What is the Difference Between 304 and 316 Stainless Steel?

Out of over 60 different grades of stainless steel, the most often used in the electrical industry are 304 stainless steel and 316 stainless steel. Aesthetically, there is no difference between the two; in fact, the only way to differentiate between them is to test them chemically. The main difference between 304 and 316 stainless steel is 316 SS has the addition of molybdenum.

The differing chemical makeups of 304 SS and 316 SS influence how each performs in a certain environment. Requirements for one grade of stainless over the other are often dependent on the application or environment; therefore, it is important to understand them both.

What is Type 304 Stainless Steel & in What Applications is it Used?

Type 304 SS is the most widely used grade of stainless steel and is considered the standard “18/8” stainless. It offers mechanical strength, corrosion, and oxidation resistance at a more economical price point.

Type 304 SS is used in a wide range of applications and industries to provide basic resistance to corrosion.

A few of these industries include:

• Food & Beverage Processing Facilities (milder environments such as dairy and vegetable processing)
• Oil & Gas (drilling & processing)
• Water & Sewage Treatment
• Heavy Industrial & Chemical Processing (depending on the chemical present, 304 SS may be sufficient)
  

Type 304 SS Chemical Composition¹

Type 316 SS is more corrosion resistant than 304 SS because of its higher nickel content and the addition of molybdenum (2-3%) as an alloying element. The addition of molybdenum enhances the metal’s resistance to crevice corrosion and pitting from chloride solutions. The overall combination of increased nickel, molybdenum and other minor alloying tweaks improves the resistance of 316 SS to stress corrosion cracking, creeping, chemicals, solvents, sulfuric acids, and extreme temperatures.

This makes 316 SS an ideal choice for electrical products subjected to industrial processing chemicals, ocean spray, or high-chloride environments.

Below are some of the industries that benefit from utilizing the higher grade of Type 316 SS:

• Food & Beverage Processing Facilities (breweries and facilites with more extreme environments such as ones processing meats, sauces, pickle liquors, etc.)
• Pharamaceutical Industry
  
• Off-shore Oil & Gas (off-shore facilities exposed to coastal/salt-water environments)
• Pulp & Paper Mills
  
• Marine & Coastal Applications
  
• Heavy Industrial & Chemical Processing (harsher chemicals)
  

Type 316 SS Chemical Composition¹

At Gibson Stainless & Specialty Inc., we offer stainless steel rigid (heavywall) conduit and complementary stainless steel fittings. Our products are stocked in the higher grade of Type 316 SS and, in some products, Type 304 SS as well. For additional questions regarding grades of stainless steel or the use of Type 304 SS vs Type 316 SS in a specific application, please contact us today.