METHOD AND DEVICE FOR BLACKENING OF ARTICLE TO BE TREATED

摘要

PURPOSE:To improve production efficiency and to reduce considerably cost by subjecting integrally articles to be treated to a stage from burn-off to blackening in the state of housing said articles in a furnace. CONSTITUTION:A cage 2 contg. sintered articles on which a cutting fluid is stuck is put into a muffle 1, and a front door 3 is closed then an evacuating valve 15 is opened; at the same time, the inside of the muffle 1 is heated to the temp. at which the cutting fluid evaporates. Steam is then introduced through a steam introducing valve 10 and is maintained for a specified time at a set temp. While the steam is introduced in succession into the muffle, the temp. is increased up to the set temp. at which the surface of the sintered articles is blackened. The valve 15 is thereafter closed and the steam is introduced into the muffle 1 to maintain the specified steam pressure therein and to maintain the inside of the muffle at the set temp. at which the articles are subjected to the afore-mentioned blackening treatment.