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potential shortfall for outsiders at any price,” he said. Linebarger said it is diffi cult to

pin down what the precise avail- ability of rare earth elements from China will be going forward due to government and commercial secrecy. Several Chinese rare earth mines have been reported to be closed due to unsafe environmental practices. “Some people think they are

hoarding [the materials] so they can drive the price up,” Linebarger said. “But the supply issue isn’t as critical if the fellow in the back room will send it to you.” T e market picture also is obscured

by the nature of the rare earth ele- ments. While Linebarger said the demand for the metals is generalized, the availability of them individually may vary. “People look upon rare earths as

one entity, but the demand may be great for terbium, for example, and not all that great for some others,” he said.

Additional Additives When examining the story of raw

materials availability in the metalcast- ing industry, one word continually comes up: China. According to Mura- tore, the market demand for silicon carbide and other recarburizers (or carbon raisers) is no exception. Muratore said the materials are

found in abundance in China and only sporadically in the U.S. Plus, the country is now a major consumer of

Lanthanum, cerium, praseodymium and neodymium are the most critical rare earth elements for the

metalcasting industry.

the additives in a variety of applica- tions, where it was recently only a minor player. “When you are making iron cast-

ings, you are almost always buying recarburizer,” he said. “And everything from the high end, totally graphitic material to the low end stuff like coke breeze is in higher demand.” As a result, the prices have been driven up. Currently, only one source of silicon

carbide, which raises silicon levels in ferrous melts in addition to carbon and induces deoxidization and increased melt rates, is operating in the U.S. And while a number of other non-Chinese providers are on the market, the Asian giant maintains a strict measure of control over the material. “Other sources were always there,

but they could not compete with China,” said Sudhir Gupta, vice presi- dent of product marketing for Miller and Co. “And because there is still not


Beyond melt treatment, rare earth metals have found a use in one other area of metalcasting—as an alloying element in magne- sium castings. According to the technical department of the American Foundry Society, Schaumburg, Ill., most standard magnesium casting alloys have low high-temperature strength. For

example, in some automotive

applications, magnesium castings will show creep, meaning the metal will shift as temperatures increase. Rare earths elevate high temperature strength and combat the effects of creep.

This air inlet frame and gearbox for aerospace accesory drives was cast in ZE41 magnesium, a specialty alloy that contains rare earth elements.

an oversupply from other produc- ers, China sets the global pricing.” An adequate supply of silicon

carbide still exists worldwide, according to a number of industry suppliers. But like so many materi- als, demand for silicon carbide is rising in other markets (e.g. abrasives, lubricants, solar cells and silicon wafer processing), and prices can escalate anywhere from 10-20% during a given pur- chasing period. “T ere could be a shortage [in

the future], but we don’t yet see one as such,” Gupta said. “T e pricing will be the issue. It is not a normal supply and demand situation where you can buy it anytime.”

Finding New Material Because the raw materials supply

picture can hinge on so many external factors, many metalcasters can feel hamstrung by rising prices. “In the scheme of things, the

foundries are a very small component,” Peaslee said. “We have zero infl uence on the pricing of those commodities. T ey are driven by other industries that use far more, and we just have to sit here and grin and bear it.” But what can be done in the case of

an actual shortage of supply? To address the rapid loss of rare

earth element supply, some research has been done to find alternative materials that serve the same func- tion in casting melts, but the most

August 2011 MODERN CASTING | 29

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