Ferrosilicon 75 is a common specification of ferrosilicon alloy, and its implementation standards mainly include national standards and international standards, etc.
National Standard
Chemical composition:
According to GB/T 2272-2009 Ferrosilicon National Standard, Ferrosilicon 75 series products are divided into FeSi72, FeSi75-A, FeSi75-B, FeSi75-C and other grades according to the content of silicon and its impurities. Taking FeSi75-A as an example, its silicon (Si) content should be not less than 75.0% and not more than 80.0%; aluminum (Al) content should be not more than 1.0%; calcium (Ca) content should be not more than 1.0%; manganese (Mn) content should be not more than 0.5%; chromium (Cr) content should be not more than 0.5%; phosphorus (P) content should be not more than 0.03%; sulfur (S) content should be not more than 0.02%.
Size:
Generally, the size of ferrosilicon 75 has various specifications, the most common ones are 10-50mm, 20-100mm, etc. The size must be uniform, and the proportion of products with size deviation outside the specified range should not exceed a certain proportion, generally less than or equal to 5%.
Physical state:
Ferrosilicon 75 should be blocky or granular, the surface should be clean, without obvious inclusions and impurities, and no serious powdering phenomenon.
International standards
Chemical composition:
International standards such as ISO 4947:1986 "Ferrosilicon Alloys" also have corresponding provisions for the chemical composition of ferrosilicon 75, which are roughly similar to national standards, but there may be slight differences in the limits of some impurity elements. For example, the silicon content is also required to be in the range of 72% - 80%, the phosphorus content is generally required to be no more than 0.04%, and the sulfur content is no more than 0.03%.
Other aspects:
In terms of size, physical state, etc., international standards also have similar regulations, requiring uniform size and clean surface of products to ensure the quality stability and versatility of products in international trade.
Different application fields and customers may have some special requirements for the standards of ferrosilicon 75, but generally they are appropriately adjusted and refined based on national or international standards.
