1; Fig. 3 shows in even more detail a sectional view t;aken along line III III of Fig. 2.

Best Mode for Carrying out the Invention The furnace for preparing and delivering alloys comprises a working chamber I (Fig. 1) enclosed in a 6 metal jacket 2 with an internal refractory lining 3.

Heaters 4 are mounted under the dome of the furnace, and its bottom part accommodates a molten metal conduit 5 made up of two runs, i.e. a lower run 6 and an upper run 7, extending at an obtuse angle o to each other.

Overlying the upper run 7 of the molten metal conduit in a spaced relationship is a partition 8 extending along the metal conduit 5, its lower part being inclined with respect to the upper arm 7 of the metal conduit 5 at an angle 50 100, defining with the upper arm 7 a gap flaring toward the lower run 6 of the metal conduit 5. Mounted externally of the working chamber I along the molten metal conduit 5 is an inductor 9 adapted to produce a travelling magnetic field. The inductor 9 is in the form of two independent sections 11 underlying, respectively, the lower run 6 and the upper run 7 of the molten metal conduit In the embodiment being described, the jacket 2 in the area of the metal conduit 5 is made of two liquidcooled radiators 12, 13 (Figs. 2 and 3) of a non-magnetic material which are elec-rically insulated and received one within the other, with the respective plates 14, 15 of the radiators 12, 13 alternating, defining a solid structure. The radiators 12 and 13 are provided with ducts 16, 17 for the flow of a liquid coolant, e.g. water.

SThe furnace has an inlet port 18 (Fig. 1) and an •outlet port 19.

The disclosed furnace is operated, as follows.

With either a meltable charge or molten metal from an electrolyzer (not shown) introduced into the furnace through its inlet port 18 to fill the working chamber 1, and with the heaters 4 energized, the melting process is started, and the section 10 of the inductor 9 is also energized to produce a magnetic field travelling from the inlet port 18 towards the

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t centre of the chamber 1. The molten metal 20 is thus agitated in the chamber 1, circulating vertically as indicated by an arrow line A in Fig. 1.

The agitation levels out the temperature of the molten metal 20 and homogenizes the composition of the melt throughout its entire volume in the working chamber 1.

With the required melt prepared, the inductor 9 is operated to reverse the magnetic field produced by the section 10, and to energize the section 11 thereof.

The travel of the magnetic field produced by the section 11 of the inductor 9 is directed from the centre of the working chamber 1 towards its outlet port thus adding itself to the travel induced by the switched-over section 10 of the inductor 9.

In this delivery mode, the molten metal 5 flows along the metal conduit 5 between the refractory lining 3 and partition 8, which prevents any mixing of the melt being delivered with the surface oxide film, thus enhancing the quality of the dispensed metal.

The molten metal is delivered via the outlet port 19 in a uniform flow, free from oxides.

Example 1 In a furnace operated for producing a silicon- -aluminium alloy of the Silumin type, the partition 8 is made of a refractory material, e.g. corundum. The width of the molten metal conduit 5 equals the width of the inductor 9.

Molten aluminium is poured from the associated electrolyzer (not shown) into the furnace, and silicon is charged into the working chamber 1 via the inlet port 18. The heaters 4 are energized, and the section 10 of the inductor 9 is also energized in the agitation direction. With the silicon dissolved, the agitation results in the final alloy being prepared 8 for delivery in about 15 minutes following the energization of the section 10 of the inductor 9. Then the section 11 of the inductor 9 is also energized, the current direction on the section 10 is reversed, and the value of the current in the section 11 is infinitely controlled to dispense the ready alloy from the furnace into a continuous casting plant.

Example 2 Aluminium charge is introduced into the working chamber 1 of the furnace via the inlet port 18, and the heaters 4 are energized, With the alumihium having melted, copper charge is fed into the furnace to produce an alloy containing 4 5% copper and aluminium the rest. The section 10 of the inductor 9 is energized at the very moment of starting the melting operation, its action speeding up the melting, and then agitating and homogenizing the melt. Depending on the power rating of the furnace, the operation of preparing the melt takes from 0.5 to 1.0 hour. With the melt prepared, it is delivered as described above in Example 1.

Industrial Applicability This invention can be used in the production of aluminium and its alloys, using electric or gas-fired furnaces.

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Claims

1. A furnace for preparing and delivering alloys, si comprising a refractory-lined working chamber enclosed in a jacket, heaters arranged under the dome of the furnace, 5 an inclined molten metal conduit for delivering the molten r( metal arranged in the bottom part of the working chamber, a partition overlying in a spaced relationship the molten metal conduit and extending longitudinally thereof, and an D inductor of a travelling magnetic field arranged externally of the working chamber along the molten metal I] conduit, wherein the molten metal conduit forms a lower P( and an upper run, with the partition overlaying the upper B, run of the molten metal conduit and arranged to extend to G a level below that of the molten metal, the inductor being .made of first and second sections separately operable and arranged respectively under the lower and upper runs of the molten metal conduit, wherein activation of the first section of the inductor causes agitation of the molten metal within the working chamber and activation of the second chamber induces delivery of the molten metal from the working chamber along the upper run to an outlet. K i

2. A furnace as claimed in claim 1, wherein the lower *25 part of the partition extends at an angle with respect to the upper run of the molten metal conduit, defining therewith a gap flaring towards the lower run of the molten metal conduit.

3. A furnace as claimed in claim 2, wherein the angle r of inclination of the lower part of the partition with respect to the upper run of the molten metal conduit is within 5-10°.

4. A furnace as claimed in claim 1, wherein the jacket in the molten metal conduit area is made of two electrically insulated liquid-cooled radiators of a non-magnetic 8893S/KLS/26.08.91 193S/: 10 material, received one within the other, the respective plates of the two radiators alternating to define a solid structure.

5. A furnace substantially as herein described with reference to the accompanying drawings. DATED this 27th day of August 1991 INSTITUT FIZIKI AKADEMII NAUK LATVIISKOI SSR AND RIZHSKY POLITEKHNICHESKY INSTITUT IMENI A. YA. PELSHE By their Patent Attorneys GRIFFITH HACK CO r r r 93S/KLS/26.08.91 r 11 FURNACE FOR PREPARING AND DELIVERING ALLOYS Ab s t r ac t The furnace includes a refractory-lined working cham- ber enclosed in a jacket heating means (4) arranged under the dome of the furnace, a conduit for delivering the molten metal and an inductor of a travelling magnetic field, arranged externally of the working chamber The molten metal conduit is made of two runs the lower and upper ones, extending at an obtuse angle c4 to each other. A partition overlies the upper run of the molten metal conduit The inductor is made of two sections (10, 11) underlying, respectively, the lower and upper runs 7) of the molten metal conduit