The tribological behaviour under rolling/sliding conditions of carbide-free bainitic steel austempered at different temperatures
2010 (English)In: 14th Nordic Symposium on Tribology: NORDTRIB 2010 : Storforsen, Sweden, June 8-11, 2010, Luleå: Luleå tekniska universitet, 2010Conference paper (Refereed)
The dry rolling/sliding wear behaviour of Si alloyed carbide free bainitic steel austempered at different temperatures and sliding distances has been evaluated. Three different batches of samples were austempered in a salt bath maintained at 250, 300 and 350 °C respectively for 1h. Rolling with 5% sliding wear tests were performed with each batch of samples for different test cycles, namely 6000, 18000 and 30000 cycles respectively, in order to study the wear performance of these specific steels. An in-depth microstructural characterization has been carried out before and after the wear tests in order to link the wear behaviour to the microstructure of each sample. The wear resistance has been expressed by means of the specific wear calculated from the mass loss after the tests. The worn surfaces were analyzed by the scanning electron microscopy and X-ray diffraction techniques. Micro-hardness profiles were also obtained to analyze strainhardening effects beneath the contact surfaces. The results indicate that the harder material exhibited overall lower wear rates for all test cycles studied i.e., the one austempered at 250°C showed superior rolling/sliding wear resistance than the rest. It is also interesting to note that the hardness increment and thickness of the hardened layer increases with increasing the austempering temperature and number of test cycles.Furthermore the results appear to indicate that the initial roughness of the samples has no major effect on the outcome of the results. The higher wear performance of the sample austempered at 250°C has been attributed to its superior mechanical properties provided by its finer microstructure. It has been evidenced that all samples suffer the TRIP phenomenon since, after wear, no retained austenite could be detected by XRD.
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2010.
Research subject Engineering Materials; Machine Elements
IdentifiersURN: urn:nbn:se:ltu:diva-29340Local ID: 2c9fa930-8369-11df-ab16-000ea68e967bISBN: 978-91-7439-124-4 (PDF)OAI: oai:DiVA.org:ltu-29340DiVA: diva2:1002563
Nordic Symposium on Tribology : 08/06/2010 - 11/06/2010
Godkänd; 2010; Bibliografisk uppgift: CD-ROM; 20100629 (ysko)2016-09-302016-09-30Bibliographically approved