Swiss Aluminium Ltd.

Alusuisse-lonza Services Ltd.

Alusuisse Technology & Management Ltd.

Bayrisches Druckguss-werk Thurner Gmbh & Co. Kg

Novelis, Inc.

Jean-Pierre Gabathuler

Corrado Bassi

Tiberiu Mizrah

Albert Maurer

Peter Kaser

Erich Rollin

Karl-Ludwig Eckert

Anton Fischer

Hansjorg Huber

Kurt Buxmann

Ludwig Gauckler

Jurgen Wust

Manfred Doll

Harald Bressler

Hans-Gunther Thurner

Ivan Gyongyos

Yves Krahenbuhl

Bernard Poyetton

Process for manufacturing diecast parts

Holding device for inductive heating of billets of metal alloys having thixotropic properties, and for holding and transporting the billets until casting. The holding device is a dish and the dish exhibits a body in the shape of a tub and a wall at each end, at least the body being out of a high melting point metal, for example steel.

Device for holding billets

Process for manufacturing shaped parts out of thixotropic metal billets in horizontal pressure diecasting machines such that inclusions of oxide skin surrounding the thixotropic metal billet are avoided in the alloy structure of the shaped part. Before introducing the thixotropic metal alloy into the space inside the mould, the oxide skin surrounding the metal billet is removed completely and collected in a container such that removal of oxide-free, homogeneous thixotropic metal alloy is minimized by taking into account the thermal and mechanical properties of the thixotropic billet, which are asymmetric with respect to the longitudinal axis of the metal billet. The removal of the oxide skin takes place in a horizontal diecasting machine which contains an oxide remover between the casting chamber and the mold. The oxide remover is represented by a ring-shaped body with a horizontal concentric middle axis and a throughput opening. The oxide remover contains a ring-shaped recess, the oxide deposit ring which is connected to the throughput opening of the oxide remover via a concentric, ring-shaped oxide remover opening, the cross-section of the oxide remover opening being asymmetric with respect to the concentric middle axis of the oxide remover (30).

Oxide remover

A metal alloy workpiece is heated convectively in a first step by heat conduction, heat radiation or further non-inductive heat transfer to a temperature lying just below the solidus temperature of the alloy and is heated inductively in a subsequent second step to the final temperature lying between solidus and liquidus temperature. The process is particularly suitable for producing workpieces having thixotropic properties intended for further processing, in particular for further processing bolts or bars in die-casting, forging, rolling and pressing plants.

Process for heating a metal alloy workpiece

An alloy melt having a solidified portion of primary crystals is maintained at a temperature between solidus and liquidus temperature of the alloy. The primary crystals are molded to give individual degenerated dendrites or cast grains of essentially globular shape and hence impart thixotropic properties to the liquid-solid metal alloy phase by the production of mechanical vibrations in the frequency range between 10 and 100 kHz in this liquid-solid metal alloy phase.

Process for producing a liquid-solid metal alloy phase for further

The process for manufacturing an open pore foam body with three dimensional ceramic network, in particular as a filter for the treatment of hot gases or as a catalyst substrate, has as its starting material a block of open pore plastic foam. This is impregnated at least once with a ceramic suspension, freed of excess ceramic suspension and heated to a temperature below the melting point of the plastic, then finally burnt off at a temperature at which the ceramic sinters together. The plastic foam block of the prescribed outer dimensions is cooled down and machined to produce a Z-flow filter with high precision longitudinal channels.

Process for manufacturing a ceramic foam body

The process for manufacturing an open pore foam body with three dimensional ceramic network, in particular as a filter for the treatment of hot gases or as a catalyst substrate, has as its starting material a block of open pore plastic foam. This is impregnated at least once with a ceramic suspension, freed of excess ceramic suspension and heated to a temperature below the melting point of the plastic, then finally burnt off at a temperature at which the ceramic sinters together. At least one plastic foam layer is impregnated, assembled into a plastic foam block with flow channels between two layers and sintered to form a Z-flow filter.

In a filter consisting of holoow cylindrical open-pore ceramic foam cylinder elements and an end plate made of gas-impermeable material, as an insert in a filter cup for cleaning exhaust gases of diesel engines, in which the exhaust gases flow through the active filter section essentially perpendicularly to the cylinder axis, bending moments which lead to breakage of the ceramic foam cylinder elements occur during fitting of the elements due to lack of surface evenness and plane-parallelism of the end faces. A filter of the aforementioned kind, in which the end faces of the ceramic foam cylinder elements are provided with temperature-resistant and thermal shock-resistant layers of material which are plastic at room temperature, avoids the bending moments.

Filter for cleaning exhaust gases of diesel engines

In a filter consisting of hollow cylindrical open-pore ceramic foam and an end plate made of gas-impermeable material, as an insert in a filter cup for cleaning exhaust gases of diesel engines, in which the exhaust gases flow through the active filter section essentially perpendicularly to the cylinder axis, a larger ceramic foam portion such as is used e.g. as an exhaust filter for a diesel engine for a truck or passenger service bus can be made from one piece only with increased requirements, because the necessary dimensional accuracy necessitates increased requirements, and hence the economy of using the ceramic foam is greatly impaired. Also, the back pressure increases considerably. In a filter of this type these disadvantages are avoided by providing a filter which includes two or more axially arranged ceramic foam cylinder elements between which is located a lamella made of gas-impermeable material with at least approximately the same diameter as the ceramic foam cylinder elements and with at least one opening in the ceramic foam cylinder-free region.

In the case of filters for cleaning the exhaust gases of diesel engines, the deposited soot particles are burnt at intervals at temperatures between 550.degree. to 700.degree. C. By using filters consisting of open-pore ceramic foam manufactured by coating an open-pore body which can be burnt out, with a ceramic powder suspension, burning out the substrate material at temperatures of 100.degree.-500.degree. C. and then sintering at elevated temperatures, which filters comprise a self-supporting ceramic structure with an internal surface area of the total pore system of 1 m.sup.2 /l to 10 m.sup.2 /l and an open porosity of 55-92%, the soot combustion temperature is reduced to between 400.degree. to 550.degree. C. When coated with catalytically active substances, the soot combustion temperature is even reduced to 350.degree. C.

In a filter consisting of hollow cylindrical open-pore ceramic foam cylinder elements and an end plate made of gas-impermeable material, as an insert in a filter cup for cleaning exhaust gases of diesel engines, in which the exhaust gases flow through the active filter section essentially perpendicularly to the cylinder axis, bending moments which lead to breakage of the ceramic foam cylinder elements occur during fitting of the elements due to lack of surface evenness and plane-parallelism of the end faces. A filter of the aforementioned kind, in which the end faces of the ceramic foam cylinder elements are provided with temperature-resistant and thermal shock-resistant layers of material which are plastic at room temperature, avoids the bending moments.

Growing community of inventors

Schleitheim, Switzerland

Jean-Pierre Gabathuler