COMPREHENSIVE TECHNICAL ANALYSIS AND DATASHEET OF ZERON 100 (UNS S32760) FASTENING SYSTEMS
Zeron 100 (officially designated as UNS S32760 or F55) is an elite "Super Duplex" stainless steel, engineered for absolute reliability in aggressive chloride-containing and acidic environments. Characterized by a perfectly balanced 50/50 austenitic-ferritic microstructure, this alloy distinguishes itself from standard super duplex grades (like 2507) through the intentional, synergistic additions of Tungsten (W) and Copper (Cu).
This advanced chemistry yields a guaranteed Pitting Resistance Equivalent Number (PREN) exceeding 40, ensuring virtual immunity to seawater pitting and crevice corrosion. Furthermore, its duplex structure provides a minimum yield strength that is more than double that of standard 316L stainless steel. It is the premier fastening solution for deep-water subsea hardware, high-pressure desalination pumps, and highly corrosive mineral processing environments where immense mechanical loads meet relentless chemical attack.
■ Product Overview & Specifications
Zeron 100 fasteners are supplied in the solution-annealed and water-quenched condition to ensure the correct phase balance and to suppress the formation of detrimental intermetallic phases (such as sigma phase).
| Material Classification | Super Duplex Stainless Steel (Copper & Tungsten Alloyed) |
|---|---|
| UNS Designation | S32760 (F55) |
| Microstructure | Ferritic-Austenitic (Approx. 50/50 balance) |
| Magnetic State | Magnetic (Due to ferrite phase) |
| Density | ~7.81 g/cm³ (0.282 lb/in³) |
| Temperature Limits | -50°C to +300°C (-58°F to 572°F) |
| Size Range | Metric: M6 to M100 | Imperial: 1/4" to 4" Custom subsea flange bolting and heavy hex nuts available. |
| Thread Types | UNC, UNF, 8UN, Metric Coarse, Metric Fine |
■ Proprietary Datasheet Download (GATED)
Access professional-grade technical data for Zeron 100, including detailed ASTM G48 pitting test results, sub-zero Charpy V-notch impact toughness charts, and NACE MR0175 sour service compliance parameters.
Zeron 100 (S32760) — Complete Technical Datasheet
Contains specific chloride stress-corrosion cracking thresholds, PREN verification formulas, and severe-service torque mapping for API 6A subsea wellhead equipment.
⬇ DOWNLOAD DATASHEET■ MTC Integration Section
For critical infrastructure in offshore and subsea environments, Ananka Group provides 100% material traceability and strict microstructural verification.
- EN 10204 Type 3.1: Detailed reporting of actual chemical analysis (verifying PREN > 40), mechanical tests, and crucial ASTM E562 metallographic examination to guarantee phase balance and absence of sigma phase.
- EN 10204 Type 3.2: Third-party witness testing (e.g., DNV, ABS, TUV) facilitated for high-pressure subsea manifolds and FPSO seawater injection systems.
■ Chemical Composition (UNS S32760)
The alloy derives its "Super" classification from its 25% Chromium and high Molybdenum content. The specific addition of Tungsten enhances localized corrosion resistance, while Copper drastically improves resistance to non-oxidizing acids like sulfuric acid.
| Chromium (Cr) | Nickel (Ni) | Moly (Mo) | Tungsten (W) | Copper (Cu) | Nitrogen (N) | Carbon (C) |
|---|---|---|---|---|---|---|
| 24.0 – 26.0 | 6.00 – 8.00 | 3.00 – 4.00 | 0.50 – 1.00 | 0.50 – 1.00 | 0.20 – 0.30 | 0.03 Max |
*Silicon (1.00 Max) and Manganese (1.00 Max) are controlled. Pitting Resistance Equivalent Number (PREN = Cr + 3.3Mo + 16N) is guaranteed to be ≥ 40.
■ Mechanical Properties
Zeron 100 offers phenomenal strength. Its yield strength allows for significant wall-thickness and fastener size reductions in high-pressure system designs, providing massive weight savings on offshore platforms.
| Property | Solution Annealed Condition (Typical Minimums) |
|---|---|
| Tensile Strength (Min) | 109 ksi (750 MPa) |
| Yield Strength (0.2% Offset, Min) | 80 ksi (550 MPa) |
| Elongation in 2" (Min) | 25% |
| Hardness (Max) | ~28 HRC (Strictly maintained for NACE sour service compliance) |
■ Equivalent Grades & Designations
| Standard / System | Designation |
|---|---|
| UNS Designation | S32760 |
| Common Trade Name | Zeron 100® (Trademark of Rolled Alloys) |
| ASTM Fastener Specs | ASTM A1082, ASTM A276, ASTM A479 |
| European / Forging Code | EN 1.4501 / X2CrNiMoCuWN25-7-4 / ASTM A182 F55 |
■ Corrosion Resistance Profile
Zeron 100 is engineered to excel where standard austenitic steels (316L, 904L) and standard duplex steels (2205) suffer catastrophic failure:
- Seawater Pitting: A PREN of >40 provides absolute resistance to pitting and crevice corrosion in warm, chlorinated seawater.
- Stress Corrosion Cracking (SCC): The ferritic phase provides near-total immunity to chloride SCC in high-temperature, high-pressure environments.
- Sour Service (H2S): Fully approved under NACE MR0175 / ISO 15156 for use in sour gas oilfield environments.
- Acid Resistance: The unique Copper and Tungsten additions provide superior resistance to sulfuric and hydrochloric acids across a wide range of concentrations compared to Alloy 2507.
■ Applications & Industries
UNS S32760 is specifically deployed in environments requiring high structural load capacity and extreme corrosion resistance:
- Subsea & Offshore: ROV hardware, subsea manifolds, umbilical connections, and splash-zone structural fastening.
- Desalination: High-pressure RO (Reverse Osmosis) pump bolting, headers, and brine heater fasteners.
- Chemical Processing: Pressure vessels and heat exchangers handling aggressive chloride and sulfuric acid mixtures.
- Pollution Control: Absorber towers, ducting, and spray headers in Flue Gas Desulfurization (FGD) systems.
■ Compatible Fastener Assemblies
To avoid galvanic corrosion in conductive electrolytes (like seawater) and to ensure uniform strength and thermal expansion, mating components must match metallurgically.
| External Threads (Zeron 100) | Recommended Mating Component (Nuts) |
|---|---|
| Zeron 100 Stud Bolts | Zeron 100 Heavy Hex Nuts |
| Zeron 100 Hex Bolts | Zeron 100 Standard / Heavy Hex Nuts |
■ Torque & Installation Guidelines
The extremely high yield strength of Zeron 100 supports immense clamping forces. However, high-performance anti-seize pastes (Nickel or MoS2 based) are strictly required to prevent thread galling, especially when installing large diameter subsea flanges.
| Nominal Diameter | Threads Per Inch (UNC) | Target Torque — Lubricated (ft-lbs) |
|---|---|---|
| 1/2" | 13 | 65 - 80 |
| 5/8" | 11 | 130 - 160 |
| 3/4" | 10 | 230 - 270 |
| 1" | 8 | 550 - 640 |
■ Why Choose Ananka Group?
Ananka Group guarantees the flawless execution of advanced duplex metallurgy, providing the offshore and chemical industries with infallible fastening packages.
- Phase Balance Verification: We strictly monitor cooling rates during solution annealing and perform metallographic testing to guarantee the critical 50/50 austenite-ferrite ratio and verify the complete absence of embrittling sigma phase.
- NACE Compliance: Strict hardness controls are maintained (Max 28 HRC) to ensure all Zeron 100 fasteners are fully compliant for sour gas (H2S) service.
- Rolled Threads: External and internal threads are rolled whenever feasible, significantly increasing cyclic fatigue life under subsea pressures.
- 100% Traceability: Every fastener is marked with a heat number and provided with a comprehensive EN 10204 3.1 MTC.
■ Frequently Asked Questions
1. What is the difference between Zeron 100 (S32760) and Alloy 2507 (S32750)?
Both are highly capable Super Duplex stainless steels with a PREN > 40. The primary difference is chemistry: Zeron 100 (S32760) contains specific additions of Copper and Tungsten. This gives Zeron 100 slightly better overall corrosion resistance in reducing acids (like sulfuric and hydrochloric acid) compared to standard 2507.
2. Is Zeron 100 magnetic?
Yes. Because its microstructure contains approximately 50% ferrite (which is strongly magnetic), Zeron 100 is magnetic. It should not be used in applications requiring low magnetic permeability.
3. Can Zeron 100 be used in cryogenic temperatures?
Zeron 100 retains excellent impact toughness down to -50°C (-58°F). However, below this temperature, the ferritic phase begins to transition to a brittle state. It is not suitable for deep cryogenic service (like liquid nitrogen or LNG storage), where austenitic alloys are required.
4. What does PREN > 40 mean?
PREN (Pitting Resistance Equivalent Number) is a predictive metric for resistance to chloride pitting. A PREN of 40 is the generally accepted threshold for a metal to be classified as a "Super" alloy capable of surviving indefinite exposure to warm, corrosive seawater without pitting.