EP1060048A1 - Method of casting a metal melt in the presence of a magnetic field - Google Patents
Method of casting a metal melt in the presence of a magnetic fieldInfo
- Publication number
- EP1060048A1 EP1060048A1 EP99907603A EP99907603A EP1060048A1 EP 1060048 A1 EP1060048 A1 EP 1060048A1 EP 99907603 A EP99907603 A EP 99907603A EP 99907603 A EP99907603 A EP 99907603A EP 1060048 A1 EP1060048 A1 EP 1060048A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- melt
- casting
- electrical conductivity
- phases
- lower electrical
- 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.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D19/00—Casting in, on, or around objects which form part of the product
- B22D19/14—Casting in, on, or around objects which form part of the product the objects being filamentary or particulate in form
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
- B22D27/02—Use of electric or magnetic effects
Definitions
- the invention relates to a process for casting a melt at a relatively low solidification rate, such as gravity die casting processes, sand casting processes, low pressure casting processes or intermediate forms of these processes, in which the solidification speed is low compared to that in pressure casting processes, the melt phases, such as pre-selections of
- Wear-resistant castings are often made from melts or alloys which have precipitations, intermetallic phases or added particles or fibers, which are intended to increase the wear resistance of the casting against the base metal or the base metal alloy.
- hypereutectic AlSi alloys are to be mentioned here, in which primarily pre-deposited silicon forms such a phase of lower electrical conductivity.
- a uniform distribution of such phases in the casting can be assumed.
- the increased wear resistance is not required at all points on the casting, but usually at surface areas that later form a sliding area, or at bearing sections or cross-sectional constrictions.
- An increased concentration of these phases in the casting can even have an adverse effect (eg embrittlement), which is why the wear resistance of castings, for example on surface sections, is not arbitrary due to enrichment such phases can be increased in the entire casting,
- electromagnetic rotary fields have already been used to counteract segregation in the up to 6 meter long sumps of steel in the strand that is just solidifying.
- the rotating field is generated by coils arranged below the continuous casting mold, i.e. in the after-cooling area, and is radiated into the strand. This is intended to achieve intimate mixing within the sump and, as already mentioned, counteract signs of segregation in order to obtain a homogeneous structure within the continuous casting.
- a method is known from DE-A-28 55 933, according to which the buoyancy forces of components of the medium which are good conductors are influenced by the combination of a current flow applied externally via electrodes in an electrically conductive fluid medium and a magnetic field applied independently thereof. It is a DC field method, ie electricity and the magnetic field are coordinated with one another in a predetermined manner in terms of time and space; they could only be changed in phase with each other.
- the document teaches the complete volume penetration of the liquid by the current or the magnetic field in order to cancel or reinforce segregation, for example in order to be able to separate a phase.
- the object of the present invention is to concentrate wear-reducing phases in the surface areas in question without having to accept the resulting negative effects in other areas of the casting.
- This object is achieved according to the invention in a method of the type mentioned at the outset in that the melt is solidified under at least local action of an alternating electromagnetic field, in that case the alternating electromagnetic field is in a surface area of a penetration depth which is dependent on the frequency of the alternating field and the conductivity of the melt penetrates and thereby an enrichment of the less conductive phases is achieved on these surface areas of the casting. It was recognized according to the invention that a force component is formed on the less conductive phases in the direction of the casting surface in the area of the penetration depth of an alternating electromagnetic field, so that these accumulate on areas of the casting surface.
- the term cast surface is to be understood in the broadest sense. This can be a bore, a channel or the like.
- the application of the method according to the invention proves to be particularly advantageous in connection with the casting of a hypereutectic or near-eutectic technical aluminum-silicon alloy, in which the silicon pre-deposits, the so-called silicon primary crystals, form the phase of lower electrical conductivity.
- Intermetallic phases such as Ni 2 Al 3 or TiAl 3 are also pre-deposited in AlSi alloys and have a lower electrical conductivity than liquid aluminum and are therefore also transported to the surface.
- the melt can also advantageously be an iron melt in which graphite or cementite pre-precipitates are the phase form lower electrical conductivity.
- Heavy metal melts as well as light or non-ferrous metal melts with particles or short fibers made of materials with lower electrical conductivity than the residual melt are also suitable for casting by the method according to the invention.
- the phase of lower electrical conductivity in the melt to be cast can also be formed by granules or else by dispersed SiC particles.
- the phase of lower electrical conductivity can also comprise fibers, such as A1 2 0 3 , Si0 2 , C or aluminum silicates (Al 2 0 3 ) • (Si0 2 ).
- the melt becomes tougher overall with increasing solidification.
- the growth of stem crystals, dendrites or plates hinders the mobility of the particles to be displaced.
- a further development of the invention suggests that it is of particular importance that by irradiating a magnetic Traveling field, in particular in addition to the alternating electromagnetic field, a tangential material flow is generated in the area of the cast part surface. This hinders the formation of large stem and plate crystals, which has proven to be advantageous in every respect.
- the solidifying melt remains thixotropic longer. The mobility of the phases to be shifted can be maintained up to higher solids contents.
- the traveling magnetic field can in particular also be generated and radiated independently of alternating electromagnetic fields. If fields with different frequencies are used, both fields work independently of each other, but it must be noted that the traveling field can also have a force effect on the less conductive phases in the normal direction.
- the position of the field vectors of the segregation field and the hiking field can have different directions. This allows the coil systems required for this to be designed more freely.
- the design of the induction coils can be constructed with complex chord as in larger three-phase motors or only from a few partial coils. Will be few 10
- harmonic fields arise.
- the third-order harmonic field is a rotating field with an opposite direction of rotation. Its depth of penetration into the material is significantly lower than that of the basic field. Therefore, the harmonic field only weakens the surface-parallel drive in the immediate vicinity of the surface of the melt or the casting formed therefrom.
- this variant of the invention is particularly suitable for melts with a relatively low electrical conductivity. If high alternating strengths of the casting to be produced are desired, the method proves to be advantageous since the tensions on the surface are always particularly high and cracks are usually triggered by larger deposits with a different modulus of elasticity, the concentrations of which in the surface area are reduced according to the invention.
- additional heating can be achieved by superimposing an additional alternating field at a significantly higher frequency by means of an additional induction field in those areas of the mold where a targeted particle enrichment is to be achieved, but without this causing a noticeable additional force effect.
- Ultrasonic fields can also be used to reduce the mutual blocking of solid phases in the course of the segregation effects to be brought about according to the invention.
- Brake drums as well as brake cylinders, pump housings and bearing shells, which are produced by the method according to the invention (claims 13-19).
- the cast part surface has an accumulation of phases with lower electrical conductivity in the area of the running surfaces of the cylinder bore or in the area of the storage chairs.
- Brake disks and brake drums produced according to the invention preferably contain SiC or Al 2 O 3 particles as wear-reducing deposits on the brake surfaces.
- the proposed solution allows the surface concentration to be increased significantly, so that the resulting locally increased brittleness does not have a negative effect because of the more ductile areas behind it.
- the casting mold and / or a core inserted into the mold comprises a coil for generating the alternating electromagnetic field.
- the mold wall of the casting mold is preferably made of a non-magnetizable material with preferably low electrical conductivity.
- An austenitic chrome-nickel steel has been used for this, on which a protective layer e.g. applied from ceramic or molybdenum, has proven to be useful.
- FIG. 1A shows a perspective illustration of a mold wall section of a mold casting device
- FIG. 1B shows a winding for generating an electromagnetic alternating field for acting on the mold wall section according to FIG. 1A;
- FIG. 2A shows a plan view of a device which can be inserted into a mold for producing a cylinder bore
- FIG. 2B shows a vertical section through the device according to FIG. 2A
- FIG. 1A shows a mold wall section 2 which is formed from a helically wound hollow profile 4 which is rectangular in cross section.
- a cooling medium can flow through the hollow profile 4, which is indicated by the connecting pieces 6, 8.
- the individual spiral paths do not abut one another, but a gap or slot 12 is formed between them, which is filled with a ceramic mass 14, which also forms an inner coating 16 of the mold wall section 2.
- the mold wall is ideally permeable to an electromagnetic alternating field to be irradiated.
- the winding 20 shown in FIG. 1B can be positioned around the mold wall section 2.
- This winding 20 corresponds to a three-phase stator winding with a structure comparable to that of an asynchronous motor.
- the coil packages are only hinted at. 17
- FIGS. 2A and 2B show a device 30 that can be inserted into a casting mold for producing a cylinder bore.
- the melt to be cast therefore reaches the peripheral surface 32 of the device 30, which is formed by a ceramic coating 34 of the peripheral surfaces of hollow profile bodies 36 running in the longitudinal direction.
- These hollow profile bodies 36 are arranged slightly spaced apart from one another in the circumferential direction, so that a gap 38 remains between them, which is filled by the ceramic coating material 34.
- the respective hollow profile bodies 36 form a longitudinally extending coolant channel 40, but they also serve as a current-carrying winding for generating an alternating electromagnetic field.
- the letters R, S and T indicate a circuit arrangement for 3-phase three-phase current for three pole pairs with a total of 18 palisade-like hollow body profile conductors.
- the phases labeled "'" are electrically offset by 180 ° and form the respective opposite phase.
- the conductors are brought together at a central point 42. There is the star point of the 3-phase three-phase connection.
- the reactive power requirement of the arrangement is reduced by permeable ferrite ring bodies.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Manufacture Of Alloys Or Alloy Compounds (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19809631A DE19809631C1 (en) | 1998-03-06 | 1998-03-06 | Method and device for pouring a melt and castings produced therefrom |
DE19809631 | 1998-03-06 | ||
PCT/EP1999/001448 WO1999044773A1 (en) | 1998-03-06 | 1999-03-05 | Method and device for casting a molten mass, and the cast parts produced according to said method |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1060048A1 true EP1060048A1 (en) | 2000-12-20 |
EP1060048B1 EP1060048B1 (en) | 2004-06-16 |
Family
ID=7859945
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99907603A Expired - Lifetime EP1060048B1 (en) | 1998-03-06 | 1999-03-05 | Method of casting a metal melt in the presence of a magnetic field |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1060048B1 (en) |
DE (2) | DE19809631C1 (en) |
WO (1) | WO1999044773A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10349980A1 (en) * | 2003-10-24 | 2005-09-22 | Hunck, Wolfgang, Dipl.-Ing. | Method for cooling e.g. metal or metal oxide melt through which current is flowing comprises feeding pulsed high direct current or alternating current through it |
DE102004046962A1 (en) * | 2004-09-28 | 2006-04-06 | Volkswagen Ag | Casting method used in the production of engine parts of vehicles comprises delaying introduction of heat in partial regions in the solidification stage of the melt |
DE102007012845A1 (en) * | 2007-03-17 | 2008-09-18 | Ks Kolbenschmidt Gmbh | Production of a partial composite fiber structure in a component via a laser remelting treatment |
DE102020116143A1 (en) | 2020-06-18 | 2021-12-23 | Voestalpine Additive Manufacturing Center Gmbh | ACTUATOR FOR A MOLD FOR THE MANUFACTURE OF METALLIC COMPONENTS |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1081616B (en) * | 1953-11-06 | 1960-05-12 | Boehler & Co Ag Geb | Process for the production of lead-containing iron or steel blocks |
FR2236584B1 (en) * | 1973-05-21 | 1976-05-28 | Siderurgie Fse Inst Rech | |
CH625728A5 (en) * | 1977-12-27 | 1981-10-15 | Concast Ag | |
AT374712B (en) * | 1980-05-22 | 1984-05-25 | Ver Edelstahlwerke Ag | METHOD FOR PRODUCING CASTING PIECES WITH FINE GRAIN STRUCTURE |
ZA813647B (en) * | 1980-06-05 | 1982-07-28 | Ti Ltd | Electromagnetic stirring |
CA1225358A (en) * | 1984-03-28 | 1987-08-11 | Michael A. Shannon | Applying magnetic field to fluid mixture including magnetic particles through a coil |
JPS6195758A (en) * | 1984-10-18 | 1986-05-14 | Shinko Electric Co Ltd | Apparatus for producing tubular casting |
DE3907021C1 (en) * | 1989-03-04 | 1990-09-13 | Fried. Krupp Gmbh, 4300 Essen, De | |
DE4418750C2 (en) * | 1994-05-28 | 2000-06-15 | Vaw Ver Aluminium Werke Ag | Process for the production of wear-resistant surfaces on molded parts |
US5545368A (en) * | 1995-01-20 | 1996-08-13 | Ford Motor Company | Method of magnetically reinforcing composite components |
-
1998
- 1998-03-06 DE DE19809631A patent/DE19809631C1/en not_active Expired - Fee Related
-
1999
- 1999-03-05 DE DE59909748T patent/DE59909748D1/en not_active Expired - Lifetime
- 1999-03-05 WO PCT/EP1999/001448 patent/WO1999044773A1/en active IP Right Grant
- 1999-03-05 EP EP99907603A patent/EP1060048B1/en not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
See references of WO9944773A1 * |
Also Published As
Publication number | Publication date |
---|---|
DE59909748D1 (en) | 2004-07-22 |
WO1999044773A1 (en) | 1999-09-10 |
EP1060048B1 (en) | 2004-06-16 |
DE19809631C1 (en) | 2000-03-30 |
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