Device for surfacing a metal alloy part

A device for surfacing of a metal alloy part by laser welding, said part comprising a recess to be surfaced, said recess being located at an overall planar area of the part, the surfacing device comprising a first protective element and a second protective element, the first protective element and the second protective element being arranged on either side of the recess, the first protective element and the second protective element each having an exposure surface which is to be at least partially covered with a layer of powder in order to enable welding by passing a laser beam over said layer of powder, the laser beam passing over the exposure surface of the first protective element during welding and then the exposure surface of the second protective element, the second protective element having a shape capable of containing a layer of powder having a height that is greater at an end, in the direction of propagation of the laser beam during welding, of the second protective element than a height at a start of the second protective element, the second protective element having a first inclined side wall, a second inclined side wall parallel to the first inclined side wall, the height of the first inclined side wall and of the second inclined side wall increasing in the direction of propagation of the laser beam.