DSpace Collection:https://repositorio.ufu.br/handle/123456789/54662026-06-01T06:05:33Z2026-06-01T06:05:33ZAvaliação de pré-formas multimateriais em aço carbono e aço inoxidável austenítico depositadas via manufatura aditiva por deposição a arcohttps://repositorio.ufu.br/handle/123456789/487042026-05-19T06:34:58Z2026-02-27T00:00:00ZTitle: Avaliação de pré-formas multimateriais em aço carbono e aço inoxidável austenítico depositadas via manufatura aditiva por deposição a arco
Abstract: In this work, the metallurgical evaluation and adhesion at the interface between carbon steel and stainless steel in clad and multimaterial pre-forms (walls) produced by wire-arc additive manufacturing (WAAM) are carried out. Two walls were produced using AWS A5.18 ER70S-6 wires as the base material and AWS A5.9 ER309LSi as the coating material, through coordinated deposition with two welding robots operating in parallel. The walls differed exclusively in terms of the distance between the deposition torches, adopting spacing of 50 mm and 100 mm, keeping all other process parameters constant. The evaluation of the adhesion and integrity of the clad interface was carried out by guided bending tests according to ASTM A264:2019, using bending up to 180°, with the coating maintained in compression. The metallurgical characterization was conducted by optical microscopy, scanning electron microscopy and Vickers microhardness tests, allowing the analysis of the base material, the interface and the coating. The microhardness maps were obtained according to ASTM E384:2011, allowing the evaluation of hardness gradients along the clad interface. The results allowed to correlate the microstructural characteristics and microhardness profiles with the behavior observed in the bending tests, evidencing the influence of the distance between the deposition torches on the formation of the interface and on the integrity of the metallurgical bond between the stainless-steel coating and the carbon steel base material produced by additive manufacturing by arc deposition.2026-02-27T00:00:00ZModelling and analysis of fluid flow problems coupled with radiative heat transferhttps://repositorio.ufu.br/handle/123456789/486332026-04-16T06:18:30Z2025-08-21T00:00:00ZTitle: Modelling and analysis of fluid flow problems coupled with radiative heat transfer
Abstract: Combustion plays a fundamental role in society, being one of the primary means of energy conversion and storage, with countless applications. As such, it is a key topic in engineering and industrial processes. In many cases, combustion and thermal radiation occur simultaneously: the high temperatures resulting from exothermic reactions, as well as the radiative interaction of the gases generated from these reactions, create an environment where complex radiative heat transfer takes place. Therefore, coupling CFD with radiative heat transfer models is essential for the accurate simulation of industrial reactive flows.
Furthermore, literature shows that thermal radiation can significantly affect heat transfer in other situations, such as in thermal cavities at ambient temperature, a problem that is frequently studied without considering radiation effects.
This work presents the development and benchmarking of a coupling between a CFD software (MFSim) and a radiative heat transfer solver for participating media (RTS), both internally developed by MFLab in the Federal University of Uberlândia. MFSim is a robust simulation package, capable of modelling turbulence, heat transfer, fluid–structure interactions, reacting flows, and Lagrangian particle transport. RTS is capable of modelling radiative transfer in gray and non-gray participating media containing gases like CO2 and H2O, as well as isotropic and anisotropic scattering phenomena.
By integrating these codes, the extensive set of physical models available in MFSim, designed to simulate complex engineering problems, now includes radiative heat transfer, enabling more realistic and accurate modelling of combustion processes. The coupling employs distinct meshes for CFD and radiation, connected via interpolation, allowing for more computational efficiency, as radiative models do not usually require the same spatial resolution as CFD. Tests have shown that the interpolation layer between both algorithms has relatively low computational cost. Benchmarks performed on canonical cases show good agreement with the literature, verifying the approach and reinforcing the importance of radiation in heat transfer simulations.2025-08-21T00:00:00ZANDRADE, Rafael Moreira. Manufatura aditiva por deposição a arco para a recuperação de matrizes para injeção de alumínio sob pressãohttps://repositorio.ufu.br/handle/123456789/485382026-03-13T06:20:42Z2026-02-26T00:00:00ZTitle: ANDRADE, Rafael Moreira. Manufatura aditiva por deposição a arco para a recuperação de matrizes para injeção de alumínio sob pressão
Abstract: Extending the service life of tooling in the high-pressure aluminum die-casting industry
represents a technical and economic challenge, given the severity of the cycles to which these
components are subjected. In this scenario, Wire Arc Additive Manufacturing (WAAM)
emerges as a strategic alternative for the restoration of functional surfaces. The present study
investigated the technical and metallurgical feasibility of applying WAAM for die repair,
comparing the performance of three distinct alloys: Maraging 250 (solid wire), Martensitic
Stainless Steel 420 (solid wire), and H13 Tool Steel (metal-cored wire). Initially, a
decommissioned mold was characterized to identify the predominant failure mechanisms,
thereby establishing the requirements to be met by additive manufacturing. The welding
stability of the Maraging alloy was also investigated regarding three shielding atmospheres,
while also varying two different deposition strategies. Maraging 250 steel stood out for its
strength and structural integrity. The alloy benefited from the reheating thermal cycles intrinsic
to the process, which promoted in-situ aging, resulting in a hardness gradient. In contrast, the
martensitic alloys (Stainless Steel 420 and H13) showed high sensitivity to deposition
strategies and cooling rates. It was observed that low heat input strategies resulted in the
formation of untempered martensite, leading to brittle fracture. Implementing strategies aimed
at heat accumulation enabled the processing of 420 Stainless Steel through the auto tempering mechanism, restoring the necessary ductility; however, this approach proved
insufficient to mitigate cracking in H13 Tool Steel due to its high hardenability and segregation
of brittle phases. Thus, thermal management is fundamental for the application of WAAM in
tool steels, validating Maraging steel as the most robust solution for the remanufacturing of
high-performance molds.2026-02-26T00:00:00ZDesenvolvimento de equipamento e metodologia para avaliação do desempenho de rebolos aplicados na retificação tangencial em vidroshttps://repositorio.ufu.br/handle/123456789/485272026-03-11T06:27:42Z2026-02-27T00:00:00ZTitle: Desenvolvimento de equipamento e metodologia para avaliação do desempenho de rebolos aplicados na retificação tangencial em vidros
Abstract: Glass grinding is an abrasive machining process widely employed in industry, in which grinding wheel performance and wear directly influence surface quality, dimensional stability, and production efficiency. In this context, the present study aimed at the development, instrumentation, and experimental validation of the TriboGlass test bench, designed to perform controlled accelerated wear tests of grinding wheels used in tangential glass grinding.
The test bench was designed and built in partnership with Diamanfer and structured to enable continuous monitoring of the Material Removal Rate (MRR) as well as the main operational process variables. In parallel, a systematic methodology for grinding wheel wear assessment was developed, including mass loss measurements, three-dimensional geometric characterization through color map scanning, cross-sectional profile evaluation, and macroscopic surface inspection.
Six experimental tests were conducted, in which initial transient regimes associated with the high aggressiveness of new grinding wheels were observed, followed by the progressive stabilization of the abrasive contact. Localized variations were also recorded due to operational events such as glass replacement, grinding wheel substitution, and mechanical interferences in the carriage displacement system. The monitoring system demonstrated high sensitivity in detecting such occurrences, confirming its reliability for continuous process evaluation.
The results confirm the structural stability, repeatability, and operational robustness of the TriboGlass test bench, validating it as a reliable experimental platform for systematic test matrices and future investigations related to tribological mechanisms involved in glass grinding processes.2026-02-27T00:00:00Z