Page 259 - Fiber Fracture

242 K. Yoshida

element simulation of the drawing of superfine wires with an inclusion, that as a large
inclusion passes through a die, drawing stress rapidly increases, inducing wire breakage.
It was estimated that inclusions with a Di/D, ratio of 0.4 or higher increase the
likelihood of wire breakage. In the production technology of a metal superconducting
multifilament wire, internal fracture and filament breaks are fatal to the wire quality. The
detection of wire defects is extremely difficult, since most of the defects exist inside the
wire and cannot be detected by surface observation. These defects were detected during
the drawing process through acoustic emission (AE) measurement, and the applicability
of this method was also investigated.

Keywords

Fracture; Wiredrawing; Internal fracture; Wire breakage; FEA; Superconducting
wire; Acoustic emission; Filament breaks