Wear phenomena in high temperature sheet shearing blades

Metal sheet shearing is necessary for dimensional control during steel forming. Due to the extreme operating conditions, like elevated temperatures, high contact stresses and corrosive environment, shearing blades suffer from severe wear and need frequent repair or outright replacement. This of course increases the maintenance costs for steel fabricators. Therefore, the goal of the current project was to gain insight into the wear phenomena that occur at high temperatures during sheet shearing. A comprehensive damage analysis was undertaken on a hot work tool steel used for such blades (steel type 1.2367) by means of optical microscopy, 3D surface topography, SEM/EDS and X-ray computed tomography. The structure of micro- and macroscopic cracking was characterised and linked to wear mechanisms. Corrosion phenomena such as oxide growth and oxidation-enhanced crack propagation were also analysed. Results indicated that the predominant wear mechanisms were thermal and mechanical fatigue in a corrosive environment leading to accelerated crack growth and material removal.