Fatigue of tool steel


Christoph Ripplinger © Copyright: IWM


Christoph Ripplinger

Research group Fatigue and Fracture Mechanics


+49 241 80 99535




The service life of cold work tools has a significant influence on the economic efficiency of forming and cutting processes. A compromise between different property requirements (e.g. high hardness and wear resistance combined with sufficient toughness and machinability) is usually derived from empirical values and a tool design according to the FKM guideline is unusual. The carbide and inclusion distributions in the microstructure of concrete tools are often not known and the FKM guideline does not specify any specifications for component design or strength values for tool steels. As a result, early tool failures often occur.

Overall objectives

  • Development and validation of a new, material-specific design concept for multiaxially stressed tools for the cold work application
  • Supplement fatigue strength and crack propagation values of tool steels in the FKM guideline


  • Influence of microstructure (carbide structure) on fatigue strength of tool steels
  • Experimental determination of the fatigue strength of tool steels under rotating bending, axial, torsional and multi-axial loads
  • Validation of design concept: Testing component geometries + calculations according to the quadratic failure hypothesis (QVH)

Industry partners

Deutsche Edelstahlwerke, Dörrenberg Edelstahl, Härterei Carl Gommann, Lohmann Edelstahl, Böhler, Hammer Werk, Köppern, GIF

  BMWK Logo Copyright: © BMWK