On-Line Monitoring of Oxidation States in a HSS Work Roll During Hot Rolling Using Pulsed Eddy Current Testing

The quality of rolled products and consumption of rolls are greatly influenced by the oxidation behavior of work roll surface in hot rolling. It is of great significance to improve the quality of rolled products and reduce the consumption of rolls to monitor and evaluate the oxidation states of work rolls in service by non-contact nondestructive inspection technology. In this study, a self-developed test apparatus simulated the high-speed steel (HSS) work roll oxidation in real hot rolling conditions. The interaction mechanism between oxidation and wear of HSS work roll under different conditions was revealed. Furthermore, a set of pulsed eddy current (PEC) nondestructive inspection system was designed and built to evaluate different oxidation states of HSS work roll in service. Variational mode decomposition (VMD) Hilbert transformation was proposed to overcome the problem of mode mixing in mode decomposition of oxidation monitoring signals. At last, the Hilbert marginal spectrum centroid was presented as a characteristic for quantifying the surface oxidation state of work rolls in service.