| 摘要 |
PURPOSE:To prevent deterioration in external appearance and development of rust in steam treatment, by using a rust preventive material which vaporizes without forming residue at a temp. not higher than 500 deg.C, in barrelling of ferriferous sintered part. CONSTITUTION:Ferriferous sinterd part is put into a barrel together with silica, steel balls, and soap soln., etc., and is abraded by rotating the barrel. In that case, the sintered body is impregnated in its void with a rust preventive in order to prevent rusting of the sintered body due to water. For the rust preventive is used polybutene liq. which vaporizes without forming residue at a temp. not higher than 500 deg.C. The rust preventive is impregnated to the sintered body once again after the barrelling. After barrelling, the sintered body impregnated with polybutene is steamtreated at about 550-650 deg.C in order to improve external appearance, rust preventive property, and sealing property. Because polybutene vaporizes completely, no decrease in the above described effect is caused. |
