Senior research engineer, W. R. and Co., Cambridge, MA
ManagerMember of ASTM, Bethlehem Steel Corporation, Homer Research Laboratories, Bethlehem, PA
Results of the Deutsches Institut für Normung (DIN) Kesternich sulfur dioxide test (DIN 50018) are compared with those of long-term industrial atmospheric exposure tests of sheet steels coated with zinc, aluminum, and Al-Zn alloy coatings. According to the Kesternich test results, Al-Zn and zinc coatings provided sacrificial protection to the steel substrate whereas the aluminum coatings did not. Durability was highest for the 55% Al-Zn and aluminum coatings. Qualitatively, these results are in good agreement with those of atmospheric tests. However, durability of 4% Al-Zn and 7% Al-Zn in the Kesternich test was better than two times greater than that provided by zinc coatings. This finding does not agree with the results of long-term atmospheric tests in an industrial environment. These comparisons demonstrate that the Kesternich test provides a useful qualitative ranking of these coatings but should not be relied on to quantitatively predict coating life.
Paper ID: JTE10763J