Fe—Al-based plated hot-stamped member and manufacturing method of Fe—Al-based plated hot-stamped member

1. A Fe-Al-based plated hot-stamped member, comprising:

a Fe-Al-based plated layer located on one surface or both surfaces of a base material, wherein

the base material contains, in mass %,

C: 0.1% or more and 0.5% or less

Si: 0.01% or more and 2.00% or less

Mn: 0.3% or more and 5.0% or less

P: 0.001% or more and 0.100% or less

S: 0.0001% or more and 0.100% or less

Al: 0.01% or more and 0.50% or less

Cr: 0.01% or more and 2.00% or less

B: 0.0002% or more and 0.0100% or less

N: 0.001% or more and 0.010% or less, and

a balance comprising Fe and impurities, wherein

the Fe-Al-based plated layer has a thickness of 10 μm or more and 60 μm or less, and formed by four layers of an A layer, a B layer, a C layer and a D layer sequentially from a surface toward the base material,

each of the four layers is a Fe-Al-based inter metallic compound containing components listed below to be 100 mass % or less in total, with a balance comprising impurities, and

the D layer further contains Kirkendall voids whose cross-sectional area is 3 μm 2 or more and 30 μm 2 or less for 10 pieces/6000 μm 2 or more and 40 pieces/6000 μm 2 or less,

the A layer and the C layer:

Al: 40 mass % or more and 60 mass % or less

Fe: 40 mass % or more and less than 60 mass %

Si: greater than 0 mass % and 5 mass % or less

Mn: greater than 0 mass % and less than 0.5 mass %

Cr: greater than 0 mass % and less than 0.4 mass %

the B layer:

Al: 20 mass % or more and less than 40 mass %

Fe: 50 mass % or more and less than 80 mass %

Si: over 5 mass % and 15 mass % or less

Mn: 0.5 mass % or more and 10 mass % or less

Cr: 0.4 mass % or more and 4 mass % or less

the D layer:

Al: greater than 0 mass % and less than 20 mass %

Fe: 60 mass % or more and less than 100 mass %

Si: greater than 0 mass % and 5 mass % or less

Mn: 0.5 mass % or more and 2.0 mass % or less

Cr: 0.4 mass % or more and 4 mass % or less.

2. The Fe-Al-based plated hot-stamped member according to claim 1 , further comprising:

an oxide layer formed by Mg oxide and/or Ca oxide with a thickness of 0.1 μm or more and 3 μm or less at a surface of the A layer.

3. The Fe-Al-based plated hot-stamped member according to claim 1 , wherein

the base material further contains, in mass %, at least any of

W: 0.01 to 3.00%

Mo: 0.01 to 3.00%

V: 0.01 to 2.00%

Ti: 0.005 to 0.500%

Nb: 0.01 to 1.00%

Ni: 0.01 to 5.00%

Cu: 0.01 to 3.00%

Co: 0.01 to 3.00%

Sn: 0.005 to 0.300%

Sb: 0.005 to 0.100%

Ca: 0.0001 to 0.01%

Mg: 0.0001 to 0.01%

Zr: 0.0001 to 0.01%

REM: 0.0001 to 0.01%

instead of a part of Fe in the balance.

4. A manufacturing method of the Fe-Al-based plated hot-stamped member according to claim 1 , comprising:

subjecting a slab of steel having a base material component containing, in mass %,

C: 0.1% or more and 0.5% or less

Si: 0.01% or more and 2.00% or less

Mn: 0.3% or more and 5.0% or less

P: 0.001% or more and 0.100% or less

S: 0.0001% or more and 0.100% or less

Al: 0.01% or more and 0.50% or less

Cr: 0.01% or more and 2.00% or less

B: 0.0002% or more and 0.0100% or less

N: 0.001% or more and 0.010% or less,

with the balance comprising Fe and impurities, to hot-rolling, pickling, cold-rolling, and then after blanking a steel sheet which is continuously subjected to annealing and hot-dip aluminum plating,

the steel sheet after blanking is heated at 850° C. or more and 1050° C. or less with a heating time of 150 seconds or more and 650 seconds or less, the heating time which is a time from putting the steel sheet after blanking into a heating facility to taking the steel sheet after blanking out,

just after that, the steel sheet is formed into a desired shape and quenched at a cooling rate of 30° C./s or more, wherein

a composition of a hot-dip aluminum plating bath used for the hot-dip aluminum plating contains:

Al: 80 mass % or more and 96 mass % or less

Si: 3 mass % or more and 15 mass % or less

Fe: 1 mass % or more and 5 mass % or less

to be 100 mass % or less in total, with the balance comprising impurities, and

a steel sheet temperature Y (° C.) and a heating time X (seconds) in the heating are controlled such that: the heating time X where Y is 600° C. or more and 800° C. or less is 100 seconds or more and 300 seconds or less; and a point where a first derivative (dY/dX) of Y with respect to X becomes zero exists in a range where Y is 600° C. or more and 800° C. or less.