5-8 September 2022
Wyndham Grand Salzburg Conference Center
Europe/Vienna timezone

Experimental and numerical investigation of heterogenous gas quenching for determining optimal heat treatment parameters

7 Sep 2022, 10:15
25m
Room 1

Room 1

Oral Presentation Modelling and simulation of thermal and surface engineering processes HEAT TREATMENT

Speaker

Nithin Mohan NARAYAN (Leibniz Institute for Materials Engineering- IWT Bremen)

Description

Abstract
For several technical engineering applications, steels are of great emphasis. Heat treatment of steels intents to attain the pre-determined material properties. After austenitisation in vacuum, gas quenching is a widely preferred heat treatment process, since in contrast to quenching by fluids, it is cleaner and more environment friendly process. In addition, gas quenching does not show the Leidenfrost effect, so that uniform cooling is possible. However, challenges reside with the selection of suitable heat treatment parameters, which are highly depending on different criteria such as sample geometry, material composition, batch properties etc. The current study superiorly focusses to develop a prediction tool based on ANN (Artificial Neural Network). The ANN is trained with the experimental and simulation results to predict the optimum heat treatment parameters in order to achieve a homogeneous quenching process under consideration of the components geometry and material as well as energy efficiency. In order to accomplish this target, the heat treatment and flow conditions during gas-based cooling as well as the development of the treated material’s microstructure and hardness are investigated in detail. To obtain a stochastic parameter field for the ANN training, different sets of samples are produced with varied process parameters including gas flow velocity, gas pressure, treatment temperature of the sample, sample geometry and sample batch. To obtain the input parameters for attendant simulation, HTC (heat transfer coefficient) and temperature curve at several sample spatial locations within the sample volume are measured by means of film probes (Glue-on-Film) glued to the probe surface and thermo-elements respectively. The investigation of the flow character is accomplished in gas quenching setup by means of CTA (Constant temperature anemometry) system and Pitot tube. After the heat treatment, the microstructure of the sample is analysed at several spatial positions by light and scanning electron microscopy to evaluate calculated local cooling curves. Hardness measurements additionally determine the microstructure constitution. Furthermore, the CFD and FEM Simulation models are developed and validated respectively by means of the experimental results achieved from this study. The validated models serve to numerically investigate the influence of quenching parameters (gas pressure, flow velocity etc.), geometry and batch dependent heat transfer between gas and treated component as well as the material properties and that provides sufficient data to introduce the ANN-based forecast tool addressed above.

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Speaker Country Germany
Register for the Tom Bell Young Author Award (TBYAA)? Yes

Primary authors

Nithin Mohan NARAYAN (Leibniz Institute for Materials Engineering- IWT Bremen) Dr Pierre LANDGRAF (Technical University of Chemnitz, Institute of Materials Science and Engineering- IWW Chemnitz)

Co-authors

Prof. Udo FRITSCHNIG (Leibniz Institute for Materials Engineering- IWT Bremen and University of Bremen, Department of Process Engineering, Bremen ) Prof. Thomas LAMPKE (Technical University of Chemnitz, Institute of Materials Science and Engineering- IWW Chemnitz)

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