Study On Synergy Effect Of Erosion-corrosion On Metal Surface In Liquid-solid Two-phase Flow

Erosion-corrosion is widely existing in the oil,natural gas,chemical industry,water conservancy and hydropower industries,and is one of the important reasons of equipment and material damage in industry.Erosion-corrosion of metal materials under liquid-solid two-phase flow is the phenomenon that the flowing fluid causes material loss on the metal surface.It includes the erosion of solid particles on the material,the corrosion of the material on the material and the synergy effect between the erosion and corrosion.In this paper,the erosion-corrosion test rig and electrochemical measurement test system were used to measure the erosion rate in the gas-solid condition,the corrosion rate in liquid and the erosion-corrosion rate in liquid-solid two-phase flow of TP140 steel and 13 Cr steel.The change law of the erosion rate,electrochemical corrosion rate,and the rate of erosion-corrosion rate under synergistic action were obtained by analyzing erosion amount were measured by weight loss measurement,electrochemical test method and the results of SEM(scanning electron microscopy).After the experimental research,the following main conclusions were drawn:Firstly,after analyzing the erosion-corrosion rates of the two steels,it was found that the erosion and corrosion rates of the two materials increased with the increase of the fluid flow rate,and the erosion erosion rate at the 45° jet angle increased faster.Secondly,the erosion-corrosion process analysis of the two materials showed that when the flush angle is 45°,the erosion-corrosion process of TP140 steel is dominated by the synergistic action of erosion and corrosion.When the fluid flow velocity is low at the 90° flush angle,the erosion-corrosion process is dominated by erosion.With the increasing of fluid flow velocity,the impact action of particles on TP140 steel is intensified,and erosion-erosion synergy dominates the erosion-corrosion process.The 13 Cr steel is dominated by flushing during the whole erosion-corrosion process.Finally,the synergistic effects of two kinds of steel in liquid-solid two-phase flow were analyzed.It was found that the erosion-corrosion rates of TP140 steel and 13 Cr steel under the synergistic action of erosion and corrosion in liquid-solid two-phase flow increased with the increase of the flow rate.The erosion-corrosion rate under the synergistic effect accounts for 20%~30% of total erosion-corrosion rate.And the erosion-corrosion rate under the synergistic action of 13 Cr steel accounted for 30%~60% of the total erosion erosion rate.