Damage mechanisms in silicon nitride wire-rolling tools: Lab-scale experiments and correlation with finite element modeling

This study addresses the failure modes and damage mechanisms in silicon nitride rolling tools applied in caliber rolling steel wires. The study is based on the experimental work conducted in conjunction with finite element simulations. Lubricated and unlubricated cold wire rolling experiments were conducted using two different grades of steel wires. The effects of lubrication and loading were taken into consideration when interpreting the outcomes. The correlation between the experimental observations and numerical results enabled explaining damage nucleation and evolution in terms of stress fields. It was shown how the failure in silicon nitride rolls "switches" from fatigue induced damage to fast fracture, depending on the tensile stress fields. The importance of lubrication was emphasized by comparing surface and subsurface damage in both cases.