Ald Vacuum Technologies Gmbh

Ald Vacuum Technologies Ag

Other

Georg Jarczyk

Matthias Blum

Alok Choudhury

Harald Scholz

David Francis Lupton

Marek Gorywoda

Peter Busse

Franz Hugo

Alfred Henn

Thomas Ruppel

Hans-G&uuml;nther Fellmann

Hans G&uuml;nther Fellmann

To produce precision castings from a melt, use is made of a metallic casting wheel ( ) which has an annular distribution channel ( ) and a plurality of interchangeable casting moulds ( ), each having at least one filling opening ( ). The melt quantity per casting operation is chosen here such that the casting moulds ( ) and the distribution channel ( ) are filled with the melt upon the rotation of the casting wheel ( ) about its axis (A&mdash;A), in such a way that after the solidification of the melt the precision castings are held together by a ring of the casting material which is formed in the distribution channel ( ), the so-called circulating material for new casting processes, and are removed from the casting wheel ( ) together with the casting moulds ( ), whereupon the precision castings are separated from the ring. In order to be able to produce precision castings with complicated three-dimensional shapes, in particular with undercuts, by this means as well, the casting moulds ( ), which can be used only once and are destructible for the purpose of demoulding, are selected from a ceramic material and are attached in a positive-locking and interchangeable manner to the casting wheel ( ) and so as to protrude therefrom. As a result, the circulating material can be fed uncontaminated to a recycling process.

Process and apparatus for producing precision castings

Molds ( ) with annular mold parts ( ) divided by at least one plane of division (E&mdash;E) and forming a plurality of cavities ( ) disposed at least substantially radially to a centrifugation axis (A&mdash;A), serve for the production of precision castings by centrifugal casting, especially of parts made of materials containing titanium for internal combustion engines, the molds ( ) and a casting system being contained in a closed chamber. To automate production, at least one mold part ( ) is made to rotate in its own rotational guide, and two mold parts ( ) together with the corresponding rotational guides are brought to a closed position for the casting and solidification and to an open position for the removal of the precision castings. When cast, the precision castings are preferably joined together at their radially inward pointing ends by a circumferential ring of the solidified metal and thus a circle of castings can be removed from the opened mold by a manipulating system.

Method and apparatus for the production of precision castings by centrifugal casting

In the production of precision castings by centrifugal casting with controlled solidification, a melt is cast under vacuum or shield gas into a pre-heated mold ( ) with a central gate ( ) and several mold cavities proceeding from the gate toward the outer circumference (D ) of the mold ( ). To prevent the formation of shrinkholes and porous areas in the castings, to save energy, and to increase the production rate, the mold ( ) is operated at temperatures which decrease from the inside toward the outside. The mold consists of a material or material combination with a coefficient of thermal conductivity lower than that of copper. Before the melt is poured, the mold ( ) is heated, starting from the gate ( ), by a heating device ( ), which projects into the gate, so that the gate ( ) reaches a temperature which is a function of the material being cast. Heating is carried out at a rate sufficient to produce a temperature Gradient of at least 100&deg; C., preferably of 200-600&deg; C., even more preferably of 300-500&deg; C., between the inside circumference (D ) and the outside circumference (D ). The invention is used preferable for the production of precision castings of metals of the group titanium, titanium alloys with at least 40 wt. % of the titanium, and superalloys.

Method and apparatus for the production of precision castings by centrifugal casting with controlled solidification

In the production of precision castings by centrifugal casting with controlled solidification, a melt is cast under vacuum or shield gas into a pre-heated mold (,) with a central gate (,) and several mold cavities proceeding from the gate toward the outer circumference (D,) of the mold (,). To prevent the formation of shrinkholes and porous areas in the castings, to save energy, and to increase the production rate, the mold (,) is operated at temperatures which decrease from the inside toward the outside. The mold consists of a material or material combination with a coefficient of thermal conductivity lower than that of copper. Before the melt is poured, the mold (,) is heated, starting from the gate (,), by a heating device (,), which projects into the gate, so that the gate (,) reaches a temperature which is a function of the material being cast. Heating is carried out at a rate sufficient to produce a temperature gradient of at least 100&deg; C., preferably of 200-600&deg; C., even more preferably of 300-500&deg; C., between the inside circumference (D,) and the outside circumference (D,). The invention is used preferably for the production of precision castings of metals of the group titanium, titanium alloys with at least 40 wt. % of the titanium, and superalloys.

Method for the production of precision castings by centrifugal casting with controlled solidification

For the oriented solidification of molten silicon to form an ingot in a bottomless crystallization chamber (9, 41) with a cooling body (11), which can be lowered relative to the chamber, the flat bottom surface of a seed body (25) of solid silicon is laid on the surface of the cooling body. The top surface of the seed body (25) is melted, and the ingot is grown on top of it as the cooling body is lowered by relative motion with respect to the crystallization chamber (9, 41) at a rate which is dependent on the supply of additional silicon and the solidification rate. For the purpose of producing large ingots with a coarsely crystalline to monocrystalline structure, a seed body (25) with a crystalline structure selected from the group ranging from coarsely crystalline to monocrystalline is used. Either lump silicon is placed on top of the seed body (25) and melted by induction, or molten silicon is produced in a forehearth (37) and poured onto the seed body (25). The seed body (25) has a thickness of 0.3-20 mm, and preferably of 1-10 mm.

Method and apparatus for the oriented solidification of molten silicon

In the production of castings from a melt of a reactive metal selected from the group consisting of titanium, titanium alloys, and titanium-based alloys, a reusable casting mold (20) is used; the mold, at least in the area of the surface which comes in contact with the melt, consists of at least one metal selected from the group consisting of tantalum, niobium, zirconium, and/or their alloys. The casting mold (20) preferably consists, at least in the area of the surface which comes in contact with the melt, of a tantalum based alloy containing at least 50 wt. % of tantalum. The casting molds can be made of a homogeneous metal, but it is also possible to insert shells of the metals in question into a base body to form the boundaries of the mold cavities, whereas the base body itself consists of some other metal or alloy or of a nonmetal such as graphite or silicon nitride. Insofar as the casting molds in question are molds for centrifugal casting, it is preferable to use titanium, a titanium alloy, or titanium aluminide as the nonmetal for the base body.

Process for manufacture of cast parts made of reactive metals and

In a process for the production of alloys from at least two alloy components (A, B, C, D, . . . ) with different melting points by melting in an inductively heated cold-walled crucible (1) with a cooled crucible base (3), in order to obtain an exact and homogeneous alloy composition at least a part of the alloy components (A, B, C, D, . . . ) are introduced into the cold-walled crucible (1) consecutively and in stacked fashion where either

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Grosskrotzenburg, Germany

Georg Jarczyk