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UDC 628.168.3
Atanov N. A., Gorshkalev P. A., Chernosvitov M. D., Smirnova A. M.
Study of drinking water aggressiveness in the Samara municipality
Summary
The results of studying corrosion rate and steel pipe passivation time in the water distribution network of the Samara municipality are presented. To determine the rate of corrosion the gravimetrical method was used. Surface (the Volga River) and underground water (treatment facilities of the Kuibyshev Region) was used as a test object. The experimental studies showed that river water was corrosive in relation to steel pipes: the corrosion rate reached 0.1665 g/(m2·h) on the fifth month of exposure so far, whereas the samples had severe pitting (one month) and crater (5 months) injuries. The values of the corrosion rate in underground water were in the range of 0.01–0.06 g/(m2·h), and the investigated samples did not have any significant corrosion injuries. The experiment timing was not enough to complete passivation. By the example of the sample (50 years working service) it was shown that complete passivation of steel pipes with corrosion processes extinction and material integrity maintaining was possible; however, later the interior face of the pipe bottom line became covered with corrosion deposits (7 mm thick). The results of studying the drinking water aggressiveness demonstrate the following: complete passivation of the interior face of steel pipes is provided by the formation of dense corrosive deposits; the growth of the corrosive deposits results in the decline of the pipe capacity; external corrosion of a non-insulated steel pipe under the wet conditions dominates and results in the formation of blue holes. Replacing steel pipe with plastic ones is economically sound.
Key words
corrosiveness , steel water pipes , corrosion injuries , electrochemical corrosion , gravimetric method
