Abstract: A method includes: manufacturing an automotive crashworthiness energy absorbing part; and assembling an automotive body by attaching the manufactured automotive crashworthiness energy absorbing part to the automotive body, wherein the manufacturing the automotive crashworthiness energy absorbing part includes: manufacturing a pre-coated part including a tubular member formed using a hat-shaped section member including a top portion and a side wall portion, and a coating part having quality of material with a strength lower than that of the tubular member, the coating part being disposed with a gap of 0.2 mm to 3 mm on an outer surface of a portion including a corner connecting the top portion and the side wall portion in the tubular member to form a coating film; and forming a coating film by forming a coating layer by electrodeposition coating in at least the gap in the pre-coated part, and thermally curing the coating layer.

Abstract: An automotive crashworthiness energy absorption part includes a tubular member formed by using a hat-shaped section part including a top portion and a side-wall portion; a coating part made of a material having a lower strength than the tubular member, the coating part being arranged on outer surfaces of the top portion and the side-wall portion at a portion including a corner portion configured to connect the top portion and the side-wall portion, with a gap of 0.2 mm or more and 3 mm or less from the outer surface of the top portion, the outer surface of the side-wall portion, and an outer surface of the corner portion; and a coating film of an electrodeposition paint formed in the gap.

Abstract: An automotive crashworthiness energy absorptive part absorbs crashworthiness energy by crushing axially when a crashworthiness load is input from a front side or a rear side of an automotive body, and includes: a tubular member formed of a steel sheet with a tensile strength of 590 MPa to 1180 MPa, the tubular member including a top portion and a pair of side wall portions continuous from both ends of the top portion via corner portions; a closed cross section space forming wall member formed of a steel sheet with a tensile strength lower than the tubular member, the closed cross section space forming wall member being disposed on an inner surface side of the tubular member and forming a closed cross section space between the closed cross section space forming wall member and at least the corner portion; and a resin provided in the closed cross section space.

Abstract: An automotive crashworthiness energy absorption part provided at a front part or a rear part of an automotive body and absorbing crashworthiness energy by undergoing axial crush when receiving input of a crashworthiness load from a front or a rear of the automotive body includes: a tubular member configured to absorb crashworthiness energy by undergoing axial crush, the tubular member including a top portion and side wall portions continuous with the top portion; and resin coated or patched on first outer surfaces including at least outer surfaces of the top portion and the side wall portions of the tubular member. The coated or patched resin has a thickness of 8 mm or less after being heated, forms at least part of a peripheral wall portion of a closed cross section space, and is bonded to the first outer surfaces with an adhesive strength of 10 MPa or more.

Abstract: A steel sheet for hot press comprises: a predetermined chemical composition; and a steel microstructure that includes ferrite and cementite and in which Mn?/Mn? is 1.4 or more, where Mn? is a Mn concentration of the ferrite and Mn? is a Mn concentration of the cementite.

Abstract: A crashworthiness energy absorption part includes: a tubular member having tensile strength of 590 to 1180 MPa grade; a closed cross section space forming wall part having tensile strength lower than the tubular member and having both edge portions joined to inner surfaces of a pair of side wall portions of the tubular member, and forming a closed cross section space between the closed cross section space forming wall part and a part of a peripheral wall portion of the tubular member; and a resin configured to fill the closed cross section space, includes a rubber-modified epoxy resin and a curing agent, and has tensile breaking elongation of 80% or more, adhesive strength to the tubular member and closed cross section space forming wall part of 12 MPa or higher, and a compression nominal stress of 6 MPa or higher at a compression nominal strain of 10%.

Abstract: An automotive crashworthiness energy absorptive part to be provided at a front portion or a rear portion of an automotive body, the automotive crashworthiness energy absorptive part including: a tubular member configured to be axially crushed to absorb crashworthiness energy, the tubular member having a top portion and side wall portions continuous to the top portion; and a resin configured to coat or patch at least inner surfaces of the top portion and the side wall portions of the tubular member, wherein the coated or patched resin has a thickness of 8 mm or less after being heated and forms at least a part of a peripheral wall portion in a closed cross-sectional space, and adheres to the inner surfaces with an adhesive strength of 10 MPa or more.

Abstract: An automotive frame part that is an A-pillar-lower part, the A-pillar-lower part including: an outer panel having approximately a T-shape in planar view and a cross section intersecting a portion corresponding to a horizontal side and a vertical side of the T-shape is a hat-shaped cross section including a top portion, a side wall portion, and a flange portion; an inner panel being connected to the flange portion and forming a closed cross section with the outer panel; and plastic stiffening members that each have one end connected to an inner surface of the outer panel and another end connected to an inner surface of the inner panel, wherein the shape and the disposition of the stiffening members are set based on an analysis result from a shape optimization analysis method and each of the stiffening members has a columnar shape or a columnar shape with both end parts bulging.

Abstract: A stiffening structure for an automotive door panel part according to the present invention includes a door outer panel 3 made of a metal sheet curved along a height direction, and in which a character line 3a is formed; and an impact beam 5 disposed at an inner surface side of the door outer panel 3. The stiffening structure improves tensile rigidity of the door outer panel 3 by attaching a stiffening member 7 made of resin to the inner surface of the door outer panel 3. The stiffening member 7 includes vertical bone portions 9 extending in a streak shape from the impact beam 5 to the character line 3a along a curve of the door outer panel 3. The vertical bone portions 9 are arranged at a predetermined interval in a front-rear direction of the door outer panel 3, and outer surface of the vertical bone portions 9 is bonded to the inner surface of the door outer panel 3.

Abstract: A stiffening structure for an automotive door panel part according to the present invention includes a door outer panel 3 made of a metal sheet curved along a height direction, and in which a character line 3a is formed; and an impact beam 5 disposed at an inner surface side of the door outer panel 3. The stiffening structure improves tensile rigidity of the door outer panel 3 by attaching a stiffening member 7 made of resin to the inner surface of the door outer panel 3. The stiffening member 7 includes vertical bone portions 9 extending in a streak shape from the impact beam 5 to the character line 3a along a curve of the door outer panel 3. The vertical bone portions 9 are arranged at a predetermined interval in a front-rear direction of the door outer panel 3, and outer surface of the vertical bone portions 9 is bonded to the inner surface of the door outer panel 3.

Abstract: A hot pressed part comprises: a predetermined chemical composition; and a steel microstructure that is a gradient microstructure in which, in a thickness direction, a surface layer is a soft layer, an inside is a hard layer, and a layer between the soft layer and the hard layer is a transition layer.

Abstract: A lap-fillet arc welding joint includes a weld bead, the weld bead being formed on an end portion of one sheet of overlapped two sheets and a surface of other sheet along the end portion. The other sheet includes a projecting portion projecting from the surface at a side of a weld toe of at least one of a start portion and a termination portion of the weld bead. The weld toe is located on a slope surface portion of the projecting portion at a side of the end portion of the one sheet.

Abstract: A steel sheet for hot press comprises: a predetermined chemical composition; and a steel microstructure that includes ferrite and cementite and in which Mn?/Mn? is 1.4 or more, where Mn? is a Mn concentration of the ferrite and Mn? is a Mn concentration of the cementite.

Abstract: A steel sheet for hot press comprises: a predetermined chemical composition; and a steel microstructure that includes ferrite and cementite and in which Mn?/Mn? is 1.4 or more, where Mn? is a Mn concentration of the ferrite and Mn? is a Mn concentration of the cementite.

Abstract: An automotive frame part that is an A-pillar-lower part, the A-pillar-lower part including: an outer panel having approximately a T-shape in planar view and a cross section intersecting a portion corresponding to a horizontal side and a vertical side of the T-shape is a hat-shaped cross section including a top portion, a side wall portion, and a flange portion; an inner panel being connected to the flange portion and forming a closed cross section with the outer panel; and plastic stiffening members that each have one end connected to an inner surface of the outer panel and another end connected to an inner surface of the inner panel, wherein the shape and the disposition of the stiffening members are set based on an analysis result from a shape optimization analysis method and each of the stiffening members has a columnar shape or a columnar shape with both end parts bulging.

Abstract: A method for manufacturing a hot press formed part, includes: preparing a hot press forming object comprising a single-ply portion and a two-ply portion; heating the hot press forming object to a temperature range from an Ac3 transformation temperature of a base steel sheet of the first coated steel sheet to 1000° C.; press forming the hot press forming object to obtain a formed body, the press forming being started upon temperatures of the single-ply portion and of the two-ply portion being no higher than solidification points of Zn—Ni coating layers of the first and second coated steel sheets and no lower than an Ar3 transformation temperature of the base steel sheet of the first coated steel sheet; and quenching the formed body to thereby obtain a hot press formed part, in which the hot press forming object has a thickness ratio from 1.4 to 5.0.

Abstract: A lap fillet arc-welded joint produced by overlapping two metal sheets and welding an end portion of one sheet of the two metal sheets to a surface of the other sheet along the end portion of the one sheet includes a protruding curved potion being bead-shaped and protruding from the surface of the other sheet; and a weld toe positioned on a top portion of the protruding curved portion.

Abstract: A hot pressed part comprises: a predetermined chemical composition; and a steel microstructure that is a gradient microstructure in which, in a thickness direction, a surface layer is a soft layer, an inside is a hard layer, and a layer between the soft layer and the hard layer is a transition layer.

Abstract: An automobile frame component includes a closed section constituted by welding a flange portion to a panel part, wherein when a welding position coordinate is represented in a coordinate system in which an end of a contact position between the flange portion and the panel part is assumed as 0, and a flange outer end side of the flange portion is assumed as negative (?) whereas a vertical wall side is assumed as positive (+), and when a radius of a circular arc-like portion connecting a vertical wall portion and the flange portion in the substantially hat-like shape is denoted as R (mm), and a weldable gap amount is denoted as a (mm), a welding position X represented by the following formula is continuously welded using a one-side welding method: +?(2Ra?a2)?X>1.5 where R?2.

Abstract: A steel sheet for hot press comprises: a predetermined chemical composition; and a steel microstructure that includes ferrite and cementite and in which Mn?/Mn? is 1.4 or more, where Mn? is a Mn concentration of the ferrite and Mn? is a Mn concentration of the cementite.