Abstract: A gas shielded arc welding method includes welding a steel sheet with a tensile strength of 780 MPa or more using a shielding gas containing Ar in an amount of 92 vol. % to 99.5 vol. %. In the gas shielded arc welding method, a value calculated from the following expression (1) is 0.20 or more: {?v/(D/2)2}×10?{(100?CAr)×I/v}×0.1 . . . (1), where CAr represents an Ar content (vol. %) in the shielding gas, D represents an inner diameter (mm) of a nozzle from which the shielding gas is supplied, v represents a welding speed (cm/min), and I represents a welding current (A).

Abstract: A gas-shielded arc welding method includes feeding a consumable electrode via a welding torch and performing welding while flowing a shielding gas. The welding torch includes a nozzle. An inner diameter of the nozzle is 15 mm or more. A nozzle-base material distance between a tip of the nozzle and a material to be welded is 22 mm or less. A ratio expressed by (the inner diameter of the nozzle/the nozzle-base material distance) is 0.7 or more and 1.9 or less.

Abstract: A gas shielded arc welding method includes welding a steel sheet with a tensile strength of 780 MPa or more using a shielding gas containing Ar in an amount of 92 vol. % to 99.5 vol. %. In the gas shielded arc welding method, a value calculated from the following expression (1) is 0.20 or more: {?v/(D/2)2}×10?{(100?CAr)×I/v}×0.1 . . . (1), where CAr represents an Ar content (vol. %) in the shielding gas, D represents an inner diameter (mm) of a nozzle from which the shielding gas is supplied, v represents a welding speed (cm/min), and I represents a welding current (A).

Abstract: A gas-shielded arc welding method includes feeding a consumable electrode via a welding torch and performing welding while flowing a shielding gas. The welding torch includes a nozzle. An inner diameter of the nozzle is 15 mm or more. A nozzle-base material distance between a tip of the nozzle and a material to be welded is 22 mm or less. A ratio expressed by (the inner diameter of the nozzle/the nozzle-base material distance) is 0.7 or more and 1.9 or less.

Abstract: A frame for a vehicle which is formed to have a closed cross section and constitutes part of a vehicle body, comprising a first face portion on which a compressive force acts when a load acts from an outside, a second face portion on which a tensional force acts when the load acts from the outside, a pair of third face portions which are located between the first face portion and the second face portion and form ridgelines together with the first face portion, and a lateral reinforcement potion which is provided at least one of the third face portions and extending in a line shape from the first face portion toward the second face portion. Accordingly, the frame for a vehicle which can increase the bending strength of the frame is provided.

Abstract: A frame for a vehicle which is formed to have a closed cross section and constitutes part of a vehicle body, comprising a first face portion on which a compressive force acts when a load acts from an outside, a second face portion on which a tensional force acts when the load acts from the outside, a pair of third face portions which are located between the first face portion and the second face portion and form ridgelines together with the first face portion, and a lateral reinforcement potion which is provided at least one of the third face portions and extending in a line shape from the first face portion toward the second face portion. Accordingly, the frame for a vehicle which can increase the bending strength of the frame is provided.

Abstract: In a first step, a roof panel and a front header are joined at plural frictional spot joint portions at a front-end frictional joint area, and the roof panel and a rear header are joined at plural frictional spot joint portions at a rear-end frictional joint area. The roof panel and a side roof rail are joined at plural frictional spot joint portions at left-side and right-side frictional joint areas. Subsequently, in a second step, the members are joined at the plural rivet joint portions at a border area of the above-described joint areas, and the members are joined at plural rivet joints at a bounder area of the above-described joint areas. Accordingly, there can be provided a joining method and structure of metal members that can properly reduce deformation due to a thermal strain.

Abstract: In a first step, a roof panel and a front header are joined at plural frictional spot joint portions at a front-end frictional joint area, and the roof panel and a rear header are joined at plural frictional spot joint portions at a rear-end frictional joint area. The roof panel and a side roof rail are joined at plural frictional spot joint portions at left-side and right-side frictional joint areas. Subsequently, in a second step, the members are joined at the plural rivet joint portions at a border area of the above-described joint areas, and the members are joined at plural rivet joints at a bounder area of the above-described joint areas. Accordingly, there can be provided a joining method and structure of metal members that can properly reduce deformation due to a thermal strain.

Abstract: A method for producing a formed member made of a steel sheet according to the present invention is characterized by preparing a steel sheet material having tensile strength of 500 MPa or less and containing a nitriding element; forming a formed member having a predetermined shape by performing a plastic forming on the steel sheet material; and performing a nitriding treatment on the formed member so that an average hardness in the sheet thickness direction of the resultant steel sheet member is Hv 300 or more by Vickers hardness, and further characterized in that the difference in hardness between the surface part and the inside center part in the thickness direction of the steel sheet member of the formed member is Hv 200 or less by Vickers hardness, thereby it is possible to reliably obtain a formed member having a sufficiently high strength after a nitriding treatment while ensuring a plastic formability of a steel sheet in obtaining a formed member made of a steel sheet member of high strength by performi

Abstract: An automobile bodyshell frame structure includes a generally elongated first panel member, and a generally elongated second panel member having opposite side edge portions connected to the first panel member to define a hollow between the first and second panel members. A filler is disposed within a portion of a cross-section of the hollow between the first and second panel members. This filler is provided on an inner surface of one of the first and second panel members and has an average compressive strength equal to or greater than 4 Pa and/or a maximum bending strength equal to or greater than 10 MPa.

Abstract: A method for producing a formed member made of a steel sheet according to the present invention is characterized by preparing a steel sheet material having tensile strength of 500 MPa or less and containing a nitriding element; forming a formed member having a predetermined shape by performing a plastic forming on the steel sheet material; and performing a nitriding treatment on the formed member so that an average hardness in the sheet thickness direction of the resultant steel sheet member is Hv 300 or more by Vickers hardness, and further characterized in that the difference in hardness between the surface part and the inside center part in the thickness direction of the steel sheet member of the formed member is Hv 200 or less by Vickers hardness, thereby it is possible to reliably obtain a formed member having a sufficiently high strength after a nitriding treatment while ensuring a plastic formability of a steel sheet in obtaining a formed member made of a steel sheet member of high strength by performi

Abstract: Material characteristics that a foamed filler material (s) to be filled in a frame cross section (fr) should have are discussed. By using a material complying with the characteristics, the energy absorbability of the frame (fr) is effectively enhanced. In a frame structure (fr) for vehicle bodies in which a filler material is filled in at least part of the cross section of a frame, the filler material is set to a mean compressive strength of not less than 4 MPa and/or a maximum bending strength of not less than 10 MPa. More particularly, the filler material is set to a mean compressive strength of not less than 5 MPa and/or a maximum bending strength of 60 MPa.