Abstract: A 5000-series aluminum alloy expanded material which does not undergo the occurrence of welding cracks even when the aluminum alloy expanded material is subjected to high-speed welding utilizing laser welding or the like; a welding-joined body comprising the aluminum alloy expanded material; and a method for efficiently welding the aluminum alloy expanded material. An aluminum alloy expanded material for welding use, which is characterized by having an Mg content of 0.2% by mass or more and less than 6.0% by mass, and containing a surface active element capable of reducing the surface tension of molten aluminum, in which the surface active element comprises at least one element selected from Sr, Ca, Sb, Li and Ba, and the content of the surface active element is 0.08 to 0.50% by mass inclusive.

Abstract: A wrought 6000-series aluminum alloy material which is suppressed in weld cracking even in cases where high-speed welding is performed by means of laser welding or the like; a welded body which contains the wrought aluminum alloy material; and an efficient welding method for the wrought aluminum alloy material. A wrought aluminum alloy material for welding, the wrought aluminum alloy material being characterized in that: the Si content is not less than 0.3% by mass but less than 2.0% by mass; the Mg content is not less than 0.3% by mass but less than 2.0% by mass; a surface active element which decreases the surface tension of molten aluminum is contained therein; the surface active element is at least one of Sr, Ca, Sb, Li and Ba; and the content of the surface active element is from 0.04% by mass to 0.50% by mass.

Abstract: Provided are: an aluminum alloy filler material which is less likely to cause welding cracks and from which a joint portion having excellent strength and toughness is formed, in high-speed joining of an aluminum alloy; an aluminum alloy welded structure manufactured using the aluminum alloy filler material; and a method for joining an aluminum material using the aluminum alloy filler material. The aluminum alloy filler material for high-speed joining according to the present invention is characterized by comprising aluminum including a surface-active element that lowers the surface tension of molten aluminum, wherein the surface-active element is at least one among Ca, Sr, and Ba, and the content of the surface-active element is 0.05-0.50 mass %.

Abstract: A joining method includes: an overlapping step of overlapping a front surface of a first metal member with a back surface of a second metal member; and a welding step of welding the first metal member with the second metal member by hybrid welding, using a hybrid welding machine including a leading laser welding unit and a trailing arc welding unit. In the welding step, laser welding, by irradiating with a laser beam, and arc welding are performed from a front surface of the second metal member, along a preset travel route which is set on an overlapped part formed by the first metal member and the second metal member overlapped with each other, to the overlapped part, and the laser beam is oscillated to cross the preset travel route.

Abstract: A joining method includes: an overlapping step of overlapping a front surface of a first metal member with a back surface of a second metal member; and a welding step of welding the first metal member with the second metal member by hybrid welding, with use of a hybrid welding machine including a leading laser welding unit and a trailing arc welding unit. In the welding step, laser welding, by irradiating a laser beam, and arc welding are performed, along a preset travel route set on an inner corner portion formed by the front surface of the first metal member and an end surface of the second metal member, to the inner corner portion and the laser beam is oscillated to cross the preset travel route.

Abstract: A joining method including an overlapping step of overlapping a front surface of a first metal member and a back surface of second metal member such that the front surface is opposed to the back surface; and a welding step of performing a laser welding and a MIG welding by using a hybrid welding machine including a preceding laser welding unit and a following MIG welding unit, in which the laser welding is performed by emitting a laser beam onto a front surface of the second metal member, the MIG welding is performed on an inner corner portion formed by the front surface of the first metal member and an end surface of the second metal member, and a target position for the laser beam from the laser welding unit is located against the second metal member relative to a target position for a MIG arc by the MIG welding unit.