NORSOK M-630 / ASTM A995 / NACE MR0175

Duplex & Super Duplex Valve Manufacturer
& Exporter from India — S31803, S32750, S32760

Supreme Valves manufactures duplex (UNS S31803 / S32205) and super duplex (UNS S32750 / S32760) stainless steel industrial valves for the most demanding offshore, subsea, and chemical process applications. Our duplex valves deliver twice the yield strength of austenitic SS316 with superior chloride stress corrosion cracking resistance. PREN > 40 for super duplex grades ensures reliable performance in hot seawater and sour gas environments.

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NORSOK M-630 NACE Compliant Offshore / Subsea Gulf Specialist

Product Range

Duplex Gate Valve

A995 4A/5A body, bolted bonnet, OS&Y rising stem. For offshore topsides and chemical process isolation. NORSOK M-630 compliant.

2" to 24"

Duplex Globe Valve

Throttling and control in corrosive and high-pressure environments. Stellite #6 or Alloy 6B hardfaced trim for erosion resistance.

1/2" to 12"

Duplex/Super Duplex Ball Valve

Floating and trunnion designs. Fire-safe API 607. Double block and bleed. For pipeline, subsea manifolds, and chemical plants.

1/2" to 16"

Duplex Butterfly Valve

Triple-offset with duplex disc for seawater and offshore utility applications. Metal-to-metal seating for zero leakage and fire-safe operation.

4" to 48"

Duplex Check Valve

Swing, dual-plate, and axial flow check designs in duplex and super duplex. For preventing backflow in subsea and chemical piping.

2" to 24"

Super Duplex Subsea Valve

S32750/S32760 valves for subsea Christmas trees, manifolds, and jumper connections. Tested to PR2 per API 17D / API 6A.

2" to 12"

Technical Specifications

Parameter Specification
Design StandardsNORSOK M-630, API 600/602/6D/608/609, ASME B16.34
Duplex GradesA995 4A (UNS S31803/S32205), A890 4A, A182 F51, PREN ≥ 35
Super Duplex GradesA995 5A/6A (UNS S32750/S32760), A890 5A/6A, A182 F53/F55, PREN ≥ 40
Mechanical PropertiesYield: 450 MPa (duplex) / 550 MPa (super duplex) — double that of SS316
Corrosion TestsASTM G48 Method A (ferric chloride pitting) at 22°C (duplex) / 50°C (super duplex)
Metallurgical TestsFerrite content 30-70%, no sigma/chi phases per ASTM A923 / NORSOK M-630 Annex B
End ConnectionsFlanged RF/RTJ (ASME B16.5/B16.47), Butt Weld, Socket Weld, Hub-type subsea
Pressure ClassesANSI 150, 300, 600, 900, 1500, 2500
Sour ServiceNACE MR0175/ISO 15156 compliant, hardness ≤ 28 HRC
CertificationsCE/PED, NORSOK, NACE, DNV, SABER, TPI by Lloyd's/BV/TUV

Materials by Application

Duplex 2205 (S31803/S32205)

The standard duplex grade with twice the yield strength of SS316 and excellent chloride corrosion resistance (PREN ≥ 35). Cost-effective for moderate offshore and chemical applications.

  • Offshore topsides piping
  • Chemical processing
  • Pulp & paper
  • Heat exchangers

Super Duplex 2507 (S32750)

Higher Cr/Mo/N content gives PREN ≥ 40 for superior resistance to hot seawater, sour gas, and aggressive chloride environments. The premium grade for critical offshore service.

  • Subsea systems
  • Hot seawater cooling
  • Sour gas production
  • FPSOs and platforms

Zeron 100 (S32760)

The most corrosion-resistant super duplex grade with Cu addition for enhanced pitting resistance. PREN ≥ 42. Specified by major operators for the most aggressive offshore and subsea applications.

  • Subsea manifolds
  • Christmas tree valves
  • High-chloride wells
  • Deep water production

Industry Applications

Offshore Oil & Gas

Topsides process and utility piping, seawater cooling, and firewater systems. NORSOK-compliant duplex and super duplex valve packages.

Subsea Systems

Christmas tree valves, manifold isolation, and jumper connectors. Super duplex S32750/S32760 with API 17D qualification.

Chemical & Petrochemical

Chloride-bearing process streams, oxidizing acids, and environments where SS316 suffers stress corrosion cracking above 60°C.

Desalination

High-pressure RO pump discharge, energy recovery, and concentrated brine handling. Super duplex for brine above 40°C.

Sour Gas Production

NACE MR0175 compliant duplex valves for H2S-containing wellhead, separator, and pipeline service. Hardness-controlled for sour resistance.

Pulp & Paper

Bleach plant (ClO2, NaOCl), digesters, and black liquor handling. Duplex 2205 for combined chloride and alkaline resistance.

Export to Saudi Arabia & Gulf Region

We are an established exporter to Saudi Arabia, UAE, Qatar, Kuwait, Oman, and Bahrain. Our Gulf clients include EPC contractors, oilfield service companies, and industrial end-users.

  • SABER compliant — Full SASO certification for Saudi import
  • EN 10204 3.1 material test reports on all orders
  • Third-party inspection — Lloyd's, BV, TUV, SGS
  • FOB Mundra / CIF destination — flexible Incoterms
  • 4-hour RFQ response with detailed technical offer

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Response within 4 business hours with detailed technical offer

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Frequently Asked Questions

What is the advantage of duplex over SS316 for valves?
Duplex stainless steel offers three key advantages over SS316: (1) Double the yield strength (450 MPa vs 205 MPa), allowing thinner walls and lighter valves, (2) Superior chloride stress corrosion cracking resistance above 60°C, where SS316 is susceptible, (3) Better resistance to pitting and crevice corrosion (PREN 35+ vs 25 for SS316). The trade-off is higher material cost and more complex welding procedures.
When is super duplex required instead of standard duplex?
Super duplex (PREN ≥ 40) is required when: (1) seawater temperature exceeds 20°C, (2) the environment contains high chloride concentrations (>1000 ppm) at elevated temperatures, (3) sour service conditions per NACE MR0175 are severe, or (4) the project specification mandates NORSOK M-630 with PREN ≥ 40. Major offshore operators (Equinor, Shell, BP) typically specify super duplex for all seawater-wetted components.
What is PREN and why does it matter?
PREN (Pitting Resistance Equivalent Number) is calculated as: PREN = %Cr + 3.3×%Mo + 16×%N. It predicts pitting corrosion resistance in chloride environments. A higher PREN means better pitting resistance. Duplex 2205 has PREN ≥ 35, super duplex 2507 has PREN ≥ 40, and Zeron 100 has PREN ≥ 42. NORSOK M-630 requires PREN ≥ 40 for seawater-exposed valve components in offshore applications.
Why is ferrite content important in duplex valve castings?
Duplex steels achieve their properties from a balanced microstructure of approximately 50% ferrite and 50% austenite. NORSOK M-630 specifies 30-70% ferrite in the finished casting. Excessive ferrite (>70%) reduces toughness and corrosion resistance. Insufficient ferrite (<30%) reduces strength and stress corrosion cracking resistance. We verify ferrite content per ASTM E562 on every heat and provide ferrite reports with shipment.
Can you supply duplex valves for subsea applications?
Yes. We manufacture super duplex ball valves and gate valves for subsea service, tested to API 17D / API 6A requirements. Subsea valves undergo extended hydrostatic testing, hyperbaric gas testing, and are supplied with full NORSOK M-630 material documentation. We support subsea projects in the Gulf of Mexico, North Sea, and offshore Middle East with TPI by DNV, Lloyd's, or Bureau Veritas.

Related Pages

Duplex Valve Manufacturer Super Duplex Ball Valve Stainless Steel Valve Manufacturer 254 SMO Valves Subsea Valve Manufacturer Duplex Valves for Chloride Service Seawater Corrosion Allowance Guide

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