Method for making light alloy components

Abstract

The invention concerns a method for making alloy components characterised in that after casting the preform ( 2 ) and before transferring it into a forging matrix ( 5 ), said preform, still hot at the end of casting, is transferred and completely immersed in a vessel ( 3 ) for graphitization coating, then, on coming out of the vessel, the preform temperature enabling the water to be evaporated so that the preform is homogeneously coated with graphite.

1 . Method for producing light alloy components of the type which implements the following phases: 
 casting the preform at between approximately 250° C. and 500° C.,    transferring the preform to a die that defines an impression the measurements of which are slightly smaller than those of the mould, the two sections of the forging die being then pressed together to exert the forging and die-stamping effect on the rough end component;    cooling the rough component at ambient temperature, the method being characterised in that after casting the heated preform and before transferring it to a forging die said preform, which is at the end of casting temperature, is transferred and totally submerged in a graphite coating tank to enable the graphite solution to be deposited on the preform, then when the preform is removed from the tank the temperature of the preform enables the water to evaporate naturally such that the preform is coated uniformly with graphite.    
     
     
         2 . Improved method for making light alloy components of the type which implements the following phases: 
 casting the preform at between approximately 250° C. and 500° C.;    transferring the cast preform obtained to a furnace where the solution heat treatment of said cast preform is carried out at the solution heat treatment temperature of the material in which the component is produced;    when the preform, which has been subjected to the solution heat treatment, is removed from the furnace, transferring it to a die that defines an impression the measurements of which are slightly smaller than those of the mould, the two sections of the die being then pressed together to exert the forging and die-stamping effect on the rough end component;    ambient temperature, accelerated or hardening cooling of the component obtained, the method being characterised in that after casting the heated preform and before transferring it to the furnace said preform, which is at the end of casting temperature, is transferred and totally submerged in a graphite coating tank to enable the graphite solution to be deposited on the preform, then when the preform is removed from the tank the temperature of the preform and that of the previous phase enables the water to evaporate naturally, it is dried such that the preform is coated uniformly with graphite, said preform being transferred to the furnace where the solution heat treatment is performed on the graphite-coated preform.    
     
     
         3 . Method as claimed in either of claims  1  and  2 , characterised in that a shade of colour is introduced into the graphite coating bath.  
     
     
         4 . Installation to implement the method of any of  claims 1  to  3 , characterised in that it comprises the following 5 successive zones: 
 a first zone (Z 1 ) where the light alloy is cast in a mould ( 1 ) enabling a preform ( 2 ) to be obtained;  
 a second zone (Z 2 ) where preform ( 2 ) is transferred into a tank ( 3 ) to be immersed and undergo graphite coating;  
 a drying phase (Z 3 ) of preformed component ( 2 ) outside the graphite bath in tank ( 3 );  
 a fourth zone (Z 4 ) where the dried preform is transferred into a tunnel furnace ( 4 ) to be subjected to temperature homogenisation;  
 a fifth zone (Z 5 ) where the preform leaves tunnel furnace ( 4 ) to be forged in a die ( 5 ) before being subjected to ambient temperature, accelerated or hardening cooling.