Tank comprising at least two portions which are connected by means of a connection ring and weld seams which are obtained by means of a friction welding method and production method for the tank

A tank comprising:

• at least first and second portions which are connected to each other in order to obtain a closed tank which delimits inner and outer zones, each of the first and second portions having an end,
• a connection ring interposed between the first and second portions and connected to the end of the first portion by a first circumferential weld seam obtained by means of a friction welding method and to the end of the second portion by a second circumferential weld seam obtained by means of a friction welding method,
• the connection ring comprising
• at least a first cylindrical portion fitted in the end of the first portion,
• at least a first shoulder positioned in a transverse plane adjacent to the first cylindrical portion and which protrudes toward the outer zone of the tank relative to the first cylindrical portion, and
• at least a first transverse web formed as a ring which comprises an outer edge connected to the first cylindrical portion and an inner edge orientated toward the inner zone of the tank,
• wherein the first transverse web is positioned in a common transverse plane with the first shoulder, and
• wherein the first circumferential weld seam is positioned in a region of a connection plane located between the first shoulder and the end of the first portion and connecting them.