A problem facing the casting industry is inclusions in
the finished parts. The inclusions can be sand from the
molds, oxides or other impurities in the metal charge.
Inclusions lead to costly part repairing or reworking.
A study was done to try and find inclusion trapping
devices that could be placed in the gating system. The
experiments consisted of pouring water and suitable
inclusion models into clear, full scale, plastic molds. The
fills were video taped for later analysis. The efficiency
of the trapping device was determined from the end location
of the inclusions. No work was done on other anti-inclusion
methods such as ceramic filters, bottom pour ladles,
chemical additives, etc.
The research showed that a swirl chamber which used
centrifugal force to separate inclusions worked quite well
if set up correctly. The optimum setup was a vertical swirl
chamber with a well. The inlet passage was choked and
located below the exit passage. It also worked much better
than any setup which tried to use buoyancy for separation.
The large volume of the swirl chamber may be
objectionable. However, properly shaped inserts, such as an
ice-cream cone shape, can be put into the chamber to reduce
fill volume while still maintaining good efficiency and
fills.
The efficiencies of the chambers behave as expected;
faster pours are less efficient and bigger chambers (for a
constant size mold) are more efficient. The use of outlet
chokes may or may not improve separation efficiency, but
will improve the filling of the part cavity. / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37024 |
| Date | 02 March 1993 |
| Creators | Buckingham, Ronald W. |
| Contributors | Davis, Lorin R. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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