Erosioncorrosion Wear Resistance of a Chromium Nickel Steel in a Multiphase Environment under Controlled Potentials

Multiphase twin screw pumps are used by the oil and gas production industry to boost the transport of hydrocarbons allowing for a greater field recovery and longer transport distances. The pumps are subjected to wear due to corrosion, erosion and erosioncorrosion. This paper presents the results of an investigation focused on investigating the wear resistance of a chromium nickel steel (X22 CrNi 172) after two different heat treatments under controlled corrosion activity. The materials were subjected to three different potentials in the passivity region of the materials and the wear resistance was investigated using different amounts of oil in a chloride ion rich standardized water phase with an addition of 10 wt.% quartz sand as erosion particles and CO₂. As a result it will be shown that at all investigated potentials an oil-in-water cut of 40% and more leads a complete inhibition and wear solely due to erosion. If the corrosion was allowed to occur, i.e. at lower cuts, the wear due to erosioncorrosion was governed mostly by the corrosion in the form of pitting corrosion. It will further be shown, that depending on the level of corrosion the use of one or the other material has its advantage.