Corrosion studies under conditions of thermal desalination. II. The influence of oxygen content, pH value, flow rate and impurities on the corrosion rates of unalloyed and low alloyed steels
✍ Scribed by Prof. Dr. E. Heitz; Dr. R. Manner
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- German
- Weight
- 938 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0947-5117
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✦ Synopsis
Abstract
Corrosion rates determined on the basis of weight loss and polarization resistance are considerably lower for a 6% chromium steel than for an unalloyed steel C 15 (DIN 17210), a base‐melt and a 5.5% Ni steel. The results of a 100 hrs test and a short duration parameter studies at various oxygen concentrations show that above 100°C there is a minimum corrosion rate at 10 ppb oxygen. At oxygen concentrations above 20 ppb there is a transition from uniform corrosion to pitting. The dependence of corrosion rate on pH is in accordance with expectations; the same is true with the dependence on flow rate. Sulphides as impurities in sea‐water become corrosion stimulators only below pH 7, but are highly active even in the ppm range. Addition of 1 ppm copper ions gives rise to considerable stimulation, too. The results obtained in this study enable conclusions to be drawn with respect to the operation of sea‐water desalination plant.