Home > Square Bar > Duplex & Super Duplex Square Bars
Grades: UNS S31803 (Duplex 2205), UNS S32750 (Super Duplex 2507)
Inox Steel India is a trusted manufacturer, supplier, stockist, and exporter of Duplex and Super Duplex stainless steel square bars, offering high-performance square bars in UNS S31803 (Duplex 2205) and UNS S32750 (Super Duplex 2507) grades. These square bars are engineered for applications requiring exceptional corrosion resistance, high mechanical strength, and long service life in aggressive environments.
Duplex and Super Duplex square bars are widely used in oil & gas, offshore platforms, chemical processing, marine engineering, desalination plants, and power projects, where conventional stainless steels fail due to pitting, crevice corrosion, or stress corrosion cracking.
All duplex and super duplex square bars supplied by Inox Steel India conform to ASTM A276 / ASTM A479 and EN 10088 standards, ensuring reliable metallurgy, controlled ferrite–austenite balance, and global project compliance.
A duplex stainless steel square bar is a solid square-section bar manufactured from stainless steel with a dual-phase microstructure consisting of approximately 50% austenite and 50% ferrite. This unique structure combines the corrosion resistance of austenitic stainless steel with the strength of ferritic stainless steel.
A super duplex square bar further enhances this composition with higher chromium, molybdenum, and nitrogen content, delivering exceptional resistance to pitting, crevice corrosion, and chloride-induced stress corrosion cracking.
Square bars in duplex and super duplex grades are preferred when:
Inox Steel India follows controlled metallurgical and manufacturing processes to ensure duplex square bars meet critical service requirements.
Manufacturing Process Overview:
This process ensures consistent corrosion resistance, high strength, and predictable fabrication performance.
Duplex and super duplex square bars offer significant advantages over conventional stainless steels:
These properties make duplex and super duplex square bars ideal for critical structural and pressure-related applications.
Inox Steel India supplies duplex and super duplex square bars in two widely used grades:
🔹 Duplex Stainless Steel S31803 (2205) Square Bars
Offers a balanced combination of strength and corrosion resistance, commonly used in chemical processing, marine equipment, and oil & gas piping systems.
🔹 Super Duplex Stainless Steel S32750 (2507) Square Bars
Provides exceptional resistance to chlorides, seawater, and harsh chemicals, making it suitable for offshore structures, subsea components, and desalination plants.
MASTER TECHNICAL DATASHEET – DUPLEX & SUPER DUPLEX SQUARE BARS
| Parameter | Duplex S31803 (2205) | Super Duplex S32750 (2507) |
|---|---|---|
| Material Category | Duplex Stainless Steel | Super Duplex Stainless Steel |
| UNS Number | S31803 / S32205 | S32750 |
| ASTM Specification | ASTM A276 / A479 | ASTM A276 / A479 |
| EN Equivalent | EN 1.4462 | EN 1.4410 |
| Chromium (Cr) | 21 – 23 % | 24 – 26 % |
| Nickel (Ni) | 4.5 – 6.5 % | 6 – 8 % |
| Molybdenum (Mo) | 2.5 – 3.5 % | 3 – 5 % |
| Nitrogen (N) | 0.14 – 0.20 % | 0.24 – 0.32 % |
| Carbon (Max) | 0.03 % | 0.03 % |
| Density | 7.8 g/cm³ | 7.8 g/cm³ |
| Tensile Strength | ≥ 620 MPa | ≥ 800 MPa |
| Yield Strength | ≥ 450 MPa | ≥ 550 MPa |
| Elongation | ≥ 25 % | ≥ 25 % |
| Hardness | ≤ 290 HB | ≤ 310 HB |
| Corrosion Resistance | Very High | Exceptional |
| Pitting Resistance (PREN) | ~35 | > 40 |
| Temperature Service | Up to 300°C | Up to 300°C (avoid >350°C) |
| Weldability | Good | Good (controlled procedure) |
| Magnetic Property | Partially Magnetic | Partially Magnetic |
| Heat Treatment | Solution Annealed | Solution Annealed |
| Surface Finish | Black / Bright / Ground | Black / Bright / Ground |
| Manufacturing Process | Hot Rolled / Forged | Hot Rolled / Forged |
| Size Range (Square) | 8 mm – 150 mm | 10 mm – 150 mm |
| Length | Random / Fixed / Cut Length | Random / Fixed / Cut Length |
| Testing | PMI, Mechanical, Ferrite | PMI, Mechanical, Ferrite, ASTM G48 |
| Certification | EN 10204 3.1 / 3.2 | EN 10204 3.1 / 3.2 |
| NACE Compliance | MR0175 / MR0103 | MR0175 / MR0103 |
| HSN / HS Code | 7222.20.11 | 7222.20.11 |
| Typical Applications | Chemical, Marine, Oil & Gas | Offshore, Subsea, Desalination |
Before selecting duplex or super duplex square bars, engineers and buyers should consider:
Correct grade selection ensures maximum durability, safety, and cost efficiency over the project lifecycle.
This section provides engineering and procurement-ready clarity for Duplex 2205 (S31803) and Super Duplex 2507 (S32750) square bars—covering sizes, weight calculations, indicative pricing, testing requirements, and application mapping for corrosive and high-load environments.
Inox Steel India supplies duplex and super duplex square bars in standard industry sizes and custom cut lengths for fabrication, machining, and offshore projects.
Standard Square Bar Sizes (mm)
8 | 10 | 12 | 16 | 20 | 22 | 25 | 30 | 32 | 35 | 40 | 45 | 50 | 60 | 65 | 70 | 75 | 80 | 100 | 120 | 150
Length: Random (3–6 m) or fixed / cut lengths
Tolerance: As per ASTM A276 / A479 & EN 10088
Finish: Hot Rolled (Black), Bright Drawn, Ground (on request)
Commonly demanded sizes include 20mm, 25mm, 40mm, and 50mm duplex square bars for marine and chemical projects.
The following steel square bar weight chart assists with BOQ preparation and cost estimation.
(Density considered: ~7.8 g/cm³)
| Square Size (mm) | Weight (kg/m) |
|---|---|
| 8 × 8 | 0.50 |
| 10 × 10 | 0.78 |
| 12 × 12 | 1.12 |
| 16 × 16 | 2.00 |
| 20 × 20 | 3.12 |
| 25 × 25 | 4.88 |
| 30 × 30 | 7.02 |
| 40 × 40 | 12.48 |
| 50 × 50 | 19.50 |
| 65 × 65 | 32.90 |
| 75 × 75 | 43.90 |
| 100 × 100 | 78.00 |
Addresses buyer queries such as:
solid square bar sizes
steel square bar weight
square bar weight per meter
Prices vary based on grade, size, finish, certification (NACE), and quantity. Below is an indicative duplex and super duplex square bar price range for reference.
Indicative Price Range (INR/kg – India)
| Grade | Approx. Price / Kg (INR) | Typical Use |
|---|---|---|
| Duplex 2205 (S31803) | ₹ 420 – ₹ 560 | Chemical, marine, oil & gas |
| Super Duplex 2507 (S32750) | ₹ 680 – ₹ 950 | Offshore, subsea, desalination |
Prices are indicative and fluctuate with nickel, molybdenum, certification scope, and order volume.
HSN Code (India): 7222.20.11
HS Code (Export): 7222.20
Applicable to stainless steel bars and rods, hot rolled or forged, used for domestic billing and international export documentation.
All duplex and super duplex square bars supplied by Inox Steel India undergo stringent testing to ensure performance in aggressive service conditions.
Standard Tests Conducted:
Certification:
Duplex and super duplex square bars are used where corrosion resistance and mechanical strength must coexist.
Project engineers, EPC contractors, and procurement teams rely on Inox Steel India for technical confidence, documentation strength, and export readiness.
Key Advantages:
Our focus is to deliver corrosion-resistant structural steel that performs reliably in the world’s harshest environments.
| Industry | Application | Preferred Grade |
|---|---|---|
| Oil & Gas | Offshore platforms, manifolds, supports | S32750 |
| Marine & Shipbuilding | Coastal & seawater structures | S31803 / S32750 |
| Chemical Processing | Structural supports, reactors | S31803 |
| Desalination Plants | Seawater intake & brine zones | S32750 |
| Power & Energy | Heat exchangers, structural members | S31803 |
| Offshore & Subsea | High-load corrosion zones | S32750 |
All duplex and super duplex square bars are packed to meet international project and export standards.
Packing Standards:
Export Markets: UAE, Saudi Arabia, Oman, Qatar, Africa, Europe, Southeast Asia
Domestic Supply: Mumbai, Gujarat, Chennai, Visakhapatnam
Whether your project requires Duplex 2205 for chemical service or Super Duplex 2507 for offshore and desalination applications, Inox Steel India offers certified quality, technical support, and dependable global supply.
52-A, Mulji Thackersi Bldg, Islampura Street, Shop No. 10, Near Alankar Cinema, Mumbai – 400 004
steel@inoxsteelindia.in
+91 9930796690
Super Duplex 2507 has higher chromium, molybdenum, and nitrogen content, providing superior resistance to chlorides and seawater.
Yes, Super Duplex S32750 is widely used in offshore and subsea applications.
Yes, duplex and super duplex square bars can be supplied as per NACE MR0175 / MR0103 requirements.
Standard sizes range from 8 mm to 150 mm, with custom cut lengths available.
The HSN code is 7222.20.11.
Yes, Inox Steel India exports to GCC, Africa, Europe, and Southeast Asia.
Inox Steel India supplies duplex 2205 & super duplex 2507 square bars. Get latest price per kg, sizes, weight chart & NACE-certified stock in India.