Super Duplex Fasteners Supplier
MT.BOLTS manufactures Super Duplex Fasteners using high-strength, corrosion-resistant duplex stainless steels such as UNS S32750 and UNS S32760. These fasteners are engineered to perform reliably in aggressive environments involving chlorides, seawater, and high-pressure chemical systems. They are widely utilized in industries such as offshore oil & gas, marine engineering, desalination plants, and chemical processing.
Our SUPER DUPLEX fasteners have the following specifications:
Diameter: M3 to M64 | #4 to 2.5″
Length: 6 mm to 500 mm | 0.25″ to 20″
Thread Pitch: Metric (Coarse/Fine) | UNC/UNF
Standards: ASME B18.2.1, ASME B18.3, ASME B18.2.2, DIN/ISO/EN (e.g., DIN 933, DIN 934)
Material Specifications:
ASTM A479 (for bars and rods)
ASTM A182 (for forged components)
UNS S32750 / S32760
Types: Bolts, Screws, Nuts, Washers, Studs, Threaded Rods
We regularly supply Super Duplex fasteners and bolts made from high-performance duplex stainless steels such as Super Duplex S32750 and S32760. For your procurement reference, their chemical composition and key characteristics are provided below:
| Alloy Grade | UNS Number | Characteristics |
| Super Duplex 2507 | S32750 | Excellent resistance to chloride-induced pitting and crevice corrosion; high strength and stress corrosion cracking resistance; ideal for marine, offshore, and chemical environments. |
| Super Duplex Zeron 100 | S32760 | Enhanced mechanical strength and corrosion resistance; contains tungsten and copper for better performance in highly corrosive media and high-pressure systems. |
These fasteners are commonly used in offshore platforms, desalination systems, chemical processing plants, and other aggressive industrial environments requiring both corrosion resistance and mechanical strength.
Super Duplex Fasteners Chemical Composition
Typical chemical composition (% by weight) for UNS S32750 / S32760:
| Element | Content (%) |
| Chromium (Cr) | 24.0 – 26.0 |
| Nickel (Ni) | 6.0 – 8.0 |
| Molybdenum (Mo) | 3.0 – 5.0 |
| Nitrogen (N) | 0.24 – 0.35 |
| Manganese (Mn) | ≤ 1.20 |
| Silicon (Si) | ≤ 0.80 |
| Carbon (C) | ≤ 0.030 |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.020 |
| Iron (Fe) | Balance |
Super Duplex Fasteners Mechanical Properties
Typical values for S32750 / S32760 (in annealed condition):
| Property | Value |
| Tensile Strength | ≥ 795 MPa |
| Yield Strength (0.2% offset) | ≥ 550 MPa |
| Elongation | ≥ 25% |
| Hardness (Brinell) | ≤ 310 HB |
| Impact Toughness | Excellent at sub-zero temperatures |
Super Duplex Fasteners Types
MT.BOLTS offers a comprehensive range of Super Duplex Fasteners for your selection to meet various application requirements:
Super Duplex Hex Head Screw Bolts
Super Duplex Square Head Bolts
Super Duplex Flange Bolts
Super Duplex Serrated Flange Bolts
Super Duplex Eye bolts
Super Duplex Carriage Bolts
Super Duplex Elevator Bolts
Super Duplex U-Bolts
Super Duplex Anchor Bolts
Super Duplex Expansion Bolt
Super Duplex Lag Bolts
Super Duplex U-Bolts
Super Duplex Hex Head Lag Screws
Super Duplex Shoulder Screws
Super Duplex Socket Cap Screws
Super Duplex Self-Tapping Screws
Super Duplex Hex Nuts
Super Duplex Serrated Flange Nuts
Super Duplex Lock Nuts
Super Duplex Wing Nuts
Super Duplex Coupling Nut
Super Duplex Square Nuts
Super Duplex Acorn Nuts
Super Duplex Wing Nuts
Super Duplex Fully Threaded Rods & Studs
Super Duplex Equal Thread Length Rods & Studs
Super Duplex Unequal Thread Length Rods & Studs
Super Duplex Single End Threaded Studs
Super Duplex Weld Studs
Super Duplex Press-In Captive Studs
Super Duplex Flat Washers
Super Duplex Lock Washers
Super Duplex Curved Washers
Super Duplex Wave Washers
Super Duplex Square Washers
Super Duplex Belleville Washers
Why Choose MT.BOLTS
- Material Diversity
- Standardized Production
- Ample Inventory
- Competitive Pricing
- Low-MOQ Customization
Reasons to Choose Super Duplex Fasteners
Exceptional Corrosion Resistance – Especially in chloride-rich environments (e.g., seawater, brines).
High Mechanical Strength – Nearly twice the strength of austenitic stainless steels.
Excellent Stress Corrosion Cracking Resistance – Ideal for offshore, subsea, and chemical applications.
Cost-effective in the long run – Due to reduced maintenance and longer service life.
Good Weldability – Can be fabricated with appropriate techniques.
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Application of Super Duplex Fasteners
Offshore oil & gas platforms
Marine & shipbuilding
Desalination plants
Chemical processing units
Pulp & paper mills
Heat exchangers and pressure vessels
Structural components in aggressive environments
FAQ About Super Duplex Fasteners and Bolts
Super duplex has higher chromium, molybdenum, and nitrogen levels than duplex, offering better strength and corrosion resistance.
Yes, due to the ferritic phase in their microstructure.
Yes, but welding must be done carefully to maintain the desired phase balance and prevent embrittlement.
They are highly resistant to seawater corrosion, making them ideal for marine use.
Common standards include ASTM A479, ASTM A276, and EN 1.4410 / 1.4501 depending on the grade.
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