Inoculants are a key component in grey and ductile iron castings. They help to eliminate chill and bring the carbon out as graphite in the cast iron. A well-selected inoculant can make the difference between a good or poor cast.
A new foundry inoculant from Elkem Silicon Products cost-effectively improves graphite structures and helps reduce chill in ductile iron castings without the use of rare earths. It can be used with any ductile iron nodularizing treatment.
The basic raw material inoculant used in foundries, Ferrosilicon is an iron-silicon alloy that contains a wide range of other elements. It is made by reducing silica with coke in electric arc furnaces. The result is a shiny, metallic-grey lump material or briquettes.
Ferrosilicon can be used in its pure form as a deoxidizer, or with other additives to improve specific properties of steel. It also provides the key element to inoculate cast irons and accelerate graphitization.
We warehouse standard 75% FeSi Foundry grade inoculant with a minimum of 2% combined weight of aluminum and calcium. This high ratio of inoculant carriers allows the inoculant to react with iron oxides in the melt to reduce chill and carbides.
American Elements produces a variety of grades of this popular product. These include Mil Spec; ACS, Reagent and Technical Grade; Food, Agricultural and Pharmaceutical Grade; and Optical Grade. In ductile irons, Resulf 30 IEP Plus is used to lower chill, increase nodule count and ferrite levels, and reduce carbides for improved machinability.
We all know what aluminum is; it’s in our soda cans, our airplanes and cars, and that snazzy new iPhone 6. It’s the second most abundant metal in the Earth’s crust and it has many useful properties. It doesn’t rust, it’s lightweight and it’s strong. It can even withstand extreme temperatures, and it won’t ignite or burn, making it perfect for cryogenic purposes.
It’s also highly conductive of both heat and electricity, and it can be made into alloys with nearly all other metals. Pure aluminum doesn’t occur in nature, but it can be extracted from mined minerals and ores like bauxite. It took humankind a long time to figure out how to do this, and only in 1824 did Hans Christian Oersted successfully extract it from alum. The element is a soft, silvery metal that is non-magnetic and corrosion resistant. It has a number of other useful characteristics and can be finished in a variety of ways, including anodizing.
One of the biggest challenges to even the most experienced foundry-man is finding the right combination of elements and practice for optimum inoculation results. In order to achieve a well-formed matrix and to avoid casting defects such as chunky graphite, a Barium containing inoculant is often used.
The developers of inoculants from Elkem Silicon Products have developed a bismuth alloy that is especially designed for ductile iron practices that use cerium-free magnesium nodulizers. It promotes the formation of small, uniformly distributed spheroidal graphite nodules in molten ductile iron. This leads to good graphite nodularity and castability, and allows the use of less inoculant. This saves money and is ecologically friendly. The alloy is available in different grain fractions to suit the inoculation location within the process – be it in ladle, in stream or in mold.
English
Write a Message