TREATMENT OF END FACE OF BILLET

摘要

PURPOSE:To seal a defective part of a billet by partial melting and to prevent progression of internal oxidation of the billet by pressing a solid thermit piece which is laminated and bound to a metallic plate to the exposed surface part of the cavity of the billet and igniting the same to bring the thermit into reaction. CONSTITUTION:An oxidizing agent such as potassium nitrate and an ignition support additive such as cryolite are added to a mixture composed of aluminum powder and iron oxide powder and the mixture is made into a solid piece by an org. binder such as phenol resin or the like. Such solid piece is bound to an about 0.5-1.5mm. thick iron plate which does not melt down by a caulking method or the like. Such solid piece is brought into contact with the exposed defective surface part of the cavity of the billet and a thermit reaction is induced by the heat of the billet or ignition, by which the defective part is melted and sealed. Oxidation is prevented from progressing to the inside of the billet by s such sealing.