The present invention provides a far-infrared radiation heating furnace for steel sheets for hot stamping configured to inhibit thermal deformation of the furnace body and furnace body parts. A far-infrared radiation heating furnace (10) includes heating units (13-1) to (13-6), a ceiling unit (19), and a furnace body frame (12) made of steel, the heating units including: blocks made of a thermal insulation material, the blocks being disposed around horizontal planes of spaces for accommodating the steel sheets for hot stamping; and far-infrared radiation heaters positioned above and below the steel sheets for hot stamping to heat the steel sheets for hot stamping, the furnace body frame being disposed around the heating units and the ceiling unit. The furnace body frame includes spacers (17-1) to (17-7) that space the heating units and the ceiling unit apart from the furnace body frame and support them.

A fabrication method for a press hardened part is provided. A sheet or a steel substrate blank for heat treatment is provided. A pre-coating is applied. The pre-coating has at least one layer of aluminum or aluminum alloy in contact with the steel substrate on at least one of the principal faces of the sheet or blank. Then a polymerized layer is deposited on the pre-coating. The polymerized layer has a thickness between 2 and 30 μm. The polymerized layer does not contain silicon, has a nitrogen content of less than 1% by weight and carbon pigments in a quantity between 3 and 30% by weight. The blank or the sheet is heated to obtain an interdiffusion between the steel substrate and the pre-coating and to give the steel a partly or totally austenitic structure. Then the blank or the sheet is hot stamped to obtain a part. The part is cooled by holding the part in a stamping tool so that the microstructure of the steel substrate includes, at least in a portion of the part, martensite or bainite.

A hot formed joined blank includes a first metal blank having an ultimate tensile strength of ≥about 1300 MPa to ≤about 2000 MPa and defining a first surface, a second metal blank having an ultimate tensile strength of ≥about 400 MPa to ≤about 1200 MPa and defining a second coated surface having a coating disposed thereon. The coating includes aluminum and silicon or in alternative variations, zinc. A third surface of the second metal blank is joined to the first surface of the first metal blank to form the hot formed joined blank. A weld nugget is disposed along a boundary between the first and second metal blanks that is configured to join the first and second metal blanks, where the weld nugget optionally includes less than or equal to about 1.5 weight percent aluminum or a microstructure comprising austenite and delta-ferrite.

A hot-stamping formed article is formed of a single steel sheet, and includes: a top sheet portion; a pair of standing wall portions; and a protrusion portion which connects the top sheet portion to the standing wall portion and protrudes outward from the top sheet portion, in which the protrusion portion includes an inner wall portion which stands upright from the top sheet portion, and an outer wall portion which is folded outward from an end edge of the inner wall portion, and an angle between the top sheet portion and the protrusion portion is 80° to 90°.

An aspect of the present invention relates to a cold-rolled steel plate for hot forming, which is excellent in corrosion-resistance and spot-weldability, contains, by weight %, C: 0.1-0.4%, Si: 0.5-2.0%, Mn: 0.01-4.0%, Al: 0.001-0.4%, P: 0.001-0.05%, S: 0.0001-0.02%, Cr: 0.5% to less than 3.0%, N: 0.001-0.02%, and a balance of Fe and inevitable impurities, satisfying formula (1) below, and includes an Si amorphous oxidation layer continuously or discontinuously formed at a thickness of 1 nm-100 nm on the surface thereof. Formula (1): 1.4≤0.4*Cr+Si≤3.2 (wherein element symbols denote measurements of respective element contents by weight %).

According to an aspect of the present disclosure, provided is a method of manufacturing a hot stamping component in which a residual stress analysis value satisfies a preset condition. The method includes heating a blank; forming a molded body by hot stamping the blank; and cooling the molded body to form a hot stamped component. The residual stress analysis value may be a product of a magnitude of an X-ray diffraction analysis (XRD) value obtained by quantifying residual stress by XRD analysis and a magnitude of an electron backscatter diffraction (EBSD) value obtained by quantifying an orientation by EBSD analysis, and the preset condition is about 2.85* 10.sup.-4 Degree*MPa/.Math.m.sup.2 or greater and about 0.05 Degree*MPa/.Math.m.sup.2 or less.

A method of manufacturing a hot stamping includes: inserting a blank having a plating layer formed on at least one surface of a base material into a heating furnace having a plurality of sections having different temperature increase rate ranges; and multi-stage heating the blank gradually while passing through the plurality of sections. The plurality of sections include: a first heating section having a first average temperature increase rate change rate; a second heating section having a second average temperature increase rate change rate different from the first average temperature increase rate change rate; and a third heating section having a third average temperature increase rate change rate different from the first average temperature increase rate change rate and the second average temperature increase rate change rate. The third average temperature increase rate change rate includes a section in which a positive value is changed to a negative value.

Provided is a hot-stamped part including a base steel sheet, the base steel sheet including an amount of about 0.19 to about 0.25 wt % of carbon (C), an amount of about 0.1 to about 0.6 wt % of silicon (Si), an amount of about 0.8 to about 1.6 wt % of manganese (Mn), an amount of about 0.03 wt % or less of phosphorus (P), an amount of about 0.015 wt % or less of sulfur (S), an amount of about 0.1 to about 0.6 wt % of chromium (Cr), an amount of about 0.001 to about 0.005 wt % of boron (B), an amount of about 0.1 wt % or less of an additive, remaining iron (Fe), and other unavoidable impurities. In an indentation strain rate with respect to an indentation depth of about 200 nm to about 600 nm is observed in a nano indentation test, a number of indentation dynamic strain aging (DSA) is about 26 to about 40.

A die steel which enables manufacturing a hot stamp die that has both high hardness and high thermal conductivity, a hot stamp die, and a manufacturing method thereof are provided. This steel for a hot stamp die has a component composition, in mass% of 0.45-0.65% C, 0.1-0.6% Si, 0.1-0.3% Mn, 2.5-6.0% Cr, 1.2-2.6% Mo, and 0.4-0.8% V, the remainder being Fe and unavoidable impurities. Further, this hot stamp die has the aforementioned component composition, and the manufacturing method is for manufacturing said hot stamp die.

An ejecting system for a workpiece from a die cavity in a stamping machine is disclosed. The ejecting system has a spring plunger mechanism to fetch the workpiece from the die cavity of the die platen of the stamping machine. The spring plunger mechanism is provided with a picker which is integrated with a vacuum system to hold the workpiece. Underneath the spring plunger mechanism, there is an actuator, including a positioning sensor, for triggering both synchronous upward and downward movement of the linear actuator to the punch of a die set.