Prestressed concrete cylinder pipe pipeline sections projected to exhibit wire breaks were detected - and one not so - were excavated, removed, inspected, and dissected. Corrosion had initiated upon the inner surface of shorting straps and spread to the prestressing wires. A mechanism for this corrosion is presented and the findings discussed.
Corrosion and structural deterioration due to microbiologically influenced sulfate reduction and hydrogen sulfide gas oxidation to sulfuric acid are responsible for much of the expense related to santiatry sewage collection systems. This paper explains the mechanism of this biologically induced corrosion, its consequence, and methods to mediate it.
Because of its hardness, dimensional tolerance and resistance to hydrogen, cadmium plating has been used to protect steel components in marine environments. However, Cadmium is thought to be toxic and a search is on for an alternative. In this paper, cadmium and zinc-nickel plating/coating were compared in water immersion, temperature cycling, rain, humidity, and salt fog testing.
Electrochemical corrosion rate probes have been constructed and tested along with mass loss coupons in an air plus water vapor and a N2/O2/CO2 plus water vapor environment. Temperatures ranged from 200º to 700ºC. Results show that electrochemical corrosion rates for ash-covered mild steel are a function of time, temperature and process environment.
The unavailability of coal fired electrical generating capacity is often attributable to corrosion in steam generators. Electricity demand grows faster than new plants come online, forcing greater use of old plants. Identifying such problems requires proper inspection tools and techniques to take the guesswork out of whether boiler tubes should be repaired or replaced.
If the iron concentration in an alkaline chelant boiler cleaning solution reaches a high value when dissolving magnetite, it sometimes continues to increase rapidly and not level, indicating corrosion of the boiler metal. A laboratory study of “runaway iron increases” investigated the cause and the best mitigation methods.