From the smallest pin to the largest skyscraper, stainless steel is an essential part of modern life.
Stainless steel’s strength, resistance to corrosion and low maintenance make it the ideal material for a wide range of applications. It also has a long life cycle and is 100% recyclable.
A wide spectrum of industries rely on stainless steel including construction, automotive and more. For many applications it’s simply the most effective solution.
Is it really stainless? No.
Stainless steel is a family of materials that gets its handle from corrosion- and oxidation-resistant properties that protect it from rust and unsightly blotches. Generally, the various steels are a mixture of iron and at least 10.5 percent chromium. When the latter chemical element is exposed to oxygen and moisture , it produces a thin oxide film that coats the product. This self-repairing feature of stainless steel ensures the object always looks smooth and shiny.
Stainless steel stains less easily than other iron-based metals, but it’s not literally “stainless”. Just like standard steel, stainless can get marked up by fingerprints and grease, develop discoloration, and eventually rust. The difference is resilience. Stainless steel can withstand much more time and abuse before showing signs of wear.
The two most common stainless steel grades are 304 and 316. The key difference is the addition of molybdenum, an alloy which drastically enhances corrosion resistance, especially for more saline or chloride-exposed environments. 316 stainless steel contains molybdenum, but 304 doesn't.
For outdoor furnishings like rails and bollards, stainless steel is an ideal corrosion-resistant material, but it will only withstand long-term exposure if the grade is appropriate for its environment. 304 is an economical and practical choice for most environments, but it doesn’t have the chloride resistance of 316. The slightly higher price point of 316 is well worth it in areas with high chloride exposure, especially the coast and heavily salted roadways. Each application for stainless steel has its own unique demands, and needs a stainless steel that’s up to the task.
304 Stainless Steel
304 stainless steel is the most common form of stainless steel used around the world, largely due to its excellent corrosion resistance and value. It contains between 16 and 24 percent chromium and up to 35 percent nickel, as well as small amounts of carbon and manganese.
The most common form of 304 stainless steel is 18-8, or 18/8, stainless steel, which contains 18 percent chromium and 8 percent nickel.
304 can withstand corrosion from most oxidizing acids. That durability makes 304 easy to sanitize, and therefore ideal for kitchen and food applications. It is also common in buildings, décor, and site furnishings.
304 stainless steel does have one weakness: it is susceptible to corrosion from chloride solutions, or from saline environments like the coast. Chloride ions can create localized areas of corrosion, called "pitting," which can spread beneath protective chromium barriers to compromise internal structures. Solutions with as little as 25 ppm of sodium chloride can begin to have a corrosive effect.
316 Stainless Steel
316 grade is the second-most common form of stainless steel. It has almost the same physical and mechanical properties as 304 stainless steel, and contains a similar material make-up. The key difference is that 316 stainless steel incorporates about 2 to 3 percent molybdenum. The addition increases corrosion resistance, particularly against chlorides and other industrial solvents.
316 stainless steel is commonly used in many industrial applications involving processing chemicals, as well as high-saline environments such as coastal regions and outdoor areas where de-icing salts are common. Due to its non-reactive qualities, 316 stainless steel is also used in the manufacture of medical surgical instruments.
Alternative 300-series grades can contain up to 7 percent molybdenum. They provide even better chloride resistance, but such heavy-duty resistance is only necessary in industrial or high concentration exposure conditions.
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