Prekel, Helmut
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Prekel, Helmut
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Prekel, Helmut
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Prekel, H.
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Item-typ:Veröffentlichung, In-situ-Untersuchung von Randschichten während des Gasnitrierens mittels Röntgendiffraktometrie und photothermischer RadiometrieThe aim of most applications of nitriding treatments at steel components is to obtain a compact compound layer and/or a deep diffusion layer. The possibility of a survey of the nitriding treatment by analyzing directly the component´s surface state during the nitriding process is particularly interesting, since it allows a process monitoring and control based on the actual nitriding result. In the present study, two measurement methods were developed and combined with the aim of direct surface state analysis during a nitriding treatment: the in-situ X-ray diffraction method and the photothermal radiometry. An experimental setup including a miniature nitriding furnace was developed in order to allow the combined application of both methods during a nitriding process under controlled atmosphere. In the present work, results of combined in-situ measurements on the steel AISI 4140 regarding the nitride layer formation during nitriding process as well as the nitride layer change during the following denitriding of the layer in nitrogen gas are presented and discussed. The investigations show that the photothermal radiometry is sensitive to the changing surface properties due to growing compound layers and when porous layers are generated. This method has a high potential for implementation in industrial nitriding furnaces, but for this, further development for quantitative evaluations of the measurements will be required.Wissenschaftlicher ArtikelBand:72Heft:395 90 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Simulation und Anwendung photothermischer Verfahren im Labor und unter prozessnahen Bedingungen(2016-07-19); ; ; Photothermal measuring methods enable to analyse near surface zones up to some millimeters below material surfaces non-destructively. This doctor thesis examines new approaches to characterise thermal properties and to detect near-surface damages with thermal waves. Based on FEM-simulations, artificial neural networks and measurements, it shows strategies for the interpretation of photothermal signals. Furthermore, a new method to detect contact patterns of gear wheels by active thermography is demonstrated as well as the possibility to analyse the growth of nidride layers within gas nitriding processes.Dissertation367 122