Understanding thermal warping and sagging in enamelled steel parts through an integrated FE simulation

摘要

When a steel part is enamelled, residual stresses are induced due to the difference in thermal dilatation between steel and enamel. Those stresses can give rise to buckling and warping. Slender designs, such as baking trays and architectural panels, are especially prone to these defects. The present paper proposes a finite element procedure which allows simulation of the complete cycle of forming, springback and enamelling and, as a result, allows prediction of warping and buckling in enamelled steel parts. To that end, the phenomenological models describing the thermomecha-nical behaviour of porcelain enamels have been implemented in Abaqus. These models allow for both stress and structural relaxation and, as a result, allow the simulation of the complete enamelling process, i.e. cooling down from around 850°C (liquid phase) to room temperature (solid phase). The finite element (FE) methodology is validated based on two case studies: simulation of the Klotz test and prediction of warping in enamelled baking trays.