In industries where corrosion resistance, strength, and durability are critical, duplex stainless steel fasteners have become the preferred fastening solution. From offshore oil platforms to chemical processing plants, duplex fasteners deliver superior performance in aggressive environments.
At Unifit Metalloys, we are a globally trusted duplex fasteners manufacturer, exporter, and supplier of high-performance Duplex 2205 and Super Duplex 2507 fasteners. With advanced manufacturing capabilities and strict quality control, we deliver reliable fastening solutions to industries worldwide.
This guide explains duplex grades, specifications, chemical composition, benefits, and why choosing the right duplex steel fasteners manufacturer matters.
What Are Duplex Stainless Steel Fasteners?
Duplex stainless steel fasteners are made from a dual-phase microstructure consisting of austenite and ferrite. This combination provides:
- Higher strength than conventional stainless steel
- Excellent resistance to stress corrosion cracking
- Superior pitting and crevice corrosion resistance
- Extended service life in chloride environments
Because of these properties, duplex stainless steel fasteners are widely used in marine, chemical, oil & gas, and power generation industries.
As an experienced duplex fasteners manufacturer, Unifit Metalloys ensures precision engineering and compliance with global standards.
Types of Duplex Fasteners We Manufacture
Duplex 2205 Fasteners (S31803 / S32205)
Duplex 2205 fasteners are the most widely used duplex grade. They provide excellent corrosion resistance and high tensile strength.
Key Features:
- Chromium: 21–23%
- Good weldability
- High mechanical strength
- Excellent chloride resistance
Common Products:
- Duplex 2205 bolts
- Stud bolts
- Hex nuts
- Threaded rods
- Washers
These fasteners are ideal for heat exchangers, pipelines, and chemical equipment.
Super Duplex 2507 Fasteners (S32750 / S32760)
For highly aggressive environments, Super Duplex 2507 fasteners offer even greater resistance and strength.
Key Features:
- Chromium: 24–26%
- High molybdenum content
- Exceptional pitting resistance
- Superior stress corrosion cracking resistance
Common Products:
- Super duplex bolt
- Heavy hex bolts
- Stud bolts
- Custom CNC fasteners
Super duplex fasteners are widely used in offshore drilling, desalination plants, and marine applications.
Chemical Composition of Duplex Stainless Steel Grades
As a leading duplex fasteners manufacturer, we use certified raw materials that meet international specifications.
| Grade | C | Mn | Si | P | S | Cr | Mo | Ni | N | Fe |
|---|---|---|---|---|---|---|---|---|---|---|
| Duplex S31803 | 0.030 max | 2.00 max | 1.00 max | 0.030 max | 0.020 max | 22.0 – 23.0 | 3.0 – 3.5 | 4.50 – 6.50 | 0.14 – 0.20 | 63.72 min |
| Duplex S32205 | 0.030 max | 2.00 max | 1.00 max | 0.030 max | 0.020 max | 21.0 – 23.0 | 2.50 – 3.50 | 4.50 – 6.50 | 0.14 – 0.20 | 63.54 min |
| Duplex S32750 | 0.030 max | 1.20 max | 0.80 max | 0.035 max | 0.020 max | 24.00 – 26.00 | 3.00 – 5.00 | 6.00 – 8.00 | 0.24 – 0.32 | 58.095 min |
| Duplex S32760 | 0.05 max | 1.00 max | 1.00 max | 0.030 max | 0.010 max | 24.00 – 26.00 | 3.00 – 4.00 | 6.00 – 8.00 | 0.20 – 0.30 | 57.61 min |
The higher chromium, molybdenum, and nitrogen levels in super duplex grades provide superior corrosion resistance.
Specifications of Duplex Fasteners
As a professional duplex fasteners manufacturer, exporter, and supplier, Unifit Metalloys manufactures products according to international standards.
| Specification Category | Details |
|---|---|
| Product Types | Hex bolts, Heavy hex bolts, Stud bolts, Threaded rods, Nuts, Washers, Custom fasteners |
| Grades | S31803, S32205 (Duplex 2205), S32750, S32760 (Super Duplex 2507) |
| Standards | ASTM A182, ASTM A276, ASTM A479, ASTM A240, ASTM A193, ASTM A194 |
| Size Range (Metric) | M6 to M100 |
| Size Range (Inch) | 1/4” to 4” |
| Length | Up to 5 meters or as required |
| Thread Types | UNC, UNF, Metric Coarse, Metric Fine, Custom Threads |
| Manufacturing Process | Hot forged, Cold forged, CNC machined, Thread rolled |
| Surface Finish | Plain, Polished, Coated, As per requirement |
| Testing | PMI, Mechanical testing, Hardness test, Corrosion test, Third-party inspection |
Benefits of Choosing a Reliable Duplex Fasteners Manufacturer
Selecting a certified duplex steel fasteners manufacturer ensures:
1. Quality Assurance
Use of certified raw materials and proper heat treatment.
2. Dimensional Accuracy
Precision machining and thread rolling.
3. Compliance with Global Standards
Products meet ASTM and international specifications.
4. Custom Solutions
Tailored super duplex bolts and duplex 2205 fasteners for project-specific needs.
5. Global Export Capability
On-time delivery with complete documentation.
Applications of Duplex and Super Duplex Fasteners
As a trusted duplex fasteners manufacturer, we serve industries such as:
- Oil & Gas
- Petrochemical
- Marine & Shipbuilding
- Desalination Plants
- Power Generation
- Pulp & Paper
- Heat Exchanger Manufacturing
Duplex 2205 bolts are ideal for moderate chloride environments, while super duplex fasteners are recommended for extreme offshore and marine applications.
Why Choose Unifit Metalloys?
Unifit Metalloys stands out as a dependable duplex fasteners manufacturer, exporter, and supplier due to:
• Premium quality materials
• Modern manufacturing facilities
• Strict inspection procedures
• Competitive pricing
• Custom engineering support
• Global shipping network
We specialize in Duplex 2205 fasteners, Super Duplex 2507 fasteners, duplex stainless steel bolts, and precision-engineered super duplex bolts for critical industrial projects.
Final Thoughts
When performance, strength, and corrosion resistance are essential, duplex stainless steel fasteners provide unmatched reliability. Whether you require Duplex 2205 bolts for chemical plants or Super Duplex 2507 fasteners for offshore platforms, choosing the right duplex fasteners manufacturer is crucial.
Unifit Metalloys combines expertise, precision manufacturing, and global supply capabilities to deliver high-performance duplex steel fasteners that meet the toughest industry standards.
Contact us today to get a customized quotation for your duplex fastener requirements.
Frequently Asked Questions (FAQs)
1. Who is a reliable duplex fasteners manufacturer for industrial projects?
A reliable duplex fasteners manufacturer should offer certified raw materials, strict quality testing, and compliance with ASTM standards. Unifit Metalloys is a trusted duplex fasteners manufacturer, exporter, and supplier providing Duplex 2205 and Super Duplex 2507 fasteners for global industries.
2. What is the difference between Duplex 2205 and Super Duplex 2507 fasteners?
Duplex 2205 fasteners offer excellent strength and corrosion resistance for moderately aggressive environments. Super Duplex 2507 fasteners provide higher chromium, molybdenum, and nitrogen content, making them suitable for offshore and high-chloride applications. A professional duplex fasteners manufacturer can help you select the right grade based on your project requirements.
3. What industries use duplex stainless steel fasteners?
Duplex stainless steel fasteners are widely used in oil & gas, petrochemical, marine, desalination, and power generation industries. A certified duplex fasteners manufacturer ensures these fasteners meet high-pressure and corrosive environment standards.
4. Do duplex fasteners require special maintenance?
Duplex fasteners are highly resistant to corrosion and require minimal maintenance compared to standard stainless steel fasteners. However, proper installation and periodic inspection are recommended for critical applications.
5. Can a duplex fasteners manufacturer provide custom sizes?
Yes. An experienced duplex fasteners manufacturer like Unifit Metalloys can supply custom Duplex 2205 bolts, Super Duplex 2507 fasteners, threaded rods, and special CNC-machined components according to project specifications.