Formation of friction martensite at the drawing - 1.6582
The rod wire should be drawn of 27 mm to 26 mm . By locally bad lubrication of the wire in the drawing die, perhaps by demolition of the drawing agent, shiny places could develop, partly with material abrasion. Because of the flow behavior influenced unfavorably, the material is locally strong hardened and heats up. Friction martensite could develop.
Rod wire 27,00 mm round - spheroidised , pickled
drawn to 26,00 mm