Effect of Process Parameters in Pinless Friction Stir Spot Welding of Al 5754-Al 6061 Alloys

• Published in: Metallography, microstructure, and analysis Vol. 9; no. 2; pp. 261 - 272
• Main Authors: Suryanarayanan, R., Sridhar, V. G.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.04.2020; Springer Nature B.V
• Subjects: Aluminum base alloys; Characterization and Evaluation of Materials; Chemistry and Materials Science; Dissimilar material joining; Dissimilar materials; Dwell time; Friction stir welding; Materials Science; Metallic Materials; Microhardness; Nanotechnology; Piercing; Process parameters; Resistance spot welding; Response surface methodology; Riveted joints; Riveting; Rivets; Shoulder; Stress concentration; Structural Materials; Surfaces and Interfaces; Technical Article; Thin Films; Welded joints; Welding parameters; Micro-hardness; Friction stir spot welding; Microstructure; Pinless tools; Tensile shear force
• ISSN: 2192-9262; 2192-9270
• DOI: 10.1007/s13632-020-00626-5

Joining of lightweight dissimilar materials by friction stir spot welding (FSSW) provides numerous advantages over conventional welding methods such as resistance spot welding and self-piercing rivets. However, the keyhole left behind by the tool is a major drawback in FSSW, as it acts as a stress concentration factor and initiates corrosion. In this paper, the keyhole is avoided in FSSW of Al 5754 and 6061 alloys using pinless tools. The process parameters such as tool rotational speed, plunging speed, dwell time, plunge depth, and shoulder diameter were optimized using response surface methodology with Box–Behnken design. The results showed that shoulder diameter was the most crucial factor that affected the joint strength. The micro-hardness analysis indicated the strengthening of the thermo-mechanically affected zone. SEM and EBSD techniques were employed to analyze the microstructure of the weld joint.