Abstract: A process for the centrifugal casting of copper, copper alloys, or other oxygen sensitive alloys, such as bronze, is effective for avoiding or reducing the formation of an oxide layer on the inner surface of the casting. The process essentially consists of applying powdered borax in a layer thickness of 0.5 mm to 4 mm onto the still liquid inner surface of the casting immediately after pouring the casting. The preferred thickness of the borax is 1 mm to 3 mm. Finely divided mixtures of metals which have an affinity for oxygen, such Mg, Li, Ce, and/or powders of graphite and/or fire clay and/or charcoal, can also be combined with the borax as additional additives for special casting processes. Apparatus for introducing the borax into the mold includes a trough which is extendable into the interior of the mold. The trough is either rotatably supported in a housing that is movable relative to the mold, or pivotally supported along a bottom portion of a pouring tube which is movable relative to the mold.

Abstract: A mold facing for producing a gas-permeable, non-gassing and, in view of its small thickness and its porosity, heat-conductive cladding of a centrifugal ingot mold for copper and its alloy contains pulverulent material in a dispersing agent, particularly water, evaporating without residue. The pulverulent material has titanium dioxide (TiO.sub.2) as the main constituent or the sole constituent, preferable with an average particle sizes of about 15 .mu.m. A process for cladding a centrifugal ingot mold by using such a mold facing contemplates at first preheating the mold and subsequently applying the mold facing by spraying to the inner wall of the centrifugal ingot mold rotating around its axis in form of a suspension free of binding agents and surface active agents as a thin layer of, as far as possible, uniform thickness of preferably 0.1 to 0.3 mm and subsequently evaporating the dispersing sheet of the mold facing without leaving any residue for obtaining a porous layer.

Abstract: A process for applying a coating to a centrifugal casting mold for casting copper or alloys thereof in which prior to introducing the molten metal into the mold, an aqueous suspension of powdery material is introduced into the mold and applied on the internal surface thereof in the form of a thin layer. The constituent components of the suspension are zirconium oxide (ZrO.sub.2) and an inorganic binder material, preferably non-sintered alumina (Al.sub.2 O.sub.3), so that a heat-conductive and gas-permeable layer is formed on the surface of the mold.