Chevrons at a cold extrusion component - 1.6571
A chevron (chevron crack) is a type of internal burst. They arise while drawing or while cold extrusion due to overstressing of the material (overdrawing). The cracks are more or less transverse defect (V-shaped changed) in the material. They are inclined under an angle of 45° against the axis of the wire. Segregations and for the deformation unfavorable microstructures (e.g. martensite) favor the appearance of these defects. The deformability of the core zone is exceeded while the surface layer still holds together. The martensitic microstructure is the reason for the defect in the following case.
cold extrusion component 16,00 mm round - untreated