Marine Grade Metals

Marine grade metals. Water-resistant metals. These terms are often thrown around in the world of manufacturing and construction, but what do they mean? If you’re starting on a project that will be exposed to the harsh conditions of the marine environment or any other situation involving water, it’s crucial to understand the definition of marine grade metals. Whether you’re designing a boat, building a dock, or constructing a structure near the water, choosing suitable materials is of utmost importance.

What is Marine Grade Metal?

When a metal is exposed to underwater or wet environments, marine grade metals may be necessary to prevent the material from failing under the conditions. Marine grade metals are specifically designed and manufactured to withstand the harsh conditions of the marine environment, such as saltwater exposure, humidity, and intense UV rays. Whether it’s a boat, yacht, or any other maritime application, these products need to be durable and reliable.

While other metals may be adequate for general use, they are unsuitable for marine applications due to their susceptibility to corrosion and degradation. For instance, regular steel can quickly corrode when exposed to saltwater, leading to structural weaknesses and decreased lifespan. Using standard materials for marine projects can result in frequent maintenance and repairs, ultimately costing more in the long run. When constructing or renovating structures in marine environments, opting for marine grade materials is essential to ensure longevity and minimize maintenance needs. By investing in the right materials, you can ensure the success and durability of your marine projects for years to come.

To be considered a marine grade metal, it must be able to resist the rust, degradation, and corrosive effects that are common in a water environment. To achieve this, special alloying elements like stainless steel, brass, and aluminum are added to these grades in order to defend against corrosion. They can withstand constant exposure to saltwater and remain durable over time.

Marine Grade Metals include:

• Carbon Steel and Alloy Steel
• Aluminum
• Stainless Steel
• Copper
• Bronze
• Brass
• Galvanized Steel

Carbon Steel and Alloy Steel

Most carbon steel is not well-suited for marine environments; however, there are several marine grade carbon steels available. AH36, DH36, and EH36 are all examples of commonly used marine grade carbon steels approved by the American Bureau of Shipping. These grades will have slightly more alloying elements, such as manganese and chromium, compared to their ASTM grade counterparts, which helps achieve higher strength and more corrosion resistance. There are also marine grades of alloy steel. Grades MD, ME, MF, MG, and others can provide the strength that normal alloy steel is known for and have also been approved by the American Bureau of Shipping for use in shipbuilding applications.

Applications: structural shipbuilding and other offshore structural applications

Aluminum

There are several different grades of aluminum that are suitable for marine conditions. Marine grade aluminum, for the most part, is limited to the 5XXX and 6XXX grades. Grade 5052 is an excellent marine grade aluminum for when formability is required. If strength is more of a concern, grade 5083 is a good alternative. 6061-T6 is an all-around popular marine grade aluminum. It has very good corrosion resistance and is precipitation hardened. These grades, for the most part, have additional chromium and manganese to help protect them from corrosive marine conditions.

Applications: structural shipbuilding, boat hulls, boat lifts, docks, and other offshore structural applications

Stainless Steel

All grades of stainless steel have some degree of corrosion resistance; however, there are several grades of stainless steel that are far more suitable for use in marine environments than others. Grade 316 is probably the most common marine grade stainless steel. It has more molybdenum than other austenitic stainless steels, which helps it resist pitting and other corrosive effects of salt water. Grade 304 is another marine grade stainless steel, although it has less molybdenum than grade 316, making it a less desirable choice in chlorine-rich environments.

Applications: marine fittings, marine fasteners, and marine structures

Copper

Several copper-nickel alloys are suitable for marine applications. Examples include C70600, which contains nickel and manganese to help resist corrosion. C71500, which has a chemical composition similar to that of alloy C70600, can also withstand marine conditions.

Applications: water lines, desalination equipment, marine fittings, fasteners, valves, and pumps

Bronze

Silicon marine grade bronze alloys like C65500 and aluminum marine grade bronze alloys like C95400 are developed to better withstand marine environments than other bronze alloys. Alternatively, the phosphor bronze alloy C51000 is another common grade suitable for marine applications.

Applications: propellers, propeller shafts, pipes, and marine fasteners

Brass

Marine brass, or naval brass as it is commonly referred to, comes in a variety of alloys. Alloys C46200 and C46400 add zinc and tin, allowing the brass alloy to resist corrosion in wet or even underwater applications. Alloys C48200 and C48500 are similar, except they have more lead in their chemical composition.

Applications: pipes, marine fittings, marine fasteners, and pumps

Galvanized Steel

Galvanized steel can be suitable for some marine environments. Zinc coatings typically fare better under cool temperatures in fresh water than warm temperatures in salt water. Salt water contains chlorides, which cause zinc to corrode rapidly. A high temperature will enable the corrosion to occur more rapidly.

Applications: marine structures

Whether you’re working on a shipbuilding project, offshore platform, or coastal construction, selecting the right marine grade metal is crucial to the success and durability of your project. Metal Supermarkets offers a wide range of high-quality marine grade metals to meet your specific needs. Our knowledgeable staff can help you find the perfect material for your application, ensuring you get the best performance and value. Visit your local Metal Supermarkets store or contact us online to learn more about our marine grade metals.