Pressure vessels have a wide range of applications in industrial and commercial areas. Among different types of vessels, composite vessels with metallic liner are of special use because of their high reliability, less leakage, faster charge and discharge and low weight. The main chalenge in making these types of reservoirs is the process of making their metal liner. In this investigation, an innovative manufacturing process that is capable manufacturing seamless liner is introduced. Seamweld removal reduces iection and non-destructive testing and ultimately reduces production time and manufacturing costs. In the presented method in this thesis, the liner is manufactured from a premade tube and another advantage is that it is possible to manufacture the product in one stroke of press. After forming the liner, subsequent stages of construction and additional operations such as cleaning, machining and gas port assembly are performed. The proposed method includes a combination of tube nosing and extrusion processes. In this research, production of aluminum liner with an outer diameter of 115 mm is studied. Having a general knowledge of the process in mind, effective parameters and their effect on the process, are determinecd and investigated based on practical tests. A die is designed and fabricated based on the liner geometry and optimized process parameters. According to the results of liner forming experiments with the desired geometry, it was determined that the strength and mechanical properties of the tube, friction and end tube geometry are the most important parameters affecting the process. By increasing the strength of the tube, due to the strain created in the deformation region and the consequent work hardening, the force required to perform the process increases and causes local buckling of the tube. Friction also plays a major role in the process, and lack of proper lubrication results in failure of the process. Also making a chamfer at the outer rim of the tube fasilitates the forming process and the nose of the liner is formed in a shorter stroke due to reduction of forming force. Keywords: Composite vessels, liner, tube nosing, forming die
