Due to its electro-mechanical properties, commercially pure aluminium wires have attracted the interest of automotive industry representing a functional and efficient economic solution to reduce ...vehicle’s weight leading to the diminishing of energy consumption and emissions in today’s society. However, to consolidate its use in this sector and in new market realities, it is necessary to increase the flexibility of the aluminium conductor wires, consenting their installation in very small spaces and with high curvatures, avoiding any failure and electrical conductivity decrease. Thus, the evolution of microstructure and service performance needs to be investigated and controlled to improve the service safety. The present research shows a new approach to continuously manufacture efficient long wires with smaller diameters and fine grains at room temperature. It is studied the strengthening effects (yield and tensile strength, plasticity, hardness), the electrical conductivity, and the microstructural changes of commercial 1370 pure aluminium (99.7% Al) when traditional wire drawing process is combined with equal channel angular drawing (ECAD) technique. The results of this proposed procedure of deformation “drawing-ECAD-drawing” show an evident benefit, compared to the classic technology of production of aluminium wire, obtaining fine grain structure product with superior mechanical strength and not influenced electrical conductivity. The proposed manufacturing approach leads to fine wires enhancing the material mechanical properties by microstructural evolution (i.e. grain size reduction) avoiding the traditional post manufacturing thermal treatments requiring a high amount of energy and time and careful steps.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Grain growth and hardness variation occurring in high-temperature heat affected zone (HAZ) during the welding processes are two thermal dependant aspects of great interest for both academic and ...industrial research activities. This paper presents an innovative finite element (FE) model capable to describe the grain growth and the hardness decrease that occur during the gas metal arc welding (GMAW) of commercial AISI 441 steel. The commercial FE software SFTC DEFORM-3D™ was used to simulate the GMAW process, and a user subroutine was developed including a physical based model and the Hall–Petch (H-P) equation to predict grain size variation and hardness change. The model was validated by comparison with the experimental results showing its reliability in predicting important welding characteristics temperature dependant. The study provides an accurate numerical model (i.e. user subroutine, heat source fitting, geometry) able to successfully predict the thermal phenomena (i.e. coarsening of the grains and hardening decrease) that occur in the HAZ during welding process of ferritic stainless steel.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Grain refinement by severe plastic deformation (SPD) techniques, as a mechanism to control microstructure (recrystallization, grain size changes,…) and mechanical properties (yield strength, ultimate ...tensile strength, strain, hardness variation…) of pure aluminium conductor wires, is a topic of great interest for both academic and industrial research activities. This paper presents an innovative finite element (FE) model able to describe the microstructural evolution and the continuous dynamic recrystallization (CDRX) that occur during equal channel angular drawing (ECAD) of commercial 1370 pure aluminium (99.7% Al). A user subroutine has been developed based on the continuum mechanical model and the Hall-Petch (H-P) equations to predict grain size variation and hardness change. The model is validated by comparison with the experimental results and a predictive analysis is conducted varying the channel die angles. The study provides an accurate prediction of both the thermo-mechanical and the microstructural phenomena that occur during the process characterized by large plastic deformation.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Equal channel angular drawing (ECAD) represents the most successful severe plastic deformation (SPD) technique for continuous industrial manufacturing of longer wires, with a constant cross section, ...characterized by smaller diameters and better mechanical properties (i.e. high strains and hardness) mainly attributed to the grain size refinement. In this paper an advanced innovative concept to impose SPD, on commercial 1370 pure aluminium wires (Al 99.7%), is proposed to improve the flexibility of the classic manufacturing method of ECAD by controlling and regulating process parameters in real time to obtain several combinations of mechanical properties and to increase manufacture productivity. This paper provides a preliminary analysis of mechanical and microstructural changes occurring during ECAD process and, preserving the principle of the ECAD method, describes an innovative concept of plastic deformation showing the potential improvements to practice. The proposed manufacturing system has been validated by finite element analysis (FEA) implementing a flow stress empirical model that includes the influence of the grain size change, for the material behaviour and two customized user-subroutines for predicting grain refinement and hardness variation. The study demonstrates the possibility to renew the classic industrial techniques within an Industry 4.0 ecosystem.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The evolution of grain size and component mechanical behaviour are fundamental aspects to analyse and control when manufacturing processes are considered. In this context, severe plastic deformation ...(SPD) processes, in which a high shear strain is imposed on the material, are recognized as the main techniques to achieve microstructural changes and material strengthening by the recrystallization, attracting both academic and industrial investigation activities. At the same time, nowadays, sustainable manufacturing design is one of the main responsibilities of the researchers looking at UN2030 agenda and the modern industrial paradigms. In this paper a new severe SPD process is proposed with the aim to steer manufacturing to fourth industrial revolution using some of Industry 4.0 pillars. In particular, additive manufacturing (AM) and numerical simulations were setup as controlling and monitoring techniques in manufacturing process of wires. Strengthening effect (yield and ultimate tensile strength, plasticity and hardness) and microstructural evolution (continuous dynamic recrystallization -CDRX-) due to severe plastic deformation were experimentally analysed and numerically investigated by an innovative finite element (FE) model able to validate the effectiveness of a properly modified process for ultra-fine aluminium alloy AA6101 wires production designed with the aim to avoid any post manufacturing costly thermal treatment. The study provides an accurate experimental study and numerical prediction of the thermo-mechanical and microstructural phenomena that occur during an advanced large plastic deformation process; it shows how the combination of smart manufacturing and simulations control represents the key to renew the traditional manufacturing methods in the perspective of the Industry 4.0, connecting and integrating the manufacturing process for the industrial evolution in production.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Burnishing is considered a super finishing process able to drastically increase surface quality in terms of hardness and roughness of the manufactured parts. Consequently, it is considered appealing ...for the performance enhancement of products where the surface quality plays a crucial role. However, when burnishing grade 5 titanium alloy, a quantitative relationship between process parameters and surface integrity is still missing. This work provides a deep analysis of the burnishing parameters and their influence on the surface integrity of Ti-6Al-4V. In particular, starting from a large experimental campaign, statistical analysis of the results is performed and models able to describe the surface integrity response based on different burnishing parameters are presented. The overall results allow us to clearly define the relationship within the input and output variables identifying, by the proposed models, different operational windows for surface integrity improvement.
Residual stresses and strains, distortions, heat-affected zone (HAZ), grain size changes and hardness variation during gas metal arc welding (GMAW), are fundamental aspects to study and control ...during welding processes. For this reason, numerical simulations of the welding processes represent the more frequently used tool to better analyse the several aspects characterizing this joining process with the aim to reduce lead time and production costs. In the present study, an uncoupled 3D thermo-mechanical analysis was carried out by two commercial finite element method (FEM) software to model an experimental single bead GMAW of AISI 441 at different processes set-up. The experimental HAZ and measured temperatures were used to calibrate the heat source of both the used numerical codes, then a validation phase was done to test the robustness of the two developed analytical procedures. One software was used to predict the residual stresses and strains and the distortions of the welded components, while in the second software, a user routine was implemented, including a physical based model and the Hall-Petch (H-P) equation, to predict grain size change and hardness evolution, respectively. The results demonstrate that the predicted mechanical and microstructural aspects agree with those experimentally found showing the reliability of the two codes in predicting the thermal phenomena characterizing the HAZ during the analysed welding process.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Surface and subsurface microstructural characterization after machining operations is a topic of great interest for both academic and industrial research activities. This paper presents a newly ...developed finite element (FE) model able to describe microstructural evolution and dynamic recrystallization (DRX) during orthogonal hard machining of SAE 8620 steel. In particular, it predicts grain size and hardness variation by implementing a user subroutine involving a hardness-based flow stress and empirical models. The model is validated by comparing its output with the experimental results available in literature at varying the cutting speed, insert geometry and flank wear. The results show a good ability of the customized model to predict the thermo-mechanical and microstructural phenomena taking place during the selected processes.
Surface characteristics of machined components, such as microstructure and hardness, play a key role to be competitive in the current industrial scenario because they strongly influence the ...functional performance of the engineered products. These characteristics can be affected by the manufacturing processes. Accurate numerical models have been developed to predict property surface changes during machining. In the present work, metallurgical changes during full face milling of the ASTM A216 WCB carbon steel have been modelled by a customised 3D finite element (FE) model with a physics-based constitutive law for the material behaviour. A user subroutine has been implemented in the FE code to simulate changes induced by the machining on the processed surface and in depth. The model was calibrated and experimentally validated at varying of the main process variables. The outcomes showed the effectiveness of the proposed FE model in predicting average max temperature trends (an average discrepancy of 5 % and maximum one of 9 % were obtained), grain size and machining affected layer changes (the error was generally contained under the 10 % for all the investigated cases) and microhardness variations (an average discrepancy of 7 % and a maximum one of 9 % were reached) at varying of the process parameters. Finally, the model has allowed understanding the evolution of microstructural changes during machining and their influence on the material behaviour through the prediction of the dynamic recrystallized grain size and dislocation density evolution.
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•Metallurgical changes on the processed material during full face milling were modelled.•A model with a physics-based material constitutive law was set and experimentally validated.•A user subroutine was implemented to simulate changes induced by the machining process.•The model effectiveness was tested in predicting temperature, grain size and microhardness variations.•The model was able to predict dynamic recrystallized grain size and dislocation density evolution.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Welding processes are the most common manufacturing solution that frequently complete the final steps of an industrial production. Their large use makes these techniques worth of attention of the ...scientific community, so that several efforts are spent for optimising and improving the way the processes are executed.
Submerged Arc Welding is widely used in the industrial scenario being semi-automatic but it cannot be ignored that this joining technique is far from the full automatization and is still dependent by the operator expertise.
In this study, an experimental investigation has been performed to build a robust data set for the subsequent application of seven machine learning classifier. The aim of the work is the definition of a suitable classifier able to detect and predict invalid process conditions which could lead to failed joint.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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