https://popups.uliege.be/esaform21/index.php?id=937 Publications of Auteurs Laurent Langlois fr 0 https://popups.uliege.be/esaform21/index.php?id=1896 Hot rolling of bars issued from continuous-casting aims at refining the material structure and guaranteeing the central soundness of the metallurgical product. The rolling route must be designed to achieve the complete closure of the shrinkage porosity inherent in the continuous casting process. To predict the void evolution, many models exist that can be implemented in the finite element simulation of the process. Nevertheless, these models need parameter adjustments to be adapted to the forming process, the formed material, and the real geometry of the void. Real scale tests being very expensive in the long product rolling mill, an improved representativeness experimental configuration was designed to reproduce at the laboratory scale the key characteristics of the thermomechanical path driving the void closure phenomenon. This testing consists of successive forming stages with shaped anvils applied to samples containing a shrinkage cavity. The shaped anvils and the forming conditions are calibrated to reproduce the levels of strain and the stress triaxiality of rolling stands, and the alternation of the forming direction of the industrial process. The geometry of the voids before and after the forming paths are measured by tomography. The simulation of the test with an explicit modelling of the void is developed parallel to the experiments. The simulation/experiment comparison allows the validation of the numerical model. The obtained model will be used in future works to perform a more extended design of experiments to characterise void closure during hot rolling of bars. Tue, 23 Mar 2021 10:30:57 +0100 Mon, 12 Apr 2021 10:04:25 +0200 https://popups.uliege.be/esaform21/index.php?id=1896 https://popups.uliege.be/esaform21/index.php?id=929 Manufacturing high value components involves complex and non-linear thermo-mechanical processes to obtain optimum combination of microstructure and mechanical properties required for the final part. Among these, the ingot-to-billet conversion process, involving forging operations of upsetting and cogging, are critical to refine the as-cast coarse, elongated, and dendritic microstructure. In this study, the first stage of the ingot-to-billet conversion process has been investigated in type 316 austenitic stainless steel, aiming to propose a novel methodology for the characterisation of the as-cast material behaviour. Hot upsetting tests were carried out on cylindrical samples taken out from an industrial-scale ingot. The resulted microstructures were analysed, using advanced image analysis method, for the fraction and distribution of the recrystallised grains, highlighting the strong dependency of recrystallisation behaviour on the initial microstructure of the as-cast material. Using a finite element (FE) model considering the anisotropic behaviour of the material, originated from the preferential grain growth during casting, the deformation of the samples were predicted with a good accuracy. The results demonstrate the importance of considering the anisotropic plastic properties in the FE models to effectively predict the as-cast material deformation, shape and thus the thermo-mechanical characteristics applied during forging. Mon, 22 Mar 2021 10:22:17 +0100 Tue, 30 Mar 2021 10:07:33 +0200 https://popups.uliege.be/esaform21/index.php?id=929