Method for precision-casting metallic molded parts and device therefor

Abstract

The invention relates to a method for precision-casting a metallic molded part or several metallic molded parts preferably of equal dimensions, in which method a metallic melt is poured into a ceramic casting mold, with the metallic melt being left to freeze thereafter. In order to achieve a void-free structure, in particular even with an intensified cooling of the melt during the freezing, it is suggested according to the invention to cool the poured melt in an intensified manner with a pressure being exerted on the melt, whereby exertion of pressure and intensified cooling are maintained at least until the dimensional stability of the freezing molded part or molded parts. The invention further relates to a device for precision-casting a metallic molded part or several metallic molded parts of equal dimensions.

1 . Method for precision-casting a metallic molded part or several metallic molded parts preferably of equal dimensions, in which method a metallic melt is poured into a ceramic casting mold, with the metallic melt being left to freeze thereafter, characterized in that the poured melt is cooled in an intensified manner with a pressure being exerted on the melt, whereby the pressure is exerted and the intensified cooling is carried out at least until the dimensional stability of the freezing molded part or molded parts.  
   
   
       2 . Method according to  claim 1 , characterized in that the melt is degassed and poured into the casting mold under vacuum.  
   
   
       3 . Method according to  claim 1 , characterized in that the pressure is exerted by means of a gas.  
   
   
       4 . Method according to  claim 1 , characterized in that the melt is closed off in a gastight manner after having been poured into the casting mold, or the melt is left to freeze in part until the melt is surrounded at least in areas by a gas-impermeable metal skin.  
   
   
       5 . Method according to  claim 1 , characterized in that the pressure is built within 30 seconds at the most.  
   
   
       6 . Method according to  claim 1 , characterized in that the pressure is built within 100 milliseconds, preferably within 10 to 50 milliseconds.  
   
   
       7 . Method according to  claim 1 , characterized in that the pressure is generated by igniting one or more charges of explosive.  
   
   
       8 . Method according to  claim 1 , characterized in that the pressure is generated by heating a liquid inert gas.  
   
   
       9 . Method according to  claim 1 , characterized in that the casting mold is inserted into a liquid coolant, in particular a gas liquid at −100° C. or a lower temperature, for the complete freezing of the melt.  
   
   
       10 . Method according to  claim 9 , characterized in that the entire surface of the casting mold is brought into contact with the coolant.  
   
   
       11 . Method according to  claim 1 , characterized in that the melt is brought into a completely frozen state within 300 seconds at the most after the pressure build-up.  
   
   
       12 . Method according to  claim 1 , characterized in that the pressure is at least 200 bar, preferably at least 800 bar.  
   
   
       13 . Method according to  claim 1 , characterized in that the melt is acted upon with ultrasound and/or an alternating voltage during the freezing.  
   
   
       14 . Method according to  claim 1 , characterized in that the casting mold and/or the melt are heated in areas in a gate area during the intensified cooling.  
   
   
       15 . Device for precision-casting a metallic molded part or several metallic molded parts preferably of equal dimensions, comprising a ceramic casting mold and a melt container via which metallic melt can be inserted into the casting mold, as well as a cooling device for the casting mold, characterized in that the cooling device is housed in a pressure-resistant chamber.  
   
   
       16 . Device according to  claim 15 , characterized in that the cooling device comprises a container for a liquid coolant.  
   
   
       17 . Device according to  claim 15 , characterized in that the casting mold can be traversed into the container.  
   
   
       18 . Device according to  claim 15 , characterized in that the chamber has at least two areas which are separated by a lock and can be evacuated or pressurized independently from one another.