A furnace which refines molten pig iron from the blast furnace and scrap into steel. In this process, the proportion of scrap used can be increased to 100% of the metal charge. Once the furnace is charged and covered, graphite electrodes are lowered through holes in the roof. The electric arc travelling between the electrodes and the metallic charge creates intense heat which melts the charge. Alloying elements can be added during the process.