Advanced Techniques for the Measure of Microstructure and Residual Stress in Components Subject to Rolling Fatigue

Demands on loaded, rotating components, e.g., bearings, shafts & gears continue to escalate. Modern manufacturing strategies require improvements in traditional measurements and process control tools. Traditionally residual stress examination in bearings was accomplished with depth profiles obtained using X-Ray diffraction (XRD) and electrochemical layer removal. More recently Barkhausen Noise Analysis (BNA) has proven itself in the evaluation of microstructure as well as surface residual stress in ferromagnetic materials. Traditional BN analysis parameters have been used for fixed measurement depths, usually near the surface. This study is an examination on a set of as-hardened and ground bearing rings manufactured with variations in processing. The Barkhausen signal was analyzed to yield information about a range of depths. XRD & BNA depth profiles were gathered and they correlate well. This allows a calibration of the BN signal to the residual stress. It is proposed that BNA can be used for quick, non-destructive assessment of residual stress depth profiles.Cross Reference: