Sulfur dioxide hydrothermal test is to expose the sample to the humid and hot gas chlorine containing SO2. After the prescribed test period, the color difference and gloss of the sample are measured, and the state of discoloration, loss of gloss, surface or edge corrosion is evaluated. The wet-heat test of sulfur dioxide resistance is suitable for evaluating the corrosion resistance of color coated panels in hot and humid atmosphere of sulfur dioxide (SO2).
Before the test, the gloss and chroma coordinates of the sample should be measured, and then the sample should be placed in the test box with SO2 gas, the heater should be opened, and the temperature of the test box should be raised to (40 + 3)C within about 1.5 hours. After the sample is placed in the box for 8 hours, the drainage and exhaust of the box body are combined with compressed air as a test cycle. Repeat the above operation from beginning to end to continue the test to the prescribed cycle or the prescribed degree of damage.
The gloss and chromaticity coordinate values and calculated chromatic aberration should be determined after the sample is taken out. The gloss loss grade, discoloration grade, foaming grade and rusting grade of the sample should be adjusted according to GB/T 1766-1995 standard, and the maximum difference of the parallel sample should be taken as the test result.