Method of fabricating inconel 718 type nickel superalloys

Abstract

A method of fabricating Inconel 718 type nickel superalloys. A last forging operation to which the nickel superalloy is subjected is such: that it takes place at a temperature lower than the δ-solvus temperature; that at all points of the nickel superalloy the local deformation ratio is not less than a minimum value; and that the nickel superalloy is not subjected to any heat treatment at a temperature higher than a threshold temperature equal to 750° C. after a quenching.

1 - 6 . (canceled) 
     
     
         7 . A fabrication method of fabricating an Inconel 718 type nickel superalloy wherein a last forging operation to which the nickel superalloy is subjected is such:
 that it takes place at a temperature lower than the δ-solvus temperature;   that at all points of the nickel superalloy the local deformation ratio is not less than a minimum value; and   the nickel superalloy is not subjected to any heat treatment at a temperature higher than a threshold temperature equal to 750° C. after a quenching.   
     
     
         8 . A fabrication method according to  claim 7 , wherein the minimum value of the local deformation ratio is equal to 0.7. 
     
     
         9 . A fabrication method according to  claim 7 , wherein the nickel superalloy is also subjected to tempering directly after the quenching following the forging operation. 
     
     
         10 . A fabrication method according to  claim 7 , wherein all of forging operations preceding the last forging operation are performed at temperatures lower than the δ-solvus temperature. 
     
     
         11 . A fabrication method according to  claim 7 , wherein at an end of the method, a size of all grains of the superalloy lies in a range of 5 μm to 30 μm. 
     
     
         12 . A fabrication method according to  claim 11 , wherein at the end of the method, the size of all the grains of the superalloy lies in a range of 5 μm to 20 μm.