الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 89 |  |  |
| | | from | 89 | | |
Abstract
Since 1991, the effect of friction stir welding (FSW) on the weld quality of aluminum alloys is intensively studied. The main parameters are supposed to be the tool shape, the rotation rate, and the welding travel speed, as well as, the tool tilt angle, and the shoulder plunge depth. In the present work, FSW is applied on 4mm thick 5083-H111 aluminum alloy sheets used in shipbuilding application. Simple tool pin and concave shoulder profile are manufactured and used in FSW of butt joints at different rotation speeds, and different traveling speeds, and two different tool shoulder plunge depths. The weld joints are evaluated using visual inspection, and macrostructure investigation, as well as tensile and hardness testing. A defect free weld is produced at 600, 800, and 1000 rpm rotation speeds, 50 mm/min welding speed, and a plunge depth of 0.1 mm. On the other hand, at 0.2 mm SPD a defect free weld is produced also at 600, and 800 rpm rotation speeds, 50 and 100 mm/min welding speeds. Defect-free FSW joints with relatively high tensile strength, using a simple cylindrical pin tool are produced. Friction stir welding at a lower speed 50 mm/min leads to better tensile properties, in case of using 0.1 mm shoulder plunge depth. This is reversed at 0.2 mm plunge depth, and a higher speed 100 mm/min leads to better tensile properties. This means that, increasing shoulder plunge depth allows the use of higher FSW speed. In terms of hardness results, the increase of plunge depth results in an increase of the hardness, and the effect of plunge depth does not strongly affect the stir zone hardness at low rotation speeds.