Investigation on dynamic strain aging behaviour of ferritic-pearlitic ductile cast irons

Abstract

The influence of ferritic and pearlitic microstructures to dynamic strain aging (DSA) of ductile iron was investigated by means of strain-controlled cyclic tests performed at temperatures ranging from room temperature to 450°C, strain rates of 10⁻⁵ to 10⁻² s⁻¹ and at three different strain amplitudes along with tensile tests. Results indicated that all tested microstructures exhibit strain aging effects at elevated temperatures in some form, similar to ferritic-pearlitic steels. Additionally, static tensile tests show hardening at intermediate temperatures, minima in elongation and serrations in stress–strain curves. Cyclic data indicates DSA related changes in stresses at 250°C and 350°C at smaller strain rates, while the effects become more suppressed at higher strain rates.

KEYWORDS:

• Cast iron
• dynamic strain aging
• cyclic testing
• ductile iron
• elevated temperature
• ferrite
• pearlite
• ferritic-pearlitic

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Kalle Jalava http://orcid.org/0000-0003-4882-6226

Joona Vaara http://orcid.org/0000-0002-8015-5998

Tero Frondelius http://orcid.org/0000-0003-2288-0902