The mold is rotated during casting while projecting at least one traveling magnetic stirring field tangentially into the melt so as to rotate melt to the mold speed.

In the manufacture of hollow metal ingots, particularly for producing seamless tubes, the liquid melt is poured rapidly into an upright or slightly inclined chill mould, the chill mould is closed and is tilted into a substantially horizontal position in which it is slowly rotated about its longitudinal axis. The hole is produced in the hollow ingots by pouring into the chill mould a quantity of melt which corresponds to the total volume of the chill mould plus the shrinkage volume and less the volume of the desired hole. The method is particularly advantageous when manufacturing hollow ingots of great length, although the method can also be used when manufacturing short hollow ingots. It is particularly advantageous to blow in an accurately dimensioned quantity of inert gas, corresponding to the hole in the hollow ingot, during and after the actual pouring operation.

In the production of castings from a melt of a reactive metal selected from the group consisting of titanium, titanium alloys, and titanium-based alloys, a reusable casting mold (20) is used; the mold, at least in the area of the surface which comes in contact with the melt, consists of at least one metal selected from the group consisting of tantalum, niobium, zirconium, and/or their alloys. The casting mold (20) preferably consists, at least in the area of the surface which comes in contact with the melt, of a tantalum based alloy containing at least 50 wt. % of tantalum. The casting molds can be made of a homogeneous metal, but it is also possible to insert shells of the metals in question into a base body to form the boundaries of the mold cavities, whereas the base body itself consists of some other metal or alloy or of a nonmetal such as graphite or silicon nitride. Insofar as the casting molds in question are molds for centrifugal casting, it is preferable to use titanium, a titanium alloy, or titanium aluminide as the nonmetal for the base body.

A tube target for cathode sputtering installations, and a process for producing a cylindrical hollow body for such a tube target and its use. The problem of providing a simple and low-cost process for producing a cylindrical hollow body for a tube target and of providing a cylindrical hollow body with a uniform, fine-grained structure is solved by the cylindrical hollow body being produced by centrifugal casting of a melt.

A method of fabricating a polycrystalline silicon wafer, which method includes the steps of radially outwardly flowing molten liquid of silicon base material on the wafer forming surface of a turntable mechanism by means of centrifugal force, thereby forming a thin molten liquid layer in a prescribed atmosphere, and cooling and solidifying the same. An apparatus for fabricating the wafer is used to carry out the method with a recover tray arranged at the wafer forming surface for receiving the excessive silicon liquid scattered, and a wafer tray placed on the recovery tray. The wafer forming surface is cooled with coolant flowing in the wafer forming mechanism. Thus, large crystalline grains can be grown on the wafer in free states with the atmosphere from the inner surfaces of the casting mold.