Gleeble Webinar Series - Episode 45 Full Abstract
Thursday, October 7, 2021
Investigation of Manufacturing Processes for Automotive and Biomedical Applications using Gleeble Systems and Physical Simulation
Join us for two presentations from researchers at Politecnico di Bari in Italy.
Presentation 1: Investigations about the solid-state foaming of the Ti6Al4V-ELI produced by Hot Isostatic Pressing
Abstract: The research activity briefly described in this presentation is focused on the possibility to produce high quality / customized titanium biomedical prostheses characterized by a porous structure. Such biomedical devices, being customized on the patient’s morphology, are capable to improve the geometrical fitting to the bone (thus reducing the relative micro-displacement and avoiding infections); in addition, having a cellular structure, can reduce the hospitalization thanks to the bone regrowth.
The investigated material is the ELI (Extra Low Interstitial) version of the well known titanium (Ti) alloy Ti6Al4V, which is largely adopted for the production of biomedical prostheses. Being the aim to produce a porous structure (which can improve the osteointegration and make the stiffness more similar to human bone) the investigated material was produced by Hot Isostatic Pressing (HIP) and then subjected to various types of heat treatments. In fact, the Ti cellular porous structure cannot be easily obtained by melting the alloy due to high reactivity of such a material. In this research (project acronym: FABRICARE; funding organization: Italian Ministry of Economic Development) Ti powders were initially poured to fill a steel can which, after evacuating the air backfilling with Argon, was shut weld and subjected to HIP. Samples extracted from such billets were then subjected to different temperature-time profiles in order to create an internal porosity due to the expansion of the argon bubbles entrapped in the material. The experiments aimed to explore, by means of the Gleeble system, the possibility of using: (i) variable temperature; (ii) constant temperature; (iii) the vacuum condition; (iv) superimposed biaxial stress. The explored conditions determined different level of porosity which were measured through metallographic investigations in terms of average size of the pores and percentage of the pores over the whole observation area.
Presentation 2: Combining finite element analysis with physical simulation for an efficient design of thermo-mechanical Press-Hardening process
Abstract: The potential of physical simulation is its capability to reproduce thermo-mechanical manufacturing processes at the laboratory scale. In the process optimization before real stamping, physical simulation can be a useful tool to combine with usual numerical simulations.
Specifically, this presentation focuses on the use of physical simulation to reproduce thermo-mechanical cycles typical of the Press-Hardening process. The present study is funded by the MIUR PICO & PRO project, which aims at optimizing of manufacturing processes related to the production of automotive components.
First, a Finite Element (FE) numerical model – developed in the framework of the commercial software AutoForm – is implemented to simulate hot-forming process with Tailored Tool Tempering approach, which is used for obtaining an automotive B-Pillar component in USIBOR®2000. In such approach, differentially heated tools are exploited to obtain a component with ductile zones (bainitic region) and high resistance areas (martensitic region).
By optimizing the quenching time and the temperature of the hot tools, it is possible to gain a completely bainitic region, while the martensitic region is obtained by fixing the tools temperature at about 80 °C.
In a second step, laboratory experiments are performed on USIBOR®2000 specimens of 2 mm thick. Thermo-mechanical cycles of the FE simulations are physically reproduced by means of the physical simulator Gleeble 3180. Moreover, micro-hardness tests are carried out on treated specimens to evaluate their mechanical properties.
Results show that combining numerical tools with physical simulation is an excellent strategy for an efficient design of the real stamping process.
Click here to download a PDF of the presentations.