Finite element simulation of ausforming of austempered ductile iron components

The mechanical properties of ductile iron can be improved by ausforming, th at is, applying work during austempering. The resulting yield strength and ductility are comparable to those of SAE 4140 steel, while the density is a pproximately 10 percent less. The viability of manufacturing components by casting a preform, austenitizing it, quenching it to the austempering tempe rature, forging it, austempering it, and finally, quenching it to the net s hape is investigated by simulating the forging operation with finite elemen t analysis. The preform geometry and die set geometry are determined such t hat the forging operation imparts a reasonably uniform equivalent plastic s train of 20 percent to the workpiece and the prescribed final component geo metry is obtained. Forging of two components of varying geometric complexit y is simulated using a commercial software package. The results indicate th at the geometry of the final part is reasonably close to the goal and that the equivalent plastic strain distribution is reasonably uniform-over 80 pe rcent of the material was plastically deformed 15-25 percent. The design of the preform and die sets appears to be an excellent application for an opt imization algorithm.