· Metodos de moldeo y materiales ·
Stephen P. Midson* and Andrew Jackson**
The Midson Group, Inc. Denver, Colorado. USA* and Arthur Jackson & Co., Ltd. UK**
67th World Foundry Congress
The first semi-solid casting process to be commercialized was
thixocasting, where a pre-cast billet is re-heated to the semi-solid solid
casting temperature. Advantages of thixocasting include the production of
high quality components, while the main disadvantage is the higher cost
associated with the production of the pre-cast billets.
Commercial pressures have driven casters to examine a different
approach to semi-solid casting, where the semi-solid slurry is generated
directly from the liquid adjacent to a die casting machine. These
processes are collectively referred to as rheocasting, and there are
currently at least 15 rheocasting processes either in commercial
production or under development around the world.
This paper will describe technical aspects of both thixocasting and
rheocasting, comparing the procedures used to generate the globular,
semi-solid slurry. Two rheocasting processes will be examined in detail,
one involved in the production of high integrity properties, while the other
is focusing on reducing the porosity content of conventional die castings.
