| 摘要 |
PURPOSE:To obtain a planted steel plate excellent in corrosion resistance, wet corrosion resistance and suitability to chemical conversion treatment, by immersing a steel plate in an Al base composite plating bath having a specific composition containing Zn and Si to which Mg, Mn, Cr and a Misch metal are added in a proper amount. CONSTITUTION:One kind or more 0.01-1.0% Mg, 0.01-0.5% Mn, 0.01-0.5% Cr and 0.01-2.0% Misch metal are added to an Al base Al-Zn alloy bath containing 1-30% Zn and 1-12% Si and, according to necessity, 0.01-0.5% Sb is further added to form a hot dipping bath material. This hot dipping bath material is heated to about 620-670 deg.C and, after a pretreated steel plate is immersed in the heated hot dipping bath to carry out plating, the adhered amount is controlled to pref., 30g/m<2> (single surface) or less by a gas squeezing method to prepare a steel plate hot-dipped in an aluminum base composite excellent in corrosion resistance, heat resistance and wet corrosion resistance and good for chemical conversion treatment and processability. |
