The last decade has seen many new developments in the foundry industry, among them the CO₂ process for curing molds and cores. The CO₂ process consists essentially of mixing dry, clay-free, silica sand with an organic liquid sodium silicate binder, then ramming this mix into molds or core boxes and injecting CO₂ gas. The CO₂ gas reacts with the sodium silicate binder forming a silica gel which hardens rapidly in atmospheric conditions. The CO₂ molds are more resistant to metallostatic pressure and erosion than either green or dry sand molds but more expensive also. The CO₂ cores are hardened rapidly without the benefit of a baking cycle characteristic of the production of conventional organically-bonded cores. The CO₂ cores are more economically compared with other core-making processes than the CO₂ molds are compared with other sand-molding processes.
The casting property, fluidity, is a qualitative measure of the ability of a metal to completely fill a mold cavity and is normally expressed as inches of flow in a small channel. Mold material variables, gating and flow-channel variables, and metallurgical variables, such as metal composition and the number of degrees superheat, all affect the fluidity values.
This paper presents a spiral fluidity pattern for determining the fluidity of aluminum-silicon alloys in CO₂ molds made by a standard procedure. A standardized molding, melting, and pouring procedure is suggested to control certain fluidity variables while investigating the influence of other fluidity variables. Finally, a statistical method is presented to ascertain the significance of the effect certain variables may have on fluidity. Preliminary investigations pertinent to the major objective of this paper indicate aluminum-silicon alloys are less fluid in CO₂ molds than in green sand. Investigations also indicate that certain variabilities in testing procedure which an operating foundry might encounter have no statistically significant effect on fluidity. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/82879 |
| Date | January 1960 |
| Creators | Agee, Marvin H. |
| Contributors | Industrial Engineering |
| Publisher | Virginia Polytechnic Institute |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis, Text |
| Format | ii, 89 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 26595765 |
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