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Duplex & Super Duplex Stainless Steel

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Industrial Flanges

Sailesh Metal Corporation supplies duplex and super duplex stainless steel pipes, tubes and fittings for buyers who need more strength and better chloride-corrosion resistance than standard austenitic stainless can offer. Our range spans lean duplex through to fully alloyed super duplex — Duplex 2205, Duplex S31803, Duplex 2304, Super Duplex 2507 and Super Duplex S32760 — giving buyers a grade to match almost any combination of strength, corrosion duty and budget.

 

Duplex grades combine an austenite-ferrite dual-phase microstructure, which is what delivers roughly double the strength of common austenitic stainless alongside markedly better resistance to pitting, crevice corrosion and chloride stress-corrosion cracking. Drawing on our metals-trade experience since 1975, we help buyers work out which duplex family — lean, standard or super — actually fits their chloride exposure, pressure rating and budget, then supply against standard specification or project-specific drawings.

Quick Overview

Requirement

Available Range / Details

Grades Offered

Duplex 2205, Duplex S31803, Duplex 2304, Super Duplex 2507 and Super Duplex S32760

Product Forms

Seamless and welded pipes, tubes, fittings and allied piping components

Grade Families Covered

Lean duplex (2304), standard duplex (2205 / S31803) and super duplex (2507 / S32760)

UNS Designations

S32205, S31803, S32304, S32750, S32760

Standards

ASTM/ASME A182, A240, A276, A479, A789, A790, A928, and equivalent project specifications

Documentation

Material Test Certificate, chemical and mechanical test reports, and inspection documentation, subject to order terms and material availability

Customisation

Supply against standard sizes or customer drawings, based on grade, dimension, pressure/temperature duty and end-use application

Duplex & Super Duplex Grades Supplied

The table below sets out the grade family, UNS designation and corrosion performance level (expressed as PREN — pitting resistance equivalent number) for each grade we supply. Buyers should confirm the exact grade and applicable standard at the enquiry stage.

Trade Name

UNS / W.Nr.

PREN (indicative)

Duplex 2205

S32205 / 1.4462

~35

Duplex S31803

S31803 / 1.4462

~33–35

Duplex 2304

S32304 / 1.4362

~25

Super Duplex 2507

S32750 / 1.4410

≥40

Super Duplex S32760

S32760 / 1.4501

≥40

Technical Specifications

Parameter

Specification / Buyer Guidance

Applicable Standards

ASTM/ASME specifications relevant to each grade (see grade tables below) plus EN/DIN and project-specific documents where required

Nominal Size Range

1/2 in NB up to 24 in NB for pipe; sheet, plate, bar and fitting sizes available on enquiry, subject to grade and form

Wall Thickness / Schedule

SCH 5S to SCH 160, or as expressed by OD and wall thickness where the project specification requires it

Product Condition

Solution-annealed and quenched, in seamless or welded construction depending on grade and intended service

Testing

Chemical analysis, tensile and impact testing, ferrite content check, and hydrostatic or non-destructive examination as called for by the applicable standard and order

Traceability

Heat-number and lot traceability maintained through supply, with Material Test Certificates matching the ordered grade, condition and size

Grade-Wise Details

Duplex 2205 (S32205)

Duplex 2205 is the grade that most buyers mean when they simply say “duplex.” Its microstructure is split roughly evenly between austenite and ferrite, which is what gives it a combination that neither straight austenitic nor straight ferritic stainless can match — close to double the yield strength of 316L, alongside markedly better resistance to chloride pitting, crevice attack and stress-corrosion cracking. It’s the tightened, modern chemistry version of the original S31803 specification, with a narrower nitrogen band that keeps phase balance more consistent from heat to heat.

Reaches for it: offshore and onshore oil & gas piping, seawater and produced-water handling systems, desalination plants, and chemical process lines where 316L begins to show pitting or cracking under chloride exposure.

Specification

Detail

UNS / Werkstoff No.

S32205 / 1.4462

Grade Family

Standard Duplex (Austenitic-Ferritic)

Indicative Composition

Cr 22.0–23.0% | Ni 4.5–6.5% | Mo 3.0–3.5% | N 0.14–0.20% | Mn 2.0% max | C 0.03% max

Pitting Resistance (PREN)

~35

Governing Standards

ASTM/ASME A182, A240, A276, A479, A789, A790, A928

Temperature Range

Practical service band –50°C to +300°C for continuous duty

 

Duplex S31803 (S31803)

S31803 is the original duplex specification that 2205 was built on, and it remains a valid, separately callable grade in its own right — some project specifications still nominate it by name. It carries a slightly wider chemical composition window than the modern S32205 chemistry, particularly on nitrogen content, which gives mills more flexibility during production while still delivering the same fundamental austenite-ferrite balance and chloride-corrosion advantage over 300-series stainless.

Reaches for it: general oil & gas and chemical process piping, marine and brackish-water systems, and any project specification that calls out S31803 by designation rather than the tightened S32205 chemistry.

Specification

Detail

UNS / Werkstoff No.

S31803 / 1.4462

Grade Family

Standard Duplex (Austenitic-Ferritic)

Indicative Composition

Cr 21.0–23.0% | Ni 4.5–6.5% | Mo 2.5–3.5% | N 0.08–0.20% | Mn 2.0% max | C 0.03% max

Pitting Resistance (PREN)

~33–35

Governing Standards

ASTM/ASME A182, A240, A276, A479, A789, A790, A928

Temperature Range

Practical service band –50°C to +300°C for continuous duty

 

Duplex 2304 (S32304)

Duplex 2304 is the economical end of the duplex family — it carries no deliberate molybdenum addition, which keeps material cost down while still delivering the same dual-phase strength advantage over austenitic grades. Its corrosion resistance sits close to 316L in most chloride environments rather than exceeding it, so it’s best suited to projects where the main draw is mechanical strength and general corrosion resistance rather than maximum resistance to aggressive, high-chloride media.

Reaches for it: structural and pressure-vessel applications, tanks and storage vessels, general process piping, and projects where the higher strength of duplex is wanted without paying for the corrosion margin of 2205 or super duplex grades.

Specification

Detail

UNS / Werkstoff No.

S32304 / 1.4362

Grade Family

Lean Duplex (Austenitic-Ferritic, molybdenum-free)

Indicative Composition

Cr 21.5–24.5% | Ni 3.0–5.5% | Mo 0.05–0.60% | N 0.05–0.20% | Mn 2.5% max | C 0.03% max

Pitting Resistance (PREN)

~25

Governing Standards

ASTM/ASME A240, A789, A790

Temperature Range

Practical service band –50°C to +300°C for continuous duty

 

Super Duplex 2507 (S32750)

Super Duplex 2507 pushes chromium, molybdenum and nitrogen well beyond standard duplex levels, giving it a pitting resistance equivalent number above 40 — comfortably ahead of 2205 and firmly in the range needed for the harshest chloride and sour-service conditions. That extra alloying also lifts mechanical strength further still, which is why it’s routinely specified where downsizing wall thickness matters as much as corrosion life.

Reaches for it: subsea and deepwater oil & gas components, seawater injection and firewater systems, desalination plants handling high-salinity feedwater, and offshore structural piping under severe chloride exposure.

Specification

Detail

UNS / Werkstoff No.

S32750 / 1.4410

Grade Family

Super Duplex (Austenitic-Ferritic, high-alloy)

Indicative Composition

Cr 24.0–26.0% | Ni 6.0–8.0% | Mo 3.0–5.0% | N 0.24–0.32% | Mn 1.2% max | C 0.03% max

Pitting Resistance (PREN)

≥40

Governing Standards

ASTM/ASME A182, A240, A276, A479, A789, A790

Temperature Range

Practical service band –50°C to +300°C for continuous duty

 

Super Duplex S32760 (S32760)

S32760 follows the same super-duplex playbook as 2507 — high chromium, molybdenum and nitrogen for a PREN of 40 or above — but adds small, deliberate quantities of tungsten and copper into the mix. Tungsten sharpens resistance to localised attack in aggressive chloride media, while copper improves resistance to sulphuric acid and general corrosion in reducing conditions, giving this grade a slightly different corrosion profile from 2507 even though the two compete for many of the same applications.

Reaches for it: seawater cooling and firewater systems, sour and high-chloride oil & gas service, chemical tankers and marine process equipment, and pulp & paper or chemical plant equipment exposed to acidic, chloride-bearing media.

Specification

Detail

UNS / Werkstoff No.

S32760 / 1.4501

Grade Family

Super Duplex (Austenitic-Ferritic, tungsten & copper-modified)

Indicative Composition

Cr 24.0–26.0% | Ni 6.0–8.0% | Mo 3.0–4.0% | W 0.5–1.0% | Cu 0.5–1.0% | N 0.20–0.30%

Pitting Resistance (PREN)

≥40

Governing Standards

ASTM/ASME A182, A240, A276, A479, A789, A790

Temperature Range

Practical service band –50°C to +300°C for continuous duty

 

  • Industries & Applications Served

    Duplex and super duplex piping from Sailesh Metal Corporation is supplied into sectors where chloride exposure, mechanical loading or both push standard stainless steel beyond its comfortable limits, including:

    • Offshore and onshore oil & gas production, including sour and high-pressure service
    • Seawater handling, injection and firewater systems
    • Desalination and water treatment plants
    • Marine, shipbuilding and offshore structural piping
    • Chemical and petrochemical process plants handling chloride-bearing media
    • Pulp, paper and other process industries with acidic, chloride-heavy streams
    • Pressure vessels, storage tanks and structural applications requiring higher strength-to-weight

  • Why Choose Sailesh Metal Corporation

    • Metals trade experience since 1975
    • Full duplex range from lean duplex through to super duplex under one roof
    • Support for both standard specification supply and drawing-based, project-specific requirements
    • Grade-selection guidance based on chloride exposure, pressure rating and budget
    • Mumbai-based supply operation serving industrial buyers across India and export markets
    • Capacity to support large-volume project requirements alongside smaller trade quantities

  • How to Send an Enquiry

    Share the following details so our team can quote accurately:

    • Grade required: 2205, S31803, 2304, 2507 or S32760
    • Product form: pipe, tube or fitting
    • Size, schedule or wall thickness, and length requirement
    • Applicable standard and product condition
    • Quantity required
    • Drawing, if the requirement is project-specific or non-standard
    • Application details such as chloride/media exposure, temperature, pressure and industry, where available

  • Frequently Asked Questions

    1. What is the difference between Duplex 2205 and Duplex S31803?
    2. Both share the same base chemistry and W.Nr. 1.4462 designation, but S32205 (2205) carries a narrower nitrogen specification than the original S31803, giving more consistent phase balance. Many current project specifications call for S32205 specifically.

    3. When should I choose Duplex 2304 instead of Duplex 2205?
    4. Duplex 2304 is a molybdenum-free lean duplex, more economical than 2205, and a good fit where the priority is mechanical strength and moderate corrosion resistance rather than maximum resistance to aggressive chloride media.

    5. What does PREN mean, and why does it matter for grade selection?
    6. PREN (pitting resistance equivalent number) is a calculated index based on chromium, molybdenum and nitrogen content, used to compare how resistant different grades are to pitting and crevice corrosion. Super duplex grades with a PREN of 40 or above are chosen for the most aggressive chloride environments.

    7. What is the difference between Super Duplex 2507 and Super Duplex S32760?
    8. Both are super duplex grades with comparable PREN levels, but S32760 (Zeron 100) includes tungsten and copper additions that improve resistance to localised attack and reducing acid conditions, giving it a slightly different corrosion profile from 2507.

    9. Do you provide Material Test Certificates with duplex and super duplex supply?
    10. Yes. Material Test Certificates, along with chemical and mechanical test reports, can be provided as per order terms and material availability.

    11. Can you supply duplex and super duplex pipes and fittings as per project drawings?
    12. Yes, supply against customer drawings and project-specific requirements is available, subject to grade, size and quantity.

Share your flange requirement with our team for grade selection, availability and pricing support.
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1006/ 1007, Prasad Chamber,
Swadeshi Mill Compound,
Opera House,
Mumbai – 400 004.

+91 22 2363 3706 /
+91 22 4971 7193

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