Erosion–Corrosion Behavior of 20Cr Steel in Corrosive Solid–Liquid Two-Phase Flow Conditions

Abstract

An experimental study was conducted on erosion–corrosion (E–C) properties of 20Cr (Chinese steel grade) steel. Three corrosive solid–liquid two-phase aqueous solutions (distilled water, 3.5 wt.% NaCl aqueous solutions and saturated CO2 aqueous solutions, respectively, mixed with quartz grain) are used at three different experiments. The research confirmed that the E–C rate increased exponentially with the increase in flow velocity. The equation V e = KV n can be used to express the relationship between E–C rate and flow velocity. Furthermore, a new regression approach called ‘segment fitting’ was proposed. It had better fitting precision to express the relationship between E–C rate and flow velocity. The analysis and SEM surface topography show that the material removal rate is controlled by electrochemical corrosion at lower flow velocity and may suffer from mechanically induced deterioration at higher flow velocity. The impact angle has complex effects on E–C rate. In the experiment condition, the E–C rate will reach highest at 45° impact angle.