Exposure Test to Evaluate Corrosion Resistance of Water Gates

摘要

Real information on the corrosion resistance for such big structures as water gates could not be expected from tests using small plate coupons free from any one of crevice geometry. Specimens chosen for this test were two box like models mainly made of type 316 steel or type 304 steel. The first was a larger one with a size of 1340 X 1000 X 500 in mm, and the second was a smaller one with a size of 400 X 400 X 200 in mm, both of which were designed to simulate real configuration of the water gates in terms of shape and welds. These specimens were exposed for 503 days to a natural river site 9 km upstream from the sea. For specimens positioned at a level between low and high tide, there occurred hardly any kind of corrosion. On the other hand, for all specimens immersed deep into the water, there occurred several forms of corrosion, for example, inside the rubber/metal crevice and under deposits, as well as dezincification from brass bearing.