APPLICATION OF ACOUSTIC EMISSION TECHNIQUE FOR ONLINE MONITORING OF FRICTION STIR WELDING PROCESS DURING WELDING OF AA6061-T6 ALUMINUM ALLOY

Acoustic Emission (AE) technique has been successfully used to monitor processes like metal cutting, grinding and electron beam welding as a nondestructive evaluation method. Friction Stir Welding (FSW) is a solid state welding that avoids problems associated with fusion welding and is used in aerospace industries. An attempt has been made to study the application of AE technique to monitor FSW process by identifying the occurrence of defect while welding is in progress and suggest means to rectify the defect. In this study, aluminum alloy AA6061-T6 has been used as work piece material. It was observed that the nature of AE signals produced during welding are helpful in identifying the occurrence of defects produced. The values of a few AE parameters derived from AE signals were found to be helpful in developing a model for online monitoring of FSW process to produce defect free welds. The model has been successfully validated.