Abstract: A vehicle body lower structure includes a side sill, a center tunnel, a floor panel disposed between the side sill and the center tunnel, a first frame member connected to a front side member, and a second frame member connected to the front side member. The first frame member extends obliquely such that, as the first frame member extends further rearward, the first frame member extends further outward in a vehicle width direction. The second frame member is connected to the side sill. The second frame member extends obliquely such that, as the second frame member extends further rearward, the second frame member extends further inward in the vehicle width direction. The second frame member is connected to the center tunnel. One of the first frame member and the second frame member is provided on an upper surface of the floor panel.

Abstract: A vehicle body lower structure includes a side sill, a center tunnel, a floor panel disposed between the side sill and the center tunnel, a first frame member connected to a front side member, and a second frame member connected to the front side member. The first frame member extends obliquely such that, as the first frame member extends further rearward, the first frame member extends further outward in a vehicle width direction. The second frame member is connected to the side sill. The second frame member extends obliquely such that, as the second frame member extends further rearward, the second frame member extends further inward in the vehicle width direction. The second frame member is connected to the center tunnel. One of the first frame member and the second frame member is provided on an upper surface of the floor panel.

Abstract: An automobile strength member, having a cross-sectional shape giving a high bending repulsion at the beginning of impact and able to reduce the production cost and lighten the weight and achieve a greater improvement in safety and a reduction of cost of an automobile, that is, an automobile strength member comprised of a rectangular steel tube with a square cross-section, simultaneously satisfying the following relations (1) to (3), and having a strength of at least 690 MPa in terms of tensile strength: R1?1.5t??(1) tR?1.1t??(2) R1?R2??(3) where, t: thickness of side (mm) tR: thickness of corner (mm) R1: outside corner R (mm) R2: inside corner R (mm) where both a maximum value and minimum value of hardness at a cross-section of the rectangular steel tube are in the range of within ±30% of the average value of the entire cross-section.

Abstract: There is provided an ultrahigh strength steel sheet containing 0.10 to 0.40 mass % of C, 0.01 to 3.5 mass % of Cr, at least one selected from the group consisting of 0.10 to 2.0 mass % of Mo, 0.20 to 1.5 mass % of W, 0.002 to 1.0 mass % of V, 0.002 to 1.0 mass % of Ti and 0.005 to 1.0 mass % of Nb, 0.02 mass % or less of P and 0.01 mass % or less of S as impurities and the balance being Fe and unavoidable impurities based on the total mass of the steel sheet and having a base structure of lower bainite, a prior austenite grain size of 30 ?m or smaller and a tensile strength of 980 MPa or higher. There is also provided an automotive strength part using the ultrahigh strength steel sheet.

Abstract: There is provided a high-tensile steel sheet containing 0.15 to 0.25 mass % of C, 0.1 to 2.0 mass % of Si, 0.10 to 1.0 mass % of Mn, 0.5 to 3.5 mass % of Cr, 0.02 mass % or less of P, 0.01 mass % or less of S and the balance being Fe and unavoidable impurities based on the total mass of the steel sheet and satisfying a content ratio of Mn/(Mn+Cr)<0.50.

Abstract: An automobile strength member, having a cross-sectional shape giving a high bending repulsion at the beginning of impact and able to reduce the production cost and lighten the weight and achieve a greater improvement in safety and a reduction of cost of an automobile, that is, an automobile strength member comprised of a rectangular steel tube with a square cross-section, simultaneously satisfying the following relations (1) to (3), and having a strength of at least 690 MPa in terms of tensile strength: R1?5t ??(1) tR?1.1t ??(2) R1?R2 ??(3) where, t: thickness of side (mm) tR: thickness of corner (mm) R1: outside corner R (mm) R2: inside corner R (mm) where both a maximum value and minimum value of hardness at a cross-section of the rectangular steel tube are in the range of within ±30% of the average value of the entire cross-section.