Duplex Stainless Steel Fasteners
Duplex and super duplex stainless steels combine the beneficial properties of both austenitic and ferritic stainless steels, offering approximately twice the strength of austenitic stainless steel along with superior corrosion resistance, particularly to stress corrosion cracking and chloride pitting.
Common Grades
UNS S31803 (2205)
Standard duplex grade, ASTM A182 F51
22% Cr, 5% Ni, 3% Mo
UNS S32205
Improved version of 2205
Higher strength and corrosion resistance
UNS S32750 (2507)
Super duplex grade, ASTM A182 F53
25% Cr, 7% Ni, 4% Mo
UNS S32760 (Zeron 100)
Super duplex with tungsten
Enhanced pitting resistance
UNS S32950
High performance super duplex
Excellent chloride resistance
UNS S32550 (Ferralium 255)
Super duplex for marine service
High strength and toughness
Product Range
| Product Type | Available Grades | Size Range |
|---|---|---|
| Stud Bolts | S31803, S32205, S32750, S32760 | M6 to M100, 1/4" to 4" |
| Hex Bolts | S31803, S32205, S32750 | M6 to M64 |
| Nuts | All duplex grades | M6 to M100 |
| Washers | All duplex grades | M6 to M100 |
| Threaded Rods | S31803, S32205, S32750 | Custom lengths available |
Specifications & Standards
- ASTM A182 - Forged duplex stainless steel fittings and flanges
- ASTM A479 - Stainless steel bars and shapes
- ASTM A276 - Stainless steel bars and shapes
- NACE MR0175/ISO 15156 - Sour service compliant
- NORSOK M-650 - Qualified duplex bolting
Applications
Offshore Platforms
Seawater resistance and high strength
Subsea Equipment
Deep water applications
Chemical Tankers
Chloride and acid resistance
Desalination Plants
Brine and saltwater service
Pulp & Paper
Bleaching and chemical processing
Oil & Gas Production
Sour gas and high chloride environments
Key Properties
Yield Strength: 450-550 MPa (approximately 2x austenitic SS)
Tensile Strength: 620-880 MPa
Corrosion Resistance: Superior to 316/316L in chloride environments
Temperature Range: -50°C to 250°C (Super Duplex)
PREN Value: 2205: ≥35, 2507: ≥40 (Pitting Resistance Equivalent Number)