Ferro silicon is a major metallurgical material traded on the Metalshub marketplace. It is often used by foundries as an inoculant to decrease chill tendency, improve graphite morphology and distribution, increase the number of eutectic cells, and improve mechanical properties.
Additions of strontium silicide with both low aluminium and low calcium grades of normal foundry ferrosilicon were tried to see if they could enhance their inoculating power when used to inoculate flake graphite irons.
Ferrosilicon is a silvery gray ferroalloy, made of coke, steel scrap and quartz (or silica) smelted in an electric furnace. It is a deoxidizer in steelmaking, and also can be used as an inoculant for cast iron.
When added to molten iron, it promotes the formation of graphite nuclei during eutectic solidification, thus reducing the chill on the edges of castings and section sensitivity in thin-sectioned castings. In addition, it can significantly reduce the supercooling degree of molten iron and enhance the precipitation and spheroidization of graphite.
The inoculant can contain barium, strontium or zirconium to increase the effectiveness of the inoculant. It can be used for liquid iron, ductile iron and gray cast iron in order to improve the spheroidizing grade, strengthen the graphitization core and refine the grains. It can reduce high manganese slag, change the mechanical properties and reduce shrinkage defects of the castings. It can also increase the high temperature heat resistance of the castings.
During the casting process, calcium is introduced as an inoculant to eliminate chill and improve graphite morphology. Having an adequate amount of inoculant is essential to the quality and strength of grey or ductile iron. Without it, the metal is susceptible to chill and will form carbides which will result in poor mechanical properties, such as tensile strength or hardness.
The inoculant is a powder that can be added to the sprue or injected directly into the molten metal. It can be sifted into different size grades depending on the intended use. For example, it is common for sprue inoculant to be fine dust-like particles that can range from 10-50 mm.
Commercially available ferrosilicon has a silicon content of 15–90 wt%. It is produced by melting quartz sand or steel scrap in an electric arc furnace with a reductant, such as coke. It can be found in lumpy or powder form and contains varying proportions of silicon and iron silicides.
Approximately 3-4 kilograms of FeSi is used to produce one tonne of regular carbon steel and up to 5-10 kg of FeSi for stainless steel production. American Elements produces and sells several standard grades of this product, including Mil Spec (military grade); ACS, Reagent and Technical; Food, Agricultural and Pharmaceutical; Optical Grade and USP/BP. We also offer custom packaging for your convenience.
This iron-silicon alloy is produced using quartz, iron ore, coke and biocarbon as raw materials. It is used in steelmaking as a deoxidizer and an alloying component.
It is also a popular raw material in foundry applications. Our inoculants are based on FeSi-based alloys. These products are added in liquid cast iron in order to improve the balance of nuclei for eutectic solidification, and they can contain active metals such as aluminium, barium, bismuth, strontium or zirconium. These inoculants must be added shortly before or during casting. This helps to avoid casting defects such as slag inclusion and porosity.
Sulfur is a highly reactive element, with the ability to form various allotropes, some of which are useful as inoculants. The rhombohedral allotrope, designated r-sulfur, is composed of rings of six sulfur atoms. This form is prepared by treating sodium thiosulfate with cold, concentrated hydrochloric acid and extracting the residue with toluene. R-sulfur is unstable and reverts to the orthorhombic allotrope, a-sulfur, upon cooling.
The inoculating effect of strontium is analogous to, but stronger than, the effect of aluminium in normal ferrosilicon. However, strontium silicide can be made to contain almost no aluminium. This inoculant is therefore virtually free of aluminium and may be used in combination with low aluminium nodular graphite irons without fear of pinhole formation.
The spheroidal shape of the graphite nucleation promoted by this inoculant can help to shorten the time required for graphite nucleation, and it also helps to improve the distribution of graphite within the cast iron. This can greatly decrease the chill tendency, and improve the mechanical properties of the gray iron castings.
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