Damage mechanisms of silicon nitride rolls in hot rolling of copper wire

Rolling accounts for the major part of all metalworking processes. Unlike conventional rolls, ceramic rolls exhibit significantly higher wear resistance and tend to produce parts with superior surface finish. Within the scope of this work, the damage of silicon nitride components, during the hot rolling of copper wire, has been investigated by means of experimental and numerical methods. FEM simulations have been carried out to estimate the thermomechanical loads in order to determine the relevant causes and the influencing factors on the failure and wearout of silicon nitride rolls. The surfaces of the rolls and roll calibres have been inspected after running the experiments. To draw the final conclusions, numerical results have been compared to the experimental outcomes. Adhesion of coper was observed directly after running the experiments. Stresses calculated were too low to cause a damage risk to the rolls but shear stresses played a significant role in defining adhesion locations and severity. Interrelated factors affect the formation of adherent copper layers on silicon nitride. These layers were found to cause the foremost damage to the rolls and roll calibres.