Super Duplex 2507 Stainless Steel
Alloy 2507( UNS S32750 )is a super duplex stainless steel with 25% chromium, 4% molybdenum, and 7% nickel designed for demanding applications which require exceptional strength and corrosion resistance, such as chemical process, petrochemical, and seawater equipment. The steel has excellent resistance to chloride stress corrosion cracking, high thermal conductivity and a low coefficient of thermal expansion. The high chromium, molybdenum, and nitrogen levels provide excellent resistance to pitting, crevice, and general corrosion.
The impact strength is also high. Alloy 2507 is not recommended for applications which require long exposures to temperatures above 570°F because of the risk of a reduction in toughness.
Corrosion Resistance
The high chromium and molybdenum content of 2507 makes it extremely resistant to uniform corrosion by organic acids like formic and acetic acid. 2507 also provides excellent resistance to inorganic acids, especially those containing chlorides.
In dilute sulfuric acid contaminated with chloride ions, 2507 has better corrosion resistance than 904L, which is a highly alloyed austenitic steel grade specially designed to resist pure sulfuric acid.
The duplex structure of 2507 provides excellent resistance to chloride stress corrosion cracking (SCC). Because of its higher alloy content, 2507 is superior to 2205 in corrosion resistance and strength.
Chemical Analysis
C | Cr | Ni | Mo | N | Others |
0.020 | 25 | 7 | 4.0 | .27 | S=0.001 |
PREN = [Cr%] + 3.3 [Mo%] + 16 [N%] ≥ 40 |
Physical Properties
Density | lb/in3 | 0.28 |
Modulus of Elasticity | psi x 106 | 29 |
Coefficient of Thermal Expansion 68-212°F/°F | x10-6/°F | 7.2 |
Thermal Conductivity | Btu/h ft °F | 8.7 |
Heat Capacity | Btu/lb/°F | 0.12 |
Electrical Resistivity | W-in x 10-6 | 31.5 |
Mechanical Properties
Ultimate Tensile Strength, ksi | 116 min. |
0.2% Offset Yield Strength 0.2%, ksi | 80 min. |
0.1% Offset Yield Strength 0.2%, ksi | 91 min. |
Elongation in 2 inches, % | 15 min. |
Hardness Rockwell C | 32 max. |
Impact Energy, ft.-lbs. | 74 min. |
Applications:
1)Oil and gas industry equipment
2)Offshore platforms, heat exchangers, process and service water systems, fire-fighting systems, injection and ballast water systems
3)Chemical process industries, heat exchangers, vessels, and piping
4)Desalination plants, high pressure RO-plant and seawater piping
5)Mechanical and structural components, high strength, corrosion-resistant parts
6)Power industry FGD systems, utility and industrial scrubber systems, absorber towers, ducting, and piping