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. It offers exceptionally high strength and outstanding corrosion resistance, particularly against chloride-induced stress corrosion cracking and pitting, making it a premier material for the most demanding offshore, chemical, 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

Its enhanced properties stem from high levels of chromium, molybdenum, and nitrogen.

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.

Very High Strength: Its duplex structure provides extremely high yield and tensile strength, enabling lighter 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.

 

Primary Applications:

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

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

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

Pulp & Paper Industry: Digesters and bleaching equipment.

 

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, molybdenum, and nitrogen, giving it a much higher PREN value (typically >40 vs. ~34 for 2205). This translates to superior corrosion resistance, especially in more aggressive environments like hot seawater or concentrated chlorides. It also offers higher mechanical strength across all temperature ranges.

 

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 in the weld metal and heat-affected zone (HAZ). Key practices include using over-alloyed filler metals (e.g., 25.9.4.L), strict control of heat input to avoid excessive ferrite formation or precipitation of brittle intermetallic phases, and ensuring adequate shielding gas (typically Ar + 30% N2) to maintain nitrogen levels. Post-weld cooling rates must be controlled, and the material should not be held in the critical temperature range (approx. 600-1000°C) for extended periods.

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, and bar forms for the most challenging corrosive and high-pressure applications. We provide full material traceability and certifications to ensure performance. If you have any requirements, please feel free to contact us.