Application of acoustic emission technique to monitor friction stir welding process to produce defect free welds

Abstract

Friction Stir Welding (FSW) is a solid - state welding technique used for joining of metals and alloys to avoid problems associated with fusion welding. Acoustic Emission (AE) technique had been successfully used to monitor processes like metal cutting, grinding and electron beam welding. An attempt has been made to study the feasibility of application of AE technique to monitor FSW process. Experiments were carried out using aluminium alloy AA 7020-T6 by continuously varying the FSW input process parameters namely tool rotational speed and weld traverse speed during welding. Variation in pattern of AE signals was observed when FSW input parameters were varied. The pattern were found helpful in identifying the defect occurred during welding, as well in developing a model for online monitoring of FSW process to produce quality welds. The developed model has been successfully used to monitor FSW process during welding of aluminum alloy AA6082-T4