Beobachtung des Austenitkornwachstums in Nb-mikrolegierten Stählen und Rückschluss auf Zener-Pinning-Kräfte bei Temperaturen zwischen 950 und 1350 °C.

Translated title of the contribution: Observation of austenite grain growth in Nb-microalloyed steels and recalculation of Zener pinning forces at temperatures between 950 and 1350 °C.

Lukas Hanifl

Research output: ThesisMaster's Thesis

Abstract

The size of the austenite grains has a significant influence on the properties of steel products. This influence is controlled by specific measures, such as the addition of microalloying elements. In this work, the focus is on the influence of niobium and nitrogen on austenite grain growth, in particular through the formation of Nb(C,N) precipitates and the resulting Zener pinning forces. This is of great importance for the production of high-quality steels with the desired mechanical properties. In the experimental part, laboratory melts with different contents of niobium (0.08 wt.-% and 0.02 wt.-%), nitrogen (60, 80 and 120 ppm) and equal carbon content (0.15 wt.-%) were prepared. The use of high temperature laser scanning confocal microscopy (HT-LSCM) was crucial for the experimental analysis of austenite grain growth. This advanced microscopy technique made it possible to examine the samples at defined time-temperature curves and to obtain high-resolution images of the sample surface. In summary, the results show that Nb(C,N) particles inhibit austenite grain growth and alloys with a higher niobium content exhibit greater grain refinement. The influence of the nitrogen content is less pronounced, but a tendency towards grain size reduction is recognizable. This understanding is crucial for the optimization of steel production processes and the development of high-quality steels with the desired mechanical properties.
Translated title of the contributionObservation of austenite grain growth in Nb-microalloyed steels and recalculation of Zener pinning forces at temperatures between 950 and 1350 °C.
Original languageGerman
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Bernhard, Christian, Supervisor (internal)
Award date28 Jun 2024
Publication statusPublished - 2024

Bibliographical note

embargoed until 11-06-2029

Keywords

  • HT-LSCM
  • Austenite grain growth
  • Nb(C
  • N) precipitations
  • Zener pinning

Cite this