Why use 316 over 304?

Stainless steel grades 316 and 304 are both widely used and versatile, but they have distinct characteristics that make one more suitable than the other depending on the specific application. Here are some reasons why you might choose to use stainless steel 316 over 304:

1. Corrosion Resistance: Stainless steel 316 offers superior corrosion resistance compared to 304, particularly in aggressive and corrosive environments containing chlorides, acids, and saltwater. This makes 316 more suitable for marine applications, coastal structures, and environments with exposure to chloride-rich substances.

2. Pitting and Crevice Corrosion: 316 stainless steel has a higher chromium and molybdenum content than 304, which provides enhanced resistance to pitting and crevice corrosion. This makes it a better choice for applications where these types of localized corrosion are a concern.

3. Chemical Resistance: 316 stainless steel's increased molybdenum content contributes to its improved chemical resistance, making it more resistant to certain acids and chemicals compared to 304.

4. High Temperature Performance: The higher nickel and molybdenum content in 316 stainless steel contribute to its better performance at elevated temperatures. It can withstand higher temperatures without losing its mechanical properties as quickly as 304.

5. Biocompatibility: Due to its corrosion resistance and higher purity, 316 stainless steel is often used in medical and pharmaceutical applications where biocompatibility and resistance to corrosion from bodily fluids are important.

6. Weldability: Both 304 and 316 stainless steels are easily weldable, but 316L (a variant of 316) is preferred for applications requiring extensive welding. The lower carbon content in 316L reduces the risk of sensitization and intergranular corrosion after welding.

7. Hygiene and Food Processing: 316 stainless steel is often preferred in food processing equipment due to its enhanced corrosion resistance and ease of cleaning.

It's important to note that while 316 stainless steel offers advantages in specific areas, it is generally more expensive than 304 due to its higher alloy content. The choice between 316 and 304 stainless steel depends on factors such as the intended environment, the level of corrosion resistance needed, cost considerations, and any industry standards that must be met.