End-cracking failures are common in cold extrusion of long automotive drive shafts. Finite element analysis of these failures shows that cracking is primarily due to the elastic tensile unloading at the exit of the extrusion die land. This paper proposes a failure mechanism and a stress based failure criterion for this cracking. It analyzes the original single reduction die, and investigates a double reduction die design for the reduction of the residual tensile stress at the die exit. It analyzes the new die and compares this stress state with that of the single reduction die. Finally, it uses the design of experiments technique for determining the optimum die design parameter for minimum tensile stress state.
| Number of Pages : | 6 |
| Published : | 11/01/2000 |
