PURPOSE: To facilitate manufacture of oxide superconducting wire stocks by filling oxide superconducting powders into a silver sheath, cold drawing the sheath, and performing intermediate annealing at a temp. in a prescribed temp. range at each time when a fractional reduction in area indicates a specific value.
CONSTITUTION: In the time of cold drawing work of a silver sheath containing oxide superconducting powders, at each halfway time when a fractional reduction in area reaches 2W50, intermediate annealing at a temp. in the temp. range of 100W300°C. is performed. The silver sheath should have a proper hardness, that is, a hardness of Vickers 80W100 is required. A hardness of the sheath recovers a suitable value for cold drawing by performing the above annealing, so that generation of breakdown or cracks on the sheath is prevented. Hence, manufacture of oxide superconducting wire stocks is facilitated.
INOUE TADASHI
SEKINE HISASHI
YAMAMOTO HIROICHI
MORI KAZUTAKA
NUMATA KOICHI
MITSUBISHI HEAVY IND LTD