Validity of constitutive equations used for calculation of stresses in cooling castings

The fundamentals of the constitutive equations used for modelling the mechanical behaviour of metallic materials over wide temperature ranges are briefly reviewed. Examples of stress-calculation problems in cooling castings are given. Four constitutive relationships used for practical calculation of the stresses are analysed. An experimental assessment of their validity, based on a comparison of stress values predicted by the models with those obtained for ring-shaped, aluminium alloy castings with metallic cores, as well as with some published data concerning beam-shaped, low-carbon steel castings, is presented. It is concluded that the essential simplifications assumed in deriving the models lead to significant disagreements with experimental results in most of the investigated cases.MST/58