| About this Abstract |
| Meeting |
Materials Science & Technology 2019
|
| Symposium
|
Retained Austenite for High and Ultrahigh Strength Steels
|
| Presentation Title |
Retained Austenite in Nanobainite Bearing 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 influence of silicon and manganese contents on austempering heat treatment of bearing steels, a Fe-1C-1.0Mn-1.8Si-1.5Cr (alloy A) and a Fe-1C-1.5Mn-1.2Si-1.5Cr (alloy B) steels were submitted to austempering heat treatments above martensite start temperature. Bainite formation kinetics and bainite transformed volume fraction were determined by dilatometry analyses. The austenite decomposition products were characterized by Scanning Electron Microscopy with Field Emission Gun (FEG). X-ray diffraction was carried out to quantify the amount of retained austenite. The strength for each treatment condition and alloy was estimated by Vickers microhardness test. The results showed that alloy A presented slower bainite formation kinetics than alloy B, reaching complete bainite transformation only for times higher than 10 h for temperatures close to 300 °C. The morphology of the austenite decomposition products presented nanostructured bainitic ferrite sheaves containing thin austenite films, of the order of 80 nm in thick. |