Erosion-corrosion assessment of materials for use in the resources industry

The erosion-corrosion properties of a range of ferrous-based materials that are currently being used or have potential for use in the resources industry have been assessed using a slurry pot erosion-corrosion (SPEC) test rig that has the capability of establishing the separate components of erosion, corrosion and synergy. Testing was performed, at 30 degrees C, in an aqueous slurry containing 35 wt% AFS 50-70 silica sand and a 3.5 wt% NaCl solution. Erosive action was supplied through high-speed rotation of a rubber-lined impeller. Erosion-corrosion performance of materials evaluated was related to composition/microstructure and hardness. Test data correlated with available service experience. The results showed that the cast Cr white irons with (i) a structure that was essentially a duplex stainless steel containing a distribution of hard carbides and (ii) a near eutectic Cr white iron exhibited the highest erosion-corrosion resistance of the materials tested. The evaluation of the Cr white irons also highlighted the influence of Cr and C levels on the E-C properties of these materials. E-C assessment of selected carbon steels confirmed that the erosion-only rates and synergistic levels showed a general decline with increasing carbon content and hardness. As expected, a low C steel pipe product displayed very mediocre erosion-corrosion behaviour as a consequence of its very low intrinsic corrosion resistance and inferior wear properties. This reflected service experience, however, such products are still being used, due to the comparatively low initial cost. A TiC particle-reinforced AISI 316 stainless steel exhibited an almost 45% improvement in the E-C resistance, when compared with an AISI 316L stainless steel. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.