New Cover Alloys for Ductile Iron Treatment

ELKEM FOUNDRY PRODUCTS is offering three new grades of its Topseed^® brand cover alloy, indicating it is responding to various needs of ductile iron foundries. By covering magnesium-ferrosilicon nodulizers in the ductile-iron treatment ladle, Topseed cover alloy delays the magnesium reaction, reducing flare and increasing magnesium recoveries. Once the magnesium reaction is finished, Topseed’s strong inoculating elements promote a fully nucleated ductile-iron structure, minimizing the risk of forming hard carbides that are difficult to machine.

Of the three new cover alloys, most foundries will use Topseed 1010 cover alloy, according to Elkem, noting it has the calcium, aluminum, and barium levels that optimize inoculation, fade resistance, and slag conditioning.

For foundries making small additions or desiring additional fade resistance and slag conditioning, Elkem offers high-barium Topseed 2005 cover alloy with reduced aluminum levels.

For foundries seeking to limit the build-up of hard aluminates in the holding furnace or treatment and pouring ladles, Elkem offers Topseed 1005 cover alloy, which contains only 0.8% maximum aluminum.

Ductile-iron foundries can maximize magnesium recoveries and reduce treatment costs by combining Topseed cover alloy with low-magnesium nodulizers like Elkem’s Lamet^® magnesium-ferrosilicon. The supplier indicated foundries are using Lamet^® magnesium-ferrosilicon “as a pound-for-pound replacement for higher-magnesium nodulizers,” which it claimed will substantially reduce treatment costs. Savings can be achieved with this practice because low-magnesium nodulizers reduce slag volumes, lower furnace- and ladle-lining costs, reduce defect losses, and improve productivity, Elkem stated

Elkem technicians are available to work with ductile iron foundries to help design a ladle pocket that optimizes the use of Topseed cover alloy and magnesium-treatment alloys.

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