Patent ID: 11939651
Assignee: POSCO CO., LTD
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. An Al—Fe alloy plated steel sheet for hot press forming, the Al—Fe alloy plated steel sheet comprising:
a base steel sheet comprising, by weight percentage (wt %), carbon (C): 0.1 to 0.5%, silicon (Si): 0.01 to 2.0%, manganese (Mn): 0.1 to 10%, phosphorus (P): 0.001 to 0.05%, sulfur (S): 0.0001 to 0.02%, aluminum (Al): 0.001 to 1.0%, nitrogen (N): 0.001 to 0.02%, and a balance of iron (Fe) and unavoidable impurities;
an Al—Fe alloy layer disposed on the base steel sheet; and
an oxide layer formed on the Al—Fe alloy layer, the oxide layer having a thickness of 2 μm or less, wherein the thickness of 2 μm or less refers to a thickness to a point having 10 wt % of oxygen concentration in an oxygen concentration profile obtained through glow discharge spectrometer (GDS) analysis,
wherein the Al—Fe alloy layer comprises, by wt %, aluminum (Al): 40 to 60%, silicon (Si): 2 to 10%, and a balance of iron (Fe) and unavoidable impurities, and a fraction of an unalloyed phase is 1 area % or less, and
wherein the Al—Fe alloy layer comprises:
a diffusion layer disposed on the base steel sheet and constituting a layer while including Si in an amount of 0.5 to 12.0 wt %; and
an intermediate layer disposed in the Al—Fe alloy layer and constituting a layer while including Si in an amount of 3.0 to 20.0 wt %, and
wherein a sum of average thicknesses of the diffusion layer and the intermediate layer is 1.0 to 10 μm.