Method for hot-dip coating of a steel flat product

A method for hot-dip coating of a steel flat product with a metallic protective coating, comprising:

• a) providing a steel flat product obtained by cold- or hot-rolling, which is produced from a steel containing at least 2.0 wt. % Ni and at least 5.0 wt. % Cr;
• b) heating of the steel flat product, for a period of 1-30 s, to a holding temperature between 700 and 1100° C., wherein the heating takes place under a heating atmosphere, wherein a dew point of the heating atmosphere is −15° C. to +30° C. and the heating atmosphere contains N2 and unavoidable contaminants, and optionally one or more of the following constituents by volume:
• H2:
• 1-50%,
• CO:
• 0.1-2.0%,
• CO2:
• 5.0-15.0%;
• c) holding the heated steel flat product at the holding temperature for a holding duration of 10-120 s under a holding atmosphere which consists of N2 and unavoidable contaminants, 1.0-50.0 vol. % H2 and up to 1.0 vol. % O2, and wherein a dew point of the holding atmosphere is −30° C. to 0° C.;
• d) cooling the steel flat product from the holding temperature to a strip inlet temperature of 430-800° C.;
• e) passing the steel flat product through an inlet zone, in which the steel flat product is held under an inert or reducing inlet atmosphere until entry into a melt bath, and subsequent passage through the melt bath in which the steel flat product is hot-dip coated with a metallic coating;
• wherein the dew point of the heating atmosphere is higher than the dew point of the holding atmosphere, and the dew point of the holding atmosphere is higher than the dew point of the inlet atmosphere.