The chemical name of the ferro-alloy is FeSiMn. Si-Mn generally contains not less than 4 % of Fe, more than 30 % of Mn, more than 8 % of Si and not more than 0.2 % of P. It is properly classifiable under subheading 7202.30.0000 of the Harmonized Tariff Schedule of the United States (HTSUS). The low C Si-Mn is a ferroalloy with the chemical specifications of minimum 55 % of Mn, minimum 27 % of Si, minimum 4 % of Fe, maximum 0.10 % of P, maximum 0.10 % of C, and maximum 0.5 % of S.

Si-Mn is available as metallic lumps with a silver/grey appearance (Fig 1). It is an odorless solid material. It is usually free from extraneous contaminations such as slag and non-metallic inclusions etc. It is normally supplied as crushed and screened material.

The normal standard sizes for Si-Mn consist of are
(i) 20 mm to 80 mm with undersize 10 % maximum
(ii) 10 mm to 50 mm with undersize 10 % maximum
(iii) 3 mm to 25 mm with undersize 5 % maximum

The oversize limit in all three cases is 10 % maximum. Si-Mn is usually delivered as bulk normally packed in big bags.