CPC B62D 29/00 (2013.01) [B21D 22/20 (2013.01); B21D 53/88 (2013.01); C21D 9/0068 (2013.01); B62D 21/15 (2013.01)] | 7 Claims |
1. A vehicle body structure comprising
a frame member which includes
a first top section,
a corner section provided at an end portion of the first top section,
a wall section extending from an end portion of the corner section, and
a second top section which is opposed to the first top section, and
a first support section and a second support section which are provided on the second top section, wherein
L/h≤6.7 is satisfied, where h represents a length between an outer surface of the first top section and an outer surface of the second top section, and L represents a length between the first support section and the second support section,
the wall section is provided with a softened layer,
in the wall section, the softened layer is provided on an area extending from a bending stop of the corner section toward the widthwise direction of the wall section by a length of h/3,
hardness of a sheet-thickness-direction central section in a portion where the softened layer is provided is greater than or equal to 400 Hv, and the softened layer is an area having hardness smaller by at least 10 Hv than the hardness of the sheet-thickness-direction central section in the portion where the softened layer is provided,
a thickness of the softened layer is greater than or equal to 2% of the sheet thickness in the portion where the softened layer is provided but smaller than 20% of the sheet thickness in the portion where the softened layer is provided,
the hardness of the softened layer at the surface is greater than or equal to 0.5 times the hardness of the sheet-thickness-direction central section in the portion where the softened layer is provided but smaller than 0.9 times the hardness of the sheet-thickness-direction central section in the portion where the softened layer is provided,
the softened layer has a first hardness changing area that is an area extending from the surface to 40% of the thickness of the softened layer in the sheet thickness direction and a second hardness changing area that is an area different from the first hardness changing area out of the softened layer,
an absolute value ΔHv1 of a change in hardness of the first hardness changing area in the sheet thickness direction is greater than an absolute value ΔHv2 of a change in hardness of the second hardness changing area in the sheet thickness direction.
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