Magnetic field components are measured at multiple longitudinal positions and used to calculate estimated longitudinal position and length of a transversely localized electric current segment flowing across a gap between conductive bodies. The apparatus can be used with a remelting furnace. The electrode and ingot act as the conductive bodies, and arcs, discharges, or slag currents are the current segments spanning the gap. Actuators for movable sensors can be coupled to the sensors in a servomechanism arrangement to move the sensors along with the moving gap. An actuator for moving one of the conductive bodies can be coupled to sensors in a servomechanism arrangement to maintain the gap distance within a selected range as the gap moves.

A production method of a maraging steel includes: the step of producing, by vacuum melting, a remelt electrode which comprises from 0.2 to 3.0% by mass of Ti and from 0.0025 to 0.0050% by mass of N; and the step of remelting the remelt electrode to produce a steel ingot having an average diameter of 650 mm or more; wherein the resulting maraging steel includes from 0.2 to 3.0% by mass of Ti.

A production method of a maraging steel includes: the step of producing, by vacuum melting, a remelt electrode which comprises from 0.2 to 3.0% by mass of Ti and from 0.0025 to 0.0050% by mass of N; and the step of remelting the remelt electrode to produce a steel ingot having an average diameter of 650 mm or more; wherein the resulting maraging steel includes from 0.2 to 3.0% by mass of Ti.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Jr, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Jr, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

A method of melting and refining an alloy comprises vacuum induction melting starting materials to provide a vacuum induction melted alloy. At least a portion of the vacuum induction melted alloy is electroslag remelted to provide an electroslag remelted alloy. At least a portion of the vacuum arc remelted alloy is vacuum arc remelted to provide a singly vacuum arc remelted alloy. At least a portion of the singly vacuum arc remelted alloy is vacuum arc remelted to provide a doubly vacuum arc remelted alloy. In various embodiments, a composition of the vacuum induction melted alloy comprises primarily one of vanadium, chromium, manganese, iron, cobalt, nickel, copper, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, tantalum, tungsten, rhenium, osmium, iridium, platinum, and gold.

A method of melting and refining an alloy comprises vacuum induction melting starting materials to provide a vacuum induction melted alloy. At least a portion of the vacuum induction melted alloy is electroslag remelted to provide an electroslag remelted alloy. At least a portion of the vacuum arc remelted alloy is vacuum arc remelted to provide a singly vacuum arc remelted alloy. At least a portion of the singly vacuum arc remelted alloy is vacuum arc remelted to provide a doubly vacuum arc remelted alloy. In various embodiments, a composition of the vacuum induction melted alloy comprises primarily one of vanadium, chromium, manganese, iron, cobalt, nickel, copper, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, tantalum, tungsten, rhenium, osmium, iridium, platinum, and gold.

Methods of reducing copper metal content of shredded scrap steel are provided. The method includes continuously separating a first scrap steel fraction from an amount of scrap steel concurrently with separating a second fraction from the amount of scrap steel; continuously separating the second fraction and providing a nonmagnetic fraction and, concurrently, a third scrap steel fraction; grinding the nonmagnetic fraction followed by magnetic separation to provide a fourth scrap steel fraction and, concurrently, an enriched nonmagnetic fraction; continuously combining the first scrap steel fraction, the third scrap steel fraction, and the fourth scrap steel fraction to obtain a combined scrap steel product comprising scrap steel with reduced copper metal content; and introducing the combined scrap steel product to an electric arc furnace. Systems of reducing copper metal content of shredded scrap steel are also provided.

Methods of reducing copper metal content of shredded scrap steel are provided. The method includes continuously separating a first scrap steel fraction from an amount of scrap steel concurrently with separating a second fraction from the amount of scrap steel; continuously separating the second fraction and providing a nonmagnetic fraction and, concurrently, a third scrap steel fraction; grinding the nonmagnetic fraction followed by magnetic separation to provide a fourth scrap steel fraction and, concurrently, an enriched nonmagnetic fraction; continuously combining the first scrap steel fraction, the third scrap steel fraction, and the fourth scrap steel fraction to obtain a combined scrap steel product comprising scrap steel with reduced copper metal content; and introducing the combined scrap steel product to an electric arc furnace. Systems of reducing copper metal content of shredded scrap steel are also provided.

In a method for preparing a nickel-based alloy, an electrode is produced by VIM, VOF or VLF, heat-treated in a furnace between 500 and 1300° C. for 10 to 336 hours to reduce stresses and aging, the heat-treatment being conducted for at least 10 hours and at most 48 hours at 1000° C. to 1300° C., and cooled to between room temperature and less than 900° C., then remelted using ESR at 3.0 to 10 kg/minute to form an ESR block which is cooled to between room temperature and less than 900° C., and remelted again using VAR at 3.0 to 10 kg/minute and a remelting rate fluctuation range of less than 15%, preferably 10%, ideally 5%; the remelted VAR block is heat-treated between 500 and 1250° C. for 10 to 336 hours, then shaped into the desired product shape and dimension by hot or cold forming.