Incremental hole drilling for residual stress measurement are widely used in industrytoday and is considered to be a cheap and fairly reliable method for stress measurements. Eventhough the method assumes isotropic material, it has been expanded to orthotropic materials suchas composite laminates. With heterogeneous material like grey cast iron, the reliability andaccuracy of the method still often fails to provide residual stress data valid for analysis. Cast ironmicrostructural aspects that complicate the analysis are the graphite and its morphology,variations in matrix structures and casting defects. These features can extend over differentlength scales and give cast iron highly localised mechanical properties. Global engineeringparameters, such as Young’s modulus and Poisson’s ratio, are used together with the locallymeasured strains to calculate the residual stresses. Utilizing global material parameters whilemeasuring locally can provide false stress results. Grey cast iron exhibits a non-linear elasticbehaviour and the Young’s modulus can change significantly and can therefore result in verydifferent calculated residual stresses. Experiments were conducted on cast stress lattices utilizingincremental hole drilling to measure strains. To calculate the residual stresses, global materialparameters and standard evaluation procedures in accordance to ASTM E837 were used. Resultsshow that the method is questionable for grey cast iron but can be used for ductile iron. Lack ofmaterial properties knowledged are suggested to be the main obstacle for residual stressevaluations on grey cast iron as the accuracy of the method decreases as hole depth approaches 1mm.

A high shake-out temperature after casting is beneficial from a production point of view due to the need of a shorter cooling line in the foundry. However, a higher shake-out temperature might also lead to increased residual stresses due to faster cooling. In order to get a good agreement between simulated and measured temperature curves it is important to adjust material data and heat transfer coefficients accordingly. A reduction of the thermal conductivity of the sand by 25% and a drastically increased HTC were the main adjustments. From the residual stress simulation, the most important lesson learned was the necessity to include the sand in the calculation. Especially internal sand cores can greatly restrict the thermal contraction of the casting. After this fine-tuning of the simulation a good agreement with measurements was obtained. It could be verified that an increased shake-out temperature will lead to significantly increased residual stresses.