Surface bursts at a tensile test - 1.7131
The wire material was drawn to bars. A teared film of lubricant in places has presumably led to a changed flow behavior at the surface. At the routine control by means of tensile test places with bursts have noticed at the surface. The bursts were arranged in a line on the surface. The microsections showed a stronger microstructural deformation in the areas concerned. The defect-free surface didn't show this microstructural changes.
Steel bars 20,50 mm round - spheroidised