| 摘要 |
PURPOSE:To make the cooling of objects to be heated uniform and prevent the variance in the hardness of heat treatment by sucking and passing an inert gas from the lower part of the objects to be treated to the upper part then cooling the same with a heat exchanger and flowing the same downward and again upward, at the stage of cooling the heated objects to be treated with the inert gas in a vacuum hardening furnace. CONSTITUTION:The object 8 to be treated which is heated to a hardening temp. in a heating chamber 3 of a vacuum hardening furnace 1 is conveyed to a gas cooling position D1 in a gas cooling chamber 4. The inert gas in the chamber 4 is sucked by a suction fan 11 in the upper part. The inert gas cools the object to be treated by flowing through the same from below to above, and this gas as a high temp. gas passes through an upper wall 4a, flows downward in a passage 14 constituted of a guide member 13 and a side wall 12 and is cooled with a heat exchanger 15 en route. This cooled inert gas passes through a dispersion guide 17, diffuses again from below the object 8, and is sucked upward, thereby cooling the object to be treated. The object to be treated is cooled uniformly, and the variance in hardening hardness owing to cooling irregularities is obviated. |
