Human society has been working with metal alloys for thousands of years. In that time, we’ve learned a great deal and have made amazing advancements in our ability to manipulate a wide variety of metals and put them to use in pretty much every industry. Yet, even after all this time, there’s still a simple weakness that even high performing metal alloys have a great deal of trouble overcoming: water.
Water is one of the most prevalent substances on the planet, yet it is the bane of designers and engineers everywhere because of the corrosive impact it has on metal. Fortunately, stainless steel has been able to largely prevail over the negative effects of water with the development of some extremely durable and anti-corrosive alloys that can perform even in the toughest of environments.
If you need a sturdy, long-lasting solution for your application, the friendly, knowledgeable team at Clinton Aluminum can help. We are dedicated to helping our customers find just the right material for every job. Contact us today to learn more.
Stainless Steel Developers Had Water In Mind
Although iron is one of the earliest metals to be utilized by ancient civilizations, we actually have very few examples that have lasted until today. Museums of ancient history have many examples of millennia-old weapons, tools, and jewelry made from silver, gold, copper, and bronze, yet there are very few iron specimens. This is because iron, in its natural form, is so susceptible to corrosion when exposed to oxygen and water.
Civilization was forever altered when steel was discovered. By combining iron with carbon, the new steel alloys proved stronger and much more durable than iron. Steel was first utilized nearly 4,000 years ago, and quickly spread throughout the ancient world. As revolutionary as steel proved in many industries, it was still quite susceptible to corrosion, in particular in marine environments.
The corrosion problem was a primary concern for scientists over the centuries. Many different experiments looked at how to make steel more durable in extreme conditions, but despite all of the trial and error, the solution was not discovered until the late 19th century. In fact, the first patented alloy that could be considered stainless steel was referred to as a ‘Water Resistant’ alloy by its creators, John T. Woods and John Clark in 1872.
The first commonly accepted stainless steel was developed forty years later by Harry Brearley of Sheffield, England. He was working to develop a corrosion-resistant alloy for gun barrels, and in the process came up with the first martensitic stainless-steel alloy. It was sold under the “Staybrite” brand and the fact that one of its most famous applications was for the entrance canopy of the Savoy Hotel in London, which is subject to consistently rainy weather conditions, indicates how effective it was at withstanding corrosion.
Why Is Saltwater So Corrosive?
While dealing with any amount of water was hard enough for iron and traditional carbon steel, even some of the most durable metals, such as aluminum and stainless steel, can be susceptible to corrosion when exposed to saltwater. This is because the chemical makeup of seawater is particularly harmful to most metals.
Corrosion in saltwater is actually an electrochemical process that stems from the electrical potential of a metal when it comes into contact with seawater. Because of the constant movement of the waves, metals in a marine environment are exposed to a variety of anodic and acidic solutions that will begin interacting with the chemistry of the metal. This is especially true when saltwater seeps into hidden cracks or crevices.
The organic microorganisms found abundantly in the oceans also strongly influence the pH balance of the water. Marine structures or ocean-going vessels are in constant contact with sand and silt that can stimulate locally corrosive conditions. Sulphate-reducing bacteria can also lead to the buildup of hydrogen sulphide concentrations, another contributor to corrosion.
Which Stainless Steel Alloys Are Best For Marine Environments?
Certain alloys are particularly adept at resisting corrosion. While they tend to be more expensive, applications that are exposed to saltwater for long periods will greatly benefit from the increased durability these alloys provide. The most popular stainless-steel alloys for marine applications are 316/316L.
These austenitic stainless-steel alloys, thanks to the high amount of nickel and molybdenum, have much better corrosion resistant properties than the more popular 304. This is especially the case for pitting and crevice corrosion in seawater environments. These alloys also respond well to elevated temperatures and have excellent formability and weldability.
Some of the many applications that frequently rely on 316/316L stainless steel include the following:
- Food and beverage equipment
- Chemical processing equipment
- Fasteners and screens for the mining industry
- Laboratory equipment
- Rubber, plastics, and paper machines
- Pollution control equipment
- Structures in high pollution environments
- Boat and ship fittings and pump trim
- Heat exchangers
- Pharmaceutical applications
- Textile equipment
- Condensers and evaporators
- Jet engine parts
- Photography equipment
- Coastal architectural structures, railings, and trim.
While grade 316 is the most common grade, grade 316L is distinguished as being a low carbon version of 316, making it highly resistant to sensitization. Therefore, 316L is widely used in heavy gauge welded components. Other versions include Grade 316H, which has a higher carbon content, making it useful at elevated temperatures, and grade 316Ti.
Summary
Clinton Aluminum has a proven track record of success when it comes to supporting manufacturers in a wide variety of industries. We take tremendous pride in our ability to help clients succeed by providing the exact product to the exact requirements. Our experienced sales team of technical professionals have worked at Clinton for an average of 13 years. Without them, Clinton could not have grown to become the Midwest’s leading supplier of aluminum and stainless-steel products.
Clinton believes in service, value, and education. We do more than just sell a product. Our goal is to be a true partner to our customers. Contact one of our friendly and knowledgeable representatives today to learn more about what stainless steel alloy is right for your marine or water-based application.
