Fatigue Life Prediction in Rapid Die Casting

During a die casting process, it is very difficult to achieve efficient and correct casting tooling endurance results by the casting designer and foundry man. However, it is very costly and time consuming to predict the tooling endurance with a trial and error method based on expertise and experience. After an extensive fatigue design study, it was possible to develop specimen design models for the simulation of the time and temperature dependent stress-strain and fracture models to determine the thermal fatigue prediction. In this research, stress-strain approach, heat transfer concept and life time calculation methods were used to predict the casting tool endurance by a computer simulation. The thermal stress and heat transfer behaviour analysis were performed using RWP casting numerical simulation software. It is shown that numerical simulation techniques can simulate stress concentration on the specimen surface to thermal behaviour. Furthermore, the result from the specimen based simulation model associated with fracture indicators permits the construction of a life time design curve independent of time and temperature. The fatigue life predicted by simulation based models and the results from experimental testing on real components are very similar. The simulation results showed that they match the experimental results, including a design safety factor.