| 摘要 |
1450330 Low-manganese steel production NIPPON STEEL CORP 31 May 1974 [31 May 1973] 24237/74 Heading C7D Molten pig iron is treated to reduce its Mn content to not more than 0À35% after which it is blown with oxygen in a converter to produce steel containing not more than 0À065% Mn, not less than 0À03% C and not more than 1000 p.p.m. of oxygen. Preferably the carbon content does not exceed 0À06% and the nitrogen 35 p.p.m. Manganese removal is effected by injection of chlorine or carbon tetrachloride, or by stirring with iron oxide having a bulk density of 0À3 to 1 gm/cm<SP>3</SP> possibly in conjunction with fluxes such as limestone silica or fluorite. The carbon content may be reduced by vacuum degassing, or at a later stage by decarburization annealing to 0À005-0À06% while prior to casting Si may be added e.g. 2À5-4%, and also one or more of Mn, S, Al, Se, N, Sb, V, Cu, P, Ti or Cr to provide a dispersed phase facilitating production of the desired phase on secondary recrystallization. |
