Abstract: A hollow arc furnace electrode comprises a central channel formed in its upper part as a tube and in its lower part as a passage extending through a graphite tip of the electrode. A metallic electrode portion is arranged around the central tube above the tip, which electrode portion is provided with channels for liquid coolant flow.

Abstract: A DC arc furnace including a hearth adapted to contain a melt and having a melt electrode which is only effective when covered by the melt, an enclosure for the hearth including a roof over the hearth, at least one arcing electrode depending downwardly through the roof and adapted to initially melt a charge of solid metal on the hearth and thereafter the resulting melt, and at least one starting electrode through which electric power is transmitted to the charge of solid metal until it is melted down by the arcing electrode to enough melt to cover the melt electrode; the starting electrode or electrodes depending downwardly through the roof at a position horizontally offset from the arcing electrode and being adapted to be moved downwardly so as to press on the charge of solid scrap on the hearth until the charge is melted down by the arcing electrode so as to cover the melt electrode and thereafter to be moved upwardly free from the charge.

Abstract: A DC arc furnace has a side wall and an electrically conductive hearth, a roof on top of the side wall and over the hearth, an arcing electrode depending through the roof, a plurality of electrical hearth connections extending from the hearth, a first DC power conductor connecting with the hearth connections to provide current and therefore magnetic field symmetry preventing arc deviations, the first and second conductors are extended from a position horizontally offset from the furnace to a point below the hearth and aligned vertically with the electrode, the first conductor forming at least two branches which extend from the point horizontally in opposite directions to beyond the side wall and upwardly so as to jointly connect with the arcing electrode, the second conductor forming at least two branches which extend horizontally from the point in opposite directions with one branch connecting with one of the hearth connections and the other branch connecting with the other one of the hearth connections.

Abstract: Apparatus for positioning an arc furnace electrode which includes a verticle tubular electrode mast which is both horizontally and vertically movable. Inside the mast is a hydraulic cylinder which has a double-acting piston. When the mast is in its uppermost position it may be locked whereby hydraulic fluid is removed from above the piston. Fluid is then introduced below the piston to raise it and the piston rod to a level above the furnace platform such that the mast can be moved horizontally over the platform.

Abstract: A DC arc furnace has power lines arranged completely symmetrically with respect to the arc so as to prevent the arc from bending angularly.

Abstract: A DC arc furnace has a hearth through which electric power is transmitted to a melt, and at least one starting electrode which can be inserted into the furnace from its outside, for pressing against a pile of scrap on the furnace's hearth so that with the furnace's arcing electrode, a circuit can be formed effecting a melt-down of the scrap. The hearth is of the type permitting electric power to be transmitted through it to the resulting melt once the melt is formed, and the starting electrode being thereafter inactivated. This starting electrode is characterized by being made of metal and having a tip of carbonaceous material, such as graphite, providing the starting electrode with the rugged characteristics required for its insertion into and removal from the furnace for start-up of the furnace, while at the same time providing a tip that is particularly resistant to the heat and possible incidental arcing occurring during the use of the starting electrode.