摘要:
The present invention relates to a method for the manufacture of galvannealed metal sheet, wherein a hot strip is produced from an IF steel containing 0.01 to 0.1 wt. % silicon, wherein the hot strip is coiled at a coiler temperature no lower than 700° C. and no higher than 750° C., wherein a cold strip is rolled from the coiled hot strip, wherein the cold strip is recrystallization-annealed in an annealing furnace in an annealing gas atmosphere, wherein the cold strip thus annealed is provided with a zinc coating in a zinc bath, and wherein the coated cold strip is post-annealed at a galvannealing temperature no lower than 500° C. and no higher than 540° C. The invention also relates to a galvannealed metal sheet which possesses improved adhesion of the coating layer to the base material and proposes a method which is suited for the manufacture of metal sheet having such properties.
摘要:
A method for producing a steel component with a metallic anti-corrosion coating from a sheet steel product comprising at least 0.4% by weight Mn is disclosed. The sheet steel product is annealed in a continuous furnace under an annealing atmosphere containing up to 25% by volume H2, 0.1% to 10% by volume NH3, H2O, N2, and process-related impurities as the remainder, at a dew point between −50° C. and −5° C. at a temperature of 400 to 1100° C. for 5 to 600 s. The annealed sheet steel product has a 5 to 200 μm thick nitration layer with a particle size finer than the particle size of the inner core layer. Once coated with a metallic protective layer, a blank is separated from the annealed sheet steel product, heated to an austenitising temperature of 780 to 950° C., hot-formed, and cooled so that a hardened structure forms.