[5A2] Measurement of the high-temperature magnetic properties of engineering steels for online NDT applications
J Wilson¹, L Zhou², F Wu², C Davis² and A Peyton¹
¹University of Manchester, UK
²University of Warwick, UK
Accurate control of microstructure in steel strip manufacture is essential to the production of a consistent product with tightly controlled mechanical properties. Although this can largely be achieved using mill models, supported by pyrometer measurements for temperature, inaccuracies can arise for some steel grades. Electromagnetic microstructure monitoring systems are increasingly being used in these applications as they are non-contact, relatively inexpensive and have the potential to provide real-time feedback to control the manufacturing process. Such systems are often reliant on establishing correlations between the finished product and measured electromagnetic parameters, but a deeper understanding can be gained by offline measurement of the magnetic properties of the materials of interest at high temperatures. To fulfil this need, a test system has been developed to measure the magnetic hysteresis (BH) properties of structural steels at temperatures up to the Curie point. The rig is based on a modified Epstein frame, constructed using specialist high-temperature materials. Materials including low-carbon and dual-phase steels have been tested, with full BH loops measured and loop parameters (permeability, coercivity) extracted during heating and cooling. Results show the developed system has the potential to provide valuable data to inform online electromagnetic monitoring systems.
