Wetting Characteristics of Silicon Containing Steel with Molten Zinc

Abstract

After being heated for a short time in a H₂-N₂ reducing gas, Si-containing steel sheets were dipped into a molten zinc. The effects of Si content in the steel, the preparatory treatment conditions before heating and the reductions in the gas on the dynamic wetting characteristics were studied by use of a measuring instrument of gas reduction type meniscograph. At the same time, a study was made on the relation between the wettability of steel and the structure of the surface layer which was changed depending on these conditions.
The following results were obtained:
1) The wettability of the steel changes depending on the preparatory treatment conditions before the reduction heating.
2) When the Si content in the steel is constant, the equilibrium wetting force is lowered by increasing the heating temperature in the gas or lengthening the heating time therein.
3) A Si-enriched oxide layer which is formed by a reduction heating is mainly composed of (FeO)₂SiO₂ and SiO_X, depending on the Si content in the steel. The wetting characteristic is deteriorated as related to the change of the structure of this Si-enriched oxide layer.