316L resists pitting corrosion significantly better than 304 in chloride environments, primarily due to its 2–3% molybdenum addition. Molybdenum enhances the passive film's stability against chloride attack and suppresses pit initiation. The Pitting Resistance Equivalent Number (PREN) quantifies this difference: 304L has a PREN of approximately 18.8, while 316L reaches about 24.2.
This gap translates directly into performance. In 6% FeCl₃ testing, the critical pitting temperature for 304L is around 15°C, whereas 316L maintains resistance up to approximately 25°C. For environments exceeding roughly 100 ppm chloride, 316L provides significantly better resistance to pitting and stress corrosion cracking. This makes 316L suitable for seawater cooling systems, brine handling, produced water, and coastal installations where 304 is not recommended. However, 316L has limits: in concentrated chlorides at elevated temperatures, even 316L may pit, and higher-alloy stainless steels or duplex grades become necessary.
Just like you, 70% customers choose long-term cooperation with BBN steel not only for our good product and service quality, good reputation in the international market, but also for our experienced one-stop raw material supply and further steel processing!
