The device (1) has a polymeric tubular connection (20) mounted around a radially external connecting zone of a metal tube (10) having a circumferential boss (12) against which a sealing joint (13) is mounted. The connection includes a ring (21) with an axial end (22) connected to the tube holding the boss via an overmolding of the tube by the ring. Another axial end of the ring is soldered to a tubular end fitting (24) of the connection, where a radially internal face (25) of the end fitting follows a free end (14) of the tube such that soldering interface is integrated to the connection. An independent claim is also included for a method for assembling a sealed coupling device.
