An alloy of iron and manganese (80% manganese) used in making additions of manganese to steel or cast-iron. Ferroalloy, An alloy of iron with a sufficient amount of some element or elements such as manganese, chromium, or vanadium for use as a means in adding these elements into molten steel. Found on https://steelforge.com/literature/steelog-the-5000-word-metals-glossary/