Single- and double-pass FSW lap joining of AA5456 sheets with different thicknesses

Abstract

Friction stir welding of AA5456 aluminium alloy with different thicknesses was investigated for single- and double-pass lap joint configurations. The influences of tool tilt angle in first and second passes, and rotational and welding speeds in second pass on metallurgical structure and joint strength were studied. The results indicated that tilt angle significantly influences material flow and imperfection formation, and accordingly controls the weld mechanical properties. The best results were achieved by tilt angle of 5° for single pass, and tilt angle, rotational speed and traverse speed of 5°, 250 rev min^− 1 an 50 mm min^− 1 respectively for double-pass. The characteristics of hooking and cold lap defects were used as criteria to recognise the influence of processing conditions on joint performance.

Keywords:

• Friction stir welding
• Aluminium alloy
• Lap joint
• Single- and double-pass
• Different thicknesses
• Imperfections
• Mechanical properties