Optimization of microstructural and mechanical properties of brass wire produced by friction stir extrusion using Taguchi method

Abstract

Friction stir back extrusion is used to produce brass wires from its chips, and then the process parameters are optimized using Taguchi L9 orthogonal design of experiments. The rotational speed, traverse speed, and the produced wire diameter are the parameters taken into consideration. The optimum process parameters are determined with respect to grain size, microhardness, and ultimate pressure strength of the produced samples. The predicted optimum values for output parameters are confirmed by conducting the confirmation test using optimum parameters. Analysis of variance shows that the rotational speed is the most dominant factor in determining the grain size and microhardness of the produced wires, and the tool traverse speed and the wire diameter are the second and the third effective parameters. However, in terms of the produced wires ultimate pressure strength, the traverse speed is the most dominant factor rather than the rotational speed. The optimum values for the rotational speed, the traverse speed, and the wire diameter are 500 r/min, 31.5 mm/min, and 6 mm, respectively, and the produced wire, by these optimum parameters, presents 14.17 µm, 127.1 HV, and 904.7 MPa for the grain size, the microhardness, and the ultimate pressure strength, respectively.