Experimental Identification of Optimized Process Parameters for FSW of AZ91C Mg Alloy Using Quadratic Regression Models

Abstract

This experimental work aims to devise and establish quadratic regression equations, including various input criteria of a friction stir welding (FSW) technique to predict and determine the responses during the fabrication of AZ91C Mg alloy joints. The input process parameters taken into consideration include the traversing speed of the tool, the speed of rotation of the tool, its pin profile (geometry) and the axial force. A five-level, 4 four-factor composite design (of central nature) was applied, and response surface methodology (RSM) was used to formulate quadratic regression models, to develop 3D response surface charts, and to anticipate the responses for various mechanical properties. The generated quadratic mathematical model was tested and validated using the technique of analysis of variance. Validation experimental trial results outlined in the form of scatter diagrams revealed precedented coincidence with that of the generated models. The AZ91C Mg alloy joints obtained using the tool having taper cylindrical pin geometry employed at 1045 rpm, 1.5 mm/s traversing speed, under the exertion of an axial load of 4.87 kN was found to exhibit improved mechanical properties.

Investigation of the Effect of Tool Temperature on Microstructure, Hardness, and Wear Behaviour of Aluminium 6061-T6 Alloy Welded by the Friction Stir Welding Process

“…It shows that the high tool temperature plasticises the material and makes the two pieces bond properly. When the tool's traverse and rotating speed both increase at the same time, the welded joints' mechanical strength rises [25].…”

Investigation of Mechanical and Microstructural Properties of Welded Specimens of AA6061-T6 Alloy with Friction Stir Welding and Parallel-Friction Stir Welding Methods

“…According to Figure 7, in the AP-FSW and RP-FSW processes, the welding area in the welded specimens increased with increasing the tool offset in the first and second passes. In the FSW process, the SZ is generally formed at the tool pin passage locus, and its width is approximately equal to the diameter of the tool pin [8,37,47,63,64]. In P-FSW techniques, in addition to the dimensions of the tool, the width of this area depends on the tool offset in the first and second welding passes.…”

“…Many factors affect the FSW joint, which are classified into two general categories of process parameters and tool geometry [5][6][7]. By changing the condition of each of the parameters, the heat and material flow distribution in the process change, which ultimately leads to a change in the mechanical quality of the joint [8][9][10][11][12][13]. The most important factors influencing the FSW process are the temperature and the material flow distribution patterns in the welding zone [14][15][16][17][18].…”

Process Parameters Optimization for Maximizing Tensile Strength in Friction Stir-Welded Carbon Steel

“…Then, the microstructural examinations were carried out on those alloys [10] and [11]. Later, the process parameter optimization studies were reported on friction stir-welded aluminium and its alloys [12] and [13]; other studies including corrosion analysis and tensile strength optimization were also reported for aluminium [14] to [16] and magnesium alloys [17] but nowadays the research focus is on high-temperature materials. A feasibility study related to friction stir welding of mild steel was initially presented by Linert et al [18], in which defect-free welds were successfully produced, but excessive tool wear was reported; the paper emphasized the need to work on the geometry of the tool in order to eliminate the issue of tool wear.…”