Abstract
It is well known that dry abrasive blasting cannot remove salts completely and therefore, some residual salts remain on the blasted steel surface. In offshore or coastal corrosive environments, it is difficult to keep the near white metal finish and control salt on the prepared surface until coating application. The bare steel can flash rust in a couple of hours. There are several commercial cleaning products to remove residual salts and to extend the surface cleanliness time. Three types of grit blasted steel surface preparation methods were performed; (1) blasted new steel to SP-10, (2) blasted pre-rusted steel to SP-10, and (3) blasted pre-rusted steel to SP-10 + cleaned with the salt removal chemical. The purpose of this study is to compare the coating performance on these three types of surface preparations. Three types of tests were conducted; rust creepage, cathodic disbondment and water immersion tests. Three different coating systems for atmospheric service and three different coating systems for immersion service were used in this study. The test results indicate that a small amount of residual salts have a detrimental impact on coating performance.
