Alloy 25CRS Super Duplex

Corrosion Resistant Alloys > Alloys > Alloy 25CRS Super Duplex

Super Duplex 25 Chrome / 2507

UNS S32750 • UNS S32760 • UNS S39274

COMMON TRADE NAMES: 25CRS, 25CRW, Super Duplex 2507, SM25CRW®, VM® 25S, SAF® 2507, Zeron® 100, Z-100, Chromium-25

Super Duplex 25 Chrome, or 2507, are cold-hardened duplex stainless steels defined by having a Pitting Resistance Equivalent Number (PREN) greater than 40. Compared to 22 Chrome / 2205 Duplex, these alloys contain higher levels of chromium, molybdenum, and nitrogen, which increases their resistance to localized pitting and crevice corrosion. In the annealed condition, these alloys have more than twice the strength of conventional austenitic stainless steels and superior corrosion resistance in many environments.

Characteristics of 25CRS

Corrosion graphic

Corrosion Resistance

Super Duplex 25 Chrome has excellent resistance to chloride-induced pitting corrosion and stress corrosion cracking. It is suitable for service environments high in chlorides, such as seawater cooling, salt evaporation, and desalination. It is also suitable for mild hydrogen sulfide, dilute reducing and organic acids, and moderate to high levels of oxidizing acids.
Service Temperature

Elevated Temperature Resistance

Super Duplex 25 Chrome may experience embrittlement if exposed to temperatures exceeding 480°F (249°C) for extended periods.
Mechanical Properties

Mechanical Properties

Super Duplex 25 Chrome has more than twice the strength of conventional austenitic stainless steels in the annealed condition. It can also be provided in the cold-worked condition with yield strength exceeding 160 ksi. It maintains good toughness at temperatures down to -50°F (-10°C).


Super Duplex 25 Chrome is used in environments containing high levels of chlorides or dissolved oxygen, such as oil and gas wells, seawater cooling, salt evaporation, desalination, geothermal wells, pulp and paper production, and chemical processing. In upstream oil and gas, Super 25 Chrome is commonly used as tubing, casing, or liners in mildly sour wells containing the presence of high chlorides with partial pressure of H2S ≤ 3 psi. CRA offers specialty Super Duplex 25 Chrome seamless pipe & tube for use in multiple industries and applications, including:

  • As tubing, casing, and liners in mildly sour oil and gas wells containing the presence of high chlorides with partial pressure of H2S ≤ 3 psi

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Chemical Composition

UNS S32750≤ 0.0324 - 266 - 8BAL≤ 1.2≤ 0.83 - 4-≤ 0.035≤ 0.02-0.24 - 0.32
UNS S32760≤ 0.0324 - 266 - 8BAL≤ 1≤ 13 - 40.5 - 1≤ 0.03≤ 0.010.5 - 10.2 - 0.3
UNS S39274≤ 0.0324 - 266 - 8BAL≤ 1≤ 0.82.5 - 3.50.2 - 0.8≤ 0.03≤ 0.021.5 - 2.50.24 - 0.32

Specified Mechanical Properties

API 5CRA / ISO 13680 Group 2 Category 25-7-4

NACE MR0175/ISO 15156
H2S Sour Service Limits
80801051102028Table A.24
H2S ≤ 3.0 psi,
Temp ≤ 450°F
1101101401251236Table A.24
H2S ≤ 3.0 psi,
Cl ≤ 120g/l
140140160145938140 Grade not recommended for sour service
*Non-standard mechanical properties and grades are made available upon agreement.

Per ASTM A789 / A790
Tensile StrengthYield StrengthElongationHardness
minimum, ksiminimum, ksiminimum, %HRC
*Higher strength properties can be provided in the cold hardened condition.

Typical Physical Properties

Thermal ExpansionX10-6/°F-
Elastic Modulus103 ksi29.
Poisson Ratio-0.3---
Thermal ConductivityBtu-in/h·ft2·°F96108120132
Specific HeatBtu/lb·°F0.
Yield Strengthksi80655850
Tensile Strengthksi1161019588

Manufacturing Process

Steel MakingElectric Arc Furnace followed by Vacuum Oxygen Decarburization (VOD) or Argon Oxygen Decarburization (AOD).
Pipe MakingConventional Seamless Cold Finished Pipe and Tube Manufacturing Processes.
Heat TreatmentCannot be hardened by heat treatment. May be provided in the annealed or cold hardened condition.

Product Availability

MIN OD: 2-1/16″ (2.0625″)
MAX OD: 10-3/4″ (10.750”)
LENGTHS: Up to 70′ (840”)

END FINISH: Plain end, Premium threads, & API threads

Standard & Non-Standard Sizes Available.

Manufactured Material Available as Quickly as 1 Week.

Non-Standard Mill Quantities Accommodated