Application of 2205 and 2507 in Marine Valves

2205 and 2507 are two types of duplex stainless steel that are widely used in marine valves (such as butterfly valves, gate valves, and check valves), particularly in environments where excellent corrosion resistance is required. Below is a comparison of their applications and key characteristics in marine valve usage:

I. Comparison of Basic Material Properties

Property	2205 (UNS S31803/S32205)	2507 (UNS S32750)
Type	Duplex Stainless Steel	Super Duplex Stainless Steel
Corrosion Resistance	Excellent, suitable for most marine environments	Superior, suitable for extreme marine and chemical environments
Pitting/Crevice Resistance	Good	Excellent
Chloride Stress Corrosion Resistance	Strong	Very strong
Yield Strength	Higher than austenitic stainless steel (e.g., 316L)	Even higher
Operating Temperature Range	-50℃ to +300℃	-50℃ to +250℃ (recommended)
Cost	Moderate	High

II. Specific Applications in Marine Valves

1. Applications of 2205:

Seawater piping systems: Valves used in ballast water and cooling water systems

Desalination systems: Butterfly and gate valves

Liquid transportation systems on oil tankers and cargo vessels

Auxiliary systems in ships with moderate corrosion exposure, such as wastewater treatment systems

Cost-effective option for general-purpose marine valves

2. Applications of 2507:

Critical valves in high-corrosion, high-pressure environments such as deep-sea operation vessels and subsea equipment

LNG carriers and chemical tankers with extremely high corrosion resistance requirements

Shipboard systems exposed to high concentrations of chlorides or acidic gases (e.g., H₂S)

Ideal for scenarios requiring long-term, maintenance-free operation or extended service life

III. Material Selection Recommendations

Application Requirement	Recommended Material
General seawater corrosion with cost-effectiveness priority	2205
Extreme corrosion (high chloride, high temperature, high pressure)	2507
Good weldability and high mechanical strength needed	2205 preferred
High safety margin and sufficient project budget	2507

In the marine valve industry, 2205 offers a cost-effective and corrosion-resistant solution suitable for wide application. 2507, on the other hand, delivers higher safety and durability in extremely harsh environments.