MODELLING OF INTERNAL STRESSES IN DC CASTING AND SAWING OF HIGH STRENGTH ALUMINUM ALLOYS SLABS

摘要

During semi-continuous casting of high-strength aluminum alloys (2xxx and 7xxx series), non-uniform cooling conditions give rise to residual (internal) stresses. These stresses are particularly high for large cross-section ingots and must be relieved by a thermal treatment before the head and foot of the ingot can be cut. Otherwise, the saw can be caught owing to compressive stresses or cut parts can be ejected thus injuring people or damaging equipment. It is essential to be able to produce these high added-value ingots in secure conditions.rnBy studying the build-up of stresses during casting, the thermal stress relieving and the sawing operations of rolling sheet ingots, key parameters for the control and optimization of processing steps can be derived. To do so, the direct chill (DC) casting of the AA2024 alloy has been modeled with ABAQUS taking into account the characteristics of the cooling conditions, the geometry of the casting equipment and the thermo-mechanical properties of the alloy. Then, the sawing operation has been simulated by removing mesh elements. Preliminary results showing the stress relief during sawing are presented.