DIRECT RESISTANCE HEATING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a direct resistance heating device capable of: uniformly heat-treating a metal shaft material by uniformly press-contacting a heat dissipation block to an outer peripheral surface on each end side of the metal shaft material in an axial direction to dissipate heat; and obtaining uniform heating temperature distribution in the metal shaft material by maintaining the state that the heat dissipation block following thermal expansion of the metal shaft material due to direct resistance heating is press-contacted to the outer peripheral surface on each end side of the metal shaft material in the axial direction to stably dissipate heat even when the thermal expansion enlarges the diameter of the metal shaft material or elongates the metal shaft material in the axial direction.SOLUTION: A direct resistance heating device can dissipate a part of thermal energy generated during direct resistance heating by press-contacting each heat dissipation block (41 and 43) to an outer peripheral surface of each end part of a metal shaft material (5) held by a pair of electrode (7 and 9) in the axial direction, and maintain the state that the heat dissipation blocks (41 and 43) following thermal expansion of the metal shaft material (5) due to direct resistance heating is press-contacted to the outer peripheral surface on each end part side of the meta shaft material (5) in the axial direction when the metal shaft material (5) is thermally expanded during the direct resistance heating.