Accurate friction and heat transfer laws for enhanced simulation models of precision forging processes

Analysis of Hip Prosthesis Production With Forging Using the Finite Element Method

“…In the same study, it has been shown that the required force for forging decreased with increasing the temperature. (Ou and Balendra, 1998) and (Doege et al, 2004) showed that at the same temperature and various friction coefficients, punch force increased by increasing the friction coefficient. Regression analysis of pressing velocity, temperature and friction coefficient on punch force showed that there were significant effects on dependent variable (Table 3).…”

Galling phenomena in metal forming

“…In the model, the sliding velocity, equivalent stress, and yield stress were considered, as shown in Fig. 17(b) [76]. An empirically-based friction model describes friction as a function of the sliding distance and the most relevant friction influencing parameters [77].…”

Reduction in post forging errors for aerofoil forging using finite element simulation and optimization

“…where [K] is the 6 × 6 press stiffness matrix, {γ} is the 6 × 1 press deflection vector, {γ eq o } is the 6 × 1 equivalent vector of the press guideway clearance and {P} is the 6 × 1 forging force vector, respectively. Therefore using equation (10), it is possible to accommodate the press elastic deflections in a forging simulation and to predict the dimensional errors of a forged part due to press elasticity. As shown in figure 5(b), 2D and 3D beam and coupling elements may be used to enable a proper load distribution and kinematic constraints between the press and the forging die in forging simulation to include the press elasticity effect.…”

“…Due to the forging dies being mounted rigidly on the press ram and table, the die surface displacement due to press elasticity at any given position can be calculated by the translation and rotation of the press ram. Based on equation (10), a matrix transformation of the press deflections may be further derived to predict the die surface deviation where {∆r i } is the 3 × 1 vector of the die surface deviation and [C i ] is the 3 × 6 coordinate transformation matrix at any given node i on the forging die surface, which represents the spatial relationships between the forging dies and the press ram. Equation ( 11) also suggests that the forging errors due to press elasticity and guideway clearance may be established by the spatial relationship of the forging dies mounted on the press ram and table, the press stiffness characteristics, the forging force and equivalent clearance values [9].…”

“…Recent development in process simulation shows that different stages of the whole forging process including pre-forging, forging and post forging may be simulated in coupling with the thermal behaviour and tool/press elasticity [7][8][9]. Parallelly to numerical simulation of forging processes, progress has been made in developing new experimental methods and constitutive models for the interfacial behaviour such as the friction and heat transfer as well as the material rheological behaviour under hot working conditions [10][11][12].…”