Can stainless steel be used in seawater environments?
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I’ve been hearing two conflicting opinions, which is confusing; I hope everyone can help answer this: 1. Stainless steel is suitable for seawater environments ； 2. Sea water contains chloride ions, which can destroy the oxide film and thus cause corrosion. How should we understand these two expressions? Also, in an chlorine-containing environment, it is said that 317 is much better than 316 due to its higher Mo content, but doesn’t it still cause damage to the oxide film?
Stainless steel cannot be used in equipment for handling seawater, as seawater causes severe corrosion of stainless steel. Most equipment used for treating seawater uses containers made of titanium alloys... just my humble opinion! For reference only.
Yes, it does. It’s just that people generally think stainless steel is not resistant to seawater or chloride ion corrosion, which is why there is little knowledge about it. The following types of steel are highly resistant to seawater corrosion; they are generally of the high-chromium, high-nickel type. High-strength maraging stainless steels resistant to seawater corrosion: 00Cr16Ni6Mo3Cu1N; high-strength stainless steels resistant to seawater corrosion: 00Cr26Ni6Mo4CuTiAl. The seawater-resistant stainless steel Yus270 (20Cr–18Ni–6Mo–0.2N) is also available. In addition, Japan has several stainless steels that are highly resistant to seawater corrosion as well: SUS317J1, SUS317J4L, SUS317J5L. There are also some duplex steels such as SUS329J3L and SUS329J4L
At present, the vast majority of heat exchangers that use seawater as a cooling medium are made of titanium, and this has become an established practice
Chloride ions cause particularly severe corrosion of stainless steel
It is still a steel framework plastic composite pipe, which is pressure-resistant and corrosion-resistant, especially resistant to chloride ion corrosion; it has a long service life and is easy to install.
Nickel-based alloy steel is corrosion-resistant, but it is expensive. Our company is currently producing nickel-based alloy steel pipes as well as stainless steel seamless pipes