The recent trend of research on joining of dissimilar alloys leads the interest towards the study and analysis of Friction Stir welding. Joining of different steel groups and Aluminium has been on the research interest on the previous decade. Recent innovative research and development area is on with Magnesium alloy groups. The Aluminium alloys and Magnesium alloys are investigated for the weld strength with respect to the change of welding parameters including tool geometry, the tool transverse speed, and the tool angular velocity. In this paper, plunging down time is considered as novelty parameter along with usual rotational speed and axial load parameters for the analysis of weld strength based on heat generation. The plunging down time is accurately measured using the coded PLC program enabled LED sensors. The effect on tensile strength and variation of micro hardness due to the varation in Plunge Down Time (PDT) were studied. The Plunge Down Time found to be one of the important weld parameter need to be considered as per the results of tensile strength and microhardness.
