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

Martensitic Induction hardening of nitrided layers

6 Sep 2022, 14:10
25m
Room 2

Room 2

Oral Presentation Surface hardening (induction, laser, electron beam…) SURFACE ENGINEERING

Speaker

Stefanie HOJA (Leibniz-Institut für Werkstofforientierte Technologien - IWT)

Description

The wear and fatigue properties of metallic components can be improved by surface heat treatment. The applied process should be chosen depending on the application, because the processes offer specific advantages and disadvantages. Nitriding is suitable for components sensitive to distortion, since due to the low treatment temperature no thorough phase transformation takes place. However, the use of nitriding is limited by the achievable nitriding hardening depth. With induction heat treatment, on the other hand, high hardness depths can be achieved in a very short time. However, the maximum hardness increase is limited by the carbon content of the material and the associated hardenability.
The current investigations are concerned with a combination of nitriding and induction hardening, as this is expected not only to result in significant savings in process time and energy, but also to produce surface layer properties that cannot be set with one of the individual processes. In order to achieve optimum surface layer properties careful coordination of the process steps is necessary, as otherwise surface layer damage and undesirable microstructural states such as soft residual austenite can occur. During nitriding, therefore, nitrided layers with low-porosity compound layers and pure diffusion layers were first produced and analyzed on the nitriding and tempering steels EN42CrMo4 and EN31CrMoV9 with a view to the subsequent induction heat treatment. Subsequently, the differently nitrided surface layers were martensitically hardened by means of inductive heat treatment and the microstructure was investigated metallographically and physically. The focus was on the dissolution of the compound layer and its effect on the microstructure formation and the hardness profile. Furthermore, it was investigated how the absence of a compound layer affects the subsequent martensitic transformation. The aim of the experiments was to determine parameters that lead to an optimum surface layer structure by the combination heat treatment.

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Speaker Country Germany

Primary author

Stefanie HOJA (Leibniz-Institut für Werkstofforientierte Technologien - IWT)

Co-authors

Mr Nicolai HAUPT (Leibniz-Institut für Werkstofforientierte Technologien - IWT) Dr Matthias STEINBACH (Leibniz-Institut für Werkstofforientierte Technologien - IWT) Prof. Rainer FECHTE-HEINEN (Leibniz-Institut für Werkstofforientierte Technologien - IWT)

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