18-8 vs. 304 Stainless Steel
If you have a project that needs fasteners, you have several options to choose from. Screws come in a wide range of sizes, threads, heads and tips. Before you start to narrow your choices down, however, you need to know what type of screw to buy. The 18-8 stainless and 304 stainless screws are some of the most popular fasteners on the market, but they have a few differences that can affect the long-term performance of your finished project.
Getting to Know 18-8 Stainless Steel vs. 304 Stainless Steel
Screws made from 18-8 and 304 stainless steel are both made using stainless steel, but their compositions vary. The differences between 18-8 stainless steel vs. 304 stainless steel may seem minor, but they can have a measurable impact.
18-8 Stainless Steel
This iron alloy earns its name due to its makeup. It is produced using approximate quantities of 18% chromium and 8% nickel, and it covers a family of fittings that include 302, 304, 305 and 384 stainless screws. These fittings all use 18-8 stainless steel as a base before they are modified with additional alloys. Screws made from 18-8 stainless steel are non-magnetic and have excellent resistance to rust and corrosion.
304 Stainless Steel
This stainless steel (SS) type is austenitic and the most widely used alloy in the AISI (American Iron and Steel Institute) 300 series. It has the chromium and nickel content of 18-8 stainless steel but contains a maximum of 0.08% carbon as well. It also shares many similar properties to 18-8 stainless steel, including resistance to corrosion and oxidation. The addition of carbon provides this alloy with extra strength and hardness that sets it apart from other alloys.
The Applications of 18-8 SS vs. 304 SS
With different chemical structures, fasteners made with 18-8 vs. 304 stainless steel offer distinct advantages. Before you make your purchase, consider the ideal applications of 18-8 vs. 304 stainless steel:
- 18-8 stainless steel: The chemical composition of 18-8 grade stainless steel makes it suitable across many industries. Fasteners made with this alloy will perform well in chemical, high-temperature and high-moisture environments. These screws will react to chlorides, like salt, and are, therefore, not recommended for use in marine applications.
- 304 stainless steel: 304 stainless steel is an alloy with a slightly different composition. This alloy provides some of the best corrosion resistance in the 300 series. The extra hardness from the carbon, combined with the benefits of chromium and nickel, makes these screws a favorite for HVAC use and construction applications like deck, gutter or roofing installation.
