The wire material was drawn in several steps from 5,50 mm
to 2,50 mm. Between the individual drawing events a solution annealing was carried
out. Material overloads then probably have appeared at one of the last drawing
steps by insufficient lubrication of the wire, lubricant demolition. The wire has
in places rubbed in the drawing die and the flow behavior was influenced adversely.
Small transverse cracks have appeared in the places of insufficient lubrication
and then, in the pulling stone, have torn the material because of the reduction
of the cross-cut. Shiny places and scaly surface are indications of this defect.
5,50 mm round - solution annealed , pickled
drawn at 2,50 mm