1, 000
l/hr humid air, contaminated with 40ppm SO
2, was continuously fed to a test chamber (about 1151 capacity) by Yamasaki's Constant Volume Gas Pumps (USA Pat. No. 3479801). The relations of stationary concentration of SO
2 gas in the chamber and corrosion rate with the number of specimens of mild steel and aluminum plate respectively were obtained under the conditions of dew-cycle (25-50°C/60-60min) and constant temperature (30°C and 50°C).
The corrosion rate in the dew-cycle test was higher than that in the constant-temperature test at the maximum temperature in the dew-cycle test. The decrease of stationary SO
2 concentration in test with specimens corresponded to the increase of corrosion rate.
It is important for the reproducibility of an accelerated test to provide not only the concentration, but the flow rate of the contaminated air and the number or the total surface area of the specimens to be tested.
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