November 2020 Volume 2

FORGING RESEARCH AND TECHNOLOGY

Fig. 1 Forging sequence of pinion gear shaft and effective strain distribution

2.1 Potential energy stored in the press frame during each forging cycle To determine the potential energy stored in the press frame of a 150-ton hydraulic press, a static stress analysis was carried out using ANSYS software package. A meshed model of the press frame is shown in Fig. 2. The piston from the hydraulic cylinder is connected to a rectangular plate with four guide rods. These rods go through the bearing bushes on the bolster. The die set (not shown) which transmit the load to the frame is secured between the flat plate and the bolster. Using the maximum forging load of 70 tons obtained from DEFORM 2D simulation for the forging sequence presented in Fig. 1, the effective stress and strain energy density in the press frame were simulated. As shown in Fig. 3 a maximum effective stress of 757 MPa was exhibited at the hole on the bottom bolster. Most of parts of the press frame experienced stresses below 400 MPa. This indicates that the press frame does not yield under the forming load of 70 tons. As shown in Fig. 4, the elastic strain energy density mainly appears in two locations; the bottom bolster and the four vertical pillars. Compared to the pillars which are under tension, the bolster location is where most of strain energy concentrates. Note that different forging press architectures will exhibit different levels of strain energy density distributions. In the interest of harnessing the potential energy, the press frame could be designed such that elastic strain energy density is concentrated in specific locations to facility energy harnessing. The total strain energy stored in press frame is 617 J. Most forging presses for small and medium size components are run at high speeds. With such systems, a substantial energy could be harnessed.

Fig. 2. Meshed Press

FIA MAGAZINE | NOVEMBER 2020 34