Since the 1980s, a range of duplex stainless steels (DSSs) has been developed that have higher alloy content, and therefore greater corrosion resistance and strength. The commonly used DSSs have good corrosion resistance in a wide range of environments and excellent resistance to stress corrosion cracking (SCC). Their high strength and hardness also gives them excellent resistance to both erosion corrosion and cavitation. There are also cast versions of many of the duplex compositions and these have seen extensive use for pumps, valves, and other equipment.
Ballast water carried by ships keeps them upright during loading and offloading operations and provides balance, stability, and trim during sailing. Because ballast water is loaded from the surrounding port or coastal waters, organisms in the ballast water sometimes establish populations resulting in biological invasions, which may have severe ecological or economic impacts. This standard is designed to test the effect of long-term accelerated exposure of treated water on coating systems.