| About this Abstract |
| Meeting |
Materials Science & Technology 2019
|
| Symposium
|
Retained Austenite for High and Ultrahigh Strength Steels
|
| Presentation Title |
Austenite Stability in Bainite Steel After Austempering Heat Treatments |
| Author(s) |
Giovani Goncalves Ribamar, Arthur Seiji Nishikawa, Hélio Goldenstein |
| On-Site Speaker (Planned) |
Giovani Goncalves Ribamar |
| Abstract Scope |
In order to study the stability of retained austenite (RA), a Fe-Cr-C steel was submitted to austempering heat treatments. Bainitic kinetics and bainite transformed volume fraction were determined by dilatometry analysis. The obtained austenite decomposition products were characterized by Scanning Electronic Mycroscopy (MEV), X-ray diffraction in order to quantify RA and estimate its carbon content, and Vickers microhardness test. The results showed that total dilation for the times studied decreased with the increase in austempering temperature. Martensite transformation during final quenching (after austempering) was observed for the highest austempering temperatures, while it was not found for those at lower temperatures. The results suggest that RA becomes more stable for low temperatures due to carbon enrichment and the small amount of austenite. At high temperatures, a large amount o austenite stays untransformed and the partitioned carbon content is not enough to stabilize RA. |