摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently heat a billet by reducing radiation loss at the time of induction-heating the billet. SOLUTION: An inner tube body 11a and an outer tube body 11b constituted with a refractoriness ceramic tube to both, are arranged in concentric-state with a fixed interval to constitute a furnace center tube 11. The outer tube 11b is covered with a heat insulating material 12 and a coil conduit tube 13 is wound on the heat insulating material 12. In the inner tube body 11a of the furnace center tube 11, the billet 20 as a material to be heated, is carried and heated with electromagnetic induction by energizing to the coil conduit tube 13.</p> |