Charakterisierung von nichtmetallischen Einschlüssen in Titan legierten ferritischen Chromstählen

Translated title of the contribution: Characterisation of non-metallic inclusions in titanium alloyed ferritic stainless steels

Denise Loder

Research output: ThesisMaster's Thesis

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Abstract

Titanium alloyed ferritic stainless steels are comparable to austenitic stainless steels concerning mechanical properties and corrosion resistance. By adding titanium a change in inclusion landscape can occur: The addition of titanium leads to the generation of TiN, TiC and Ti(C,N), which can interact with other endogenous or exogenous non-metallic inclusions. The resulting inclusions can cause casting problems, for example Clogging, and surface defects on the final product. To improve the castability and the surface quality of these steels it is necessary to analyse the formation of non-metallic inclusions in order to control the inclusion formation and -modification specifically. Within the scope of this work the inclusion landscape of the Ti-alloyed steel 1.4520 was analysed systematically from secondary metallurgy to cold rolled strip and the results were compared with literature. The primarily used analytical methods were the optical microscopy and the automated SEM/EDS analysis. The characterisation of the inclusion landscape in Ti-alloyed ferritic chromium steels involves different metallographical challenges, which are described detailed in this work. The different types of TiN are characterised and discussed. Based on the metallographic results conclusions about possible reaction mechanisms and sites regarding inclusion formation and modification are drawn, which are the basis for further process optimisation.
Translated title of the contributionCharacterisation of non-metallic inclusions in titanium alloyed ferritic stainless steels
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Michelic, Susanne Katharina, Co-Supervisor (internal)
  • Reip, Thomas, Supervisor (external), External person
  • Bernhard, Christian, Supervisor (internal)
Award date29 Jun 2012
Publication statusPublished - 2012

Bibliographical note

embargoed until 25-06-2017

Keywords

  • titanium alloyed ferritic chromium steels
  • steel cleanness
  • titanium nitride
  • automated SEM/EDS analysis
  • stability diagram for TiN
  • inclusion morphology

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