B06 · Seawater Desalination

Selection and 4 Part Lists of Stainless Steel for Desalination Applications

We have organized four parts in stainless steel used in desalination: commonly used 2507 / 2205 / 316L, with thickness ranging from 2-15 mm.

Stainless water tanks, pumps, and large diameter pipes for water treatment
Water treatment and drainage: Tanks, pumps, and large-diameter piping (diagram; actual selection based on medium, temperature, and drawings)

List of parts and materials for four sections

Section / PartRecommended gradeSpecification / ThicknessSurfaceMain Failure ModesReference Standards
RO High-Pressure Pump/Energy Recovery Device2507(S32750/1.4410)Casting/Forging/TubeSurface/PassivationHigh Pressure Sea Water 60–80 bar + Cl⁻ + Cavitation CorrosionASTM A240;EN 10217-7;NORSOK M-650
Sea Water Feed Pipe/Fittings2507/2205Pipe Wall 2–15 mmPassivationHigh Chloride Sea Water + High Speed Scrubbing + Crevice CorrosionASTM A240/A789;EN 10217-7
RO Membrane Shell/Filter316L/2205/25072–10mmPassivation / 2BHigh Pressure Sea Water Corrosion + Membrane ContaminationASTM A240;GB/T 3280
Dechlorinated Water Delivery Pipe304L/316L2–8mm2B / PassivationLow Chloride Product Water + External AtmosphereGB/T 3280
Select materialsShow usage conditionsMaterial selection tips

Variations based on media, temperature, and welding methods

  • The most common grades in this industry are 2507 (3), 2205 (2), and 316L (2) —— numbers in parentheses indicate the number of affected areas, useful for quoting and material ordering.
  • Common sources of corrosion are chloride ions and salts (pitting, crevice corrosion) (4/4 hits).
  • Thickness range: 2–15 mm (thin plates used for forming parts, consider springback and deep drawing cracking; thick plates used for welded structures, consider heat input and sensitization).

Common issues

Which stainless steel is used most for seawater desalination?
By total number of occurrences, the top three are 2507 (3), 2205 (2), and 316L (2). Specific parts may require different grades depending on the medium and temperature.
What type of part is the most problematic?
Based on failure descriptions, typical issues are "RO high-pressure pump/energy recovery device": High pressure seawater 60–80 bar + Cl⁻ + cavitation corrosion. Recommended grade 2507 (S32750/1.4410), available in cast, forged, and tube forms. For this type of application, it's recommended to specify medium concentration, temperature, and cleaning methods during the design phase.
What thickness should I choose?
Thickness range in the list is 2–15 mm. For thin plates, consider forming and surface quality; for thick plates, welding and structural strength. Different manufacturers may have different values for the same part; review your drawing or operating conditions.

Related materials and adjacent industries

Applications4
Thickness2–15mm
Grades250
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