Lost-wax method associated with piezocrystallization and a device for carrying out said method

Abstract

The inventive casting method consists in extruding a melt from a metal reservoir into the cavity of a shaped investment mold at a temperature above liquidus and a pressure enabling a maximum splash-free liquid metal flow and increasable along with the melt crystallization to a pressure sufficient for further filling the mold in proportion to the amount of cast shrinkage. The inventive device for carrying out said method comprises a metal reservoir arranged as a removable insert lined from the inside and provided with an annular flange, and a container which comprises the shaped investment mold and a hollow neck provided with a removable thimble. The flange is mounted in such a way that its inner diameter matches with the outer diameter of the thimble, wherein the inner diameter of the flange is smaller than the inner diameter of the insert.

1 . A lost-wax method associated with piezocrystallization comprising the steps of extruding a melt from a metal reservoir lined by a refractory material into a cavity of a shaped investment mold disposed under said metal reservoir and holding said melt at a pressure till the end of crystallization, characterized in that the melt is extruded into the cavity of the shaped investment mold at a temperature above liquidus and a pressure enabling a maximum splash-free liquid metal flow rate as the investment mold is being filled, said pressure, after the investment mold has been filled with the melt, being maintained at a level obtained in the process of extrusion during crystallization of the melt layer butting against the investment mold walls, and whereafter said pressure being smoothly increased during crystallization of the entire melt to a pressure sufficient for further filling the mold in proportion to the amount of cast shrinkage. 
   
   
       2 . A device for carrying out the lost-wax method with piezocrystallization according to  claim 1 , said device comprising a metal reservoir mounted on a bottom table and arranged as a base and a removable insert lined from the inside with a heat-insulating layer between them, a container with a shaped investment mold, said container being fixed above said metal reservoir and comprising a housing, a cover with a neck in axial alignment with said metal reservoir axis, characterized in that the outer surface of the container neck is provided with a thimble and a lined annular flange is mounted at the exposed edge of the metal reservoir insert, said flange matching along its inner diameter with the outer diameter of said thimble, wherein the inner diameter of said lined flange being smaller than the inner diameter of said lined insert. 
   
   
       3 . The device according to  claim 2  characterized in that the difference between the inner diameters of said lined insert and said thimble is radially greater that the total thickness of the single-side melt layer crystallized on the lined insert wall and the thimble wall in the process of pouring-in and holding the melt till the end of crystallization.