A coupling piece for an outer end of a multilayered conduit, includes a coupling pipe which is provided on the outer side with a radially upright wall, wherein the wall is widened in an axial direction at a radial distance from the outer side of the body. The outer side of the coupling pipe, the upright wall and the widened portion enclose an annular insertion space into which the outer end of the conduit can be directly inserted, wherein the inner wall of the coupling pipe is reinforced with an adjacent reinforcing layer which has a greater strength than the material of the coupling pipe. The reinforcing layer is provided with axial engaging elements, while the inner wall is provided with axial connecting elements which correspond with and connect to the engaging elements.

An object of the invention is to provide a laser welding quality determination method for improving a determination accuracy of a welding quality which is strongly affected by an inner defect of a welding bead, and a laser welding apparatus which includes a mechanism for performing the quality determination method. There is provided a laser welding quality determination method of determining a welding quality in laser welding, including: capturing an image of a molten pool formed by emitting a laser beam to a welding target material to acquire image data of the molten pool; measuring a width of the molten pool in a direction orthogonal to a welding direction from the acquired image data of the molten pool; calculating a penetration depth from the measured width of the molten pool; and determining the welding quality from the measured width and the calculated penetration depth of the molten pool.

A method, for repairing a discrepant weld in a workpiece arrangement including at least two workpieces, comprising positioning a mechanical intermediary adjacent the discrepant weld and inserting the intermediary through the discrepant weld and into at least a distal workpiece of the two workpieces, wherein upon insertion, a proximate surface of the intermediary is exposed at a proximate side of the workpiece arrangement. The method further includes delivering weld energy to the intermediary. The intermediary is configured, and the weld energy provided, so that energy passes through the intermediary in a pre-determined manner. Energy passing through the intermediary in the pre-determined manner generates heat in material of the workpieces causing the material to melt at an arrangement interface. The method further comprises allowing or causing the material melted to cool, wherein the melted material, when cooled, forms and/or strengthens a robust joint connecting the workpieces.

A method and a system including a welding device, an inspection device having an inspection head having two sensors, a controller, and a memory for assessing a butt weld of plastic pipes or fittings in a welding device.