High Quality Super Duplex Steel S32750 | S32760 Pipes & Tubes

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Super Duplex Stainless Steel Chemical Composition Comparison
S32750 vs S32760 – Key Differences Highlighted
S32750 Super Duplex
UNS S32750
Fe
Iron (Base) Balance (~62%)
Cr
Chromium 24-26%
Ni
Nickel 6-8%
Mo
Molybdenum 3-4%
N
Nitrogen 0.24-0.32%
C
Carbon ≤0.03%
Mn
Manganese ≤1.2%
Higher nitrogen content: 0.24-0.32% N (Better pitting resistance)
S32760 Super Duplex
UNS S32760
Fe
Iron (Base) Balance (~61%)
Cr
Chromium 24-26%
Ni
Nickel 6-8%
Mo
Molybdenum 3-4%
N
Nitrogen 0.2-0.3%
Cu
Copper 0.5-1.0%
C
Carbon ≤0.03%
Copper addition: 0.5-1.0% Cu (Improved corrosion resistance in sulfuric acid)

What is Duplex Stainless Steel S32750 & S32760?

Duplex Stainless Steel S32750 and S32760, also known as Super Duplex grades, are high-alloy duplex stainless steels designed for exceptional performance in highly corrosive and demanding environments. They combine superior mechanical strength with excellent resistance to pitting, crevice corrosion, and stress corrosion cracking, making them ideal for marine, chemical processing, oil & gas, and desalination industries.

Super Duplex S32750

Chromium (Cr)

24.0 – 26.0%

Nickel (Ni)

6.0 – 8.0%

Molybdenum (Mo)

3.0 – 5.0%

Copper (Cu)

0.5 – 1.0%

Tungsten (W)

0.5 – 1.0%

Carbon (C) Max

0.03%

Manganese (Mn) Max

1.2%

Silicon (Si) Max

0.8%

Phosphorus (P) Max

0.035%

Sulfur (S) Max

0.02%

Nitrogen (N)

0.24 – 0.32%

Iron (Fe)

Balance

Super Duplex S32760

Chromium (Cr)

24.0 – 26.0%

Nickel (Ni)

6.0 – 8.0%

Molybdenum (Mo)

3.0 – 4.0%

Copper (Cu)

0.5 – 1.0%

Tungsten (W)

0.5 – 1.0%

Carbon (C) Max

0.03%

Manganese (Mn) Max

1.0%

Silicon (Si) Max

1.0%

Phosphorus (P) Max

0.035%

Sulfur (S) Max

0.01%

Nitrogen (N)

0.20 – 0.30%

Iron (Fe)

Balance

Types of Duplex S32750 & S32760 Pipes & Tubes

Ratnadeep Steel & Engg. Co. specializes in manufacturing Duplex S32750 and S32760 seamless and welded pipes & tubes, offering unmatched corrosion resistance, strength, and durability for challenging applications in harsh environments.

Duplex S32750/S32760 Seamless Pipes & Tubes

Seamless pipes and tubes are produced from solid billets to provide superior mechanical strength and consistent performance. Their high resistance to chloride-induced stress corrosion cracking makes them suitable for subsea equipment, pressure vessels, and chemical processing systems operating under extreme conditions.

Duplex S32750/S32760 Welded Pipes & Tubes

Welded pipes and tubes are ideal for large-diameter applications requiring high corrosion resistance and mechanical stability. They are widely used in marine, desalination, and offshore platforms where reliability, weld integrity, and long service life are crucial factors.

Specification of Super Duplex Steel S32760/S32750 Seamless & Welded Pipes And Tubes

Specification Details
Super Duplex Steel Pipe Specification ASTM A790 / ASME SA790, ASTM A789 / ASME SA789
Grade UNS S32760, S32750
Size ½” NB – 24″ NB
Outer Diameter 6.0 – 630mm
Thickness Range 0.3mm – 50 mm, SCH 5, SCH10, SCH 40, SCH 80, SCH 80S, SCH 160, SCH XXS, SCH XS
Type Seamless / ERW / Welded / Fabricated Pipes
Form Round, Square, Rectangular, Oval, Hydraulic Etc
Length Single Random, Double Random & Required Length
End Plain End, Beveled End, Threaded
End Protection Plastic Caps
Delivery Condition Annealed and Pickled, Polished, Bright Annealed, Cold Drawn
Inspection, Test Reports Mill Test Certificates, EN 10204 3.1, Chemical Reports, Mechanical Reports, PMI Test Reports, Visual Inspection Reports, Third Party Inspection Reports, NABL Approved Lab Reports, Destructive Test Report, Non Destructive Test Reports
Packing Packed in Wooden Boxes, Plastic Bags, Steel Strips Bundled, or as per Customers Requests
Specials Sizes and Specifications other than above can be manufactured on request

Super Duplex Steel S32760/S32750 Pipe Dimensions & Weight Chart

OD (mm) WT (mm) NPS (dn) Schedule Weight (kg/m)
21.34 2.77 1/2″ 40S 1.29
21.34 3.73 1/2″ 80S 1.65
26.67 2.87 3/4″ 40S 1.71
26.67 3.91 3/4″ 80S 2.23
33.40 3.38 1″ 40S 2.54
33.40 4.55 1″ 80S 3.29
48.26 3.68 1.1/2″ 40S 4.11
48.26 5.08 1.1/2″ 80S 5.49
60.33 3.91 2″ 40S 5.52
60.33 5.54 2″ 80S 7.60
88.90 5.49 3″ 40S 11.47
88.90 7.62 3″ 80S 15.51
114.30 6.02 4″ 40S 16.27
114.30 8.56 4″ 80S 22.69
168.28 7.11 6″ 40S 28.63
168.28 10.97 6″ 80S 43.15

Super Duplex Steel S32760/S32750 Tube Size Chart

Wall Thickness (mm) Available Sizes (OD in mm)
1.0 – 2.0 6.0 – 25.4
1.5 – 3.0 25.4 – 50.8
2.0 – 4.0 50.8 – 76.2
2.5 – 5.0 76.2 – 101.6
3.0 – 6.0 101.6 – 152.4
4.0 – 8.0 152.4 – 219.1
5.0 – 10.0 219.1 – 323.9
6.0 – 12.0 323.9 – 406.4
8.0 – 15.0 406.4 – 508.0
10.0 – 20.0 508.0 – 630.0

Pressure Ratings for Super Duplex S32760/S32750 Tubing (PSIG)

OD (mm) WT 2.0mm WT 3.0mm WT 4.0mm WT 5.0mm WT 6.0mm WT 8.0mm WT 10.0mm
12.7 15,200 22,800 N/A N/A N/A N/A N/A
25.4 7,600 11,400 15,200 N/A N/A N/A N/A
38.1 5,067 7,600 10,133 12,667 N/A N/A N/A
50.8 3,800 5,700 7,600 9,500 11,400 N/A N/A
76.2 2,533 3,800 5,067 6,333 7,600 10,133 N/A
101.6 1,900 2,850 3,800 4,750 5,700 7,600 9,500
152.4 1,267 1,900 2,533 3,167 3,800 5,067 6,333

Chemical Composition of Super Duplex Steel S32760/S32750 Pipes and Tubes

Element S32760 (%) S32750 (%)
Carbon (C) 0.03 max 0.03 max
Manganese (Mn) 1.00 max 1.20 max
Phosphorus (P) 0.03 max 0.035 max
Sulfur (S) 0.01 max 0.02 max
Silicon (Si) 1.00 max 0.80 max
Chromium (Cr) 24.0 – 26.0 24.0 – 26.0
Nickel (Ni) 6.0 – 8.0 6.0 – 8.0
Molybdenum (Mo) 3.0 – 4.0 3.0 – 5.0
Nitrogen (N) 0.20 – 0.30 0.24 – 0.32
Copper (Cu) 0.50 – 1.00 0.50 max
Tungsten (W) 0.50 – 1.00
Iron (Fe) Balance Balance

Mechanical Properties of Super Duplex Steel S32760/S32750 Pipes and Tubes

Grade Tensile Strength min (MPa) Yield Strength (0.2% Offset) min (MPa) Elongation (% in 2″) min Hardness max
S32760 750 550 25 Rockwell C (32)
Brinell (310)
S32750 800 550 25 Rockwell C (32)
Brinell (310)

Physical Properties of Super Duplex Steel S32760/S32750 Pipes and Tubes

Grade Density (kg/m³) Elastic Modulus (GPa) Mean Coefficient of Thermal Expansion (μm/m°C) Thermal Conductivity (W/m.K) Specific Heat 0-100°C (J/kg.K) Electrical Resistivity (nΩ.m)
S32760/S32750 7800 200 13.0 (0-100°C)
13.5 (0-200°C)
14.0 (0-300°C)
19.0 (at 100°C)
23.0 (at 300°C)
460 850

Equivalent Grades for Super Duplex Steel S32760/S32750 Pipes and Tubes

STANDARD WERKSTOFF NR. UNS EN AFNOR BS
S32760 1.4501 S32760 X2CrNiMoCuWN25-7-4 Z3CNWD25-07-04 318S13
S32750 1.4410 S32750 X2CrNiMoN25-7-4 Z3CNWD25-07-04Az 318S17

💡 Practical Difference in Use

Use S32750 when: maximum pitting resistance and higher strength are required in chloride environments. → Example: offshore oil & gas systems, seawater cooling systems, chemical process equipment.

Use S32760 when: enhanced corrosion resistance in sulfuric acid environments is needed along with chloride resistance. → Example: chemical processing with sulfuric acid, flue gas desulfurization systems, pulp and paper digesters.

Uses of Super Duplex S32750/S32760 Stainless Steel Pipes

The uses are defined by its exceptional strength, superior corrosion resistance, and excellent performance in aggressive environments. Pipes are used in critical applications where reliability is paramount.

  • Handling Aggressive Corrosive Media: Super duplex pipes excel in transporting highly corrosive substances including seawater, chlorides, acids, and chemical process streams where standard stainless steels would fail.
  • High-Pressure and High-Temperature Applications: With yield strength nearly double that of standard austenitic grades, these pipes are ideal for high-pressure systems and elevated temperature service.
  • Critical Process Systems: Used in systems where failure is not an option, providing long-term reliability in the most demanding industrial environments.

When to Choose S32750 vs. S32760?

This is a critical decision for engineers. Both are super duplex grades but have different alloy compositions that make them suitable for specific corrosive environments.

Choose S32750 when:

  • Maximum chloride pitting resistance is required
  • Higher nitrogen content for better structural stability
  • Applications in seawater and high-chloride environments
  • Standard super duplex performance is sufficient
  • Cost-effective super duplex solution

Choose S32760 when:

  • Enhanced resistance to reducing acids like sulfuric acid
  • Copper content provides better resistance to sulfuric acid
  • Tungsten addition improves overall corrosion resistance
  • More versatile in mixed acid environments
  • Applications with both chloride and acid exposure

Key Performance Differences: S32750 vs S32760

S32750 (Standard Super Duplex)

  • PREN: 40-43
  • Key Alloys: Cr 25%, Ni 7%, Mo 4%, N 0.3%
  • Strength: 550 MPa yield strength
  • Best For: Seawater, chloride environments
  • Cost: More economical super duplex
  • Limitations: Less effective in sulfuric acid

S32760 (Enhanced Super Duplex)

  • PREN: 40-43
  • Key Alloys: Cr 25%, Ni 7%, Mo 3.5%, Cu 0.7%, W 0.7%
  • Strength: 550 MPa yield strength
  • Best For: Mixed acid/chloride environments
  • Cost: Premium super duplex
  • Advantages: Better sulfuric acid resistance

Industries That Use Super Duplex S32750/S32760 Stainless Steel Pipes

Super duplex pipes are specified in industries where extreme corrosion resistance and high strength are required simultaneously. Here are the primary applications:

Offshore Oil and Gas Industry

This is one of the largest applications for super duplex pipes due to the harsh marine environment.

Uses

Subsea pipelines, risers, process piping, seawater cooling systems, firewater systems, and hydraulic lines.

Material Choice

S32750: Standard offshore applications, seawater systems
S32760: Systems with H₂S and CO₂ presence, more corrosive well fluids

Chemical and Petrochemical Processing

For handling highly corrosive chemicals where standard stainless steels are inadequate.

Uses

Reactor piping, heat exchanger tubes, acid transport lines, and process equipment in aggressive chemical environments.

Material Choice

S32750: Chloride-rich processes, organic chemicals
S32760: Sulfuric acid plants, mixed acid environments, phosphoric acid

Desalination and Water Treatment

Critical for handling seawater and brine in desalination plants.

Uses

Seawater intake lines, high-pressure RO membranes, brine handling systems, and chemical dosing lines.

Material Choice

S32750: Standard seawater applications, RO systems
S32760: Plants with acid cleaning cycles, aggressive brine conditions

Power Generation

Used in both conventional and nuclear power plants for critical systems.

Uses

Flue gas desulfurization systems, condenser tubes, cooling water systems, and feedwater lines.

Material Choice

S32750: Seawater cooling, general FGD applications
S32760: Aggressive FGD environments, high-chloride cooling water

Pulp and Paper Industry

For the most aggressive chemical environments in paper processing.

Uses

Digester piping, bleach plant equipment, chemical recovery systems, and black liquor lines.

Material Choice

S32750: Chlorine dioxide bleaching, general digesters
S32760: Sulfuric acid digesters, aggressive chemical recovery

Marine and Shipbuilding

Critical for vessels operating in corrosive seawater environments.

Uses

Seawater piping systems, ballast systems, hydraulic systems, and exhaust scrubber systems.

Material Choice

S32750: Standard marine applications, ballast systems
S32760: Exhaust scrubbers, systems with acid exposure

Mining and Mineral Processing

For handling aggressive slurries and processing chemicals.

Uses

Slurry transport lines, acid leaching systems, tailings pipelines, and processing equipment.

Material Choice

S32750: General mineral processing, moderate acids
S32760: Sulfuric acid leaching, aggressive chemical processing

Pharmaceutical and Fine Chemicals

For critical processes where contamination cannot be tolerated.

Uses

High-purity process lines, CIP systems, reactor vessels, and utility systems in aggressive chemical synthesis.

Material Choice

S32750: High-purity water systems, general chemical synthesis
S32760: Sulfuric acid-based processes, aggressive organic synthesis

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