Steelmaking apparatus

Steelmaking apparatus comprising an arc furnace having arc generating electrodes for producing ordinary steels and alloy steels from cold charges of steel scrap as raw material and fume evacuation means for drawing exhaust fumes out of the furnace and simultaneously creating a negative pressure therein during the operation thereof, the arc furnace comprising:

• a furnace wall formed of carbonaceous brick upward from a level slightly above a slag line within the furnace and cooled by water-cooled boxes imbeddedly sandwiched between the carbonaceous bricks;
• a furnace roof having an outer peripheral part made of steel-cased, magnesite-chrome bricks, a central part around electrode insertion holes provided with high-alumina ramming mass, and a part around a fume exhaust hole provided with a water-cooled ring and a high-alumina ramming mass disposed therearond;
• and
• a plurality of oxygen -- fuel oil burners each mounted in inserted state at a specific angle in the furnace wall through an opening therein provided with water-cooling means, the part of the furnace wall around each water-cooling means being provided with burner tiles, each of the burners being constructed to eject a stream of a mixture of air and fuel oil atomized therein from a flame emitting end of a burner cylinder and to eject a large quantity of oxygen in the form of a high-velocity convergent stream encompassing the stream of the mixture until the oxygen stream converges at an intersection with the mixture stream at a point which is a certain distance downstream from the burner thus becoming a long-focus stream, the burners thereby operating to cut melt directly the steel scrap and, simultaneously, to combust the combustibles which have been charged into the furnace together with the steel scrap.