Patent ID: 7556865
Filing Date: 2009-07-07
Classification: C23C,Y10S,Y10T

Abstract:
1. A method for hot-dip coating a strip of iron-carbon-manganese austenitic steel comprising: 0.30% ≦C ≦1.05%, 16% ≦Mn ≦26%, Si ≦1%, and Al ≦0.050%, the contents expressed by weight, in a liquid zinc bath comprising aluminum and having a temperature T heat treating said strip in a furnace which has an atmosphere that reduces iron, said heat treating comprising running said strip covered with oxide layers through said liquid zinc bath to coat the strip with a zinc-based coating, wherein the aluminum content in said bath is adjusted to a value at least equal to the content needed for the aluminum to completely reduce the crystalline MnO manganese oxide layer and at least partially reduce the amorphous (Fe,Mn)O oxide layer to form, on the surface of the strip, said coating comprising three iron-manganese-zinc alloy layers and one surface zinc layer, to form a coated steel strip.