Iron

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…these. Today blast furnaces that use blasts of air heat the iron with ferroalloys to produce steel. (Encarta, 1996). The steel is then shaped into screws which are used to hold the face mask on the shell of the football helmet. Steel is used for this purpose due to its strength. The physical properties of iron are totally changed once it has become steel and therefore good to make screws as it will no longer rust.