Thesis: B.S., Massachusetts Institute of Technology, Dept. of Metallurgy, 1958 / Cataloged from PDF version of thesis. / Includes bibliographical references (leaf 18). / An investigation was made to determine the effects of various mold variables on the surface condition of CA-15 alloy steel castings. This alloy often suffers from a peculiar defect known as measles, and an attempt was made to determine what reactions at the old-metal interface cause this defect. To this end, small cylindrical pins were rammed in sand molds and heated or melted in a small induction furnace. The type of sand and clay used were held constant while various atmospheres were provided in the mold flask. It was found that samples heated to 50°C below the melting point in an oxidizing atmosphere showed the characteristic measles defect encountered in casting CA-15 alloy in green sand molds. Samples melted, cooled to 50°C below the melting point, and held at that temperature in an oxidizing atmosphere showed a combination of the two defects. It was found that the measles defect is due to a liquid state reaction in which the chromium in the melt is oxidized to Cr₂O₃·Fe₂O₃ and Cr₂O₃·FeO. The mechanism was found to be akin to a pitting form of corrosion. The oxidizing atmosphere is provided by moisture in the molding material and carbon dioxide formed by the combustion of organic binders. / by Harold G. Fraunhofer. / B.S. / B.S. Massachusetts Institute of Technology, Dept. of Metallurgy
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/138709 |
| Date | January 1958 |
| Creators | Fraunhofer, Harold G. |
| Contributors | Massachusetts Institute of Technology. Department of Metallurgy., Massachusetts Institute of Technology. Department of Metallurgy |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Academic theses., Academic theses., Thesis |
| Format | iii, 33 leaves, application/pdf |
| Rights | MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided., http://dspace.mit.edu/handle/1721.1/7582 |
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