Abstract: A flat heat exchanger tube is formed from a single metal strip and comprising two opposite spaced apart broad sides in a thickness direction of said tube and two opposite nose-forming narrow sides in a width direction of said tube. The strip has two longitudinal edges, the first longitudinal edge being contiguous to the first broad side and the second longitudinal edge being contiguous to the second broad side. The two longitudinal edges of the strip are joined together at a first one of the narrow sides, both longitudinal edges being convex-shaped so that the first edge forms an outer convex bend and the second edge forms an inner convex bend that fits in the outer convex bend and conforms to its internal curvature.

Abstract: A heat exchanger may include a first component composed of a first material and a second component composed of a second material. The first component and the second component may each have an edge zone. The first component and the second component may abut against one another in an overlapping manner at the edge zone and may be joined together. At least the edge zone of the first component may consist of a material impermeable to laser beams. The edge zone of the first component may externally overlap the edge zone of the second component and abut against the edge zone of the second component in direct contact and may be joined thereto via a fusion bond.