QUANTIFICATION DES DÉFAUTS EN FONDERIE SOUS PRESSION PAR RADIOSCOPIE NUMÉRIQUE ET TOMOGRAPHIE HAUTE RÉSOLUTION HIGH PRESSURE DIE CASTING DEFECT QUANTITATIVE MEASUREMENT BY RADIOSCOPIC AND TOMOGRAPHY ANALYSIS

Quantification of internal defects on aluminium high pressure die castings contributes to a better definition and harmonization of acceptance specifications. The radioscopic image analysis allowed extracting reference images (blowhole or shrinkage type) correlated to porosity levels. High resolution tomography (from 3µm to 20µm voxel) enabled to calculate the volume of internal defects and to determine the distribution of the pores among classes in order to specify maximum allowed pore sizes. Moreover, this technology, still no very used industrially, makes it possible to measure the distance between pores and the distance of pores from surface, an important criterion for the dynamic stress strength.