Energy and Force Analysis of Ti-6Al-4V Linear Friction Welds for Computational Modeling Input and Validation Data

Abstract

The linear friction welding (LFW) process is finding increasing use as a manufacturing technology for the production of titanium alloy Ti-6Al-4V aerospace components. Computational models give an insight into the process, however, there is limited experimental data that can be used for either modeling inputs or validation. To address this problem, a design of experiments approach was used to investigate the influence of the LFW process inputs on various outputs for experimental Ti-6Al-4V welds. The finite element analysis software DEFORM was also used in conjunction with the experimental findings to investigate the heating of the workpieces. Key findings showed that the average interface force and coefficient of friction during each phase of the process were insensitive to the rubbing velocity; the coefficient of friction was not coulombic and varied between 0.3 and 1.3 depending on the process conditions; and the interface of the workpieces reached a temperature of approximately approximately 1273 K (1000°C) at the end of phase 1. This work has enabled a greater insight into the underlying process physics and will aid future modeling investigations.

Modelling the influence of the process inputs on the removal of surface contaminants from Ti–6Al–4V linear friction welds

“…Previous work by the authors [6] detailed how Design Expert V.7, a design of experiments (DOE) software package, was used to determine a set of experiments to relate the main process inputs (amplitude, frequency, applied force and burn-off) to the process outputs, such as the power input, coefficient of friction and interface force generated over a phase for Ti-6Al-4V workpieces with the dimensions shown in Fig. 3(a).…”

“…Despite being one continuous process, LFW is said to occur over four [4][5][6] phases: Phase 1 -initial phase. Contact exists between asperities on the two surfaces to be joined and heat is generated due to frictionsee Fig.…”

“…Various authors have developed two [1,[6][7][8][9][10][11][12][13][14][15][16] and three [15,[17][18][19][20][21][22][23][24][25] dimensional (2D/3D) computational models. These models have been used to predict various weld responses, such as: residual stress formation [11,13], strain rates [1], flash morphology [1,12], flash formation rates [1,8,9,12,19], thermal fields [1,6,[8][9][10][11][12]14,17,[19][20][21]25] and microstructural evolution [23]. Although the 2D models do not model the material expulsion perpendicular to the direction of oscillation they do provide a good insight into the process without requiring the heavy computational times of the 3D models.…”

“…Although the 2D models do not model the material expulsion perpendicular to the direction of oscillation they do provide a good insight into the process without requiring the heavy computational times of the 3D models. According to the reviewed literature, there are three main approaches that may be taken when finite element modelling the LFW process [1,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25], which are illustrated in Fig. 2.…”

3D Modelling of Flash Formation in Linear Friction Welded 30CrNiMo8 Steel Chain

“…'Hero' is the designation given to the chains joined with this process. Due to the rapid nature of the process, modelling is often used to describe the weld phenomena in terms of flash formation, surface self-cleaning ability, and thermal histories in order to provide as much insight as possible, which would not be possible with experimental work alone [10][11][12]. Despite this, 2D modelling has been of preference for the majority of published work, regarding the fact that it provides considerable information on the LFW process, without the significant computational effort drawback experienced in 3D modelling.…”