Method of making a turbine blade and runner including such a blade

A method of making a blade of a hydroelectric turbine installation, the method comprising the steps of:

• providing that the blade includes a first edge, a second edge, a third edge, a fourth edge, a first surface, a second surface, a first aperture, a second aperture, and a passage extending between the first aperture and the second aperture, the first aperture being located at the first edge, the second aperture being located at the second edge, the first surface and the second surface each including three disjoint areas which are defined by projecting an outline of the passage to a corresponding one of the first surface or the second surface, the three disjoint areas of the first surface being a first area, a second area, and a third area, the three disjoint areas of the second surface being a first area, a second area, and a third area, for the first surface the first area of the first surface and the third area of the first surface being located beside the passage and the second area of the first surface being located vertically relative to the passage, for the second surface the first area of the second surface and the third area of the second surface being located beside the passage and the second area of the second surface being located vertically relative to the passage, the blade further including a first part and a second part;
• machining the first part and the second part so as to form a profile of the first surface and the second surface of the blade;
• composing the blade by welding the first part to the second part, wherein the welding forms a first weld seam located on the first surface and a second weld seam located on the second surface;
• and
• machining the first weld seam and the second weld seam, the first part and the second part being provided by casting, the first part including the first area of the first surface, the first area of the second surface, and the second area of the second surface, and the second part including the second area of the first surface, the third area of the first surface, and the third area of the second surface.