Authors: P Janaki Ramulu R Ganesh Narayanan Satish V Kailas Jayachandra Reddy
Publish Date: 2012/06/14
Volume: 65, Issue: 9-12, Pages: 1515-1528
Abstract
Welding parameters like welding speed rotation speed plunge depth shoulder diameter etc influence the weld zone properties microstructure of friction stir welds and forming behavior of welded sheets in a synergistic fashion The main aims of the present work are to 1 analyze the effect of welding speed rotation speed plunge depth and shoulder diameter on the formation of internal defects during friction stir welding FSW 2 study the effect on axial force and torque during welding c optimize the welding parameters for producing internal defectfree welds and d propose and validate a simple criterion to identify defectfree weld formation The base material used for FSW throughout the work is Al 6061T6 having a thickness value of 21 mm Only butt welding of sheets is aimed in the present work It is observed from the present analysis that higher welding speed higher rotation speed and higher plunge depth are preferred for producing a weld without internal defects All the shoulder diameters used for FSW in the present work produced defectfree welds The axial force and torque are not constant and a large variation is seen with respect to FSW parameters that produced defective welds In the case of defectfree weld formation the axial force and torque are relatively constant A simple criterion ∂τ/∂pdefective ∂τ/∂pdefect free and ∂F/∂pdefective ∂F/∂pdefect free is proposed with this observation for identifying the onset of defectfree weld formation Here F is axial force τ is torque and p is welding speed or tool rotation speed or plunge depth The same criterion is validated with respect to Al 5xxx base material Even in this case the axial force and torque remained constant while producing defectfree welds
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