Introduction to 316 SS pipe flange features and applications

Compared with 304 stainless steel, 316 stainless steel contains additional nickel and molybdenum, and in China it is commonly known as 18Cr-12Ni-2.5Mo steel. Typically, 316 stainless steel has 2.0–3.0% more molybdenum than 304, which significantly improves its resistance to corrosion and high temperatures.

Key Properties of 316 Stainless Steel Flange

Enhanced corrosion resistance

Performs better than 304 stainless steel in chloride-rich and harsh chemical environments.

Atmospheric & high-temperature resistance

Withstands aggressive atmospheres and elevated temperatures without losing strength.

Excellent work-hardening & non-magnetic

Provides reliable performance during processing and in demanding applications.

Resistance to Sulfuric Acid

Sulfuric acid is one of the most widely used industrial chemicals.

Type 304 stainless steel: Resistant only to 3% sulfuric acid at room temperature.

Type 316 stainless steel: Resistant to 3% sulfuric acid up to 50 °C, and to 20% sulfuric acid at room temperature.

Type 904L and Alloy 20: Suitable for higher concentrations above room temperature.

This makes 304 unsuitable for sulfuric acid applications, while 316 and higher grades provide much better protection.

Applications of 316L Stainless Steel Flanges

316L stainless steel flanges are widely known as “marine grade” stainless steel, offering superior corrosion resistance compared to 304. However, they are not fully resistant to warm seawater.

They are particularly suitable for equipment exposed to acids and aggressive chemicals, including:

Sulfuric acid

Phosphoric acid

Formic acid

Acetic acid

Common Uses:

Marine and coastal environments

Pumping systems and pipeline connections

Chemical processing equipment

Food and beverage industry

Irrigation and water treatment systems

Stainless steel pipeline networks

Conclusion

With its extra molybdenum content, 316 stainless steel delivers better corrosion resistance, high-temperature strength, and chemical durability than 304 stainless steel. For industries dealing with marine environments, chemical media, or acidic conditions, 316L stainless steel flanges are the preferred choice, ensuring safety, reliability, and long service life.