Application characteristics of 304 and 316 stainless steel

Stainless steel provides a clean and crisp surface with low maintenance costs. 304 stainless steel is the most commonly used stainless steel in the world, mainly due to its excellent corrosion resistance and value. It contains 16 to 24 percent chromium and up to 35 percent nickel, along with 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% chromium and 8% nickel. 304 can withstand corrosion from most oxidizing acids. Durability makes 304 easy to sterilize, making it ideal for kitchen and food applications. In buildings, decorations and site furnishings are also common.

304 stainless steel does have one disadvantage: it is susceptible to corrosion from chloride solutions or saline environments such as the coast. Chloride ions can create localized areas of corrosion, called pitting, that can diffuse beneath the protective chromium barrier to damage internal structures. Solutions as low as 25 ppm sodium chloride may start to have a corrosive effect.

Grade 316 is the second most common form of stainless steel. It has nearly the same physical and mechanical properties as 304 stainless steel and contains a similar material composition. The key difference is that 316 stainless steel contains about 223% molybdenum. This addition increases corrosion resistance, especially to chlorides and other industrial solvents.

316 stainless steel is commonly used in many industrial applications involving chemical processing, as well as in high salt environments such as coastal areas and outdoor areas where deicing salt is commonly used. 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% molybdenum. They offer better chloride resistance, but this heavy resistance is only necessary in industrial or high-concentration exposure conditions.

Both 304 and 316 stainless steels (as well as other 300 series grades) use nickel to maintain their austenitic composition at lower temperatures. Austenitic steels ensure a diverse balance of strength, machinability, and corrosion resistance, making them ideal for outdoor architectural features, surgical instruments, and food processing equipment.

A large number of stainless steels (especially 316 stainless steel) produced today can be found in products related to the food and beverage industry. Stainless steel is commonly used in commercial kitchens and food processing plants because it serves a variety of needs: it can be easily formed and fabricated into the shapes needed to produce a variety of equipment and machinery, such as cooking stations, fume hoods, storage tanks and hopper.

It is available in a wide range of decorative and polished finishes. It can withstand the shock and wear conditions found in a kitchen or food processing plant. It can be easily cleaned and can withstand repeated washes with chemicals and cleaning agents used to meet public health requirements. It does not react to alkalis and acids in milk, cooked food, vegetables and food additives.