Performance of Modern DCI Materials – Investigation of Microstructural, Temperature and Loading Rate Effects on Mechanical and Fracture Mechanical Properties

Abstract:

Design and safety assessment of advanced ductile cast iron (DCI) components like windturbines or transport and storage casks for radioactive materials require appropriate material data interms of strength and fracture toughness. Therefore, it is of vital importance to characterize andunderstand the deformation, damage and fracture behaviour of DCI which may substantially changefrom ductile to brittle by increasing loading rate, decreasing temperature and/or increasing stresstriaxiality. This paper reports on recent BAM investigations on different qualities of the widely usedDCI grade EN-GJS-400 with varying pearlite shares (none and 18 % respectively). The focus wason the influences of microstructure, temperature (ambient and -40 °C) and loading rate (quasi-staticto crash) on strength (YS, UTS, flow curve) and fracture mechanical properties (R-curve, crackinitiation toughness, fracture toughness). Systematic metallographical and fractographical analyseswere performed accompanying the whole test program and a systematics of specific damagebehaviour and fracture mechanisms was derived from the results.

• Periodical: Materials Science Forum (Volumes 783-786)
• Pages: 2244-2249
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.783-786.2244
• Online since: May 2014
• Authors: Wolfram Baer*
• Keywords: Damage Behavior, Ductile Cast Iron, Fracture Mechanics, Fracture Toughness, Loading Rate, Mechanical Property, Microstructure, Pearlite, Temperature

References

[1] W. Baer, D. Bösel, A. Eberle, D. Klingbeil, Development and application of a key curve-method for fracture mechanical material characterization of cast iron materials under dynamic loading, Final report on the German Science Foundation research projects BA 1913/2-1 and BA 1913/2-2, BAM Berlin, (2009).

DOI: 10.1016/j.engfracmech.2009.06.015

[2] W. Baer, D. Bösel, A. Eberle, D. Klingbeil, Determination of dynamic crack resistance of ductile cast iron using the compliance ratio key curve method, Engineering Fracture Mechanics 77 (2010) 374-384.

DOI: 10.1016/j.engfracmech.2009.06.015

[3] W. Baer, P. Wossidlo, B. Abbasi, M. Cassau, R. Häcker, R. Kossert, Large scale testing and statistical analysis of dynamic fracture toughness of ductile cast iron, Engineering Fracture Mechanics 76 (2009) 1074-1086.

DOI: 10.1016/j.engfracmech.2009.01.005

[4] EN 1563, Founding – Spheroidal Graphite Cast Irons, (2011).

[5] W. Baer, Advanced Fracture Mechanics Testing of DCI - a Key to Valuable Toughness Data, 2013 Keith Millis Symposium on Ductile Cast Iron, Nashville, TN, Oct 15-17, (2013).