| 摘要 |
PURPOSE:To manufacture a pure Nb-rolled sheet for a superconducting material having high RRR value and in which the contamination and defects on the surface are prevented by subjecting a pure Nb ingot obtd. by electric beam melting to specified cold rolling and thereafter executing annealing at a specified temp. in vacuum. CONSTITUTION:The ingot of pure Nb is cast by an electric beam melting process. This ingot is cold rolled at <=100 deg.C material temp. At this time, its total draft is regulated to 60 to 99%, its draft per pass to <=15% and its rolling speed to <=30m/min. This cold-rolled sheet is heated to 900 to 1100 deg.C in vacuum of <=1X10-<4>Torr and is annealed. In this way, the pure Nb-rolled sheet for a superconducting material highly purified, in which the contamination on the surface is prevented, having high RRR value, in which the generation of surface defects such as cracks and flaws is suppressed and stably maintainable its superconducting condition can be obtd. |
