Improvements in or relating to the manufacture of unstainable irons and steels

摘要

198,423. Wild, R., and Wild, A. H. March 1, 1922. Alloys.-In a process for the production of ferroalloys, particularly iron-chromium alloys, such as ferro-chrome or unstainable iron or steel, of the type in which compounds of one or more of the metals are reduced by means of silicon, the reduction is effected in presence of an excess of the reducible compounds over the quantity chemically equivalent to the reducing-agent. The reducing- agent may be ferro-silicon, and the reduction may be effected in the presence of lime or other slag-forming material. A charge of chromite may be first fused with a bath of iron or steel and the silicon reducing-agent added, whereafter a further charge of chromite substantially equivalent to the reducing-agent is added; or the chromite and reducing-agent may be heated together and iron or steel afterwards added: or a ferro-chrome may be first prepared using excess of chromite as described above and the fused product may be mixed with molten iron or steel preferably containing dissolved oxygen or oxides. A small proportion of a deoxidizing agent such as ferro-manganese, silico-manganese, ferro-silicon, or aluminium, may be added to the bath prior to the addition of the silicon reducing-agent. The material may be submitted to an oxidizing blow at any convenient stage, preferably in presence of an element such as manganese which is more readily oxidizable than chromium, as described in Specification 197,733. In some cases part or all of the excess of reducible compound may be provided by another compound such as iron oxide. Specification 174,618 is referred to.