PIPE OF GATING SYSTEM MADE OF METAL

PURPOSE:To provide a pipe of gating system made of metal which prevents the erosion effect and carburization phenomenon of the changing flow of molten metal by forming an Al2O3 film on the in side surface side of a metallic pipe in contact with the molten metal and an Fe-Al alloy layer wherein the concn. and thickness of Al are specified in continuation therewith. CONSTITUTION:An Fe-Al alloy layer wherein the concn. of the Al in the outermost part is 15-35wt% and the thickness is 0.1-1.0mm. is formed on at least the side (inside surface side) of a metallic pipe made of carbon steel, alloy steel, stainless steel or the like in contact with molten metal. The Al2O3 film on the surface is dense, prevents the intrusion of oxygen atoms and metallic atoms and withstands the erosion effect of the charging flow. Since the film prohibits the intrusion of carbon atoms, it can be prevented from a carburization phenomenon. The metallurgical binding between the Al2O3 film and the alloy and between the alloy and the base of the metallic pipe is secure and there is no possibility of failure, etc. caused by thermal impact in the stage of casting. Such pipe of gating system is suited for a casting mold, etc.