Method and apparatus for the production of precision castings by centrifugal casting with controlled solidification

摘要

In the production of precision castings by centrifugal casting with controlled solidification, a melt is cast under vacuum or shield gas into a pre-heated mold (15) with a central gate (19) and several mold cavities proceeding from the gate toward the outer circumference (D_a) of the mold (15). To prevent the formation of shrinkholes and porous areas in the castings, to save energy, and to increase the production rate, the mold (15) is operated at temperatures which decrease from the inside toward the outside. The mold consists of a material or material combination with a coefficient of thermal conductivity lower than that of copper. Before the melt is poured, the mold (15) is heated, starting from the gate (19), by a heating device (20), which projects into the gate, so that the gate (19) reaches a temperature which is a function of the material being cast. Heating is carried out at a rate sufficient to produce a temperature Gradient of at least 100° C., preferably of 200-600° C., even more preferably of 300-500° C., between the inside circumference (D_i) and the outside circumference (D_a). The invention is used preferable for the production of precision castings of metals of the group titanium, titanium alloys with at least 40 wt. % of the titanium, and superalloys.