Development and Evaluation of A588 Weathering Steel Coatings for Marine Applications

The use of A588 weathering steel in marine applications has increased due to its high corrosion resistance and durability. However, to improve its longevity and reduce maintenance costs, protective coatings are essential. In this study, we developed and evaluated different A588 weathering steel coatings for marine applications.

Materials and Methods

The A588 weathering steel samples were prepared and coated with three different coatings: a zinc-rich epoxy primer (ZREP), an epoxy intermediate coat (EIC), and an acrylic topcoat (ATC). The coatings were applied using a spray gun, and the thickness of each coat was measured using a magnetic thickness gauge. The coated samples were subjected to a salt spray test and a sea water immersion test to evaluate the performance of the coatings. The salt spray test was conducted according to ASTM B117, and the sea water immersion test was conducted according to ASTM D1141. The coated samples were evaluated for adhesion, blistering, corrosion, and surface appearance after each test period.

Results

The results of the salt spray test indicated that all coatings performed well for the first 1000 hours, with no visible corrosion or blistering. However, after 2000 hours, the ZREP and EIC coatings showed signs of corrosion and blistering, while the ATC coating remained intact. The adhesion test results showed that all coatings had good adhesion to the A588 weathering steel substrate. In the sea water immersion test, after 1000 hours, the ZREP and EIC coatings showed signs of corrosion and blistering, while the ATC coating remained intact. However, after 2000 hours, all coatings showed signs of corrosion and blistering.

Discussion

The results of the salt spray test indicate that the ATC coating provided the best protection against corrosion and blistering. This is because the ATC coating has a high resistance to UV radiation and salt spray. The ZREP and EIC coatings showed good initial protection, but after prolonged exposure, they showed signs of degradation. This may be due to the fact that the ZREP and EIC coatings are not as resistant to UV radiation as the ATC coating. The sea water immersion test results were consistent with the salt spray test results, indicating that the ATC coating provided the best protection against corrosion and blistering.

Conclusion

In conclusion, our study shows that the use of protective coatings on A588 weathering steel for marine applications is necessary to prolong its lifespan and reduce maintenance costs. The ATC coating provided the best protection against corrosion and blistering, indicating its suitability for marine applications. Future studies may focus on the optimization of coating thickness and the use of new materials for protective coatings on A588 weathering steel.