When many people pump seawater or saturated salt water, they are given priority to stainless steel pumps. They feel that stainless steel is durable and will not be repaired. However, they are found to be faster and the stainless steel pumps are seriously corroded.

In fact, seawater is a very complex multi-component aqueous solution. The main elements in seawater are Na ions, K ions, CL ions, SO4 ions, etc., and most of these contents are above 1 mg.

Various authoritative books have strict requirements on the corrosion of stainless steel in the CL ion environment: The content of CL ions should be less than 25ppm, otherwise stress corrosion, pitting corrosion and intergranular corrosion will occur. The content of CL ion in seawater is more than 1mg, far exceeding the content requirement for stainless steel corrosion. Therefore, under normal circumstances, stainless steel material is not recommended for seawater pumps.

If stainless steel material has been selected, it is recommended that appropriate inhibitors be added or replaced with plastic pumps if the process conditions permit. The use of plastic pumps for pumping seawater is not only very good against seawater corrosion but also reduces the cost of use.