A new corrosion test for organically coated galvanized steel products

摘要

A new approach to obtain predictions on cut-edge corrosion resistance in organic coated galvanised steel (OCS) products has been developed which, unlike many accelerated tests, can be performed in any desired external environment. The testing procedure is based on the monitoring of cationic zinc (Zn{sup}(2+)) released from OCS panels prepared prior to exposure with an exceptionally high cut edge length per unit area. There is an excellent correlation between the total quantity of cationic zinc leached from the exposed edge over a three-month period of external exposure and the observed cut edge corrosion performance after a 4-year natural external exposure period in the same environment. The results of conventional accelerated testing methodologies have been found to fail to accurately predict external exposure as accurately as this testing procedure. The test can be performed in any weathering regime and can accurately predict the difference in environmentally sensitive materials performance.