Laser welding device (1000) includes: laser oscillator (100); optical fiber (300) that transmits a laser beam (LB) generated in laser oscillator (100); laser beam emitting head (400) that is attached to the emission end of optical fiber (300) and emits laser beam (LB) toward workpiece (600); manipulator (500) with laser beam emitting head (400) attached thereto; and controller (200) that controls laser beam emitting head (400) so as to cause laser beam (LB) to be scanned three-dimensionally on the surface of workpiece (600). Controller (200) controls laser beam emitting head (400) so as to change a focal position of laser beam (LB) in accordance with a shape of a welded portion in workpiece (600).

Laser welding device (1000) includes: laser oscillator (100); optical fiber (300) that transmits a laser beam (LB) generated in laser oscillator (100); laser beam emitting head (400) that is attached to the emission end of optical fiber (300) and emits laser beam (LB) toward workpiece (600); manipulator (500) with laser beam emitting head (400) attached thereto; and controller (200) that controls laser beam emitting head (400) so as to cause laser beam (LB) to be scanned three-dimensionally on the surface of workpiece (600). Controller (200) controls laser beam emitting head (400) so as to change a focal position of laser beam (LB) in accordance with a shape of a welded portion in workpiece (600).

A welded structure, in which a second tubular member is welded to an inner circumference of a first tubular member made of metal, the second tubular member being made of metal and having an outer diameter smaller than an inner diameter of the first tubular member, includes welded portions at which a portion of the first tubular member and a portion of the second tubular member are melted and solidified, a surface melted and solidified from an inner circumferential surface side of the first tubular member toward an end surface of the second tubular member forms a smoothly-continuous curved surface, and the first and the second tubular members are bonded to each other. A portion of each of the welded portions is located on an outside of a projection region obtained by projecting the second tubular member onto an outer surface of the first tubular member.

A welded structure, in which a second tubular member is welded to an inner circumference of a first tubular member made of metal, the second tubular member being made of metal and having an outer diameter smaller than an inner diameter of the first tubular member, includes welded portions at which a portion of the first tubular member and a portion of the second tubular member are melted and solidified, a surface melted and solidified from an inner circumferential surface side of the first tubular member toward an end surface of the second tubular member forms a smoothly-continuous curved surface, and the first and the second tubular members are bonded to each other. A portion of each of the welded portions is located on an outside of a projection region obtained by projecting the second tubular member onto an outer surface of the first tubular member.

A method for welding coated steel sheets, particularly steel sheets that are coated with an aluminum-silicon metallic coating layer, is provided. A configuration of two laser beams is provided, wherein the laser beams act on a weld pool that is to be formed, at least one laser beam rotates around a rotation axis so that the laser beams execute a movement relative to each other, and the laser beams are guided along a welding axis. In order to achieve a mixing of the weld pool, a defined stirring effect and a defined welding speed in relation to each other are adhered to, wherein a mathematically defined condition applies to the stirring effect.

A method for welding coated steel sheets, particularly steel sheets that are coated with an aluminum-silicon metallic coating layer, is provided. A configuration of two laser beams is provided, wherein the laser beams act on a weld pool that is to be formed, at least one laser beam rotates around a rotation axis so that the laser beams execute a movement relative to each other, and the laser beams are guided along a welding axis. In order to achieve a mixing of the weld pool, a defined stirring effect and a defined welding speed in relation to each other are adhered to, wherein a mathematically defined condition applies to the stirring effect.

A method for inspecting a welding defect of the present invention includes: a threshold resistance setting step (S100) of measuring a resistance of a welded portion of a sample group and deriving a threshold resistance value which becomes an evaluation standard of a weak welding; a resistance measuring step (S200) of measuring a resistance value of a welded portion to be inspected; and a step (S300) of determining as a weak welding if the resistance value measured in the resistance measuring step exceeds the threshold resistance value, wherein the threshold resistance setting step (S100) and the resistance measuring step (S200) include measuring a resistance using a microresistance measuring instrument having a resolution of nanoohm to microohm units.

The welding defect inspection method of the present invention shows excellent detection power for the welding defect by a weak welding.

A method for inspecting a welding defect of the present invention includes: a threshold resistance setting step (S100) of measuring a resistance of a welded portion of a sample group and deriving a threshold resistance value which becomes an evaluation standard of a weak welding; a resistance measuring step (S200) of measuring a resistance value of a welded portion to be inspected; and a step (S300) of determining as a weak welding if the resistance value measured in the resistance measuring step exceeds the threshold resistance value, wherein the threshold resistance setting step (S100) and the resistance measuring step (S200) include measuring a resistance using a microresistance measuring instrument having a resolution of nanoohm to microohm units.

The welding defect inspection method of the present invention shows excellent detection power for the welding defect by a weak welding.

A bead appearance inspection device includes an acquisition unit that acquires input data related to a welding bead, a storage unit that stores a first determination standard and a second determination standard used for an inspection of a defect of the welding bead, a first determination unit that executes a first inspection determination on the welding bead, and k second determination units, where k is an integer of 1 or more, that execute a second inspection determination on the welding bead. An appearance inspection result of the welding bead is created and output by using a determination result indicating whether a first inspection result acquired by the first inspection determination satisfies the first determination standard and a determination result indicating whether a second inspection result satisfies the second determination standard.

A bead appearance inspection device includes an input unit configured to enter input data related to a welding bead of a workpiece produced by welding, a preprocessing unit configured to perform a preprocessing of converting a shape of the welding bead into a predetermined shape on the input data, and k inspection determination units, where k is an integer of 1 or more, that are equipped with k types of artificial intelligence and that are configured to inspect and determine presence or absence of a welding defect of the welding bead based on processings of the k types of artificial intelligence targeting input data on which the preprocessing is performed.