Abstract: The inlet and/or outlet edge of a blank which is to be converted into the vane of an impeller for use in a centrifugal pump is reinforced by providing an exposed surface of the blank with a pair of contiguous recesses which extend along the edge and the deeper of which is immediately adjacent to the edge. The recesses are then filled with metallic armoring material by cladding so that some of the surplus extends beyond the recesses and/or beyond the edge. In the next step, the surplus of armoring material is removed by one or more material removing tools, together with a portion of the blank in the region of the edge so that the exposed surface is provided with a fresh edge which is defined by the armoring material.