TESTING 1-2-3
Optimizing SiC Addition for Cupola Melting
One metalcasting company set out to determine the effects of silicon carbide purity on cupola melting. A MODERN CASTING STAFF REPORT
Holdings LLC’s Iron Mountain, Mich., facility is melted in a cupola. About 50% of cupola shops nationwide use steel as their primary charge material. Tis requires the addition of consider- able amounts of carbon and silicon to the melt to produce quality iron. One common material used to
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introduce carbon and silicon to ferrous melts is the silicon carbide (SiC) briquette. According to a group of Grede researchers and oth- ers, the briquettes generally contain either 36% or 65% SiC and variable
ADDING IT ALL UP Breaking down the industry’s latest research papers is as easy as 1-2-3:
“Effects of Varying SiC Purity on Cupola Performance” Adam Buchcuski, Brent Buchcuski and Greg Jarski, Grede-Iron Mountain; James Cree, Grede-New Castle
Background—To achieve the maximum benefits of silicon carbide (SiC) as an alloying agent in cupola melting, the differences in the performance of 36% SiC and 65% SiC must be better understood. Procedure—Consecutive cupola tests, each with a unique combination of SiC and coke, were run over a week’s time at Grede Holdings LLC’s Iron Mountain, Mich., facility. Results and Conclusions—For overall melt yield and reducing slag generation, high purity (65%) SiC outperformed 36% SiC. No statistically significant differences were found for other performance metrics.
36 | MODERN CASTING June 2012
ike 60% of the liquid iron produced in the U.S. in 2007, the alloy used to make castings at Grede
amounts of coal or high-sulfur petro- leum coke and sand. “Te 36% SiC contains well over double the amount of impurities as the 65% SiC per unit weight of contained SiC,” write Adam Buch- cuski, Iron Mountain plant manager, Brent Buchcuski, Iron Mountain melt superintendent, Greg Jarski, Iron Mountain plant metallurgist, and James Cree, Grede New Castle plant metallurgist, in their paper “Effects of Varying SiC Purity on Cupola Performance.” “Many of these dif- ferences can affect cupola operation. Te complexity of the effects and the difficulties in making meaningful measurements has led to great confu-
sion in assessing their relative values.” Using funding from the American
Foundry Society (AFS), the research- ers performed an in-plant study at Grede Iron Mountain to determine the precise differences between two common forms of SiC.
Question What is the relative value of 36%
SiC vs. 65% SiC in terms of melt yield, elemental recovery and melt efficiency?
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Background Te use of SiC as an
alloying agent in cupola melting can produce signifi- cant cost savings and reduc-
tions in carbon monoxide and carbon dioxide emissions. To achieve the maximum benefits, the differences in the performance of 36% SiC and 65% SiC need to be better under- stood. Because of the complexity of the two materials, each may perform more effectively in some cupolas but not in others. Recent research has provided
greater understanding of some aspects of the role of SiC in cupola operations, but the work has not specifically examined the differences between 36% SiC and 65% SiC. Tis study builds on the previous work to provide the information needed by metalcasting facilities to maximize the benefits of the materials in their cupola operations.
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