Description

Nominal electrical resistivity of metal materials has been used as a sensitive signal to detect potential for breaking of bead wire in the cold-drawing process. As the size of non-metal inclusions with higher hardness or tensile strength approach the size of the wire diameter, so-called “inclusion size effect” may increase the nominal resistivity of the wire dramatically and result in a break. Optimum conditions for rod bundles are lower nominal resistivity in a series of pass reductions and/or higher total percent-reduction at which the nominal resistivity reaches a minimal value.