This paper describes the application of a new multifrequency sensor system to an industrial rod mill. The system operates by analysing the response of the rod to an excitation signal which contains a range of frequencies. The sensor system is able to successfully monitor the transformation of the material. Sensor configurations that could be deployed online have been considered and a prototype system has been built and tested in the Stelmor section of the Scunthorpe Rod Mill fitted in the enhanced cooling zone. Initial results are shown, demonstrating that the phase spectra is essentially unaffected by variations in lift-off and the lay pattern of the rod on the run-out table. The system was also able to detect different phase spectra from different grades of steel and also to detect features of the process which are known to affect microstructure.

The effects of bending moments on the frequency of 10 MHz fundamental crystals using AT and SC cuts of quartz has been studied. The bending was applied in two different configurations, one a cantilever and the other a symmetrical arrangement with bending about a diameter defined by a knife edge with the central part removed.The effects obtained with the cantilever mounting of the AT crystal can be split into two components, one antisymmetrical centred at JI = 180° with a periodicity of 360° (in JI) and the other with a periodicity of 9 0 ' .The second component is absent in the results obtained on the sc cut.The symmetrical bending results show that the SC cut is considerably less sensitive than the AT cut. The observations are consistent with the proposition that the frequency changes for symmetrical bending of AT cut crystals are due to the higher order effects (approximately square law with stress) which are also responsible for the component with 90° periodicity found in the cantilever case.It is expected that the SC cut should have distinct advantages over the AT cut when considering frequency stability in the presence of forces perpendicular to the plane of the crystal especially when these forces are large.