The main objective of this study is to implement a reliable FE model of the orthogonal machining ... more The main objective of this study is to implement a reliable FE model of the orthogonal machining of a Nickel based superalloy for the prediction of microstructural changes occurring during the process. A FE numerical model was properly calibrated using an iterative procedure based on the comparison between simulated and experimental results. A user subroutine was implemented in the FE code to simulate the dynamic recrystallization and consequently the grain refinement and hardness variation when orthogonal cutting of Nickel based superalloy is performed. Thus, Zener-Hollomon and Hall-Petch equations were implemented to predict the grain size and micro hardness, respectively. In addition, the depth of the affected layer was predicted using the critical strain equation. The obtained results proved the adequacy of the proposed model showing a good agreement between the simulated and the experimental results.
ABSTRACT In the last few years, important step forwards have been made on Finite Element Simulati... more ABSTRACT In the last few years, important step forwards have been made on Finite Element Simulation of machining operations. Wrought Ti6Al4 V alloy has been deeply investigated both numerically and experimentally due to its wide application in the industry. Recently, Additive Manufacturing technologies as the Electron Beam Melting and the Direct Melting Laser Sintering are more and more employed in the production of biomedical and aeronautical components made of Ti6Al4 V alloy. Fine acicular microstructures are generated by the application of additive manufacturing technologies, affecting the mechanical properties and the machinability. By the consequence, this peculiarity has to be considered in modelling the material behaviour. In this work, a numerical analysis of cylindrical external turning on Electron Beam Melted (EBM) Ti6Al4 V alloy is presented. A Johnson-Cook constitutive equation was implemented as a flow stress model and adapted with respect to the wrought Ti6Al4 V alloy. The model was calibrated and validated through the cutting forces and temperatures measurements acquired under dry and cryogenic lubricating conditions.
ABSTRACT Finite element analysis of cutting processes of difficult-to-cut alloys is attracting mo... more ABSTRACT Finite element analysis of cutting processes of difficult-to-cut alloys is attracting more and more interest among the scientific community thanks to the change of predicting difficult to measure parameters as cutting forces, specific cutting pressures, cutting temperatures and the chip morphology. Aiming to calibrate and validate an FE numerical model, the predicted variables have to be compared with experimental results. Nowadays, Additive Manufactured Titanium alloys are being increasingly employed in the production of surgical implants and aero engine parts, but their peculiar fine acicular microstructure have to be taken into account dealing with their thermomechanical behavior as during machining operations. Based on the lack of literature works concerning experimental investigations on the machinability of Additive Manufactured Titanium alloys, this paper is aimed to investigate the cutting forces and temperatures arising during orthogonal cutting of an Electron Beam Melted (EBM) Ti6Al4V alloy.
The main objective of this study is to implement a reliable FE model of the orthogonal machining ... more The main objective of this study is to implement a reliable FE model of the orthogonal machining of a Nickel based superalloy for the prediction of microstructural changes occurring during the process. A FE numerical model was properly calibrated using an iterative procedure based on the comparison between simulated and experimental results. A user subroutine was implemented in the FE code to simulate the dynamic recrystallization and consequently the grain refinement and hardness variation when orthogonal cutting of Nickel based superalloy is performed. Thus, Zener-Hollomon and Hall-Petch equations were implemented to predict the grain size and micro hardness, respectively. In addition, the depth of the affected layer was predicted using the critical strain equation. The obtained results proved the adequacy of the proposed model showing a good agreement between the simulated and the experimental results.
ABSTRACT In the last few years, important step forwards have been made on Finite Element Simulati... more ABSTRACT In the last few years, important step forwards have been made on Finite Element Simulation of machining operations. Wrought Ti6Al4 V alloy has been deeply investigated both numerically and experimentally due to its wide application in the industry. Recently, Additive Manufacturing technologies as the Electron Beam Melting and the Direct Melting Laser Sintering are more and more employed in the production of biomedical and aeronautical components made of Ti6Al4 V alloy. Fine acicular microstructures are generated by the application of additive manufacturing technologies, affecting the mechanical properties and the machinability. By the consequence, this peculiarity has to be considered in modelling the material behaviour. In this work, a numerical analysis of cylindrical external turning on Electron Beam Melted (EBM) Ti6Al4 V alloy is presented. A Johnson-Cook constitutive equation was implemented as a flow stress model and adapted with respect to the wrought Ti6Al4 V alloy. The model was calibrated and validated through the cutting forces and temperatures measurements acquired under dry and cryogenic lubricating conditions.
ABSTRACT Finite element analysis of cutting processes of difficult-to-cut alloys is attracting mo... more ABSTRACT Finite element analysis of cutting processes of difficult-to-cut alloys is attracting more and more interest among the scientific community thanks to the change of predicting difficult to measure parameters as cutting forces, specific cutting pressures, cutting temperatures and the chip morphology. Aiming to calibrate and validate an FE numerical model, the predicted variables have to be compared with experimental results. Nowadays, Additive Manufactured Titanium alloys are being increasingly employed in the production of surgical implants and aero engine parts, but their peculiar fine acicular microstructure have to be taken into account dealing with their thermomechanical behavior as during machining operations. Based on the lack of literature works concerning experimental investigations on the machinability of Additive Manufactured Titanium alloys, this paper is aimed to investigate the cutting forces and temperatures arising during orthogonal cutting of an Electron Beam Melted (EBM) Ti6Al4V alloy.
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Papers by Stano Imbrogno
the prediction of microstructural changes occurring during the process. A FE numerical model was properly calibrated using an
iterative procedure based on the comparison between simulated and experimental results. A user subroutine was implemented in
the FE code to simulate the dynamic recrystallization and consequently the grain refinement and hardness variation when
orthogonal cutting of Nickel based superalloy is performed. Thus, Zener-Hollomon and Hall-Petch equations were implemented
to predict the grain size and micro hardness, respectively. In addition, the depth of the affected layer was predicted using the critical
strain equation. The obtained results proved the adequacy of the proposed model showing a good agreement between the simulated
and the experimental results.
the prediction of microstructural changes occurring during the process. A FE numerical model was properly calibrated using an
iterative procedure based on the comparison between simulated and experimental results. A user subroutine was implemented in
the FE code to simulate the dynamic recrystallization and consequently the grain refinement and hardness variation when
orthogonal cutting of Nickel based superalloy is performed. Thus, Zener-Hollomon and Hall-Petch equations were implemented
to predict the grain size and micro hardness, respectively. In addition, the depth of the affected layer was predicted using the critical
strain equation. The obtained results proved the adequacy of the proposed model showing a good agreement between the simulated
and the experimental results.