Microstructure and mechanical properties of austempered AISI 9255 high-silicon steel

ABSTRACT

The present investigation is focused on evaluating the microstructure and mechanical properties of American Iron and Steel Institute 9255 high-silicon steel austempered at different temperatures and durations. Material characterisation was done using a scanning electron microscope and an X-ray diffractometer. Results show the bainite microstructure over a temperature range of 280–400°C. Bainite structure gains coarseness at higher temperatures at 360 and 400°C. A significant improvement in the tensile properties was observed for all austempered specimens; with a maximum tensile strength of 1852 MPa and elongation up to 35%. An excellent strain hardening response was observed from the samples austempered at temperatures of 360 and 400°C. Tensile properties were found to be superior at 15 min of austempering duration for all austempering temperatures.

KEYWORDS:

• High-silicon steel
• austempered
• bainite
• strain hardening

Acknowledgements

The authors gratefully acknowledge Steelmart, Mumbai, India for providing this specific grade of steel as per the requirement. We are also thankful to National Institute of Technology Karnataka, Surathkal, India for providing necessary facilities to carry out this investigation.

Disclosure statement

No potential conflict of interest was reported by the authors.