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THE DUCTILE IRON FOUNDRY

The popularity of the Ductile Iron family of alloys arises from their versatility and good economy. Practical observations and adaptations by thousands of producing foundries have made the production of Ductile Iron castings, routine. Making Ductile Iron castings resembles the production of other ferrous castings; experience and craftsmanship are integral parts of founding.

A "small, but adequate" addition of magnesium is the basic step in changing graphite shape from flake to spheroidal. This treatment of the liquid iron is usually done with ferrosilicon-magnesium alloy. Equally important is the inoculation of the treated alloy by an addition of ferrosilicon when filling the pouring ladle.

The control over alloy composition involves approximately twenty elements. The determination of all is not absolutely necessary which highlights the need for reliable charge materials. Routine determination of carbon and silicon contents in the furnace is essential even in the smallest operation.

The successful foundry invariably has an established practice of careful production and quality control. As stated earlier, such control is not the designer's responsibility. However, if the foundry is not equipped with the most basic quality control equipment, or else, fails to use it, the integrity of the castings is suspect.

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