Measurement of oxide properties for numerical evaluation of their failure under hot rolling conditions

In this work a method based on combination of hot tensile measurements and finite element (FE) modelling is discussed—a method of direct measurement of oxide scale properties that are crucial for numerical characterisation of oxide scale failure in metal forming. This requires a combination of experiments under appropriate operating conditions and computer-based models for interpretation of test results and implementation of physical insight into predictions for technological operations. Separation loads for scale failure in tension have been measured using a modified hot tensile test technique. The separation loads seem to be critical mechanical parameters characterising scale failure and they depend on morphology of the particular oxide scale, scale growth temperature and are also very sensitive to the chemical composition of the underlying steel. Application of the micro-scale FE model to provide numerical analysis of experimental results significantly improves accuracy of determination of the separation loads. The method has been demonstrated for low carbon steel oxides.