Snecma

Societe Nationale D'etude Et De Construction De Moteurs D'aviation

Bernard Louis Lallement

Jean-Louis Martial Verger

Yvan Rappart

Ghislaine E Lamanthe

Patrick Albert Calero

Umberto Aprile

Serge Tenne

Jean-Claude Jacques Giral

Alain Puissant

Jean-Claude Giral

Jean- Louis Verger

Jean- Claude Giral

A method including preheating a set of N shell molds for lost-wax casting, where the method can comprise: individually charging shell molds into n unit electric furnaces, each of which has previously been preheated to an initial loading temperature; starting a predefined preheating cycle for each shell mold charged in the unit electric furnaces, with a preheating cycle comprising raising the temperature of the furnace in compliance with a predefined ramp up to a predetermined setpoint temperature, and holding the furnace at the setpoint temperature for a predetermined duration; and at the end of each preheating cycle, unloading the shell mold in question and repeating the two preceding operations for another non-preheated shell mold.

Method of preheating a set of shell molds for lost-wax casting

A process for manufacturing at least one single-crystal seed that can be used as a starter seed in the manufacture of a single-crystal high-pressure turbine nozzle, with at least one vane between two platforms, by metal casting, is disclosed. The process includes producing a wax pattern that includes a pattern for the nozzle, a pattern for the starter seed, and a pattern for a crude seed; forming a ceramic shell mold from the wax pattern; incorporating a starter seed into the mold; pouring metal into the mold; directionally solidifying the metal in the mold from the starter seed; and separating the crude seed from the nozzle. The starter seed and the crude seed each include a flat face for localizing the crystalline orientations. The crude seed has the same crystallographic structure as the nozzle.

Process for manufacturing single-crystal seeds simultaneously with the casting of single-crystal parts

A casting mold is disclosed for preventing growth of parasitic grains in the casting of a workpiece from a liquid metal by a single crystal solidification technique. The mold has a mold portion which defines a casting cavity in the shape of the desired workpiece as well as a feeder portion which defines a separate feeder cavity not in communication with the casting cavity. The feeder portion is in heat exchange contact with the mold and is located adjacent to the areas of the workpiece in which a parasitic grain may be nucleated during the controlled solidification. The feeder portion is filled with a thermal mass which emits heat to slow the liquid metal solidification in these zones in order to prevent a growth of the parasitic grain. The thermal mass in the feeder cavity may consist of a liquid metal which undergoes a phase change at the same temperature, or a slightly higher temperature than that of the liquid metal located in the casting cavity from which the workpiece is cast.

Casting mold for single crystal solidification casting

A heat shield for a casting furnace consists of at least two elements slidably mounted in the furnace. The elements are generally planar in shape and extend between heating and cooling zones to provide the requisite heat insulation characteristics. The heat shield elements are movable in a direction generally parallel to their plane which extends generally perpendicularly to the path of movement of the mold from the heating zone into the cooling zone. Each of the heat shield elements consists of a generally planar, substantially rigid portion slidably mounted in the furnace and a generally planar second portion formed of a flexible refractory material. Distal edges of the second portions may overlap each other and may define an opening, the contour of which closely approximates that of the cross sectional contour of the mold.

Heat shield for a casting furnace

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Eaubonne, France

Bernard Louis Lallement