Melting plated manner null of spelter of low temperature heating and reduction abbreviation die or spelter based

摘要

PURPOSE:To allow hot dip coating of zinc of a reduction omission type with low-temp. heating by subjecting the surface of a steel sheet to Ni plating, etc., of a specific thickness prior to heating up and adjusting the oxide film of the above-mentioned plating metal at the time of immersion into a molten bath to a specific thickness. CONSTITUTION:One kind selected from Ni, Co, Cu, Sn, and Mn is plated on the surface of the steel sheet at 0.1 to 3.0g/m2 and thereafter, the steel sheet is heated near to the temp. of the molten bath of the zinc or zinc alloy in an oxidative atmosphere. This steel sheet is immersed as it is into the molten bath of the zinc or zinc alloy and is thereby plated. The oxygen concn. of the heating atmosphere or the heating rate (time) is adjusted to previously adjust the oxide film thickness of the plated metal to 20 to 2000Angstrom at the time of the immersion into the molten bath at this time. The hot dip coated steel sheet having an excellent adhesive property is obtd. by the low-temp. heating in this way even if the steel sheet is immersed as it is in the molten bath without subjecting the steel sheet to a reduction cooling stage.