Friction stir welding is a relatively new solid state joining process, which is suitable for welding similar and dissimilar materials. The present research work concentrates on the effect of tool rotational speed on the tensile, microstructural properties and microhardness of the friction stir welded joints of different grades of austenitic stainless steel sheets. Four different tool rotational speeds are used in the experimentation while the other process parameters like traversing speed and the tool tilt angle are kept constant. The tensile testing, micrography and microhardness measurements were carried out in the welded samples. It is observed from the results of tensile testing that the joint made at the tool rotational speed of 1320 rpm has the maximum strength among the experimented speeds. The measured microhardness values at heat affected zone and parent metal zone have shown higher hardness than the weld zone. Fine and equi-axed grains are observed in the welded region at all experimented speeds with a negligible amount of transformation of austenite into martensite. These results have impact on the development of welding procedure for dissimilar stainless steel friction stir welding process.

Friction stir welding (FSW) is solid state joining process with more advantages than that of fusion welding. Nylon -6 is one of the engineering plastics used widely in various industrial applications. The main aim of this research work is to investigate the effect of tool rotational speed and tool traversing speed on the mechanical and microstructural properties of the nylon-6 butt welded joints made by FSW. The FSW process was performed in a computer numerically controlled (CNC) vertical milling machine using a cylindrical tool with threaded pin made of heat treated high carbon high chromium (HCHCr) steel. The tensile testing and microscopic examinations were carried out to study the mechanical and microstructural properties of the welded joints. In visual inspection, it is observed that the excessive flashes are observed on either sides of the weld line in all cases. From the results, it is observed that the maximum tensile properties are achieved in a joint made which is approximately 18% and 26% of the parent material’s ultimate tensile strength (UTS) and yield strength (YS) respectively with the tool rotational speed 1200 rpm and the tool traversing speed of 30 mm/min within the experimented process parameters. Overall, the tensile properties of the welded joints made using the experimented process parameters are very much lower than the parent material.

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Abstract. Composite materials are heterogenous materials containing one or more solid phases. In recent years cost-effective composite making is an ideal task. Hence we have come out with a natural fibre composite, which contains goat hair and epoxy as a binding element, with the combination of Graphene as a main source of enhanced mechanical property. Fabrication of natural composite consists of five layers of goat hair sandwiched in epoxy matrix. These composites made are tested for mechanical properties including Tensile strength, Flexural strength, Inter laminar shear and Impact strength. The mechanical properties of the six composite sets are analyzed and reported.

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