David R Mathews

US Patent:

45817456, Apr 8, 1986

Filed:

Jan 16, 1985

Appl. No.:

6/691945

Inventors:

David R. Mathews - Las Vegas NV
Robert J. Krieger - Las Vegas NV

Assignee:

Timet - Pittsburgh PA

International Classification:

H05B 720

US Classification:

373107

Abstract:

Electric arc apparatus and an associated method are provided. Pairs of aligned cooperating coils are positioned on opposed sides of a crucible. In a preferred embodiment, three such pairs which overlap each other are employed so as to sequentially generate magnetic fields so as to provide a uniform magnetic field which will rotate the arc between the electrode and the crucible interior in a first direction. The arc rotation may be reversed. It is preferred that the maximum magnetic field created by each pair of coils be out of time phase with respect to the other coil's magnetic field. This apparatus and the associated method serve to resist undesired irregularities in the ingot exterior surface which irregularities would require subsequent treatment and result in loss of metal.