A Study of the Effect of Tool Pin Profiles on Tensile Strength of Welded Joints Produced Using Friction Stir Welding Process

Abstract

Friction stir welding (FSW) has evolved into a process focused on joining of arc-weldable (5xxx and 6xxx) and which are difficult to weld (2xxx and 7xxx) aluminium alloys. The method described in this article for the prediction of tensile properties and optimization can eliminate the need for performing experiments on the basis of conventional trial and error method. The present study is aimed to identify the most influencing significant parameter and percentage contribution of each parameter on tensile strength of friction stir welded AA 7075–T6 aluminium joints by conducting minimum number of experiments using Taguchi orthogonal array. In this study, tool pin profiles like square head and conical head are used. Signal–to-noise (S/N) ratio and analysis of variance (ANOVA) are employed to find the contribution of the main welding parameters like tool rotational speed, weld traversing speed, and plunge depth on tensile strength of the welded joint. Confirmation experiments were conducted to validate the estimated value of tensile strength. It has been also observed that in both the tool profiles, the tool rotational speed exhibits more influence on tensile strength than weld traversing speed (welding speed) and plunge depth, and that the tool having conical profile results in better joint efficiency than the tool having square profile.

Keywords:

• Friction stir welding
• Joint efficiency
• Tensile strength
• Tool profile

ACKNOWLEDGMENTS

The authors wish to express sincere thanks to Aeronautical Research and Development Board (ARDB), New Delhi, for financial support rendered through R&D project No. DARO/08/2031473/M/I. Authors are thankful to Prof. Satish V. Kailas, Professor, Department of Mechanical Engineering, Indian Institute of Science (IISc), Bangalore, for extending facilities of FSW setup to carry out this investigation.