What is 1.4480 Stainless Steel?

1.4480 stainless steel, commonly known as 32760 or UNS S32760, is a super duplex stainless steel that offers an exceptional combination of high strength, outstanding corrosion resistance, and excellent weldability. With its balanced ferritic-austenitic microstructure enhanced by the addition of tungsten and copper, it provides superior resistance to pitting, crevice corrosion, and stress corrosion cracking in aggressive chloride environments. This makes it an ideal choice for the most demanding offshore, chemical processing, and subsea applications.

 

This premium super duplex grade is standardized under key international systems.

Standard	Equivalent Grade
EN (Europe)	1.4480
ASTM/AISI (USA)	32760, UNS S32760
Common Name	Super Duplex 32760, Zeron 100

Its superior performance is achieved through a high, balanced alloy content including tungsten and copper for enhanced properties.

Element	C	Si	Mn	P	S	Cr	Ni	Mo	N	W	Cu
Content (%)	≤ 0.03	≤ 1.0	≤ 1.0	≤ 0.03	≤ 0.01	24.0 - 26.0	6.0 - 8.0	3.0 - 4.0	0.20 - 0.30	0.50 - 1.00	0.50 - 1.00

It provides extreme strength and toughness, even in aggressive conditions.

Property	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HB)	Impact (J)
Typical Value	≥ 550 MPa	750 - 1000 MPa	≥ 25%	≤ 300	≥ 45 (-40°C)

 

Key Characteristics and Applications of 1.4480 / 32760

Unmatched Corrosion Resistance: Possesses an exceptionally high Pitting Resistance Equivalent Number (PREN > 40), offering best-in-class resistance to pitting, crevice corrosion, and stress corrosion cracking in hot, chloride-laden environments. The tungsten addition further enhances pitting resistance at elevated temperatures.

Extremely High Strength: Delivers yield strength approximately double that of standard austenitic steels, enabling significant weight and cost savings in pressure vessels and structural components.

Enhanced Weldability: The balanced composition, including tungsten and copper, promotes a stable microstructure in welds, making it more forgiving to weld than some other super duplex grades with similar corrosion resistance.

Excellent Sour Service Resistance: Outstanding performance in H₂S-containing environments, making it ideal for oil and gas applications meeting NACE MR0175/ISO 15156 requirements.

 

Primary Applications:

Subsea & Offshore: Christmas trees, manifolds, flowlines, risers, and umbilicals in deepwater oil & gas production.

Chemical & Process: Reactors, columns, heat exchangers, and piping handling aggressive mixtures of acids, chlorides, and other corrosive media.

Pollution Control: FGD scrubbers, absorber towers, and critical ductwork in power plant desulfurization systems.

Pulp & Paper: High-pressure and high-temperature digesters and bleaching equipment.

Marine Engineering: Propeller shafts, seawater pumps, and valve systems.

Desalination: High-pressure piping and evaporator systems.

 

How does 32760 (1.4480) differ from Super Duplex 2507 (1.4410)?
While both are super duplex grades, 32760 contains additional alloying elements-tungsten (W) and copper (Cu)-that 2507 does not. Tungsten further enhances pitting and crevice corrosion resistance, particularly at elevated temperatures, and improves the stability of the microstructure during welding by retarding the formation of detrimental intermetallic phases. Copper enhances resistance to reducing acids like sulfuric acid. This gives 32760 a performance edge in the most complex and severe corrosive environments, especially those involving both chlorides and acids, or where higher operating temperatures are encountered. It also offers improved toughness at low temperatures and better resistance to sulfide stress cracking in sour service.

 

What makes welding 32760 different from welding standard duplex steels?
Welding 32760 follows similar principles (controlling heat input, using over-alloyed filler) but benefits from its enhanced composition. The tungsten content helps retard the formation of detrimental intermetallic phases (sigma, chi) in the heat-affected zone (HAZ), providing a wider "processing window" and reducing the risk of embrittlement. Recommended heat input is typically 0.5-2.0 kJ/mm, with interpass temperature below 150°C. Matching filler metals (e.g., 32760 type or Zeron 100X) are available, or over-alloyed nickel-based fillers may be used for highest corrosion resistance. It still requires careful procedure qualification but is generally considered to have better weldability than other super duplex alloys of similar corrosion resistance.

 

What industry standards and certifications apply to 32760?
32760 is approved for use under numerous international standards and by major certification bodies. It meets the requirements of NACE MR0175/ISO 15156 for sour service applications in oil and gas. It is approved for pressure vessel manufacture under ASME Boiler and Pressure Vessel Code (Section VIII, Division 1) and for piping under ASME B31.3. It also meets the requirements of NORSOK M-630 for offshore applications. Material is typically supplied with EN 10204 3.1 certification and can be provided with additional third-party inspections by major classification societies (DNV, ABS, Lloyd's, BV) for marine and offshore applications.

 

Looking for a Reliable Supplier of 1.4480 / 32760 Stainless Steel?
GNEE Steel supplies the premium super duplex grade 32760 (1.4480/UNS S32760) for the most critical and corrosive applications. We provide plate, pipe, fittings, bar, and forging forms with full traceability and comprehensive certifications (EN 10204 3.1, NACE, etc.). If you have any requirements, please feel free to contact us.