Xenith Steel
Xenith Steel
Why choose duplex over super duplex, or 316L for that matter? The answer lies in PREN, chloride concentration, and budget per ASTM A790/A790M-24 and NORSOK M-001. 2205 (UNS S32205) delivers PREN 22-23 with 450 MPa min yield per ASTM A790 Table 3, enough for most petrochemical and marine environments. But when chlorides exceed 1000 ppm or temperatures reach 60°C, 2507 (UNS S32750) with PREN >40 and zero pitting per ASTM G48 Method A becomes the only choice — at 30-40% cost premium over 2205. All duplex pipes undergo solution annealing at 1040-1120°C per ASTM A790 §5.2 followed by water quenching, 100% PMI per ASTM E1476, and intergranular corrosion testing per ASTM A262 Practice E (weight loss ≤ 2.0 g/m²h). MTC per EN 10204 3.1 from Xenith Steel's Cangzhou facility, SGS-verified.

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Special Products

Duplex steel pipe 2205/2507 ASTM A790 seamless and welded bundle
Duplex steel pipe end view showing wall thickness and seamless construction
Duplex stainless steel pipe surface finish after solution annealing and pickling
Duplex steel pipe UNS S32205 and S32750 ready for shipment in steel crates

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

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
Tension Test, Flattening Test, Hardness Test, or Bend Test; Hydrostatic Test or nondestructive electric test.
  • Packing & Delivery



Frequently Asked Questions

1. What is the difference between 2205 and 2507 duplex stainless pipes?

Per ASTM A790/A790M-24 §5.2 and EN 10216-5: 2205 (UNS S32205) contains 22% Cr, 3% Mo, 5-6% Ni with PREN 22-23. Suitable for most corrosive environments.

2507 (UNS S32750) contains 25% Cr, 4% Mo, 7% Ni with PREN >40. Superior chloride resistance per ASTM G48 Method A at 40°C for 24h: 2507 shows zero pitting vs 2205 surface attack <10μm.

2507 costs 30-40% more than 2205. Selection depends on chloride concentration per ISO 15156-3 and operating temperature.

2. What are the key advantages of duplex stainless steel pipes?

Per ASTM A790:

(1) Corrosion resistance — 2-3x pitting resistance of 316L per ASTM G48.

(2) Strength — 2x yield strength (min 450 MPa for 2205 per §6, vs 170 MPa for 316L).

(3) Cost — less nickel (5-7% vs 10-14%) reduces raw material cost ~20-30%.

(4) Weldability — per ASME Section IX: no preheating needed for thickness <25mm; interpass ≤150°C.

(5) Fatigue — per ASTM E466: duplex outperforms austenitic by 40% in high-cycle (>10⁶) seawater conditions. Ideal for offshore, desalination, and chemical processing.

3. What is PREN and why is it important?

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

Guidelines per NACE: PREN >32 suitable for seawater service per ISO 21457; PREN >40 for aggressive chloride environments.

2205: PREN 22-23 — limited seawater. 2507: PREN >40 — excellent for offshore and FGD. 316L: PREN 18-20.

Higher PREN = better resistance to pitting and crevice corrosion in chloride environments per ASTM G48 Method A.

4. What testing do you provide for duplex stainless pipes?

Per ASTM A790 §7-9 and EN 10216-5:

(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, no pitting.

(4) Hydrostatic test per §7.3 — 3000-5000 psi hold ≥ 5s.

(5) Dimensional per ASTM A999 — OD ±0.13mm (≤25mm).

(6) Ultrasonic per ASTM E213 or Eddy current per ASTM E309. MTC per EN 10204 3.1.

5. What are the welding considerations for duplex pipes?

Per AWS D1.6 §3 and ASME Section IX:

(1) Filler — ER2209 for 2205, ER2509 for 2507 per AWS A5.9.

(2) Interpass — 150°C max (2205), 100°C max (2507) per NORSOK M-601 §7.4.

(3) Heat input — 1.0-2.5 kJ/mm.

(4) Gas backing — Argon (99.99%) at 10-15 L/min.

(5) PWHT — not required for <25mm per ASME B31.3 §328.6.5. Post-weld pickling per ASTM A380.

6. What quality standards and certifications apply to duplex pipes?

Duplex pipes must meet: ASTM A790/A790M-24 (seamless/welded), EN 10216-5 (pressure), NORSOK M-650 (manufacturing), NACE MR0175/ISO 15156-3 (sour service), PED 2014/68/EU (CE), ASME B31.3 (process piping).

Certifications: ISO 9001:2015 QMS, EN 10204 3.1 MTC, SGS/BV third-party.

Ferrite content per ASTM E562 — 35-55% verified by point count. Hardness per ASTM A790 Table 3: ≤ 32 HRC, ≤ 290 HB.

  • Tolerance table

Super Duplex Steel Pipe 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

Chemical Composition for Duplex Stainless Steel Pipe(%)


C

Mn

P

S

Si

Cr

Ni

Mo

N

Cu

UNS

S32101

0.03max

2.0max

0.03max

0.03max

1.0max

20.0~23.0

1.0~3.0

0.6max

0.05~0.17

1.0max

UNS

S31803

0.03max

2.0max

0.03max

0.02max

1.0max

21.0~23.0

4.5~6.5

2.5~3.5

0.08~0.20

/

UNS

S32205

0.03max

2.0max

0.03max

0.02max

1.0max

22.0~23.0

4.5~6.5

3.0~3.5

0.14~0.20

/

UNS

S32750

0.03max

1.2max

0.035max

0.02max

0.8max

24.0~26.0

6.0~8.0

3.0~5.0

0.24~0.32

0.5max

Duplex steel Pipe & Tube Mechanical Properties

Mechanical properties Tensile,min,ksi[MPa] Yield,min,ksi[MPa] Elongation,%(min) Hardness,HB(max)
S31803 90 [620] 65 [450] 25 290
S32205 95 [655] 65 [450] 25 290
S32750 116 [800] 80 [550] 15 300
S32760 109 [750] 80 [550] 25 300

Duplex Stainless steel pipes are manufactured according to the ASME B36.19 standard.
DUPLEX PIPE:S31803 Pipe, S32205 Pipe
SUPER DUPLEX PIPES:S32750 Pipe, S32760 Pipe
Duplex pipes and Super Duplex pipes match the following fittings materials: ASTM A815 (butt weld fittings) and ASTM A182 F51 / F53 / F55 / F60 (flanges / forged socket weld and threaded fittings).
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