What is 1.4410 Stainless Steel?

1.4410 stainless steel, commonly known as Super Duplex 2507 or UNS S32750, is a super duplex stainless steel with a balanced ferritic-austenitic microstructure that offers exceptionally high strength and outstanding corrosion resistance. With its high chromium, molybdenum, and nitrogen content, it provides superior resistance to pitting, crevice corrosion, and stress corrosion cracking in aggressive chloride environments, making it the material of choice for the most demanding offshore, chemical processing, and desalination applications.

 

This high-performance super duplex grade is standardized under key international designations.

Standard	Equivalent Grade
EN (Europe)	1.4410
ASTM/AISI (USA)	2507, UNS S32750
JIS (Japan)	SUS329J4L
Common Name	Super Duplex 2507

Its enhanced properties stem from high levels of chromium, molybdenum, and nitrogen, with a typical PREN > 40.

Element	C	Si	Mn	P	S	Cr	Ni	Mo	N
Content (%)	≤ 0.03	≤ 0.80	≤ 1.2	≤ 0.035	≤ 0.02	24.0 - 26.0	6.0 - 8.0	3.0 - 5.0	0.24 - 0.32

It provides nearly double the yield strength of standard austenitic steels with excellent toughness.

Property	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HB)	Impact (J)
Typical Value	≥ 550 MPa	750 - 1000 MPa	≥ 25%	≤ 310	≥ 80 (20°C)

 

Key Characteristics and Applications of 1.4410 / Super Duplex 2507

Exceptional Corrosion Resistance: Possesses a very high Pitting Resistance Equivalent Number (PREN > 40), offering superb resistance to pitting, crevice corrosion, and stress corrosion cracking in aggressive chloride environments, including seawater and concentrated brines.

Very High Strength: Its duplex structure provides extremely high yield and tensile strength, enabling significant weight reduction and more cost-effective designs for pressure-containing parts.

Good Erosion and Wear Resistance: The ferritic phase contributes to good resistance against erosion-corrosion and abrasive wear, particularly important in high-velocity flow applications.

Excellent Fatigue Strength: Superior fatigue performance compared to austenitic grades, beneficial for dynamic loading applications.

 

Primary Applications:

Offshore & Marine: Subsea pipelines, Christmas trees, manifolds, flowlines, seawater cooling systems, propeller shafts, and riser systems.

Chemical Processing: Reactors, heat exchangers, columns, and piping for highly corrosive acids and chlorides.

Desalination & FGD Plants: High-pressure RO membranes, evaporator tubes, brine heater tubes, and scrubber systems.

Pulp & Paper Industry: Digesters, bleaching equipment, and handling systems for chloride-containing process streams.

Oil & Gas: Downhole tubing, process equipment, and topside piping in sour service environments.

Cargo Tanks: Chemical tankers and container vessels carrying corrosive cargoes.

 

How does Super Duplex 2507 (1.4410) differ from standard Duplex 2205 (1.4462)?
The main differences are in alloy content and resulting performance. 2507 contains significantly higher levels of chromium (25% vs. 22%), molybdenum (4% vs. 3%), and nitrogen (0.27% vs. 0.17%), giving it a much higher PREN (typically >40 vs. ~34 for 2205). This translates to superior corrosion resistance, especially in more aggressive environments like hot seawater (up to 60°C vs. 30°C for 2205) or concentrated chlorides. It also offers higher mechanical strength across all temperature ranges, with yield strength approximately 20% higher than 2205. 2507 is selected for the most severe corrosive conditions where 2205 would be inadequate.

 

What are the critical factors for welding Super Duplex 2507 stainless steel?
Welding 2507 requires stringent control to maintain the optimal 50/50 ferrite-austenite balance and prevent detrimental phase formation. Key practices include:

Using over-alloyed filler metals (e.g., 25.10.4.L type)

Strict control of heat input (0.5-1.5 kJ/mm recommended)

Ensuring adequate shielding gas (typically Ar + 25-30% N₂) to maintain nitrogen levels

Keeping interpass temperature below 100°C to avoid overheating

Controlling post-weld cooling rates to prevent brittle intermetallic phases (sigma, chi)

Avoiding prolonged exposure in the critical temperature range (600-1000°C)

Preheating is generally not required, and post-weld heat treatment is not recommended

 

What is the maximum service temperature for 2507 in chloride environments?
For continuous immersion in seawater or other chloride-containing environments, 2507 offers excellent performance up to approximately 60°C (140°F). Above this temperature, the risk of pitting and crevice corrosion increases, and more highly alloyed materials (such as super austenitic grades or nickel-based alloys) may be required. For non-immersed applications or where chlorides are not present, 2507 can be used at higher temperatures, but care must be taken to avoid prolonged exposure to temperatures above 300°C due to the risk of sigma phase embrittlement. For structural applications at elevated temperatures, the material retains good strength but corrosion resistance may be affected.

 

Looking for a Reliable Supplier of 1.4410 / Super Duplex 2507 Stainless Steel?
GNEE Steel supplies premium Super Duplex 2507 (1.4410) stainless steel in plate, pipe, fittings, bar, and forging forms for the most challenging corrosive and high-pressure applications. We provide full material traceability and certifications (EN 10204 3.1) to ensure performance, and offer comprehensive processing services including cutting, forming, and welding support. If you have any requirements, please feel free to contact us.