Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm.sup.2 if hot-formed or hot-rolled; and measuring 800 mm.sup.2 if cold-rolled, does not contain non-metallic inclusions of diameter>10 μm, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 μm over 100 mm.sup.2, the observation being performed by image analysis over a polished surface measuring 650 mm.sup.2.

Disclosed is a steel composition including specified ranges of Ni; Mo; Co; Mo+Co+Si+Mn+Cu+W+V+Nb+Zr+Ta+Cr+C; Co+Mo; Ni+Co+Mo; and traces of Al; Ti; N; Si; Mn; C; S; P; B; H; O; Cr; Cu; W; Zr; Ca; Mg; Nb; V; and Ta in specified ranges; the remainder being iron and impurities. The inclusion population, as observed by image analysis over a polished surface measuring 650 mm.sup.2 if hot-formed or hot-rolled; and measuring 800 mm.sup.2 if cold-rolled, does not contain non-metallic inclusions of diameter>10 μm, and, in the case of a hot-rolled sheet, does not contain more than four non-metallic inclusions of diameter 5-10 μm over 100 mm.sup.2, the observation being performed by image analysis over a polished surface measuring 650 mm.sup.2.

A method of vacuum arc remelting an ingot provided in a crucible assembly having an electrode includes generating a rotating magnetic field normal to a longitudinal axis of the ingot and localized to an arc region during remelting. The rotating magnetic field interacts with a melting current to produce a rotating arc directed radially outward.

A method of vacuum arc remelting an ingot provided in a crucible assembly having an electrode includes generating a rotating magnetic field normal to a longitudinal axis of the ingot and localized to an arc region during remelting. The rotating magnetic field interacts with a melting current to produce a rotating arc directed radially outward.

Magnetic field components measured around and along a remelting furnace and other measured furnace parameters are used to estimate concentricity of the electrode within the crucible of the furnace, to estimate a distribution of drip shorts across a gap between the electrode and the melt pool, or to detect, locate, and categorize anomalous events during the remelting process. Those can be used to control the operation of the furnace during the remelting process, or incorporated into a longitudinal or three-dimensional map of the resulting ingot. Artificial intelligence, machine learning, or a neural network can be employed.

Magnetic field components measured around and along a remelting furnace and other measured furnace parameters are used to estimate concentricity of the electrode within the crucible of the furnace, to estimate a distribution of drip shorts across a gap between the electrode and the melt pool, or to detect, locate, and categorize anomalous events during the remelting process. Those can be used to control the operation of the furnace during the remelting process, or incorporated into a longitudinal or three-dimensional map of the resulting ingot. Artificial intelligence, machine learning, or a neural network can be employed.

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, Ir, 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, Ir, 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 vacuum arc remelting system for forming an ingot from an electrode is provided that includes a crucible assembly configured to accommodate the electrode and the ingot, an electromagnetic energy source arranged about the crucible assembly, and a lift mechanism operable to move the electromagnetic energy source along a longitudinal axis of the crucible assembly. A magnetic field generated by the electromagnetic energy source is localized to an arc region during remelting, and in one form, the electromagnetic energy source is a coil assembly having a magnetic core and a plurality of coil pairs wrapped around the core, wherein the coil assembly is operable to generate a magnetic field from the coil based on electric current flowing in the plurality of coil pairs.

A vacuum arc remelting system for forming an ingot from an electrode is provided that includes a crucible assembly configured to accommodate the electrode and the ingot, an electromagnetic energy source arranged about the crucible assembly, and a lift mechanism operable to move the electromagnetic energy source along a longitudinal axis of the crucible assembly. A magnetic field generated by the electromagnetic energy source is localized to an arc region during remelting, and in one form, the electromagnetic energy source is a coil assembly having a magnetic core and a plurality of coil pairs wrapped around the core, wherein the coil assembly is operable to generate a magnetic field from the coil based on electric current flowing in the plurality of coil pairs.