| 摘要 |
<p>1,246,736. Making steel in an induction crucible. HUTTENWERK OBERHAUSEN A. G. Nov. 4, 1969 [Nov. 29, 1968], No. 54041/69. Heading C7D. A process for making steel in an induction crucible furnace having a cylindrical crucible surrounded by a cylindrical induction coil comprises maintaining the ratio of the induction coil input to the crucible contents at a value high enough to form a dome on the bath so elevated at the centre that the slag provided to absorb from the bath elements that are undesirable in the steel forms a toroidal vortex round it, which serves to drag below the slag surface charge materials introduced on to the dome. The preferred conditions are a specific power at 50 c/sec of at least 350 KW/tonne, and at other frequencies the quotient of the specific power input and the square root of the frequency is at least 49À5. The charge material may be low density material such as sponge iron in lump granular or powder form, the material being charged on the slag free dome of metal. The charge material may be added at a rate matching the power input to the coil at the time, so that the heat required to melt down the additions, form any fresh slag, and support the reactions, corresponds exactly to the heat being generated inductively in the bath. The carbon content of the bath may be regulated to less than 0À1% by weight. This may be achieved by oxidizing ore additions, by blowing with oxygen or by periodically adding a carburizing agent. A semi continuous method may be used wherein 40-50% of the contents are tapped in each cycle. Slag formers that promote de-phosphorization may be added with the sponge iron or after the tapping the first slag. Desulphurizing agents may also be added.</p> |
