HMS is 'Heavy Melting Scrap'. It is the generic term for most types of heavy steel scrap, normally cut to a size not exceeding 1.5m x 0.5m. It consists of cut lengths of pipe, re-bar, angles, steel poles, H or I beams, ships plate and so on. HMS 1 is the term for heavier scrap which has a density of at least 0.7 tons per cubic meter, whereas HMS 2 would be lighter steel scrap such as thin wall tubing (eg bicycle frames), sheet scrap less than 3.2mm thick and so on. The two are normally sold together with a ratio of 80/20 heavy and light, and so this would be the typical product being referred to when scrap dealers and traders talk about 'HMS'. HMS is the description used worlwide, with Americans trading a similar type of scrap called ISRI grade 201. 201 is shorter (1m x 0.5m) and should be at least 6mm thick, making it a slightly superior grade to HMS.