S31803 vs 316L vs S32750: Differences

When selecting stainless steel materials for oil & gas, chemical processing, marine, or pressure piping systems, choosing the wrong grade can lead to premature corrosion, excessive maintenance costs, or over-specification.
Among the most commonly compared grades, 316L, S31803 (Duplex 2205), and S32750 (Super Duplex 2507) differ significantly in mechanical strength, corrosion resistance, and total lifecycle cost.

This technical knowledge page explains the key differences to help engineers and procurement teams make the right material choice.

 

S31803 vs 316L vs S32750:  Material 

Grade	Stainless Steel Type	Microstructure
316L	Austenitic	Fully austenitic
S31803	Duplex	~50% ferrite + 50% austenite
S32750	Super Duplex	Optimized duplex with higher alloy content

 

S31803 vs 316L vs S32750:  Chemical Composition and Corrosion Resistance

Grade	Key Alloying Elements	PREN*
316L	16–18% Cr, 10–12% Ni, 2–2.5% Mo	~24–26
S31803	21–23% Cr, 4.5–6.5% Ni, 2.5–3.5% Mo, N	~34–36
S32750	24–26% Cr, 6–8% Ni, 3–5% Mo, N	≥40

 

 S31803 vs 316L vs S32750:  Mechanical Properties 

Grade	Yield Strength (0.2%)	Tensile Strength
316L	~205 MPa	~515 MPa
S31803	≥450 MPa	620–880 MPa
S32750	≥550 MPa	800–1000 MPa

 

S31803 vs 316L vs S32750:  Corrosion Performance in Service Environments

Environment	316L	S31803	S32750
Chloride-bearing fluids	Limited	Very good	Excellent
Stress corrosion cracking	Susceptible	Highly resistant	Extremely resistant
Seawater piping	Restricted	Suitable (moderate temp)	Ideal
Acidic / chemical media	Moderate	Very good	Excellent

 

S31803 vs 316L vs S32750: Temperature Limitations

Grade	Recommended Continuous Service Temperature
316L	Up to ~400°C
S31803	~280–300°C
S32750	~250–280°C

 

S31803 vs 316L vs S32750:  Cost and Lifecycle Value

Grade	Relative Material Cost	Lifecycle Cost Efficiency
316L	Low	Moderate in mild environments
S31803	Medium	High in corrosive/pressure service
S32750	High	Best for extreme environments

 

 

S31803 vs 316L vs S32750: Applications

316L: Food processing, general chemical equipment, architectural use

S31803 (Duplex 2205): Oil & gas pipelines, heat exchangers, pressure vessels, desalination systems

S32750 (Super Duplex 2507): Offshore platforms, subsea piping, seawater injection systems

 

S31803 vs. 316L vs. S32750: How to choose?

The differences between S31803, 316L, And S32750 Stainless Steel lie in their Microstructure, Alloy Content, Strength, And Corrosion Resistance.For most industrial piping and pressure applications, S31803 Offers The Best Cost-To-Performance Ratio, while S32750 Is Reserved For The Most Aggressive Environments and 316L Remains Suitable For Mild Service Conditions.

If you have a need for any of the above products, please feel free to place an order. GNEE has a large inventory of best-selling products for you to choose from. These materials can be processed into various practical product forms, including plates, coils, tubes, bars, and wires. For detailed chemical composition information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.