Keith Dwight Millis (May 20, 1915 – July 6, 1992) was an American

metallurgical Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sc ...

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the limit ...

and inventor of

ductile iron Ductile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron and SG iron, is a type of graphite-rich cast iron discovered in 1943 by Keith Millis. While most varieties of cast iron are ...

. Keith Millis grew up in Rensselaer, New York and earned his Bachelor of Science in Metallurgical Engineering as a 1938 graduate of Rensselaer Polytechnic Institute. A year later he was conferred a Master of Science degree in Metallurgical Engineering at RPI. Early in the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

, chromium was considered critical to the war effort and experimentation was conducted by Millis to find a substitute. He made his discovery while experimenting with molten iron and

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

. The original intent was to find another element that would cause all the

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

in the

cast iron Cast iron is a class of iron– carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impur ...

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...

to be combined as

carbide In chemistry, a carbide usually describes a compound composed of carbon and a metal. In metallurgy, carbiding or carburizing is the process for producing carbide coatings on a metal piece. Interstitial / Metallic carbides The carbides of th ...

. Magnesium was a known carbide former. Instead, the

graphite Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on lar ...

in the iron formed into spheroidal shapes, and the cast iron had high tensile strength plus it exhibited ductility. Thus was born

in 1943. Millis and others at the International Nickel Company (Inco) sought and obtained U.S. patent 2,485,760 on October 25, 1949 for magnesium additions to cast iron that would spheroidize the graphite and dramatically ductilize the material. As an employee of Inco, Millis worked to promote the use of ductile iron as it began to be used as a commercial material. He also helped to found the Ductile Iron Society, an organization whose purpose is to promote the production and application of ductile iron castings. Millis died in 1992.

Legacy

Since his death, the Ductile Iron Society has held the "Keith Millis World Symposium on Ductile Iron", a technical meeting concerning all facets of ductile iron material, processing and applications. The event has been held approximately every 5 years: * 1993 - Hilton Head Island, SC * 1998 - Hilton Head Island, SC * 2003 - Hilton Head Island, SC * 2008 - Las Vegas, NV * 2013 - Nashville, TN The most recent symposium was co-sponsored by the

American Foundry Society The American Foundry Society (AFS) is a professional, technical and trade association for foundries and the broader metal casting industry. The society promotes the interests of foundries to policymakers, provides training for foundry workers, ...

. He was inducted into RPI's alumni hall of fame in 1999. A perpetual international scholarship has been awarded by the Ductile Iron Society Foundry Educational Foundation in Millis's name since 1991.

References

External links

Ductile Iron SocietyAmerican Foundry Society
{{DEFAULTSORT:Millis, Keith 1915 births 1992 deaths American metallurgists Foundrymen Rensselaer Polytechnic Institute alumni People from Rensselaer, New York Scientists from New York (state)