Prozess- und Produktoptimierung zur Herstellung von kaltgepilgerten Rohren aus Edelstahl

Translated title of the contribution: Process and product optimization for the fabrication of cold pilgered stainless steel tubes

Katharina Ragger

Research output: ThesisDoctoral Thesis


Cold pilgering is a major step in the processing line of seamless stainless steel tubes. It is used for the further reduction of the outer diameter and the wall thickness of a generally hot worked preliminary tube (hollow). Predominantly, the process is used for the fabrication of high precision tubes, which require the achievement of accurate dimensions and a close surface tolerance. Its incremental nature, combined with a favourable stress state, enables high plastic strains that cannot be achieved by common deformation processes, like e. g. cold drawing. The preferred use of Super Duplex stainless steels is due to their unique corrosion properties as well as good mechanical properties. In contrast to this, the deformation of these steel types is more difficult. The cold deformation of hollows made of Super Duplex steel type 2507 such as e. g. 1.4501 or 1.4410 not only leads to high rolling forces but recurring fractures of the forming tools. Sometimes also cracks at the inner surface of the deformation zone between the ingoing hollow and the final tube can be observed. The investigation of these undesired effects is in the focus of the present work. Therefore, the finite element method (FEM) is chosen. By way of finite elements, new findings should be gained that could lead to an enhancement of the tool lifetime as well as to a decrease or prevention of the cold pilger cracks. Besides these technological aspects, the deformation behaviour of the two-phase structure during cold pilgering is considered. The focus is laid on the cold working behaviour as well as the textural development of austenite and ferrite. A unique combination of FEM, Electron Backscatter Diffraction (EBSD) and nanoindentation is used for this study. The results are also useful to verify some basic considerations within the model setup as well as to evaluate the calculated results. In this doctoral thesis, the capability of FEM to investigate the complex seamless tube making by cold pilgering is shown. Furthermore, the deformation behaviour of austenite and ferrite of the steel 1.4410 during this process is studied in detail and thus contributes to an enlarged knowledge about this steel grade’s properties.
Translated title of the contributionProcess and product optimization for the fabrication of cold pilgered stainless steel tubes
Original languageGerman
  • Clemens, Helmut, Assessor B (internal)
  • Buchmayr, Bruno, Assessor A (internal)
Publication statusPublished - 2016

Bibliographical note

embargoed until null


  • cold pilgering
  • process optimization
  • product optimization
  • damage
  • simulation
  • Super Duplex steel
  • microstructural analysis
  • EBSD
  • nanoindentation

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