Extrema of micro-hardness in fully pearlitic compacted graphite cast iron

ABSTRACT

For improving the mechanical strength of cast irons, a fully pearlitic matrix is sought by alloying with tin, copper and manganese. This applies in particular to the compacted graphite irons considered here. While average macro- and micro-hardness values were similar for the four fully pearlitic alloys under study, it was found that high copper and low tin content showed some very high maximum micro-hardness values, significantly higher than the corresponding mean. Such values may be seen as hard points in the material that would certainly impair machinability. Discussion of the reasons for these extreme values opens directions for further studies.

KEYWORDS:

• Iron alloys
• casting
• carbon and graphite
• hardness
• pearlite

Acknowledgements

Thanks is due to David de Jonghe for performing the micro-hardness measurements during a one-month internship at CIRIMAT laboratory. This research did not receive any specific grant from funding agency in the public, commercial, or not-for-profit sectors.

Disclosure statement

No potential conflict of interest was reported by the authors.