316L castings, seawater corrosion
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Sea water at 39 degrees Celsius has a chloride ion concentration of 18,800 mg/L and a pH value of 8–8.3. Pumps made of 316L cast material are used in such conditions; can they resist corrosion over a period of one month? What potential corrosion-related issues might arise? Is it possible for these pumps to resist corrosion or not? Are there any specific methods for calculating and determining this? Please, experts, share your insights
It is recommended to use plastic pumps, as they are cost-effective and offer better corrosion resistance than stainless steel. Polymer ones will work.
A metal pump has been selected, but the user suddenly needs to pump seawater, which is why this problem has arisen
Personally, I recommend following suggestion #2 and choosing a pump made of plastic – it is cost-effective and reliable, and can be used in the future as well. If you insist on using a stainless steel pump for seawater treatment for a month straight, be prepared to consider it scrap metal once it’s no longer useful. Because the seawater temperature is 39°, other parts of the pump may be corroded more severely than the pump casing
Let’s not talk about anything scary. According to API610, it’s possible to select materials based on data sheets and PID values; for pumps used on decks in some platforms, A-8+ and D-1 are used； Those submerged in seawater, such as seawater lift pumps, generally use Monel in accordance with the requirements of offshore oil operations
For dealing with seawater, 2507 super duplex steel is commonly used; 316L, to be honest, won’t hold up for long – probably only half a year to a year at most
The tolerance of 316L stainless steel to chloride ions is approximately 250 mg/L; at this concentration, 316L cannot resist corrosion. It is recommended to use 2205 or fluorinated-lined pumps.
If the temperature is in the 30s, it should be fine; at 40 degrees, corrosion becomes significant