PREDICTING RESIDUAL STRESSES CASUED BY HEAT TREATING CAST ALUMINUM ALLOY COMPONENTS

摘要

The objective of this work is to develop and verify a mathematical model that enables the prediction of residual stresses caused by heat treating cast aluminum alloy components. The model uses the commercially available software (ABAQUS) and an extensive database that is developed specifically for aluminum alloy under consideration (in this case. A356). The database includes the mechanical, physical, and thermal properties of the alloy all as functions of temperature. The database is obtained through a search of the open literature and measurements made on A356 alloy specimens using an Instron tensile testing machine. In addition, boundary conditions - in the form of heat transfer coefficients for each of the heat treatment steps - are obtained from measurements performed with a special quenching system. The database and boundary conditions are used in the software to predict the residual stresses that develop in a commercial A356 cast component that is subjected to a standard commercial heat treating cycle. In order to verify the accuracy of the model predictions, the predicted residual stresses are compared to residual stresses measured using x-ray diffraction.