The influence of the dew point on the wettability of twinning-induced-plasticity steels by liquid Zn-0.23-wt% Al

The influence of the dew point on the wettability of the 17-wt% Mn twinning-induced-plasticity steels by liquid Zn-0.23-wt% Al alloy was investigated. Samples annealed at dew points ⩾ −20 °C exhibited a higher contact angle which did not change with time and a poor coating quality during hot-dipping galvanizing. Samples annealed at dew points dew points ⩽ −40 °C showed a relatively lower contact angle, leading to complete coating during hot-dip trials. The drastic change in the wetting behavior was explained by the selective oxidation on the surface (from a thick MnO layer to a relatively thin MnAl2O4 layer as dew point decreased).