| 摘要 |
PURPOSE:To treat the surfaces of a metallic mold for casting made of gray cast iron at a low cost by a simple method by subjecting the surfaces of said mold to an electrolytic etching treatment, an impregnating treatment with suspension of graphite and heat insulating refractory powder, and an impregnating and reinforcing treatment with a binder. CONSTITUTION:The surfaces of a metallic mold of gray cast iron which is machined or has as-cast black skins is first subjected to an electrolytic etching treatment. If the bases having intricately curved surfaces of the structure of the gray cast iron and enclosing the flake graphite 1 in many branched forms are removed, extremely porous surface layers are obtained. The thickness of the surface layers consisting of such flake graphite can be changed by electrolytic conditions. Next, the surface layers are impregnated with suspension of graphite powder and heat resistant refractory powder, after which the solvent is removed. Finally, the surface layers are impregnated with an inorg. binder and are sintered in order to reinforce the flake graphite in said layers and to bind the impregnated powder. |
