ADVANCED FRACTURE MECHANICS TESTING OF DCI - A KEY TO VALUABLE TOUGHNESS DATA

作者：Baer Wolfram^*

来源：International Journal of Metalcasting, 2014, 8(2): 25-34.

DOI：10.1007/bf03355579

• DCI
• ductile cast iron
• mechanical properties
• fracture mechanics testing
• fracture toughness data
• microstructure
• loading rate
• temperature

The challenge of how to adequately characterize the toughness behavior of ductile cast iron (DCI) materials had been solved through the development and application of fracture mechanics concepts. Outstanding examples are found in the design and safety assessment procedures of sophisticated DCI components for wind turbines or transport and storage casks for radioactive materials. An essential requirement for these procedures is to have adequate fracture mechanics toughness data available.
Because DCI materials may substantially change their deformation, damage and fracture behavior from ductile to brittle by increasing loading rate, decreasing temperature, increasing pearlite share and increasing stress triaxiality, the corresponding experimental measuring techniques and analysis concepts have to be chosen and adapted with deliberation. Long-time experience in this field is imperative to provide valuable data.
BAM has been dealing with mechanical and fracture mechanical characterization of DCI materials for more than 30 years. This paper demonstrates state-of-the-art fracture mechanics test methods for the determination of quasi-static and dynamic fracture toughness. Among others, it is exemplarily shown for a variety of DCI materials conforming to grade EN-GTS-400 how mechanical and fracture mechanical properties are influenced by temperature, loading rate and microstructure. A major lesson to be learned is that fracture toughness data of DCI should always be discussed, reported and used in correlation with microstructural parameters.

• 出版日期2014