STRUCTURAL AND MAGNETIC PROPERTIES OF CAST IRON FOR CYCLOTRONS

At IBA, the steels used to build the magnets of the Cyclone230® cyclotron are cast on demand, using very strict criteria, casting procedure, requirements and quality control. Among the various steps performed at the foundry, a thermal annealing is made. In this work, we assess the usefulness of such thermal treatment. Samples of pure iron casts have been magnetically and structurally characterized. Progressive magnetic softening was observed upon successive annealing steps. These changes of the magnetic properties were attributed to the relief of internal stresses. Results, obtained by X-ray diffraction, electron microscope and precise determination of magnetization curve and hysteresis loop, will be presented and commented.