Wear Testing of Thermally Oxidised Tool Steel Specimens with alpha-Fe2O3 Layers

The paper presents results of wear investigations of thermally oxidised tool steel specimens with an alpha-Fe2O3 coating. The friction reducing ability of alpha-Fe2O3 layers on tool steel was shown in previous studies. Reduced friction and the layer s stability are prerequistes to realise a dry sheet metal forming process that avoids the use of additional drawing oils. This in turn will make the forming process more eco-friendly. The wear investigations were carried out on a wear test bench with the high strength sheet metal DP600 Z at a surface pressure of 80 MPa. Several thermally oxidised specimens were tested with different numbers of strokes in order to characterise the wear behaviour of the oxide layers. The surface analyses of the specimens were carried out using digital and scanning electron microscopy. Even after 5000 strokes (300 m of sheet metal) the 0.2 micrometre thin alpha-Fe2O3 coating was only partly degraded so that a wear reducing effect can be exploited in actual applications.