Place: Materials Science & Technology 2012, Pittsburgh, USA
Given that controlling the precipitates in bearing steels plays a very important role in enhancing their wear resistance and fatigue properties, in this work Transmission Electron Microscopy (TEM) and Local field Electrode Atom Probe (LEAP) were applied to study carbides in high carbon bearing steel 100Cr6 with bainite matrix. TEM investigation proves the spheroidized carbides in 100Cr6 are (Fe, Cr)3C. 3 Dimensional Atom Probe analyses show concentration and distribution of elements, i.e. C, Si, Mn, Cr, Fe in carbides and the results further reveal that spheroidized (Fe, Cr)3C with a mean Cr content of 10 at% shows a 10-15nm pure cementite layer on its surface after the followed bainitizing process. Moreover, results also show that during higher bainitizing temperature, the second phases within bainite are mostly Θ-phase, while in lower temperature ε-phase is indicated. The influences of interstitials and alloy elements on precipitates and the property enhancements through precipitates are further discussed.