Home > Seamless Pipe > ASTM A790 / ASME SA790
Grades: S31803 & S32205 (Duplex 2205 Series)
Inox Steel India is a leading manufacturer and global exporter of ASTM A790 / ASME SA790 Duplex Stainless Steel Seamless Pipes, supplying premium-quality S31803 and S32205 duplex grades to offshore platforms, desalination plants, oil & gas companies, chemical processing units, and marine engineering projects.
Duplex stainless steels provide an excellent combination of high mechanical strength, superior corrosion resistance, and excellent resistance to chloride-induced stress corrosion cracking (SCC) — making them ideal for harsh and aggressive environments. With a perfect ferrite–austenite balance, Duplex 2205 offers nearly double the strength of 300-series stainless steel, along with superior pitting resistance.
Our manufacturing includes hot extrusion, cold drawing, solution annealing, pickling, passivation, ultrasonic testing, eddy current testing, PMI testing, and strict surface inspection, ensuring complete compliance with ASTM A790 / SA790 standards. Inox Steel India supplies both seamless and welded duplex pipes with sizes ranging from ½″ to 24″, including SCH 10 to SCH XXS.
UNS S31803 is the standard duplex grade, while UNS S32205 is the upgraded version with higher nitrogen content, offering improved strength and superior pitting resistance, especially in seawater, chlorides, and high-pressure brine lines.
ASTM A790 (SA790) is the governing specification for seamless and welded duplex stainless steel pipes used in:
Duplex stainless steels contain high chromium (21–23%), nickel (4.5–6.5%), molybdenum (2.5–3.5%), and nitrogen which provide:
This process produces high-integrity duplex pipes capable of long-term performance in aggressive environments.
| Feature | S31803 | S32205 |
|---|---|---|
| Nitrogen Content | Standard | Higher (improved pitting resistance) |
| Strength | High | Higher strength |
| PREN Value | ~32–34 | ~34–36 |
| Chloride Resistance | Excellent | Superior |
| Marine Use | Very Good | Ideal |
| Availability | Standard | Most demanded globally |
| Parameter / Property | UNS S31803 | UNS S32205 |
|---|---|---|
| Material Type | Duplex Stainless Steel | Duplex Stainless Steel (Improved 2205) |
| Standard | ASTM A790 / ASME SA790 | ASTM A790 / ASME SA790 |
| Common Name | Duplex 2205 | Duplex 2205 (Higher N Content) |
| Chromium (Cr) | 21.0–23.0% | 22.0–23.0% |
| Nickel (Ni) | 4.5–6.5% | 4.5–6.5% |
| Molybdenum (Mo) | 2.5–3.5% | 3.0–3.5% |
| Nitrogen (N) | 0.08–0.20% | 0.14–0.20% (Higher for strength) |
| Ferrite–Austenite Balance | ~50–50 | ~50–50 |
| Tensile Strength (MPa) | 620 Min | 620–700 |
| Yield Strength (MPa) | 450 Min | 450–550 |
| Elongation (%) | 25 | 25 |
| Hardness (HB) | 290 Max | 290 Max |
| Pitting Resistance Equivalent (PREN) | ~32–34 | ~34–36 (Higher corrosion resistance) |
| Temperature Range | −50°C to 300°C | −50°C to 300°C |
| Corrosion Resistance | Excellent | Superior (Chloride / Pitting) |
| Manufacturing Method | Seamless / Welded | Seamless / Welded |
| Equivalent EN Grade | 1.4462 | 1.4462 |
| Available Sizes | ½″ – 8″ NPS (Seamless) / ½″–24″ (Welded) | Same |
| Schedules | SCH 10 – SCH XXS | SCH 10 – SCH XXS |
| End Finishes | Plain / Bevelled | Plain / Bevelled |
| Key Properties | High strength, chloride resistance | Higher nitrogen → better toughness |
| HSN Code | 7304.41.00 (Seamless Duplex) | 7304.41.00 (Seamless Duplex) |
| Certifications | EN 10204 3.1 / 3.2 | EN 10204 3.1 / 3.2 |
Corrosion Environment (Chlorides / Seawater)
S32205 is ideal for brine lines, seawater, offshore, and desalination.
Pressure Rating
Duplex pipes have almost double the strength of SS 316L, reducing wall thickness requirements.
Temperature Stability
Stable from −50°C to 300°C without loss of performance.
Weldability Requirements
Both grades weld well, but heat input must be controlled to maintain duplex balance.
Low Maintenance & Long Service Life
Ideal for projects requiring long-term corrosion resistance.
India:
Desalination plants, chemical units, offshore equipment, O&G pipelines.
Middle East:
Massive demand for duplex pipes in:
Africa:
Used in mining, chemical processing & seawater treatment.
Europe & Americas:
High requirement for chemical and subsea applications.
Inox Steel India exports globally via JNPT, Mundra & Hazira with full export documentation.
ASTM A790 Duplex Stainless Steel Seamless & Welded Pipes supplied by Inox Steel India are engineered for highly corrosive, chloride-rich, and high-stress environments. Duplex 2205 (S31803/S32205) combines the strength of ferritic steel with the corrosion resistance of austenitic steel — perfect for offshore, chemical, marine & desalination projects.
Below are the grade-wise applications, dimensional charts, indicative pricing, HSN code & QA protocols — all matching your preferred structured format.
UNS S31803 — Standard Duplex 2205 Grade
Service Use:
General duplex application where high corrosion resistance and strength are required.
Typical Applications:
Corrosion Resistance:
Excellent (pitting, crevice, SCC)
Size Range:
Seamless: ½″ – 8″ NPS
Welded: ½″ – 24″ NPS
Industries:
Chemical | Petrochemical | Mining | Water Treatment
UNS S32205 — Improved Duplex 2205 (Higher Nitrogen)
Service Use:
Advanced duplex grade for high-chloride and high-pressure service.
Typical Applications:
Corrosion Resistance:
Superior (higher PREN 34–36)
Size Range:
Seamless: ½″ – 8″ NPS
Welded: ½″ – 24″ NPS
Industries:
Offshore | Marine | Oil & Gas | Desalination | Refinery
| NPS (Inch) | OD (mm) | Wall Thickness (SCH 40) | Approx. Weight (kg/m) |
|---|---|---|---|
| ½″ | 21.3 | 2.77 | 1.27 |
| 1″ | 33.4 | 3.38 | 2.73 |
| 2″ | 60.3 | 3.91 | 5.44 |
| 3″ | 88.9 | 5.49 | 10.88 |
| 4″ | 114.3 | 6.02 | 14.98 |
| 6″ | 168.3 | 7.11 | 28.26 |
| 8″ | 219.1 | 8.18 | 41.95 |
| 10″ | 273.1 | 9.27 | 62.42 |
| Grade / Type | Avg. Price (INR/kg) | Approx. USD/kg | Condition |
|---|---|---|---|
| S31803 – Seamless | ₹ 480 – ₹ 560 | $6.30 – $7.40 | Annealed & Pickled |
| S31803 – Welded | ₹ 350 – ₹ 410 | $4.70 – $5.40 | A/P |
| S32205 – Seamless | ₹ 520 – ₹ 620 | $6.80 – $8.10 | A/P |
| S32205 – Welded | ₹ 380 – ₹ 450 | $5.10 – $5.85 | A/P |
| S32205 – Polished | ₹ 580 – ₹ 680 | $7.60 – $9.10 | Polished |
✔ HSN 7304.41.00 — Duplex Stainless Steel Seamless Pipes
✔ For welded pipes → HSN 7306.40.00
Duplex stainless steel requires strict metallurgical control to maintain ferrite–austenite balance. Our QA process ensures chemical accuracy, corrosion resistance, and dimensional integrity.
Quality Tests Conducted:
Documentation Supplied:
Inox Steel India is a globally recognized manufacturer and exporter of ASTM A790 Duplex Stainless Steel Pipes, delivering high-strength, corrosion-resistant piping solutions for the offshore, marine, chemical, desalination, and oil & gas industries.
With specialized manufacturing systems, strict quality checks, and export-oriented packaging, we ensure Duplex 2205 pipes meet the world’s most demanding project specifications.
Key Reasons to Choose Inox Steel India
Inox Steel India ensures unmatched reliability in chloride-rich, corrosive, and high-pressure duplex applications.
| Industry | Application | Preferred Grade |
|---|---|---|
| Offshore Oil & Gas | Subsea pipelines, risers, manifolds | S32205 |
| Marine Engineering | Cooling & seawater systems | S32205 |
| Desalination Plants | RO feed & brine reject | S31803 / S32205 |
| Chemical & Petrochemical | High-corrosion process lines | S31803 |
| Refinery Units | High-chloride & corrosive media | S32205 |
| Pulp & Paper | Bleaching systems | S31803 |
| Water Treatment | High-pressure piping | S31803 / S32205 |
| Mining | Acidic & abrasive environments | S32205 |
We ensure the highest standard of packaging for Duplex pipes to prevent corrosion, surface scratches, or mechanical damage during shipping.
Packaging Includes:
🌍 Regular Export Destinations:
UAE • Saudi Arabia • Qatar • Oman • Kuwait • Bahrain
USA • Canada • Mexico
Germany • Italy • Netherlands • UK
South Africa • Nigeria • Egypt
Malaysia • Singapore • Indonesia
If you are looking for a Duplex S31803 / S32205 Stainless Steel Seamless Pipe Supplier near Alankar Cinema, Mumbai, Inox Steel India is the most reliable and trusted option.
We offer:
Trusted by EPC contractors, offshore fabricators, marine companies, and chemical process plants.
We offer technical material selection, MTC samples, documentation, and quotations within 24 hours.
📥 Downloads:
Datasheet • Price List • NDT Report Samples • Ferrite Number Report • Size Chart (PDF)
52-A, Mulji Thackersi Bldg, Islampura Street, Shop No. 10, Near Alankar Cinema, Mumbai – 400 004
steel@inoxsteelindia.in
+91 9930796690
Inox Steel India
Email
Phone
Yes — Duplex 2205 offers double the yield strength of 316L.
Yes — S32205 is ideal for high-chloride seawater and brine applications.
Hydro, UT, ECT, PMI, Ferrite Number (FN) testing are mandatory.
Yes — but welding must control heat input to maintain duplex phase balance.
✔ Seamless — 7304.41.00
✔ Welded — 7306.40.00
Yes — regular shipments to GCC, Europe, Africa, USA & Asia.
Yes — all documentation provided.
Inox Steel India manufactures and supplies premium Duplex Stainless Steel Pipes (S31803 & S32205) for high-performance, corrosion-resistant industrial applications.
We ensure certified quality, global exports, and fast service.