A method of manufacturing a hot dip coated steel strip, wherein coating takes place by leading the strip through a bath of molten metal including Al, the remainder of the metal being Zn, inevitable impurities and optionally a maximum of 0.3% of one or more additional elements, wherein the composition of the bath is controlled so as to have an aluminium content of more than 0.50%.

A method of manufacturing a hot dip coated steel strip, wherein coating takes place by leading the strip through a bath of molten metal including Al, the remainder of the metal being Zn, inevitable impurities and optionally a maximum of 0.3% of one or more additional elements, wherein the composition of the bath is controlled so as to have an aluminium content of more than 0.50%.

Provided is a solution composition for steel sheet surface treatment, comprising 30 wt % to 60 wt % of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B); 0.2 wt % to 0.4 wt % of a rust-inhibiting and corrosion-resisting agent; 0.1 wt % to 0.3 wt % of a molybdenum-based compound; 5 wt % to 10 wt % of a water-soluble cationic urethane resin; 0.5 wt % to 2.0 wt % of a silane coupling agent; and 27.3 wt % to 64.2 wt % of water, a zinc-based plated steel sheet surface-treated with the same, and a manufacturing method therefor, the zinc-based plated steel sheet surface-treated with the solution composition for steel sheet surface treatment containing trivalent chromium may have an excellent effect on corrosion resistance, blackening resistance, fingerprint resistance, oil resistance, and alkali resistance.

Provided is a solution composition for steel sheet surface treatment, comprising 30 wt % to 60 wt % of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B); 0.2 wt % to 0.4 wt % of a rust-inhibiting and corrosion-resisting agent; 0.1 wt % to 0.3 wt % of a molybdenum-based compound; 5 wt % to 10 wt % of a water-soluble cationic urethane resin; 0.5 wt % to 2.0 wt % of a silane coupling agent; and 27.3 wt % to 64.2 wt % of water, a zinc-based plated steel sheet surface-treated with the same, and a manufacturing method therefor, the zinc-based plated steel sheet surface-treated with the solution composition for steel sheet surface treatment containing trivalent chromium may have an excellent effect on corrosion resistance, blackening resistance, fingerprint resistance, oil resistance, and alkali resistance.

There is provided a hot-stamped body including: a steel base metal; and a metallic layer formed on a surface of the steel base metal, wherein the metallic layer includes: an interface layer that contains, in mass %, Al: 30.0 to 36.0%, has a thickness of 100 nm to 5 μm, and is located in an interface between the metallic layer and the steel base metal; and a principal layer that includes coexisting MgZn.sub.2 phases and insular FeAl.sub.2 phases, is located on the interface layer, and has a thickness of 3 μm to 40 μm.

There is provided a hot-stamped body including: a steel base metal; and a metallic layer formed on a surface of the steel base metal, wherein the metallic layer includes: an interface layer that contains, in mass %, Al: 30.0 to 36.0%, has a thickness of 100 nm to 5 μm, and is located in an interface between the metallic layer and the steel base metal; and a principal layer that includes coexisting MgZn.sub.2 phases and insular FeAl.sub.2 phases, is located on the interface layer, and has a thickness of 3 μm to 40 μm.

Provided is a hot-dip galvanized steel sheet having excellent low-temperature adhesion and workability, and a manufacturing method therefor, the hot-dip galvanized steel sheet comprising: an inhibition layer formed on a base steel sheet and comprising an Fe—Al-based intermetallic alloy phase; a hot-dip galvanized layer formed on the inhibition layer; and an Al—Mn-based alloy phase discontinuously formed between the inhibition layer and the hot-dip galvanized layer.

Provided is a hot-dip galvanized steel sheet having excellent low-temperature adhesion and workability, and a manufacturing method therefor, the hot-dip galvanized steel sheet comprising: an inhibition layer formed on a base steel sheet and comprising an Fe—Al-based intermetallic alloy phase; a hot-dip galvanized layer formed on the inhibition layer; and an Al—Mn-based alloy phase discontinuously formed between the inhibition layer and the hot-dip galvanized layer.

A method of forming an Al—Zn—Si—Mg alloy coating on a steel strip includes dipping steel strip into a bath of molten Al—Zn—Si—Mg alloy and forming a coating of the alloy on exposed surfaces of the steel strip. The method also includes controlling conditions in the molten coating bath and downstream of the coating bath so that there is a uniform Al/Zn ratio across the surface of the coating formed on the steel strip. An Al—Zn—Mg—Si coated steel strip includes a uniform Al/Zn ratio on the surface or the outermost 1-2 μm of the Al—Zn—Si—Mg alloy coating.

A method of forming an Al—Zn—Si—Mg alloy coating on a steel strip includes dipping steel strip into a bath of molten Al—Zn—Si—Mg alloy and forming a coating of the alloy on exposed surfaces of the steel strip. The method also includes controlling conditions in the molten coating bath and downstream of the coating bath so that there is a uniform Al/Zn ratio across the surface of the coating formed on the steel strip. An Al—Zn—Mg—Si coated steel strip includes a uniform Al/Zn ratio on the surface or the outermost 1-2 μm of the Al—Zn—Si—Mg alloy coating.