Stainless steel 304# and 316# are the most popular types of stainless for railing systems. Railing systems made from each of these two types offer different strengths and weaknesses. Understanding your options and which applications are suited for each is essential when specifying a new steel railing.
304-grade stainless is also known as “18-8 stainless,” referring to its composition of 18% chromium and 8% nickel. This type of stainless steel is often used in indoor applications. Finishes from satin (240 grit) to finer finishes, including mirror finish, are available. In addition to looking good, these finishes serve a practical purpose as well: satin finishes, for example, are easy to maintain while mirror finishes offer ultimate corrosion resistance.
In addition to interior applications, 304-grade stainless also performs well in outdoor environments where conditions are not overly harsh or extreme, or where the railing system is protected from the environment.
Maintaining a 304-grade stainless steel railing system is easier than carbon steel systems. Simply wipe regularly with soap and water to maintain its appearance. While 304-grade stainless costs more than carbon steel, it requires far less maintenance and upkeep. 304-grade is ideal for indoor applications where good looks and low maintenance are desired.
Regardless of grade, stainless steel resists corrosion when its chromium content interacts with the air around it. It oxidizes into a thin, extremely stable layer of protective atoms that stop further oxidation, or rust, from occurring. If the material is scratched or nicked in any way, the chromium content quickly reoxidizes – in essence, repairing itself before corrosion can set in.
This does not mean stainless steel is impervious to rust and corrosion. When used in highly chlorinated areas such as near swimming pools or in a coastal location where it is exposed to saltwater in the air, the chromium cannot always create that protective layer as quickly.
316-grade stainless tackles harsh environments with a slightly higher nickel content and two percent molybdenum to further strengthen its corrosion resistance. In turn, these added alloys make 316-grade the ideal choice for outdoor applications or where harsh environmental factors require a more durable material. As with 304-grade stainless, no protective coating is required and a variety of finishes are available to create the right look for any application.
316-grade steel is the most popular choice for outdoor and industrial applications due to its proven performance in harsh conditions. While no material is completely impervious to corrosion, 316-grade stainless can withstand years of abuse if properly maintained.