A hot stamped component, includes: a base material; and a Zn-based plating layer provided in contact with the base material as a layer above the base material and containing Zn. A base material side of the Zn-based plating layer is a Fe—Zn solid solution, and two or more twins exist in 10 crystal grains of the Fe—Zn solid solution adjacent to an interface between the base material and the Zn-based plating layer.

A method for producing a coated steel sheet having a tensile strength TS of at least 1450 MPa and a total elongation TE of at least 17% includes the successive steps of providing a cold rolled steel sheet made of a steel having a chemical composition comprising, in weight %: 0.34%C0.45%, 1.50%Mn2.30%, 1.50Si2.40%, 0%<Cr0.7%, 0%Mo0.3%, 0.10%Al0.7%, and optionally 0%Nb0.05%, the remainder being Fe and unavoidable impurities, annealing the cold-rolled steel sheet at an annealing temperature AT higher than the Ac3 transformation point of the steel, quenching the annealed steel sheet by cooling it down to a quenching temperature QT lower than the Ms transformation point of the steel and comprised between 150 C. and 250 C., and reheating the quenched steel sheet to a partitioning temperature PT between 350 C. and 450 C. and maintaining the steel sheet at the partitioning temperature PT for a partitioning time Pt of at least 80s, and coating the steel sheet by galvannealing, with an alloying temperature GAT comprised between 470 C. and 520 C.

A method for producing a high strength coated steel sheet having an improved ductility and an improved formability, the chemical composition of the steel containing: 0.13%C0.22%, 1.9%Si2.3%, 2.4%Mn3%, Al0.5%, Ti<0.05%, Nb<0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000 C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200 C. and 280 C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430 C. and 490 C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.

A plated steel sheet for hot stamping including a base metal and a galvanized layer that is formed on a surface of the base metal, wherein the galvanized layer includes a galvannealed layer, a solidified zinc layer, and an oxide layer containing Al, in this order from the base metal, and a proportion of a content of Zn (g/m.sup.2) in the solidified zinc layer to a content of Zn (g/m.sup.2) in the galvanized layer is 10 to 95%.

A metallic component includes a core formed of steel. A zinc alloy layer is disposed on the core. The zinc alloy layer is formed of zinc and a very small amount of aluminum, such as 0.14 weight percent or less. A method of creating a component includes providing a steel core, providing a zinc bath consisting of essentially of 0.01 to 0.14 weight percent aluminum, and hot dipping the steel core into the zinc bath to form a zinc coating on the steel core resulting in a zinc-coated steel component. The aluminum may be provided in even lower contents, such as less than 0.08 weight percent, or even less than 0.05 weight percent. The zinc-coated steel component may then be spot welded to another component without first annealing the zinc-coated component. Rather, heat treating is performed locally at the weld joint by the welding procedure alone.

Provided is a galvannealed steel sheet having high strength and excellent deep drawability, and being further excellent in slab cracking resistance and secondary working embrittlement resistance. A base metal steel sheet of the galvannealed steel sheet has a chemical composition containing, in mass %: C: 0.0080% or less; Si: 0.7% or less; Mn: 1.0 to 2.5%; P: more than 0.030 to 0.048%; S: 0.025% or less; Al: 0.005 to 0.20%; N: 0.010% or less; Ti: 0.005 to 0.040%; Nb: 0.005 to 0.060%; and B: 0.0005 to 0.0030%, with the balance being Fe and impurities, satisfying Formula (1) to (4). A galvannealed layer contains 7 to 15 mass % of Fe.
25P+4Si3.6(1)
BX10.0005(2)
C(12/93)NbX20.0035(3)
110Si+48Mn+550P120(4)

Provided is a method of manufacturing an HPF part comprising: preparing a steel sheet comprising C: 0.18% to 0.25%, Si: 0.1% to 1.0%, Mn: 0.9% to 1.5%, P: 0.03% or less, S: 0.01% or less, Al: 0.01% to 0.05%, Cr: 0.05% to 0.5%, Ti: 0.01% to 0.05%, B: 0.001% to 0.005%, N: 0.009% or less, and a balance of Fe and impurities; heating the steel sheet at 550 C. to 850 C. followed by maintaining at 640 C. to 680 C., and immersing the steel sheet in a hot dip aluminum plating bath, and a balance of Al and impurities; cooling the plated steel sheet at 15 C./s or faster; heating the cooled hot dip aluminum plated steel sheet at 880 C. to 930 C. followed by maintaining for a certain time; and hot forming the alloyed hot dip aluminum plated steel sheet and quenching at a range of 300 C. or lower at the same time.

High strength steel sheet having a tensile strength of 800 MPa or more comprising a middle part in sheet thickness and a soft surface layer arranged at one side or both sides of the middle part in sheet thickness, wherein each soft surface layer has a thickness of more than 10 m and 30% or less of the sheet thickness, the soft surface layer has an average Vickers hardness of 0.60 time or less the average Vickers hardness of the sheet thickness position, and the soft surface layer has a nano-hardness standard deviation of 0.8 or less is provided.

A zinc-coated steel may be produced by performing a pre-alloying heat treatment after galvannealing the steel and prior to the hot stamping the steel. The pre-alloying heat treatment is conducted at a temperature between about 850 F. and about 950 F. in an open coil annealing process. The pre-alloying heat treatment allows for shorter time at the austenitization temperature to form a desired -Fe phase in the coating by increasing the concentration of iron. This also decreases the loss of zinc, and a more adherent oxide exists after hot stamping.

A method is for producing a high strength coated steel sheet having an improved ductility and an improved formability, and a chemical composition containing: 0.13%C0.22%, 1.9%Si2.3%, 2.4%Mn3%, Al0.5%, Ti0.05%, Nb0.05%, the remainder being Fe and unavoidable impurities. The sheet is annealed at temperature TA higher than Ac3 but less than 1000 C. for a time of more than 30 s, quenched by cooling to a quenching temperature QT between 200 C. and 280 C. in order to obtain a structure consisting of austenite and at least 50% of martensite, the austenite content being such that the final structure can contain between 3% and 15% of residual austenite and between 85% and 97% of the sum of martensite and bainite, without ferrite, heated up to a partitioning temperature PT between 430 C. and 490 C. and maintained at this temperature for a time Pt between 10 s and 100 s, hot dip coated and cooled to the room temperature.