A hot stamped body with high strength and good bendability, comprising a chemical composition consisting of: in mass %, C: 0.06% or more to less than 0.20%, Si: 0.010 to 1.00%, Mn: 1.20 to 3.00%, P: 0.100% or less, S: 0.010% or less, Al: 0.010 to 0.500%, N: 0.010% or less, Nb: 0.0010 to 0.020%, Ti: 0 to 0.10%, V: 0 to 0.10%, Cr: 0 to 0.50%, Mo: 0 to 1.00%, B: 0 to 0.0100%, Ni: 0 to 0.50%, REM: 0 to 0.0100%, Mg: 0 to 0.010%, Ca: 0 to 0.0100%, and Co: 0 to 2.0%, with the balance: Fe and impurities, wherein a microstructure includes martensite: 85% or more, a proportion of regions in the martensite where GAIQ values are 35000 or more to less than 45000 is 30 area % or more, and TS×α, is 105000 or more, and α is 75 or more.

To solve a problem about warpage of a steel sheet due to a difference in temperature raising rate between an overlapped part and a one-sheet part. This manufacturing method includes: a step of heating an overlapped blank; a step of transferring the heated overlapped blank; and a step of performing presswork on the heated overlapped blank by using a die, in which in the heating step, when sheet thicknesses of the first and second steel sheets are set to t1 and t2, respectively, and an average heating rate at a sheet temperature from 20 to 800° C. of a portion with a total sheet thickness (t1+t2) of an overlapped portion, and that of a non-overlapped portion are set to V and v1, respectively, the total sheet thickness (t1+t2) is 2.5 to 5.0 mm, a maximum length L of the overlapped portion is 100 to 1100 mm, an area S1 of the first steel sheet, an area S2 of a portion, of the second steel sheet, which is overlapped with the first steel sheet, and the average heating rates V and v1 satisfy Expressions (1) to (3), and the heating is performed at a heating temperature and for a heating time within a specific range on a plane of coordinates defined by the heating time and the heating temperature.

Fe-Al-based plated hot-stamped member exhibiting excellent formed part corrosion resistance and post-coating corrosion resistance and manufacturing method. The hot-stamping member includes Fe-Al-based plated layer on one or both surfaces of a base material, the base material has a predetermined steel component, Fe-Al-based plated layer has a thickness of 10 μm or more and 60 μm or less, formed by A, B, C and D layers sequentially from a surface toward the base material, and each of the four layers is a Fe-Al-based intermetallic compound containing Al, Fe, Si, Mn and Cr for predetermined contents with the balance made up of impurities, the D layer further contains Kirkendall voids each of which cross-sectional area is 3 μm.sup.2-30 μm.sup.2 for 10 pieces/6000 μm.sup.2 or more and 40 pieces/6000 μm.sup.2 or less.

press hardening method includes the following steps: A. the provision of a steel sheet for heat-treatment, precoated with a zinc- or aluminum-based pre-coating, B. the deposition of a hydrogen barrier pre-coating over a thickness from 10 to 550 nm, and comprising at least one element chosen from among: nickel, chromium, magnesium, aluminum and yttrium, C. batch annealing of the precoated steel sheet to obtain a pre-alloyed steel sheet, the cooling after the batch annealing being performed at a speed of 29.0° C.h.sup.−1 or less, D. the cutting of the pre-alloyed steel sheet to obtain blank, E. thermal treatment of the blank to obtain a fully austenitic microstructure in the steel, F. the transfer of the blank into a press tool, G. the hot-forming of the blank to obtain a part, H. the cooling of the part obtained at step G).

press hardening method includes the following steps: A. the provision of a steel sheet for heat-treatment, precoated with a zinc- or aluminum-based pre-coating, B. the deposition of a hydrogen barrier pre-coating over a thickness from 10 to 550 nm, and comprising at least one element chosen from among: nickel, chromium, magnesium, aluminum and yttrium, C. batch annealing of the precoated steel sheet to obtain a pre-alloyed steel sheet, the cooling after the batch annealing being performed at a speed of 29.0° C.h.sup.−1 or less, D. the cutting of the pre-alloyed steel sheet to obtain blank, E. thermal treatment of the blank to obtain a fully austenitic microstructure in the steel, F. the transfer of the blank into a press tool, G. the hot-forming of the blank to obtain a part, H. the cooling of the part obtained at step G).

This cooling device includes a first cooling mechanism and a second cooling mechanism. The first cooling mechanism includes a first nozzle disposed to be aligned with a heating coil on a downstream side and whose injection direction of a refrigerant is a first injection direction, a second nozzle disposed to be aligned with the first nozzle on a downstream side and whose injection direction of the refrigerant is a second injection direction intersecting the first injection direction, a first valve selectively switching a supply destination of the refrigerant between one and the other of the first nozzle and the second nozzle, and a first control unit controlling the first valve. The second cooling mechanism includes a third nozzle disposed on a side opposite to the first nozzle and the second nozzle with the extension line sandwiched therebetween and whose injection direction of the refrigerant is a third injection direction forming an angle of 20 degrees or more and 70 degrees or less with respect to a bent inner circumferential surface of a bent portion.

A forming sheet metal part (1) for a vehicle frame includes: a first portion (2) being locally heat-softened after the sheet metal part (1) has been formed out. The part (1) further includes a dedicated three-dimensional distortion-absorbing area (4), defining an internal boundary (6) within which the first portion (2) is to be locally heat-softened after the sheet metal part (1) has been formed out. The distortion-absorbing area (4) is dimensioned such that once said locally heat-softening step has been performed, the internal boundary (6) is adjacent to the first portion (2) and encloses the first portion (2) to absorb the dimensional distortions induced by the locally heat-softened first portion. The invention further relates to a method for producing a forming sheet metal part (1).

A forming sheet metal part (1) for a vehicle frame includes: a first portion (2) being locally heat-softened after the sheet metal part (1) has been formed out. The part (1) further includes a dedicated three-dimensional distortion-absorbing area (4), defining an internal boundary (6) within which the first portion (2) is to be locally heat-softened after the sheet metal part (1) has been formed out. The distortion-absorbing area (4) is dimensioned such that once said locally heat-softening step has been performed, the internal boundary (6) is adjacent to the first portion (2) and encloses the first portion (2) to absorb the dimensional distortions induced by the locally heat-softened first portion. The invention further relates to a method for producing a forming sheet metal part (1).

A press hardening method includes the following steps: A. the provision of a steel sheet for heat treatment, precoated with a zinc- or aluminum-based pre-coating for anti-corrosion purpose, B. the deposition of a hydrogen barrier pre-coating over a thickness from 10 to 550 nm, C. the batch annealing of the precoated steel sheet in an inert atmosphere to obtain a pre-alloyed steel sheet, D. the cutting of the pre-alloyed steel sheet to obtain blank, E. the thermal treatment of the blank to obtain a fully austenitic microstructure in the steel, F. the transfer of the blank into a press tool, G. the hot-forming of the blank to obtain a part, H. the cooling of the part obtained at step G).

A press hardening method including the following steps: A. the provision of a steel sheet for heat treatment being optionally coated with a zinc- or aluminum-based pre-coating, B. the flexible rolling of the steel sheet in the rolling direction so as to obtain a steel sheet having a variable thickness, C. the cutting of the rolled steel sheet to obtain a tailored rolled blank, D. the deposition of a hydrogen barrier pre-coating over a thickness from 10 to 550 nm, E. the heat treatment of the tailored rolled blank to obtain a fully austenitic microstructure in the steel, F. the transfer of the tailored rolled blank into a press tool, G. the hot-forming of the tailored rolled blank to obtain a part having a variable thickness,H. the cooling of the part having a variable thickness obtained at step G).