Round-robin prediction of the fatigue limit of a ring of spheroidal graphite cast iron

Mechanical properties, especially fatigue strength, of ferritic spheroidal graphite cast iron might depend not only on the graphite size but also on the ferrite grain size, little systematic research has been made on these factors. To clarify the influences of these structural factors as well as loading condition, fatigue tests have been carried out on ferritic spheroidal graphite cast iron with different sizes of graphite nodules and ferrite grains, under the axial loading with mean stress from -70MPa to 240MPa. The results obtained in this study are summarized as follows: (1) The fatigue limits are decreased with increasing graphite nodule and matrix grain sizes. (2) The fatigue limit decreases with increasing tensile mean stress. The fatigue limit at an arbitrary mean stress has been estimated by the modified Goodman diagram as well. (3) The parameter α is evaluated from the experimental results relating to the stress ratio R, for the mean stress acting on the tensile side and on the compressive side separately. For the case of R0, the value of α is 0.324. The result has been applied to the fatigue limit evaluation equation of Y.Murakami et al, the fatigue limit ratio falls within the range of about ±10%.

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Effects of Number of Graphite Nodules on Fatigue Limit and Fracture Origins in Heavy Section Spheroidal Graphite Cast Iron

MATERIALS TRANSACTIONS ◽

10.2320/matertrans.f-m2015841 ◽

2016 ◽

Vol 57 (3) ◽

pp. 379-384 ◽

Cited By ~ 5

Author(s):

Naoto Shiraki ◽

Yuki Usui ◽

Toshitake Kanno

Keyword(s):

Cast Iron ◽

Fatigue Limit ◽

Spheroidal Graphite ◽

Heavy Section ◽

Spheroidal Graphite Cast Iron ◽

Graphite Cast Iron

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Color Etching for Characterization the Grain Orientation in Spheroidal Graphite Cast Iron

Materials Science Forum ◽

10.4028/www.scientific.net/msf.537-538.389 ◽

2007 ◽

Vol 537-538 ◽

pp. 389-396 ◽

Cited By ~ 2

Author(s):

Ibolya Kardos ◽

Zoltán Gácsi ◽

Péter János Szabó

Keyword(s):

Cast Iron ◽

Crystallographic Orientation ◽

Grain Orientation ◽

Test Material ◽

Spheroidal Graphite ◽

Metallic Materials ◽

Additional Information ◽

Spheroidal Graphite Cast Iron ◽

Graphite Cast Iron ◽

Back Scattering

Color etching is a widely used technique for visualizing different phases in metallic materials. Its advantage to the traditional etching techniques is that it gives additional information within one phase, namely, the color shade of a given phase can change in a certain range. This paper demonstrates that, due to the physics of the color etching, the shade of a phase also depends on the crystallographic orientation of the investigated grain. As a test material, spheroidal graphite cast iron was used, and individual grain orientation was identified by automated electron back scattering diffraction (EBSD). Results showed that there is a strong correlation between grain orientation and the shades obtained by color etching.

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