Haiko, O., Kaikkonen, P., Somani, M., Valtonen, K., & Kömi, J. (2020). Characteristics of carbide-free medium-carbon bainitic steels in high-stress abrasive wear conditions. Wear, 456–457, 203386. https://doi.org/10.1016/j.wear.2020.203386
Characteristics of carbide-free medium-carbon bainitic steels in high-stress abrasive wear conditions
|Author:||Haiko, Oskari1; Kaikkonen, Pentti1; Somani, Mahesh1;|
1Materials and Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, Finland
2Materials Science and Environmental Engineering, Tampere Wear Center, Tampere University, Finland
|Online Access:||PDF Full Text (PDF, 5.3 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2020070947182
|Publish Date:|| 2020-07-09
This study encompasses a comprehensive account of the abrasive wear properties of carbide-free, ultrahigh-strength bainitic steels processed through ausforming at three different temperatures well below the recrystallization stop temperature followed by bainitic transformation at temperatures close to the Mₛ temperature. Five medium-carbon, high-silicon compositions were designed for the study by suitably varying the alloying levels of carbon, vanadium, niobium, molybdenum, and aluminum. While ausforming at lower temperatures enabled a large number of nucleation sites leading to significant refinement of bainitic laths, the decomposition of austenite at relatively low transformation temperatures was accelerated due to the presence of a high dislocation density, thus enabling completion of bainitic transformation in a reasonable length of time. The steels were characterized in respect of microstructural features and mechanical properties, besides evaluation of wear resistance through a high-stress abrasive wear testing method with natural granite abrasives. The microstructures comprised different fractions of bainitic ferrite and/or granular bainite (56–68%), martensite (0–25%), besides a significant fraction of retained austenite (20–34%) manifesting as pools and also interlath films, depending on the ausforming conditions and subsequent cooling paths. A tensile strength of 1900 MPa level was achieved with hardness exceeding 500 HV for the medium-temperature ausformed steel containing a high carbon content that also showed lowest mass loss in the wear test. The hardness-to-mass loss ratio appeared highly promising with some of the carbide-free bainitic steels on par with or better than the reference martensitic steel. The high work-hardening capability as a consequence of the strain-induced austenite to martensite transformation was considered as the main factor for the superior abrasive wear resistance of the carbide-free bainitic steels.
Wear. An international journal on the science and technology of friction, lubrication and wear
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
This study has received support from RFCS under contract RFCS-2015-709607 TIANOBAIN, and project partners are also acknowledged for providing materials.
© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).