Friction Stir Lap Welding of Thin AA6061-T6 and AISI304 Sheets at Different Values of Pin Penetrations

The present paper focuses on the influence of pin penetration on joint strength achieved in friction stir lap welding between AA6061-T6 and AISI304. Penetration of pin into the steel substrate, which is placed below the aluminium, has an influencing role in achieving a good weld. Beyond a certain depth of penetration of pin into the steel, non-uniform thicker intermetallic compound and the weld defects have been found. Defects were found to be located in the stir zone. Thus, an excessive penetrations of the pin into the steel matrix has been produced a detrimental effect to the weld strength. An optimum penetration of pin has been experimentally found out.