In finifsh-cogging a high-purity titanium material into a cylindrical form as
the final shape, if cylindrical cogging is performed in all stages of warm forging
or if cylindrical cogging is performed in the initial stage of the warm forging,
there is no need of peripherally restricting the cylindrical cogging material,
so that even if longitudinal upset-forging is effected with an upsetting ratio
of 2, the condition that the major diameter/minor diameter ratio of the section
after forging is not more than 1.01 can be satisfied, developing superior upset-forgeability.
This makes it possible, in producing disk-like targets for sputtering, to minimize
cutting loss produced during the rolling and machining and to maximize the yield
of products; therefore, the material can be widely used as a semiconductor material
for electrodes and the like using a high-purity titanium material.