A piston unit of a working cylinder includes a piston and a piston rod. The piston has an axial bore hole formed therein. The piston rod is received in the axial bore hole. The piston rod and the piston are connected by a material-bond by a circumferential laser ring weld seam. The laser ring weld seam defines a pressure medium-tight sealing plane.

A welding method of a battery cover plate includes performing at least two times of continuous welding along a connecting zone between a cover plate and a shell, and adjusting laser welding power, welding speeds, and defocusing amounts. Welding power of a first continuous welding is less than welding power of a second continuous welding. An amount of deformation of the shell is less than or equal to 0.6 mm after the first continuous welding, and the amount of deformation of the shell is less than or equal to 1.0 mm after the second continuous welding.

There is provided a laser welding method of joining a bus bar and an intermediate member by irradiating a laser beam on a surface of the intermediate member with the bus bar and the intermediate member being overlapped with each other. The laser welding method includes: a first welding step of forming a first welding line by moving the laser beam in a C shape from a welding start point to a welding intermediate point when viewed from a direction orthogonal to a surface of the intermediate member; and a second welding step of forming a second welding line continuous with the first welding line by moving the laser beam from the welding intermediate point to a welding end point located in a welding region formed inside the first welding line from the welding start point and the welding intermediate point.

A welding component is provided for welding to a component via at least one welding region. The welding component includes: at least one welding indicator arrangement provided on the welding component; and, the at least one welding indicator arrangement includes a welding region minimum indicator to be covered by the at least one welding region and a welding region maximum indicator not to be covered by the at least one welding region.

A method of manufacturing a secondary battery according to the disclosure includes an attaching step of attaching a sealing plate to an open end of a case main body including a closed bottom, and a welding step of laser-welding the case main body and the sealing plate together by scanning a laser beam along a peripheral edge portion of the sealing plate. In the welding step, the laser beam applied to the peripheral edge portion of the sealing plate and to an edge of the open end of the case main body may be a pulsed laser beam including a rectangular wave and having a pulse width of from 400 μm to 800 μm and a frequency of from 1.2 kHz to 1.4 kHz, and the laser beam is scanned such that adjacent laser pulses of the pulsed laser beam have an overlap rate of 84.4% to 86.6%.

A joint body includes first and second metal members and a joint portion including a welded portion where the first and second metal members are joined together, the welded portion having a line shape. The joint portion includes first and second longitudinal portions and a plurality of connecting portions. The first longitudinal portion has first intersecting portions arranged in a first direction and extends in the first direction. The second longitudinal portion has second intersecting portions arranged in the first direction and extends in the first direction. The welded portion intersects itself at the first and second intersecting portions. The connecting portions are arranged in the first direction. The connecting portions extend in a first direction and connect the first and second longitudinal portions.

A joint body includes first and second metal members and a joint portion including a welded portion where the first and second metal members are joined together, the welded portion having a line shape. The joint portion includes first and second longitudinal portions and a plurality of connecting portions. The first longitudinal portion has first intersecting portions arranged in a first direction and extends in the first direction. The second longitudinal portion has second intersecting portions arranged in the first direction and extends in the first direction. The welded portion intersects itself at the first and second intersecting portions. The connecting portions are arranged in the first direction. The connecting portions extend in a first direction and connect the first and second longitudinal portions.

A welding structure includes: a first metal member and a second metal member that are superimposed and welded together. The first metal member has a hole. The second metal member includes a nugget portion where a part of the second metal member has been melted by heat of laser light and has re-solidified. A peripheral portion of the hole in the first metal member covers the nugget portion. A part of the nugget portion is exposed through the hole.

A welding structure includes: a first metal member and a second metal member that are superimposed and welded together. The first metal member has a hole. The second metal member includes a nugget portion where a part of the second metal member has been melted by heat of laser light and has re-solidified. A peripheral portion of the hole in the first metal member covers the nugget portion. A part of the nugget portion is exposed through the hole.

A method for producing a cam phaser for a cam shaft of an internal combustion engine, the cam phaser including a rotor, a stator and at least one cover, the method including arranging the at least one cover at the stator; and welding the at least one cover with the stator, wherein a first weld, a second weld and a third weld are formed at least on a large radius or on a small radius during the welding, and wherein the small radius is smaller than the large radius. The invention furthermore relates to a cam phaser for a cam shaft of an internal combustion engine, the cam phaser including a rotor; a stator and at least one cover.