Patent ID: 7363822

Claim:
Apparatus for direct resistance heating of a metallic object, the apparatus comprising: first and second mechanical devices for securely holding the object along corresponding first and second attachment areas thereon; and first and second conductive devices for making abutting electrical contact with the object along first and second contact areas, respectively, on a surface of the object and routing electrical self-resistive heating current through a gauge length of the object situated between the first and second contact areas so as to self-resistively heat the gauge length, the first and second conductive devices being situated on the object inward of the first and second attachment areas, respectively, and spanning the gauge length and within a region of the object bridged by the first and second attachment areas thereby defining first and second end sections of the object situated between the first and second attachment areas and the first and second contact areas, respectively; and wherein said first and second mechanical devices are suitably configured such that the heating current flows between the first and second contact areas and through the gauge length and each of the first and second conductive devices has an appropriate pre-defined resistance and is suitably dimensioned such that for a specified amount of the heating current passing through the first and second conductive devices, the first and second contact areas and the gauge length, the first and second conductive devices self-resistively heat and impart additional heat to the object beyond that generated in the gauge length in order to produce a pre-defined thermal gradient across the gauge length but without self-resistively heating the first and second end sections of the object.