METHOD OF ASSESSING RESISTANCE OF PIPELINE STEELS TO "GROOVE" CORROSION Russian patent published in 2020 - IPC G01N3/60 G01N17/02 

FIELD: measurement technology.

SUBSTANCE: invention relates to protection of field oil from corrosion and can be used for evaluation of resistance of pipeline steels to "groove" corrosion. Plate is made of analyzed steel, its bend to required bending deflection, temperature control in aggressive medium, inspection after tests, evaluation of resistance to corrosion. Length and the residual bending deflection of the plate are taken at a ratio ensuring the occurrence in the plate of residual stresses occurring in the pipeline. Circular notch with depth of 0.4–0.6 mm is applied across the plates at its middle point to measure its radius. Plate is held in thermostat with 2–3 % aqueous NaCl solution at 65 to 75 °C for 5 to 50 hours with supply of air flow to the point of incision and measurement of notch radius after tests. Depth index of "groove" corrosion rate is calculated by formula taking into account change of notch radius for time t, mm, time of temperature control of plate, hour, and number of hours in year.

EFFECT: possibility of quantitative assessment of resistance of pipeline oil of field oil pipelines to corrosion in pumped water-oil emulsions in conditions of simultaneous action of corrosive medium, mechanical stress and erosion particles on pipe.

1 cl, 2 tbl, 7 dwg