Abstract: In a hollow-cast component, a core opening (13) created during manufacturing is closed with a closure piece (14). This closure piece is located inside a recess (15) in the component, whereby the recess is arranged so that it is imbedded completely in the cast material, and completely covers the core opening. Because of this installation, the closure piece is fixed in a form-fitting manner in the direction of two spatial axes, so that the closure piece only needs to be secured with an additional joint in the installation direction. It is preferred that the installation direction is normal in relation to the direction of maximal stress of the closure piece, so that a joint is subject to a relatively small stress and therefore can be produced with little expenditure and a high degree of operational safety.

Abstract: Tubular metal articles are produced by centrifugal casting in a rotary metal mold lined by centrifugally distributing a quantity of a dry finely particulate free flowing refractory material on the active mold surface with the quantity being in excess of that required for the lining, densifying the layer by rotating the mold at a rate such that the refractory layer is subjected to centrifugal force adequate to establish an equivalent specific gravity of at least 7.5, determined by multiplying the actual specific gravity of the refractory material by the number of gravities of centrifugal force, contouring the densified layer and removing the excess refractory material, rotating the mold at the casting rate and then introducing the molten metal for casting while continuing to rotate the mold at least that rate. Articles so cast have relatively smooth outer surfaces which require only finish machining.

Abstract: Tubular metal articles are produced by centrifugal casting in a rotary metal mold lined by centrifugally distributing a quantity of a dry finely particulate free flowing refractory material on the active mold surface with the quantity being in excess of that required for the lining, densifying the layer by rotating the mold at a rate such that the refractory layer is subjected to centrifugal force adequate to establish an equivalent specific gravity of at least 7.5, determined by multiplying the actual specific gravity of the refractory material by the number of gravities of centrifugal force, contouring the densified layer and removing the excess refractory material, rotating the mold at the casting rate and then introducing the molten metal for casting while continuing to rotate the mold at least that rate. Articles so cast have relatively smooth outer surfaces which require only finish machining.