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Project Status: complete

Title: SF6 replacement evaluation in magnesium sand and investment casting

Principal Investigator / Author(s): Victor Okhuysen, Ph.D.

Contractor: Cal Poly Pomona University

Contract Number: 09-366

Research Program Area: Emissions Monitoring & Control

Topic Areas: Stationary Sources


Sulfur hexafluoride (SF6) will not be allowed for use in magnesium casting after January 1, 2013 given its high global warming potential of 23,900, and the magnesium casting industry needs to find a suitable replacement. This study explored the use of Novec 612 on dry sand, green sand and investment magnesium casting as a replacement alternative. Three facilities with different melting and pouring practices participated in this investigation. The levels of Novec 612 gas used were high to determine feasibility and but not optimal parameters. Castings were subsequently processed per customer specifications and attrition rates due to gas cover related defects were assessed. Novec 612 provided adequate protection as a cover gas for the production of magnesium castings in sand and investment casting applications. The scrap rates were not higher than with the use of SF6 gas protection. Mechanical properties were unchanged. Novec 612 requires the purchase of gas evaporating, mixing and metering equipment. The price depends on the features necessary to successfully use the Novec 612 given operational differences. Based on the results of this study in todayís prices there would be a net increase in production costs to the foundries from tens of thousands of dollars per year depending on the gas usage and specific equipment purchases related to the switch. However, it is important to note that this comparison is being made from optimized SF6 gas delivery systems with non-optimized Novec 612 systems. It is expected that lower quantities of Novec 612 would produce successful castings, but these quantities are not yet known.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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