A Nonlinear elastic visco-plastic thermo-mechanical steel microstructure model is coupled with a Gurson-Tvergaard-Needleman (GTN) model to predict local damage and failure in the columnar solidification zone of a steel casting. The new model operates on two scales - a unit cell grain model of micro-scale in the columnar zone as well as a macro-model tensile specimen to map observations with experiments. The model aims to investigate inter-granular embrittlement at intermediate temperatures during solidification processes. This embrittlement occurs due to pro-eutectoid ferrite film formation and precipitation of inclusions at the prior-austenite grain boundaries. This behavior of the unit cell is then mapped onto macro-model tensile specimens to measure reduction in ductility. The effect of ferrite film and temperature are studied by calculating the micro-strains, macro-strains and void fractions at which cracks begin to form during the continuous casting process.
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|Published - 2015