On the critical flow velocity for erosion-corrosion of Ni-based alloys in a saline-sand solution
By Yi, J. Z.; Hu, H. X.; Wang, Z. B.; Zheng, Y. G.
Published in Wear
Wear
2020
Abstract
Critical flow velocity (CFV) is an effective parameter to evaluate the erosion-corrosion property of passive material. The CFV accumulation for different passive materials contributes to the material selection of hydraulic equipment applied in multiphase flow environments. In this paper, the CFV behaviors of Inconel 600, Inconel 625 and Incoloy 825 under impingement by a saline-sand solution have been investigated by potentiostatic polarization methods and mass loss tests. In addition, the repassivation behaviors of three Ni-based alloys were studied by a self-made indentation apparatus to clarify the CFV mechanism for erosion-corrosion. The results show that the CFV values are 13 m/s for Inconel 600, 14 m/s for Inconel 625 and 14 m/s for Incoloy 825, respectively. The higher CFV values for Inconel 625 and Incoloy 825 are mainly based on their higher repassivation rates compared with Inconel 600. The addition of Cr and Mo elements for Ni-based alloy can remarkably improve the repassivation rate, and then increase the CFV value.