Abstract: Structural components, for example rotor components for a flow-dynamic engine, are first tacked to each other prior to final joining. The tacking is accomplished by a spot resistance welding or a high energy ray welding using a small welding material ball at each welding spot or location. The balls are supplied to a welding spot through a hollow, evacuated electrode of the resistance welding apparatus.

Abstract: A T-root, centrifugal turbine rotor blade which is manufactured from sheet stock. The T-root is produced by shaping the rim of the sheet stock under pressure. The sheet stock is given a rim contour which is geometrically similar to the final contour of the blade root, but is larger by a seam which is shaped under pressure for forming a T-shape having the rim contour of the blade root. After the sheet rim is shaped, a plurality of blades are cut or stamped from the sheet stock. The latter may be in annular form, and may possess various curvatures over its circumference. The sheet stock may be curved three-dimensionally before the T-rim produced.