Duplex Steel Products
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High-strength, corrosion-resistant duplex stainless steel engineered for oil & gas, marine, and chemical processing — supplied ASTM-certified, at competitive factory-direct prices, with fast worldwide delivery.
Kalpaturu Piping is a trusted manufacturer, supplier, and exporter of premium duplex steel products in India, serving demanding industries across more than 40 countries. Duplex stainless steel unites the best of two worlds — the high mechanical strength of ferritic steel and the superior corrosion resistance of austenitic steel — thanks to its balanced two-phase microstructure. This unique combination allows our clients to reduce wall thickness, cut overall weight, and extend service life in environments where standard grades like 304 and 316 simply cannot survive. From duplex steel pipes and plates to bars, fittings, flanges, and fasteners, every item we ship is produced to strict international standards including ASTM, ASME, and DIN, and is fully backed by mill test certificates. With decades of combined metallurgical expertise, an extensive ready stock of UNS S31803 and S32205 (2205) grades, and rigorous in-house quality control, we deliver reliable, long-lasting duplex steel solutions at a transparent, competitive price. Whether your project involves subsea pipelines, pressure vessels, desalination plants, or aggressive chemical media, we help you specify the right product with confidence — on time, every time.
Table of Content
- Types of Duplex Stainless Steel
- Duplex Steel Specifications
- Duplex Steel Chemical Composition
- Duplex Steel Mechanical Properties
- Duplex Steel vs. Austenitic Stainless Steel
- Duplex Steel Applications & Industries
- Manufacturing, Quality & Certifications
- Duplex Steel Price
- FAQ’s About Duplex Steel Products
Types of Duplex Stainless Steel
We offer various types of duplex stainless steel products including duplex steel bars, duplex steel pipe, duplex steel plates & sheets etc. As a leading duplex stainless steel supplier offering duplex steel material grades with ASTM & ASME standard specifications with high quality.
Duplex Steel Specifications
Correct specification is critical to project success. Our duplex steel products conform to the following international standards:
|
Item |
Specification |
|---|---|
|
Common Grades |
UNS S31803 / S32205 (2205), DIN 1.4462, ASTM A182 F51 |
|
Product Standards |
A790 (pipe), A789 (tube), A240 (plate/sheet), A182 (flanges/forgings), A276/A479 (bars), A815 (buttweld fittings), EN 10088-3 |
|
Dimensional Refs |
ASME B36.19M (pipe), ASME B16.5/B16.47 (flanges), ASME B16.9 (BW fittings), ASME B16.11 (forged fittings) |
|
Finish / Condition |
Hot rolled, cold drawn, pickled & passivated, polished, solution annealed |
|
Documentation |
EN 10204 3.1 / 3.2 MTC, PMI report, heat charts |
|
Testing (options) |
ASTM A923 (intermetallic), ASTM G48 (pitting), UT/ET, hydrostatic |
|
Tolerances |
Per ASTM/ASME/EN; tight tolerances & cut lengths on request |
Duplex Steel Chemical Composition (%)
|
Grade (UNS) |
Cr |
Ni |
Mo |
N |
Others |
|---|---|---|---|---|---|
|
S31803 |
21.0–23.0 |
4.5–6.5 |
2.5–3.5 |
0.08–0.20 |
C ≤0.03, Mn ≤2.0 |
|
S32205 |
22.0–23.0 |
4.5–6.5 |
3.0–3.5 |
0.14–0.20 |
C ≤0.03, Mn ≤2.0 |
Duplex Steel Mechanical Properties
|
Property |
S31803 (2205) |
S32205 (2205) |
|---|---|---|
|
Tensile Strength (min) |
620 MPa (90 ksi) |
620 MPa (90 ksi) |
|
Yield Strength 0.2% (min) |
450 MPa (65 ksi) |
450 MPa (65 ksi) |
|
Elongation (min) |
25% |
25% |
|
Hardness (max) |
293 HB / 31 HRC |
293 HB / 31 HRC |
|
PREN (typical) |
≥ 34 |
≥ 35 |
Duplex Steel vs. Austenitic Stainless Steel
A quick comparison shows why duplex 2205 often outperforms conventional austenitic grades in corrosive, high-pressure service:
|
Property |
Duplex 2205 |
Austenitic 316L |
|---|---|---|
|
Yield Strength |
~450 MPa |
~205 MPa |
|
Chloride SCC Resistance |
Excellent |
Moderate |
|
Pitting Resistance (PREN) |
≥ 34 |
~24 |
|
Nickel Content |
Lower (4.5–6.5%) |
Higher (10–14%) |
|
Magnetic |
Yes (magnetic) |
No (non-magnetic) |
|
Relative Weight for Same Load |
Lighter |
Heavier |
|
Best For |
Aggressive/high-strength service |
General corrosion service |
Duplex Steel Applications & Industries
- Oil & Gas: pipelines, risers, manifolds and process equipment resistant to chloride stress-corrosion cracking.
- Chemical Processing: heat exchangers, pressure vessels and storage tanks handling aggressive media.
- Marine & Shipbuilding: propeller shafts, seawater systems and desalination plants with excellent seawater resistance.
- Pulp & Paper: digesters and bleaching equipment exposed to corrosive process chemicals.
- Power & Desalination: condensers, cooling systems and reverse-osmosis units.
- Water Treatment & Infrastructure: bridges, storage and structural components requiring durability with reduced weight.
Manufacturing, Quality & Certifications
Every batch of duplex steel we supply passes a controlled quality workflow before it leaves our facility. Material is verified by Positive Material Identification (PMI) and cross-checked against mill heat charts. Corrosion performance is validated through ASTM G48 pitting tests and ASTM A923 intermetallic-phase testing, while integrity is confirmed by ultrasonic (UT), eddy-current (ET) and hydrostatic testing where applicable.
Standards & Approvals We Work To
- ASTM / ASME / EN 10088 material and dimensional standards
- EN 10204 Type 3.1 & 3.2 material test certificates
- ISO-aligned quality management and traceability
- Compliance support for NACE MR0175 sour-service requirements
Duplex Steel Price
The price of duplex steel is influenced by grade, product form, size, order quantity, and the global cost of alloying elements such as nickel and molybdenum. While the initial cost is typically higher than standard austenitic grades like 304 or 316, duplex steel’s superior strength and corrosion resistance deliver significant long-term value by reducing maintenance, downtime, and replacement costs. Because duplex uses less nickel than austenitic grades, its pricing is often more stable against nickel market swings. For an accurate, project-specific quotation, contact the Kalpaturu Piping sales team.
