| abstract |
(57) [Summary] [Purpose] In the production of hot-dip galvanized steel sheet and alloyed hot-dip galvanized steel sheet using high-strength steel sheet with Si content of 0.2% by weight or more as the base material, plating wettability is ensured and no plating occurs. To accelerate the alloying treatment speed and efficiently produce a plated steel sheet with good surface quality. [Structure] By coating an oil or solution containing a calcium and / or magnesium compound before plating, or by adding a calcium and / or magnesium compound to rolling oil, washing water, etc., the total amount in terms of metal can be calculated. 0.1 -50 mg / m 2 of calcium and / or magnesium compound is attached to the surface of steel sheet, and in a non-oxidizing atmosphere or in an oxidizing atmosphere such that the amount of iron oxide deposited after preheating is 5 g / m 2 or less in terms of Fe. After preheating, the material is heated and reduced in the temperature range of 600 to 900 ° C, immersed in a molten zinc bath for plating, and further alloyed if necessary. |