This standard covers the requirements for eight classes of carbon steel billets, blooms, slabs and bars for forgings designated as Class 1A, 2, 2A, 3, 3A, 4, 5 and 6 ( see Table 1 ).
IS 1875-1978 history
1978IS 1875-1978 Specification for carbon steel billets, billets, slabs and bars for forgings