Abstract: A process of coating a crown wall of at least one raised part of an extrusion screw which includes the following stages: a metal bead of hardness D1 is deposited on and in proximity to at least one edge of the crown part of each raised part to be coated, said bead occupying only a fraction of the width of said crown part; a second material of hardness D2 is then deposited on the rest of the uncoated crown part, said hardness D2 being significantly different from hardness D1; the deposits made in the preceding stages are ground in order to obtain the profile and the dimensions of each raised part on the screw.

Abstract: An extruder screw having at least one raised part forming a thread projecg on a core intended to be rotatably mounted inside an extruder roll in which the raised part includes a crown wall and side walls intersecting with the crown wall, the intersections between each of the side walls and the crown wall forming edges intended to cut the material, the crown wall of said raised part being provided with a coating of at least two materials of different hardnesses placed side by side on the crown wall.