Influence of the pin shape of the tool during friction stir welding on the process output parameters

Abstract

In this paper, computer simulation of the friction stir welding (FSW) of AlMg6Mn0.6 aluminum alloy sheet blanks by means of the DEFORM-3D software package is carried out to select the optimum pin geometry based on the calculation of the displacement and speed of displacement of the material points. Pins in the shape of a cylinder and a truncated cone with the cone angles of α =10, 20, and 30° were considered. The friction coefficient of 0.5 was assumed. Instrumental steel AISI-D2 was chosen as the material for the tool. To reduce the computation time and avoid the instability of solution, the model of welded blanks was built as a single body of 3 mm thickness and 40 and 30 mm length and width, respectively. The behavior of the AlMg6Mn0.6 alloy was described using the Johnson-Cook model. The FSW process was simulated at the tool moving speed v = 2 mm / s, rotation frequency ω =1000 rpm and axial force P = 25 kN. The initial temperature of the workpiece and the tool was 20°C. When welding the blanks, the conditions of heat exchange with the environment were set. The simulation results solution have shown that the flow of the material of the workpiece depends on the shape of the pin and is different over the thickness of the workpiece. The material in the lower area of the workpiece is practically not subjected to mixing for all values of the cone angle of the pin, in contrast to the middle and upper areas of the workpiece, where the material is noticeably mixed. Of all the tips considered, the most preferred for the FSW is a pin in the form of a truncated cone with the cone angle of 10°, since it provides good mixing in the plane of the workpiece, the maximum displacement of the material towards the root of the weld, and also allows one to get the most symmetrical seam.

Experimental and Numerical Analysis of Refill Friction Stir Spot Welding of Thin AA7075-T6 Sheets

“…A constant interface heat transfer coefficient of was applied for contact interfaces between workpiece-tools [ 29 ]. The convective heat transfer coefficient h = 0.02 [ 30 ] was employed to define heat transfer between tools/workpiece and environment. The emissivity in the model is assumed as 0.7 [ 31 ].…”

A Numerical Study on the Effect of Tool Speeds on Temperatures and Material Flow Behaviour in Refill Friction Stir Spot Welding of Thin AA7075-T6 Sheets

“…For conduction between the workpiece and toolset, a conductive heat transfer coefficient of 11 N mm s K was used [43,44]. For convective heat transfer from tools/workpieces to the environment, the heat transfer coefficient h = 0.02 N mm s K was used [44,49]. The side faces of the workpiece were constrained in all degrees of freedom.…”

Effect of the length of the tool pin on the hardening of 2024 aluminum alloy under friction stir processing

“…Моделировали обработку при скорости перемещения инструмента 3 см / мин, частоте вращения 1000 об / мин и осевом усилии 2 кН. Конечно-элементная модель листа состояла из 60 000 элементов, а инструмента -из 32 000 (более подробно описана в [17]).…”