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Fe-based hardfacing alloys with high carbon and chromium content possess good wear resistance properties in severe environmental conditions [1]. In the present study, the wear behaviour of Norem02, a duplex stainless steel containing 1.3 wt.% carbon and 24 wt.% chromium and elaborated by Hot Isostatic Pressing (HIP), was investigated. HIP represents an attractive pressure-assisted sintering technique resulting in the elaboration of dense materials with a fine-grained microstructure, generally associated to improved wear properties [2]. Wear tests were carried out using a pin-on-disk tribometer under a load of 2, 5 and 10 N against a ball counterpart of WC. 3D optical profilometers characterisations of wear tracks obtained under different loads were performed and revealed the presence of grooves and of redeposited material on the edges of the tracks. SEM-EDX analysis of the worn surfaces indicated the typical morphology of adhesive wear. However, the characterisations showed also the presence of a Fe-Cr oxide layer, that suffered more or less important plastic deformation/delamination phenomena function of the applied load, suggesting the occurrence of oxidative wear. These results are in agreement with the friction force-distance curves, displaying clearly the existence of two friction behaviours. Finally, a friction coefficient was calculated and a wear rate was estimated. Even if the friction coefficient of Norem02 elaborated by HIP is higher than the value found for the alloy obtained by more conventional techniques, the surface damage is reduced. This suggests that the microstructure obtained by HIP allows the alloy to better withstand the mechanical stresses occurring during the wear tests, although it is responsible for a more severe friction.
[1] Sachin Pawar et al., Int. J. Refract. Met. Hard Mater. 78 (2019) 288-295.
[2] U. Malayoglu et al, Wear 255 (1–6) (2003) 181-194.
| Speaker Country | France |
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