ToughSteel Event

CEN Workshop on 'Fracture toughness evaluation methodologies applied to advanced high strength steel sheets'

The sheet metal forming sector faces a major challenge with respect manufacturing of metal sheet parts, represented by the lack of adequate test methods to assess sheet formability and part performance at the product design stage. This is essential to be able to develop high-performance parts at a reduced cost with new high strength materials, such as high strength steel (AHSS). Such high strength makes them processing sensitive, so forming parameters and sheet properties must be assessed to assure a zero-defect production and part quality, avoiding unexpected defects that cannot be predicted at the product design stage using traditional experimental or computational approaches.

The implementation of a fracture toughness approach has proved to be effective to address crack-related issues in AHSS sheets in response to the industry growing need of knowing the fracture properties of this material. Several methodologies exist for the evaluation of fracture toughness, with different complexity and procedures.

The main objective of the CEN/WS ‘Fracture toughness evaluation methodologies applied to advanced high strength steel sheets’ is to provide a guideline describing these different methodologies, informing about their suitability, and to provide recommendations that can be applied by the manufacturers during the planning, design, and operational phases of the manufacture of AHSS sheets.

The CEN/WS has developed two CEN Workshop Agreements (CWA): 

  • The first CWA describes the existing methodologies for fracture toughness evaluation in metal sheets. It compiles relevant findings from research developed in previous and ongoing RFCS projects and academic research. It also provides recommendations to be applied during the planning, design, and operational phases of the manufacture of AHSS sheets and components, as well as successful industrial case studies.
  • The second CWA describes a new testing procedure to estimate the crack propagation resistance of AHSS sheets using a Cracking Resistance Index (CRI) based on fracture mechanics. The procedure provides a fast and simple method that can be implemented as a routine procedure for in-plant quality control and material selection and/or acceptance.
Eurecat