  Bi2Sr2CaCu2O8+x (Bi-2212) superconducting long-length wires are mainly
limited in obtaining high critical currents densities (JC) by the internal gas
pressure generated during the heat treatment, which expands the wire diameter
and dedensifies the superconducting filaments. Several ways have been developed
to increase the density of the superconducting filaments and therefore
decreasing the bubble density: much higher critical currents have been reached
always acting on the final as-drawn wires. We here try to pursue the same goal
of having a denser wire by acting on the deformation technique, through a
partial use of the groove-rolling at different wire processing stages. Such
technique has a larger powders compaction power, is straightforwardly adaptable
to long length samples, and allows the fabrication of samples with round,
square or rectangular shape depending on the application requirements. In this
paper we demonstrate the capability of this technique to increase the density
in Bi-2212 wires which leads to a three-fold increase in Jc with respect to
drawn wires, making this approach very promising for fabricating Bi-2212 wires
for high magnetic field magnets, i.e. above 25 T.
