ASTM A790 / A789 S32205 Duplex Stainless Steel Welded Pipe: Manufacturing Capabilities & Product Specifications

Short Description:

Womic Steel supplies ASTM A790 / A789 S32205 (Duplex 2205) welded stainless steel pipe for applications requiring high strength and exceptional resistance to chloride stress corrosion cracking, pitting, and crevice corrosion. S32205 offers minimum yield strength of 450 MPa (65,300 psi) – approximately twice that of 316L – and tensile strength of 655 MPa (95,000 psi). The duplex microstructure (50% austenite / 50% ferrite) provides superior resistance to stress corrosion cracking in chloride-containing environments. Manufacturing includes ERW for small diameters and EFW for large diameters, both with full penetration and post-weld solution annealing. Outside diameter from 6.35mm to 1219mm (1/4″ – 48″), wall thickness 0.5mm – 50mm (Schedule 5S to XXS), standard length up to 12m, custom up to 24m. Mill certificate, hydrotest, 100% UT, solution annealed and pickled finish, beveled or plain ends available. Suitable for offshore platforms, desalination plants, chemical tankers, pulp & paper digesters, flue gas desulfurization, and seawater cooling systems.

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Product Description

Welded Duplex Stainless Steel Pipe Size: Outside Diameter: 6.35mm – 1,219mm (1/4″ – 48″), Wall Thickness: 0.5mm – 50mm (Schedule 5S, 10S, 40S, 80S), Length: 6m – 12m standard, custom lengths up to 24m

Standard & Grade of Welded Stainless Steel Pipe: ASTM A790 (pipe) / ASTM A789 (tubing) S32205; also UNS S32205, UNS S31803 (previous grade); EN 10217-7 1.4462; Equivalent to Duplex 2205

Usage of Welded Stainless Steel Pipe: Offshore oil and gas platforms (seawater cooling, firewater, ballast lines), desalination plants (high pressure brine piping), chemical tankers and cargo piping, pulp and paper digesters and bleach plants, flue gas desulfurization (FGD) systems, heat exchangers (chloride service), chemical processing (acetic acid, formic acid), marine exhaust scrubbers, bridge components and structural applications

Womic Steel offering high quality & competitive prices of ASTM A790 S32205 welded duplex stainless steel pipe, ERW duplex pipe, EFW duplex tube, high strength corrosion resistant pipe, chloride SCC resistant pipe. Mill certificate EN 10204 3.1/3.2, hydro test, UT, solution annealed, beveled/plain ends, pickled finish available. Factory direct supply for offshore, desalination, and chemical projects worldwide.

Womic Steel: Manufacturing Capabilities & Company Strength

Womic Steel Group is a premier manufacturer and global exporter with over 20 years of expertise in producing carbon, stainless, and duplex stainless steel tubular products. Our specialized duplex stainless steel welded pipe production facility utilizes multiple advanced welding technologies with strict control of heat input to maintain the required ferrite/austenite balance (35-65%):

ERW (Electric Resistance Welding) Line: For diameters from 6.35mm to 610mm (1/4″ – 24″), wall thickness from 0.5mm to 12.7mm. High-frequency welding with low heat input to prevent ferrite imbalance. Ideal for small to medium diameter duplex pipes for instrumentation and process lines.

EFW (Electric Fusion Welding) Line: For diameters from 219mm to 1219mm (8″ – 48″), wall thickness from 4.0mm to 50mm. TIG (GTAW) root pass with SAW fill passes, with nitrogen backing gas to maintain duplex microstructure.

LSAW / SAWL Line for Duplex: For diameters from 406mm to 1524mm (16″ – 60″), wall thickness up to 60mm. Submerged arc welding of rolled duplex plates with controlled heat input and interpass temperature.

All duplex stainless steel welded pipes undergo solution annealing (heat treatment) at 1040-1120°C followed by water quenching to restore the balanced austenite-ferrite microstructure and corrosion resistance, followed by pickling and passivation.

Quality Certifications & Regulatory Compliance:

ISO 9001:2015 Certified for quality management

PED 2014/68/EU (CE Marking) for pressure equipment

EN 10204 3.2 Certification with third-party validation (TÜV, BV, SGS, LR)

Third-Party Inspection (TPI) approved by SGS, BV, ABS, DNV, TÜV

NORSOK M-650 (mandatory for offshore duplex applications)

DNV GL approval for offshore duplex pipes

Womic Steel supplies duplex stainless welded pipes to over 50 countries across offshore, desalination, chemical, and marine industries.

Production Flexibility:

ERW: 6.35–610mm OD × 0.5–12.7mm WT × ≤ 12m

EFW: 219–1219mm OD × 4.0–50mm WT × ≤ 12m (longer upon request)

LSAW: 406–1524mm OD × 6.0–60mm WT × ≤ 18m

Finishing options: Annealed and pickled, bright annealed

ASTM A790 / A789 S32205: Material Composition & Performance Characteristics

UNS S32205 is a 22% chromium, 5% nickel, 3% molybdenum duplex stainless steel. It has a two-phase microstructure (approximately 50% austenite / 50% ferrite) that combines the high strength of ferritic steels with the corrosion resistance and toughness of austenitic steels. S32205 replaces the earlier UNS S31803 with tighter composition limits (higher N, lower C, narrower Cr range) for improved weldability and corrosion resistance.

Chemical Composition (Ladle Analysis, % by mass):

Element	UNS S32205 (ASTM A790)	UNS S31803 (previous)
C	≤ 0.030	≤ 0.030
Mn	≤ 2.00	≤ 2.00
P	≤ 0.030	≤ 0.030
S	≤ 0.020	≤ 0.020
Si	≤ 1.00	≤ 1.00
Cr	22.0 – 23.0	21.0 – 23.0
Ni	4.5 – 6.5	4.5 – 6.5
Mo	3.0 – 3.5	2.5 – 3.5
N	0.14 – 0.20	0.08 – 0.20
Fe	Balance	Balance

Mechanical Properties (Room Temperature, Solution Annealed):

Property	S32205 (Duplex 2205)
Yield Strength (min, 0.2% offset)	450 MPa (65,300 psi)
Tensile Strength (min)	655 MPa (95,000 psi)
Elongation (min, 50mm gauge)	25%
Hardness (max)	90 HRB (or 290 HV)
Impact Toughness (min) @ -46°C	27 J (Charpy V-Notch)

Physical Properties:

Density: 7.85 g/cm³

Modulus of Elasticity: 200 GPa (29 × 10⁶ psi)

Thermal Conductivity: 15 W/m·K at 100°C

Coefficient of Thermal Expansion: 13.5 × 10⁻⁶/°C (20-100°C)

Corrosion Resistance:

Pitting Resistance Equivalent Number (PREN) = Cr% + 3.3(Mo%) + 16(N%) ≈ 35-38 (vs 316L ≈ 24-26)

Excellent resistance to chloride stress corrosion cracking (SCC) – superior to 304L and 316L

Very high resistance to pitting and crevice corrosion in chloride environments

Good resistance to organic acids, caustic solutions, and sour service (H₂S)

Superior erosion and corrosion-fatigue resistance due to high strength

Microstructure Requirements (per ASTM A790): Ferrite content shall be 35-65% after solution annealing. Womic performs ferrite measurement using image analysis or magnetic induction method on every heat.

Dimensional Range & Standards Compliance

Item	Specification
Standard	ASTM A790 / ASME SA790 (pipe); ASTM A789 (tubing)
Manufacturing Processes	ERW, EFW, LSAW
Outside Diameter Range	ERW: 6.35 – 610mm; EFW/LSAW: 219 – 1524mm
Wall Thickness Range	ERW: 0.5 – 12.7mm; EFW/LSAW: 4.0 – 60mm
Schedule Range	5S, 10S, 40S, 80S (for NPS 1/8″ – 48″)
Length Range	Standard: 6m; Extended: 12m, 18m, up to 24m
End Finish	Plain End (PE), Beveled End (BE)
Surface Finish	Annealed & Pickled, Bright Annealed
Tolerances	OD: ±0.5% or ±3.2mm; WT: ±12.5% (per ASTM A999); Length: +50mm / -0mm

Available Dimensions & Specifications – ASTM A790 S32205 Welded Duplex Pipe (Selected Typical Sizes)

NPS	OD (mm)	Schedule	WT (mm)	Weight (kg/m)	Standard Length	Typical Application
1/2″	21.3	10S	2.11	1.00	6m	Instrument lines
3/4″	26.7	10S	2.11	1.28	6m	Chemical dosing
1″	33.4	10S	2.77	2.09	6m	Offshore hydraulic
1-1/2″	48.3	10S	2.77	3.11	6m	Process lines
2″	60.3	10S	2.77	3.93	6m / 12m	Seawater lines
3″	88.9	10S	3.05	6.46	6m / 12m	Heat exchangers
4″	114.3	10S	3.05	8.37	6m / 12m	Chemical process
6″	168.3	10S	3.40	13.8	6m / 12m	Desalination
8″	219.1	10S	3.76	20.0	12m	Offshore platform
10″	273.0	10S	4.19	27.8	12m	Seawater intake
12″	323.9	10S	4.57	36.0	12m	Firewater main
16″	406.4	10S	4.78	47.4	12m	Ballast lines
20″	508.0	10S	5.54	68.6	12m	Large diameter
24″	609.6	10S	6.35	94.4	12m	Main headers

*Custom dimensions outside these ranges available. For NORSOK M-650 certified pipes, please specify requirement.*

Common Duplex Stainless Steel Standards & Grades Manufactured by Womic Steel

Standard	Steel Grades	Typical Application	Welding Process
ASTM A790	S32205, S31803, S32750, S32760	Offshore, desalination, chemical	EFW/LSAW
ASTM A789	S32205, S31803, S32750, S32760	Tubing, heat exchanger	ERW (cold finished)
ASTM A928	S32205, S31803, S32750	Electric fusion welded duplex	EFW
EN 10217-7	1.4462 (2205), 1.4410 (2507)	Pressure purposes, duplex	SAW/ERW
NORSOK M-630	22Cr (2205), 25Cr (2507)	Offshore Norwegian sector	EFW/LSAW

Usage: Offshore seawater systems, desalination high pressure piping, chemical tanker cargo lines, FGD scrubbers, pulp mill digesters.

Manufacturing Process – Welded Duplex Stainless Steel Pipe (ERW, EFW, LSAW)

Duplex stainless steel welding requires careful control of heat input and interpass temperature to maintain the required ferrite/austenite balance (35-65%). Excessive heat input can form detrimental intermetallic phases (sigma, chi) that reduce corrosion resistance and toughness.

ERW (Electric Resistance Welding) Process – Small to Medium Diameter (6.35–610mm OD):

Raw Material (Strip/Coil) Inspection: Duplex stainless steel strip verified for S32205 composition (Cr 22-23%, Mo 3.0-3.5%, N 0.14-0.20%). Each coil has unique heat number.

Uncoiling & Leveling: Coil uncoiled and leveled.

Strip Edge Trimming: Edges precision trimmed.

Forming: Continuous roll forming.

High-Frequency Welding: Low heat input welding (≤ 1.5 kJ/mm) to avoid ferrite imbalance. Welding speed controlled.

Seam Annealing: Weld seam induction annealed (1040-1120°C) followed by water quench.

Sizing & Straightening

Cutting to Length

Non-Destructive Testing: Eddy current test (100%) plus optional UT.

Solution Annealing (Full Pipe Heat Treatment): 1040-1120°C, water quench. Critical for restoring duplex microstructure.

Hydrostatic Test

Pickling & Passivation

Ferrite Measurement: Confirms 35-65% ferrite.

Final Inspection & Marking

EFW (Electric Fusion Welding) Process – Large Diameter, Heavy Wall (219–1219mm OD, 4.0–50mm WT):

Plate Preparation: Duplex plate cut to size, edges beveled (X bevel).

Roll Forming: 3-roll or 4-roll bending.

Tack Welding

TIG (GTAW) Root Pass: Root pass with matching duplex filler metal (ER2209), nitrogen backing gas (N₂ + Ar) to prevent nitrogen loss.

SAW Fill & Cap Passes: Multi-pass SAW with controlled heat input (≤ 2.0 kJ/mm), interpass temperature ≤ 150°C.

Inner Weld (for large diameters)

100% Radiographic Testing (per ASTM A928)

Solution Annealing: Full pipe heat treatment in car-bottom furnace (1040-1120°C), water quench.

Pickling & Passivation

Hydrostatic Test

Ferrite Measurement & PMI

Dimensional Inspection & Marking

LSAW Process for Duplex – Very Large Diameter (406–1524mm OD, 6.0–60mm WT):

UOE or JCOE forming from duplex plate

Double-sided SAW welding with strict heat input control

Full solution annealing after welding

Ferrite measurement on every pipe

Critical Control Points for Duplex Welding:

Heat input: ≤ 2.0 kJ/mm (preferably ≤ 1.5 kJ/mm)

Interpass temperature: ≤ 150°C

Backing gas: Nitrogen + Argon (to prevent nitrogen loss from weld pool)

Solution annealing: 1040-1120°C, water quench – mandatory after welding

Ferrite content: 35-65% (typically 40-60%)

Quality Control & Testing Procedures for ASTM A790 S32205 Welded Duplex Pipe

Stage	Inspection Method	Purpose
Raw Material	Chemical Analysis (OES)	Verify S32205 limits (Cr 22-23%, Mo 3.0-3.5%, N 0.14-0.20%)
Raw Material	Tensile Testing	Verify yield ≥ 450 MPa, tensile ≥ 655 MPa
Raw Material	Ferrite Measurement	Ensure starting plate 40-60% ferrite
Raw Material	Charpy @ -46°C	Verify impact toughness ≥ 27 J
In-Process	Heat Input Monitoring (EFW/LSAW)	Ensure ≤ 2.0 kJ/mm
In-Process	Interpass Temperature	≤ 150°C
Weld (ERW)	Eddy Current Test (100%)	Detect weld discontinuities
Weld (EFW/LSAW)	100% UT (or PAUT)	Detect weld defects
Weld (EFW/LSAW)	RT (10-100% per spec)	Weld quality verification
Weld	Dye Penetrant Test (PT)	Surface cracks (weld toes)
After Solution Annealing	Ferrite Measurement (per ASTM E562)	35-65% ferrite (target 40-60%)
After Solution Annealing	Hardness Test	≤ 90 HRB (or 290 HV)
Finished Pipe	Hydrostatic Test	Pressure integrity
Finished Pipe	Charpy @ -46°C (weld and HAZ)	≥ 27 J (typical 60-120 J)
Finished Pipe	Pitting Corrosion Test (ASTM G48)	Pass (no pitting at 22°C, 24h)
Finished Pipe	PMI (XRF)	Confirm grade (Cr, Mo, N)
Finished Pipe	Visual & Marking	Surface, traceability

Optional Tests for Critical Offshore Service (NORSOK M-650):

Ferrite measurement on weld (weld centerline, HAZ, base metal)

Microstructure examination for intermetallic phases (sigma, chi)

Hardness traverse across weld (max 320 HV)

Corrosion testing in simulated seawater

Primary Applications – ASTM A790 S32205 Welded Duplex Stainless Steel Pipe

Offshore oil and gas platforms: Seawater cooling systems, firewater ring mains, ballast lines, deck drains, and hydraulic control lines. Replaces 316L with longer service life.

Desalination plants: High pressure brine piping (reverse osmosis feed and reject lines), interconnecting piping, and evaporator tubes. Resists pitting from high chloride brines.

Chemical tankers and cargo piping: Stainless steel cargo piping for chemicals such as acetic acid, formic acid, and organic chlorides.

Pulp and paper digesters: Continuous digesters and bleach plant piping (chlorine dioxide, sodium chlorate). Duplex provides high strength and corrosion resistance.

Flue gas desulfurization (FGD) systems: Absorber tower recirculation piping, spray headers, and oxidation air lines in coal-fired power plants. Resists highly chloridic acidic environment.

Heat exchangers: Shell and tube heat exchangers using seawater or brackish cooling water. Higher strength allows thinner tubes.

Marine exhaust scrubbers: Exhaust gas cleaning systems on ships (SOx removal). Duplex resists sulfuric acid condensation.

Structural components: Bridge components, offshore platform topsides, and crane booms – high strength reduces weight.

Packaging & Shipping – ASTM A790 S32205 Welded Duplex Pipe

Packaging:

Anti-corrosion protection: Pipes oiled or VCI paper. For offshore, plastic wrap recommended.

End caps: Heavy-duty plastic caps for beveled ends.

Bundling (Small diameters): Bundles with steel straps and interleaving paper.

Individual packaging (Large diameters): Plastic film wrap.

Wooden crates for critical offshore projects.

Shipping:

Containers for ≤ 610mm, break-bulk for larger diameters.

Documentation: MTC 3.1/3.2, hydrotest report, eddy current/UT reports, ferrite measurement report, PMI report, Charpy reports, G48 test report, dimensional report, packing list, COO. For NORSOK M-650 projects, additional documentation package.

Womic Steel Advantages & FAQ – ASTM A790 S32205 Duplex Welded Pipe

Why Partner with Womic Steel for Duplex Welded Pipe?

Complete Size Range: ERW 1/4″ – 24″, EFW/LSAW 8″ – 60″.

Full solution annealing after welding (1040-1120°C, water quench).

In-house ferrite measurement and microstructure examination.

NORSOK M-650 qualified for offshore Norwegian sector.

DNV GL approval for duplex pipes.

Competitive lead times: 30-40 days for ERW, 40-60 days for EFW/LSAW.

Frequently Asked Questions (FAQ) – ASTM A790 S32205 Duplex Welded Pipe

Q: What is the difference between UNS S32205 and UNS S31803?
A: S32205 has tighter composition limits (Cr 22-23% vs 21-23%, N 0.14-0.20% vs 0.08-0.20%) and higher minimum nitrogen, which improves pitting resistance and weldability. S32205 has largely replaced S31803 in modern specifications (ASTM A790 now includes both, but S32205 is preferred).

Q: Why is solution annealing mandatory for duplex welded pipe?
A: Welding disrupts the balanced ferrite/austenite microstructure and can form detrimental intermetallic phases (sigma, chi) in the heat-affected zone. Solution annealing at 1040-1120°C followed by water quench restores the 35-65% ferrite balance and dissolves intermetallic phases. Without solution annealing, corrosion resistance and toughness are severely compromised. Womic performs solution annealing on all duplex welded pipes.

Q: What is the maximum service temperature for S32205?
A: S32205 is suitable for continuous service up to 280°C in chloride environments. Above 300°C, embrittlement can occur due to sigma phase formation (even in annealed material over time). For temperatures below 300°C, duplex has excellent performance.

Q: Can S32205 be used for sour service (H₂S)?
A: Yes. Duplex 2205 is qualified for sour service per NACE MR0175/ISO 15156 for H₂S partial pressures up to 0.3 psi (0.02 bar) in specific hardness ranges. For higher H₂S, super duplex (S32750) is recommended. Womic supplies duplex with hardness ≤ 28 HRC per NACE requirements.

Q: What is the pitting resistance equivalent (PREN) of S32205?
A: PREN = Cr% + 3.3(Mo%) + 16(N%) = 22 + 3.3×3.2 + 16×0.17 ≈ 35-38. This is significantly higher than 316L (PREN ≈ 24-26), indicating much better resistance to pitting in chloride environments. S32205 is suitable for seawater service at temperatures up to 30-40°C.

Q: Do you provide NORSOK M-650 certification?
A: Yes. Womic Steel is qualified to NORSOK M-650 for duplex stainless steel welded pipes. We provide full documentation including ferrite measurement, hardness traverses, corrosion testing, and microstructure examination. This is often required for offshore projects on the Norwegian continental shelf.

Q: What is the typical lead time for duplex welded pipe?
A: 30-40 days for ERW (small to medium diameters), 40-60 days for EFW/LSAW (large diameters). NORSOK M-650 documentation adds 10-15 days. Third-party inspection adds 7-14 days.

Project Reference – North Sea Offshore Platform Seawater Cooling System Upgrade

Country: Norway (North Sea, Troll field)
Standard & Grade: ASTM A790 S32205 (Duplex 2205) – NORSOK M-650 qualified
Dimensions & Quantity:

OD 219.1mm (8″) × Schedule 10S (3.76mm WT) – 2,200 meters (approx. 35 tons) – EFW process

OD 323.9mm (12″) × Schedule 10S (4.57mm WT) – 1,500 meters (approx. 39 tons) – EFW process

OD 60.3mm (2″) × Schedule 10S (2.77mm WT) – 4,000 meters (approx. 14 tons) – ERW process

Total: 7,700 meters (7.7 km), approx. 88 tons

Specifications: ASTM A790 S32205 solution annealed and pickled, beveled ends. Hydrostatic testing. 100% UT for EFW pipes, eddy current for ERW. PMI on every pipe. Mandatory ferrite measurement (40-60% target, achieved 45-55%). Charpy impact at -46°C (spec 27J, achieved 80-140J). Pitting corrosion test per ASTM G48 Method A (24h, 22°C) – no pitting. NORSOK M-650 documentation package including hardness traverses and microstructure examination. Third-party inspection by DNV Norway.

Application: Seawater cooling system upgrade on a North Sea platform (Troll field). The system pumps filtered seawater (4-12°C, 3.5% salinity, pH 8.1) to cool gas compressors and hydraulic power units. Previous 316L piping suffered pitting and crevice corrosion after 8 years of service. Duplex 2205 was selected for its higher pitting resistance (PREN 35-38 vs 316L PREN 24-26) and higher strength (allowing thinner walls and reduced weight on platform).

Technical Challenges & Solutions:

Pitting and crevice corrosion resistance in North Sea seawater – Seawater temperature 4-12°C, but stagnant conditions in dead legs can lead to crevice corrosion. Womic supplied S32205 with verified PREN ≥ 36. G48 Method A pitting test (24h, 22°C) showed no pitting. Critical pitting temperature (CPT) testing per ASTM G48 Method C (1M NaCl, 1V) achieved CPT ≥ 50°C (well above service temperature). The client accepted.

Weld ferrite balance and intermetallic phase control – EFW welding required strict heat input control (≤ 1.8 kJ/mm) and interpass temperature ≤ 100°C to avoid sigma phase. Womic performed ferrite measurement on weld cross-sections (10 positions per weld). Results: weld metal ferrite 48-55%, HAZ 45-52%, base metal 48-58% – all within 35-65% requirement. Microstructure examination showed no sigma or chi phases.

NORSOK M-650 documentation – Norwegian sector requires NORSOK M-650 certification for duplex materials. Womic provided full documentation: ferrite measurement charts, hardness traverses (weld metal max 280 HV10, HAZ max 275 HV10, base metal max 270 HV10), corrosion test results, and weld procedure qualification records. DNV surveyor approved all documentation.

Charpy impact at -46°C – North Sea winter temperatures and potential Joule-Thomson cooling from gas depressurization required low-temperature toughness. Womic performed Charpy V-Notch testing at -46°C on weld, HAZ, and base metal. Results: base metal 120-160J, weld 80-120J, HAZ 90-130J – all well above 27J requirement.

Lightweight design due to high strength – Duplex 2205 has yield strength 450 MPa vs 316L at 170 MPa. Platform designers used Schedule 10S instead of Schedule 40S for seawater lines, reducing pipe weight by 60% and saving 50 tons of structural support. Womic supplied pipes with consistent dimensions to ensure proper fit-up.

Logistics to North Sea platform – Pipes shipped from Shanghai to Bergen, Norway via break-bulk vessel, then to platform via supply vessel. DNV witnessed loading and stowage. All 88 tons delivered without damage.

Result: Seawater cooling system commissioned in Q2 2024. After 12 months of operation, in-line inspection (ILI) and coupon testing showed no pitting, crevice corrosion, or cracking. The operator has selected duplex 2205 for all future seawater system upgrades across their North Sea assets. Womic Steel is now an approved supplier for duplex pipes for this operator under NORSOK M-650.

Contact:
Website: www.womicsteel.com
E-mail: sales@womicsteel.com

Tel / WhatsApp / WeChat:
Victor: +86 15575100681
Jack: +86 18390957568

Womic Steel – Your reliable partner for ASTM A790 S32205 duplex stainless steel welded pipes for offshore, desalination, chemical, and marine applications worldwide.