There's a choppy sea. The sound of the water increased in volume to an unbearable roar. The waves battered the ship relentlessly, and the waves could be seen waving on the deck a long distance away. On the high seas, it's much like every other day. However, even in the absence of a storm, ships are continuously exposed to salt water or air, as well as seawater, salt water, or port water.
It goes without saying that not all materials are suitable for shipbuilding. In addition to many other materials, saltwater resistant aluminum is required in this application, and strict specifications must be followed. Do you know which aluminum alloy is best suited for your shipbuilding project's specific requirements?
What does it imply to be "seawater resistant" exactly?
It goes without saying that aluminum is utilized in shipbuilding primarily due to its low weight and excellent structural stability. Of course, you can anticipate that there would be a significant difference in overall weight and energy usage between using aluminum shipbuilding profiles and equivalent steel profiles when comparing the two materials. Particularly large marine vessels, such as cruise ships and cargo ships, should be avoided.
As previously said, saltwater resistance is needed for aluminum alloys, as previously stated. But what does this really imply in practice? Shipbuilding and marine engineering define saltwater resistance as the material characteristics that allow materials to be utilized as construction materials, to be welded, and to exhibit excellent corrosion behavior in seawater and in the presence of seawater in their environment. In this instance, the terms "seawater suitable" and "seawater resistant" are used by Germanischer Lloyd and DIN 81249-1. Bottom line: The alloy should not be subjected to any corrosion damage throughout its anticipated service life.
Which aluminum alloys are most suited for use in shipbuilding applications?
Pure aluminum has long been known for its corrosion resistance, although it has been utilized in industry in very small quantities. Because the necessary end product must be treated, pure aluminum is not appropriate for this use in most cases. As a result, other metals must be alloyed in order to accomplish machining and corrosion resistance at the same time. Aluminum gets its excellent corrosion resistance via the use of magnesium as the primary alloying element. Aluminum magnesium alloys (AlMg) are used in shipbuilding for a variety of reasons, including:
This kind of aluminum alloy is not only resistant to salt water and the maritime environment, but it is also lightweight. An additional factor that influences the shipbuilding industry is the interaction of aluminum alloy with other materials. The phrase "contact corrosion" are important. The majority of the time, aluminum seamless tubing, aluminum wire, aluminum plates, aluminum plates, aluminum rods, aluminum rods and Co. are joined together with other components and parts made of other materials on board by welding, brazing, tightening, riveting, or some other method of attachment. If the aluminum alloy comes into touch with other valuable metals in the structure, such as iron or copper, the entrance of moisture will result in the formation of the so-called contact element, which is an electrochemical reaction.
The electrolytic conductivity of water or moisture allows electrons to move from less costly metals to more expensive metals, as is the case at the connecting point between aluminum profiles and copper screws, for example. Corrosion appeared here and there within a few millimeters of each other in a very short amount of time, making it difficult to make lasting, secure connections.
