We are supply Heavy melting steel. ... ISRI 203 (HMS 2): Wrought iron or steel scrap, black and galvanized, 18 inch (3.175 mm) and larger in thickness. ISRI 204 (HMS 2): Same as ISRI 203 except piecesmust be smaller than 36 in Ã? 18 in (914 mm Ã? 457 mm).