| Abstract: | Butt welding of AA6063 aluminium cylindrical shells was performed using the orbital friction stir welding (FSW) method. Tool rotation speed and orbital speed (i.e., traverse speed of rotating cylinder during welding) were considered as variable, and the strength and the mechanical properties including tensile strength, microhardness, mode I fracture energy and mode I crack growth behaviour of manufactured cylinders were investigated experimentally. A novel and subsized test specimen was designed and manufactured for fracture testing of specimens extracted from both base metal and weld zone region of cylinders. The initial precrack was introduced along (i) the tool penetration through the pipe thickness (i.e., T‐direction) and (ii) along the tool travelling direction (i.e., L‐direction). It was found that the crack growth resistance and fracture energy values of FSW samples are greater than the corresponding values of base aluminium material along both “L”‐ and “T”‐directions. Also, the fracture resistance value in T‐direction was higher than the L‐direction for the whole tested FSW samples with different welding speeds. |
