Microstructure engineering for superior wear and impact toughness strength of hypereutectoid powder metallurgy steel

ABSTRACT

In this study, powder metallurgical steel samples containing 1.5% C by weight were produced by sintering in a vacuum atmosphere at 1200°C. The impact test and dry sliding wear test specimens were prepared in accordance with ISO 5754 and ASTM G-99 standards, respectively. The wear and impact toughness properties of spherical cementite in the bainitic matrix (SCBM) microstructured specimens produced with different heat treatment routes were compared with pearlite plus primary cementite, fully tempered martensitic, fully bainitic and spherical cementite microstructured specimens in ferritic matrix (SCFM). Microstructural characterisations of all specimens were performed by SEM, EBSD and XRD analyses methods. Compared to fully tempered martensitic and fully bainitic microstructured specimens with similar hardness, both the dry sliding wear and the impact toughness properties of the specimens having SCBM microstructures were improved with the increased austempering time after spheroidisation treatment.

KEYWORDS:

• Spherical cementite
• bainitic microstructure
• powder metallurgy steel
• wear and impact toughness

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study has been financially supported by the Gazi University Scientific Research Projects Coordination Unit [under Project Number FGA-2021-7002].

Notes on contributors

Onur Altuntaş

Dr. Onur Altuntaş completed his Ph.D. at Gazi University, Department of Metallurgical and Materials Engineering. He is still working as a doctor lecturer at the Vocational School of Technical Sciences. 1 registered national patent and 5 scientific articles have been published. He successfully completed 2 national project coordinators. His main scientific interest and activities are related to Powder Metallurgy and heat treatment.

Ahmet Güral

Prof. Ahmet Güral completed his Ph.D. at Gazi University, Department of Metallurgical Education. He has published more than 45 scientific papers, supervised 2 Ph.D. thesis and 10 master thesis. He has 1 registered national patent. He successfully completed 2 national project coordinators. His main scientific interest and activities are related to Powder Metallurgy, heat treatment and ultra-plastic deformations.

Süleyman Tekeli

Prof. Süleyman Tekeli completed his Ph.D. at University of Manchester Institute of Science and Technology (UMIST) Department of Materials. He has published more than 45 scientific papers, supervised 5 Ph.D. thesis and 12 master thesis. His main scientific interest and activities are related to Powder Metallurgy, heat treatment, ultra-plastic deformation and ceramic materials. He is still the dean of Gazi University Faculty of Technology.