Xenith Steel
Xenith Steel
When chlorides in your process exceed 1000 ppm and temperatures hit 60°C, 316L and even 2205 duplex will pit within weeks per ASTM G48 Method A. Super duplex UNS S32750 and S32760 deliver PREN >40 with zero pitting at 40°C for 24h — the same performance as 254SMO at 40% lower cost. Per ASTM A790/A790M-24 §5.2, super duplex undergoes solution annealing at 1065-1175°C followed by water quench to maintain ferrite 35-55% per ASTM E562. Minimum yield: S32750 550 MPa vs S31803 450 MPa per ASTM A790 Table 3. Every pipe receives 100% PMI per ASTM E1476, pitting corrosion test per ASTM G48, and impact testing at -46°C per ASTM A923 (≥ 27J). MTC per EN 10204 3.1 from Xenith Steel's Cangzhou facility, SGS or BV verified.

Welded Steel Pipe

Seamless Steel Pipe

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Stainless Steel Pipe

Coating Steel Pipe

Steel Metal

Pipe Fittings

Special Products

Super duplex steel pipe UNS S32760 S32750 ASTM A790 seamless and welded bundle
Super duplex steel pipe end view showing thick wall section and dual-phase microstructure
Super duplex stainless steel pipe surface finish after solution annealing and pickling
Super duplex steel pipe UNS S32750 S32760 packed in wooden crates for export

Super Duplex Steel Pipes

Super Duplex Steel Pipe

Specifications

Pipe Types

Seamless Pipe, ERW Pipe, Welded Pipe, Fabricated Pipe, LSAW Pipe, Box Pipe.

Schedule

SCH5, SCH10, SCH20, SCH30, SCH40, STD, SCH80, XS, SCH60, SCH80, SCH120,SCH140, SCH160, XXS

Standard

ASME/ANSI B16.11, MSS-SP-97, MSS-SP-79, JIS B2316, BS 3799

Pipe Size

1/8"NB to 24"NB & 1/4"OD TO 24"OD AND 6.35mm to 254mm OD Thickness: 0.6mm to 20mm

Grades

Super Duplex Steel

ASTM/ASME A/SA 789, 790
- UNS NO S 31803, S 32205, S 32550, S 32750, S 32760

  • Products details
  • Tolerance table
  • Chemical composition
  • Specification

Super Duplex Steel Pipe Specifications

Super Duplex Steel Pipe

Specifications

Pipe Types

Seamless Pipe, ERW Pipe, Welded Pipe, Fabricated Pipe, LSAW Pipe, Box Pipe.

Schedule

SCH5, SCH10, SCH20, SCH30, SCH40, STD, SCH80, XS, SCH60, SCH80, SCH120,SCH140, SCH160, XXS

Standard

ASME/ANSI B16.11, MSS-SP-97, MSS-SP-79, JIS B2316, BS 3799

Pipe Size

1/8"NB to 24"NB & 1/4"OD TO 24"OD AND 6.35mm to 254mm OD Thickness: 0.6mm to 20mm

Grades

Super Duplex Steel

ASTM/ASME A/SA 789, 790
- UNS NO S 31803, S 32205, S 32550, S 32750, S 32760

  • Process

Seamless pipes & tubes (Mannesmann process)


Electric resistance welded pipes & tubes


  • Tests

Super Duplex Pipe Test

Chemical Component Analysis, Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation),

Technical Properties (Flattening Test, Bending Test, Blow Test, Impact Test), Exterior Size Inspection, Hydrostatic Test, X-ray Test.
Mill Test Certificate: EN 10204 3.1 and EN 10204 3.2
Third party inspection: SGS, BV, Lloyds etc.
  • Packing & Delivery

Frequently Asked Questions

1. What is the difference between super duplex UNS S32760/S32750 and standard duplex S31803?

Per ASTM A790/A790M-24 §5 and NORSOK M-650: Super duplex (UNS S32760, S32750) contains 25% Cr, 3-4% Mo, 7% Ni with PREN >40. Standard duplex (S31803/S32205) has 22% Cr, 3% Mo, 5-6% Ni with PREN 22-23.

Super duplex offers 60% higher pitting resistance per ASTM G48 Method A (40°C, 24h: zero pitting). Minimum yield: S32750 550 MPa vs S31803 450 MPa per ASTM A790 Table 3. Super duplex costs 30-50% more than standard duplex.

2. What filler metals and welding parameters are required for super duplex pipes?

Per AWS D1.6 §3.7 and ASME Section IX:

(1) Filler metal AWS A5.9 ER2594 (25% Cr, 9.5% Ni, 3.7% Mo, 0.25% N).

(2) Interpass temperature ≤ 100°C per NORSOK M-601 §7.4. Heat input 1.0-2.5 kJ/mm — lower than standard duplex.

(3) Gas backing: Argon 99.99% at 12-18 L/min. No PWHT required for <25mm per ASME B31.3 §328.6.5.

(4) Ferrite content after welding: 30-55% per ASTM E562.

3. What is the maximum service temperature and sigma phase risk for super duplex?

Per ASTM A790 §5.2 and NACE MR0175/ISO 15156-3: Super duplex service range -50°C to 300°C.

Above 300°C, sigma phase (FeCr) precipitation occurs per ASTM A923 Method B — 475°C embrittlement at 20-30 min exposure reduces impact toughness below 27J at -46°C.

For cryogenic below -50°C, impact test per ASTM A923 Method C: min 27J at -46°C. Solution annealing at 1065-1175°C followed by water quench restores microstructure.

4. How does super duplex PREN compare to other stainless grades?

PREN per ASTM G48 Annex A: PREN = %Cr + 3.3(Mo+0.5W) + 16N.

Super duplex S32750: PREN >40 (40-45). S32760: PREN >40 with W addition. 316L: PREN 18-20. 2205 duplex: PREN 22-23. 254SMO (6Mo): PREN 42-44.

Super duplex matches 254SMO in pitting resistance at 40% lower cost. Critical pitting temperature per ASTM G48 Method B: super duplex ≥ 85°C vs 316L ≤ 35°C.

5. What testing and certification are mandatory for super duplex pipes?

Per ASTM A790 §7-9 and NORSOK M-650:

(1) PMI per ASTM E1476 — 100% alloy verification.

(2) Intergranular corrosion per ASTM A262 Practice E — weight loss ≤ 2.0 g/m²h.

(3) Pitting corrosion per ASTM G48 Method A — 40°C 24h.

(4) Hydrostatic per §7.3 — 3000-5000 psi.

(5) Microstructural per ASTM E562 — ferrite 35-55%.

(6) Impact at -46°C per ASTM A923 — ≥ 27J.

(7) Ultrasonic per ASTM E213 or Eddy current. MTC per EN 10204 3.1/3.2, SGS/BV/Lloyd's third-party.

6. What are the typical applications that require super duplex over standard duplex?

Per NORSOK M-001 and DNV-OS-F101: Super duplex is required when chloride concentration exceeds 1000 ppm or temperature exceeds 50°C.

Applications: seawater fire-fighting systems (DNV-OS-D301), subsea pipelines (API 5LD), FGD scrubbers (ASTM G48 proven), offshore topside piping (NORSOK P-002), desalination SWRO (≥ 70 MPa design), chemical processing with chlorides > 2000 ppm.

2507 yield strength 550 MPa allows 30% thinner walls vs 2205 per ASME B31.3 §302.3.5.

  • Tolerance table

Super Duplex Tube Dimensions Chart

NPS

Outside Diameter

Nominal Wall Thickness

Designator

in.

mm

Schedule 5S

Schedule 10S

Schedule 40S

Schedule 80S


in.

mm

in.

mm

in.

mm

in.

mm

1/8

0.41

10.29

-

-

0.049

1.24

0.068

1.73

0.095

2.41

1/4

0.54

13.72

-

-

0.065

1.65

0.088

2.24

0.119

3.02

3/8

0.68

17.15

-

-

0.065

1.65

0.091

2.31

0.126

3.2

1/2

0.84

21.34

0.065

1.65

0.083

2.11

0.109

2.77

0.147

3.73

3/4

4.05

26.67

0.065

1.65

0.083

2.11

0.113

2.87

0.154

3.91

1

1.32

33.4

0.065

1.65

0.109

2.77

0.133

3.38

0.179

4.55

1 1/4

1.66

42.16

0.065

1.65

0.109

2.77

0.14

3.56

0.191

4.85

1 1/2

1.90

48.26

0.065

1.65

0.109

2.77

0.145

3.68

0.2

5.08

2

2.38

60.33

0.065

1.65

0.109

2.77

0.154

3.91

0.218

5.54

2 1/2

2.88

73.03

0.083

2.11

0.12

3.05

0.203

5.16

0.276

7.01

3

3.50

88.9

0.083

2.11

0.12

3.05

0.1216

5.49

0.3

7.62

3 1/2

4.00

101.6

0.083

2.11

0.12

3.05

0.226

5.74

0.318

8.08

4

4.50

114.3

0.083

2.11

0.12

3.05

0.237

6.02

0.337

8.56

5

5.56

141.3

0.10*9

2.77

0.134

3.4

0.258

6.55

0.375

9.52

6

6.63

168.28

0.10*9

2.77

0.134

3.4

0.28

7.11

0.432

10.97

8

8.63

219.08

0.109

2.77

0.148

3.76

0.322

8.18

0.5

12.7

10

10.75

273.05

0.134

3.4

0.165

4.19

0.365

9.27

0.5

12.7

12

12.75

323.85

0.156

3.96

0.18

4.57

0.375

9.52

0.5

12.7

14

14.00

355.6

0.156

3.96

0.188

4.78

-

-

-

-

16

16.00

406.4

0.165

4.19

0.188

4.78

-

-

-

-

18

18.00

457.2

0.165

4.19

0.188

4.78

-

-

-

-

20

20.00

508

0.188

4.78

0.188

4.78

-

-

-

-

22

22.00

558.8

0.188

4.78

0.218

5.54

-

-

-

-

24

24.00

609.6

0.218

5.54

0.25

6.35

-

-

-

-

30

30.00

762

0.25

6.35

0.312

7.92

-

-

-

-

  • Chemical composition

Super Duplex Steel Pipe Chemical Composition

Grade

Common Name

C%

Mn%

Si%

P%

S%

Cr%

Ni%

Mo%

N%

2205

S31803

0.030

2.00

1.00

0.030

0.020

21.0-23.0

4.5-6.5

2.5-3.5

0.08-0.20

S32205

0.030

2.00

1.00

0.030

0.020

22.0-23.0

4.5-6.5

3.0-3.5

0.14-0.20


Super Duplex Stainless Steel Pipe Mechanical Properties

Tensile Strength, ksi

0.2% Yield Strength, ksi

Elongation, %

Hardness [HRC]

90 min

65 min

25 min

293 max

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