Abstract: A mold comprising a core which is open at one end and has the negative contour of the workpiece and a sheet-metal outer container surrounding the core. High dimensional stability of the core, easy removability of the workpiece from the mold and a smoother surface of the workpiece are obtained by isostatic pressing of titanium powder in the spaces in the mold. The core consists, at least at its negative contour surface for the workpiece, of a high-temperature alloy, particularly one having a base of nickel or iron. This and the titanium powder material of the workpiece are neutral in chemical reaction and low in or free of diffusion with respect to each other upon the hot isostatic pressing. The core is in the form of a ring of segments surrounded by a solid holding ring.