Name: China Duplex Stainless Steel Plate 2507 2205 Manufacturers Suppliers Factory - Shenzhoutong Steel Pipe
Brand: Shenzhoutong
SKU: 299092747

Both materials are "duplex" alloys, meaning they have a mixed microstructure of approximately 50% austenite and 50% ferrite. This dual-phase structure provides roughly twice the yield strength of standard austenitic stainless steels (like 304/316) combined with excellent corrosion resistance

Duplex 2205 (Standard Duplex): UNS S32205 (or S31803). It is the workhorse grade for moderate corrosion environments .

Super Duplex 2507 (Super Duplex): UNS S32750. It is a high-alloy grade designed for extreme corrosive conditions, specifically where chlorides and high temperatures are present

Property	Duplex 2205 (UNS S32205)	Super Duplex 2507 (UNS S32750)
Specifications (Plate)	ASTM A240 / ASME SA-240	ASTM A240 / ASME SA-240
Classification	Standard Duplex	Super Duplex
Chromium (Cr)	21.0 – 23.0 %	24.0 – 26.0 %
Nickel (Ni)	4.5 – 6.5 %	6.0 – 8.0 %
Molybdenum (Mo)	2.5 – 3.5 %	3.0 – 5.0 %
Nitrogen (N)	0.08 – 0.20 %	0.24 – 0.32 %
PREN	~34 – 36	≥ 40 (typically 42-43)

Mechanical Strength

One of the main selling points for these grades is their high mechanical strength, which allows for lighter weight designs (thinner wall thickness) compared to austenitic steels.

Yield Strength (Min): 2205 offers 450 MPa (65 ksi), while 2507 offers 550 MPa (80 ksi).

Tensile Strength (Min): 2205 offers 620 MPa (90 ksi); 2507 offers 795 MPa (116 ksi).

Hardness: 2507 is slightly harder (max 310 HBW) compared to 2205 (max 293 HBW).

Temperature Limit: Both grades have a maximum continuous service temperature limit of approximately 300°C (572°F) . Exceeding this can lead to embrittlement (475°C embrittlement or sigma phase formation).

Application Scenarios (Selling Points)

Choose Duplex 2205 when:

The environment involves seawater at ambient temperatures (non-contact side or open systems) .

Chloride levels are moderate (<50,000 ppm) and temperatures are below 60°C .

The requirement is for high strength combined with good weldability and a lower budget.

Applications: Chemical tankers, structural components, heat exchangers (shell side), and topside piping

Choose Super Duplex 2507 when:

The application involves direct seawater service at elevated temperatures (>20°C) or with crevice conditions .

High chloride concentrations (>50,000 ppm) combined with temperatures above 80°C .

Subsea equipment (manifolds, flowlines), desalination plants (high-pressure piping), and sour gas environments (NACE MR0175 Zone 1) .

Weight reduction is critical (e.g., deepwater risers), as the higher strength allows for thinner wall sections.

Fabrication & Welding (Key Considerations for Buyers)

Buyers often worry about fabrication costs. You must highlight that 2507 requires more stringent welding controls than 2205.

Filler Metal: 2205 uses ER2209; 2507 uses ER2594.

Heat Input: Both require controlled heat input (0.5–2.5 kJ/mm) and a maximum interpass temperature of 150°C. However, 2507 is more sensitive to intermetallic phase precipitation (sigma phase). If the heat input is too high, the corrosion resistance (PREN) in the Heat Affected Zone (HAZ) drops significantly.

Shielding Gas: Both require a mix of Argon + 2% Nitrogen to maintain the correct austenite-ferrite balance in the weld .

Post-Weld Heat Treatment (PWHT): Not generally required for either grade, which saves on processing costs.

Products Description

2507 (UNS S32750) is a super duplex stainless steel designed for applications which require exceptional strength and corrosion resistance. 2507 is a 25% chromium, 4% molybdenum, and 7% nickel alloy resulting in excellent resistance to chloride pitting and crevice corrosion attack.

Usage of 2507 should be limited to applications below 600° F (316° C). Extended exposure to elevated temperatures can reduce its toughness and corrosion resistance

》High resistance to chloride stress corrosion cracking

》Strong resistance to chloride pitting and crevice corrosion

》High strength

》Strong general corrosion resistance

》Suggested for applications up to 600° F

》Good weldability / workability

》Resistant to pitting and crevice corrosion in seawater

Specifications:

UNS: S32750

W. NR.: 1.4410

ASTM: A 240, A 276, A 479, A 182

ASME: SA 240, SA 276, SA 479, SA 182