Method for manufacturing a core

Abstract

The invention relates to a method for manufacturing a core (1) for producing a leading edge of a fan blade. The method comprises the steps of: (a) providing an initial core (11) made of a nickel-base alloy, (b) thermal spraying of a layer (12) of a cobalt-base alloy, comprising chromium and at least one element of tungsten and/or molybdenum, on the initial core.

1 . A process for manufacturing a core for the production of a leading edge of a fan blade, characterized in that it comprises the steps of:
 (a) providing an initial core of a nickel-based alloy,   (b) thermally spraying a layer of a cobalt-based alloy, comprising carbon, chromium and at least element among tungsten and/or molybdenum, onto the initial core.   
     
     
         2 . The process as claimed in  claim 1 , wherein the cobalt-based alloy comprises between 26% and 32% molybdenum, between 7% and 20% chromium, between 1% and 5% silicon, and less than 1% carbon. 
     
     
         3 . The process as claimed in  claim 1 , wherein the cobalt-based alloy comprises between 25% and 35% chromium, between 5% and 10% tungsten, between 0% and 7% molybdenum, between 0% and 4% nickel, between 1% and 3% silicon, and less than 2% carbon. 
     
     
         4 . The process as claimed in  claim 3 , wherein the cobalt-based alloy comprises between 28% and 30% chromium, between 1.2% and 1.6% carbon, and between 1.2% and 1.8% silicon. 
     
     
         5 . The process as claimed in  claim 1 , wherein the layer has a hardness comprised between 40 and 65 HRC. 
     
     
         6 . The process as claimed in  claim 1 , wherein the deposited layer has a thickness comprised between 100 microns and 2 millimeters. 
     
     
         7 . The process as claimed in  claim 1 , wherein step (b) is performed using a method selected from: supersonic flame spraying, blown arc plasma spraying or plasma torch deposition. 
     
     
         8 . The process as claimed in  claim 1  further comprising, following the thermal spraying step (b), a step (c) of heat treatment of the layer, carried out between 800 and 1000° C. 
     
     
         9 . The process as claimed in  claim 1  further comprising, following the thermal spraying step (b), a grinding step (d). 
     
     
         10 . The process as claimed in  claim 1 , comprising, following the thermal spraying step (b), a heat treatment step (e) in air, comprising a first stage of about thirty minutes at a temperature comprised between 300° C. and 400° C., a second stage of about thirty minutes at a temperature comprised between 500° C. and 700° C., a third stage of about thirty minutes at a temperature comprised between 800° C. and 1000° C., and cooling in ambient air, to oxidize the layer. 
     
     
         11 . A nickel-based alloy core obtained by a process as claimed in  claim 1 , said core having a layer composed of a cobalt-based alloy comprising chromium, carbon, and at least element among tungsten and/or molybdenum and/or carbon and/or silica obtained by thermal spraying of a cobalt-based alloy, comprising chromium and at least element among tungsten and/or molybdenum.