| 摘要 |
PURPOSE:To produce easily a steel sheet galvanized on one side in the stage of galvanizing the one surface of the steel sheet by forming a strippable inside layer having a specific compsn. on the non-plated surface and forming an oxide layer having poor wettability with molten zinc thereon. CONSTITUTION:A stop-off agent for molten zinc having an excellent release property is coated on the non-plated surface of a steel sheet in the stage of producing the steel sheet galvanized on one side. The compsn. consisting of 35-50% MgO, 5-30% alkali salt of silicic acid, 18-30% boric acid and 12-20% alkali metallic hydroxide is made into a slurry with an adequate amt. of water to prepare such stop-off agent. Said agent is coated on the surface of the steel sheet so as to be coated at 35-100g/m<2> by weight after drying, by which an inside layer is formed. Pulverous powder consisting of oxide such as TiO2, Al2O3, MgO, ZrO2, SiO2 or the like and having 200 mesh is coated thereon as an outside layer and is dried. Such steel sheet is immersed in a galvanizing bath and is thus plated on the one side. The stop-off agent layer for the plating bath consisting of the above-mentioned inside and outside layers is easily stripped and the steel sheet plated on one side is manufactured. |
