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Super Duplex Steel 2507 Bolt
QS Fastener: Super Duplex Steel 2507 Bolt
Name: Super Duplex Steel 2507 Bolt
Standard: ANSI, DIN, UNS, ASTM
Material: S32750
Size: 5/16 to 4 inch
Length: 30 to 3000 mm
Grade: A
Class: 12.9
Application: Used for Chemical Processing, Petrochemicals and Subsea Equipment
Standard: ANSI, DIN, UNS, ASTM
Material: S32750
Size: 5/16 to 4 inch
Length: 30 to 3000 mm
Grade: A
Class: 12.9
Application: Used for Chemical Processing, Petrochemicals and Subsea Equipment
Quantity
Super Duplex Steel 2507 Bolts are manufactured from premium S32750 material, compliant with international standards including ASTM, ANSI, and DIN. Available in sizes ranging from 5/16"to 4"(30mm to 3000mm) with Grade A/12.9 strength classification. These bolts deliver exceptional corrosion resistance, high tensile strength, and stress cracking resistance, specifically engineered for demanding applications in chemical processing, petrochemical, and subsea equipment - making them ideal fasteners for high-temperature, high-pressure, and high-chloride environments.
Super Duplex Stainless Steel 2507 (UNS S32750) combines near-nickel-alloy corrosion resistance and mechanical properties at significantly lower cost, establishing Super Duplex Steel 2507 Bolts as the economical choice for highly corrosive environments. Compared to nickel alloys like Hastelloy (C276, C22) and Inconel 625, 2507 demonstrates clear advantages in chloride resistance, mechanical strength, and procurement costs for high-strength fastening applications across petrochemical, offshore, and acidic environments.
1. Cost Comparison: 2507 vs. Nickel Alloys
Nickel alloys' high costs stem from ≥50% nickel content and precious metal additions (Mo, Cr), while Super Duplex Steel 2507 Bolts contain only 6-8% nickel for superior cost efficiency:
Nickel alloys' high costs stem from ≥50% nickel content and precious metal additions (Mo, Cr), while Super Duplex Steel 2507 Bolts contain only 6-8% nickel for superior cost efficiency:
| Material | Typical Composition (wt%) | Ni Content (%) | Market Price (¥/ton, 2024) |
| 2507 (S32750) | Cr25-Ni7-Mo3.5-N0.28 | 7 | 60,000–80,000 |
| Hastelloy C276 | Ni57-Cr16-Mo16-W4-Fe5 | 57 | 350,000–450,000 |
| Inconel 625 | Ni58-Cr21-Mo9-Nb3 | 58 | 300,000–400,000 |
Cost Advantages:
- Super Duplex Steel 2507 Bolts cost merely 1/5–1/6 of Hastelloy C276 bolts and 1/4–1/5 of Inconel 625 bolts.
- Compared to 6Mo super austenitic stainless steels (e.g., 254SMO), 2507 offers 30–40% cost savings while maintaining equivalent PREN (≥40).
- Super Duplex Steel 2507 Bolts cost merely 1/5–1/6 of Hastelloy C276 bolts and 1/4–1/5 of Inconel 625 bolts.
- Compared to 6Mo super austenitic stainless steels (e.g., 254SMO), 2507 offers 30–40% cost savings while maintaining equivalent PREN (≥40).
2. Corrosion Resistance Performance
Super Duplex Steel 2507 Bolts excel in chloride media, H₂S/CO₂ environments, and seawater as premium alternatives to nickel alloy fasteners:
- In 3.5% NaCl solution (simulated seawater), the pitting potential (Epit) of Super Duplex Steel 2507 Bolts approaches Hastelloy C276 levels (2507≈1.0V vs. SCE).
Super Duplex Steel 2507 Bolts excel in chloride media, H₂S/CO₂ environments, and seawater as premium alternatives to nickel alloy fasteners:
- In 3.5% NaCl solution (simulated seawater), the pitting potential (Epit) of Super Duplex Steel 2507 Bolts approaches Hastelloy C276 levels (2507≈1.0V vs. SCE).
- In H₂S-containing oil wells (50,000ppm Cl⁻, 0.1bar H₂S), corrosion rates for Super Duplex Steel 2507 Bolts remain <0.1mm/year - matching Inconel 625 at 70% cost reduction.
3. Mechanical Properties & Service Life
The duplex microstructure of Super Duplex Steel 2507 Bolts delivers enhanced strength and fatigue resistance for critical fastening applications:
The duplex microstructure of Super Duplex Steel 2507 Bolts delivers enhanced strength and fatigue resistance for critical fastening applications:
| Property | 2507 (S32750) | Hastelloy C276 | Inconel 625 |
| Tensile Strength (MPa) | 800–1000 | 760–900 | 830–1100 |
| Yield Strength (MPa) | 550–600 | 350–450 | 410–550 |
| Hardness (HB) | 290–320 | 200–230 | 220–250 |
| Fatigue Limit (MPa) | 400 (10⁷ cycles) | 450 (10⁷ cycles) | 480 (10⁷ cycles) |
Performance Highlights:
- Super Duplex Steel 2507 Bolts provide 1.5× higher yield strength than C276 bolts, ideal for flanged connections and pump/valve securing.
- Under dynamic loading (e.g., offshore platforms), fatigue life rivals nickel alloys at lower cost.
- Super Duplex Steel 2507 Bolts provide 1.5× higher yield strength than C276 bolts, ideal for flanged connections and pump/valve securing.
- Under dynamic loading (e.g., offshore platforms), fatigue life rivals nickel alloys at lower cost.
4. Recommended Applications
Super Duplex Steel 2507 Bolts enable cost-effective replacements for nickel alloy fasteners in:
- Marine Engineering: Seawater pipeline flange bolts, heat exchanger fasteners (60% cost savings vs. Inconel 625).
- Petrochemical: Chloride/H₂S pipeline connections (80% cost reduction vs. C276 with equivalent lifespan).
- FGD Systems: Flue gas desulfurization equipment (50% strength increase over 904L stainless).
Super Duplex Steel 2507 Bolts enable cost-effective replacements for nickel alloy fasteners in:
- Marine Engineering: Seawater pipeline flange bolts, heat exchanger fasteners (60% cost savings vs. Inconel 625).
- Petrochemical: Chloride/H₂S pipeline connections (80% cost reduction vs. C276 with equivalent lifespan).
- FGD Systems: Flue gas desulfurization equipment (50% strength increase over 904L stainless).
Limitations:
- Not recommended for strongly oxidizing acids (e.g., concentrated HNO₃) or temperatures >250°C where Hastelloy bolts remain necessary.
- Not recommended for strongly oxidizing acids (e.g., concentrated HNO₃) or temperatures >250°C where Hastelloy bolts remain necessary.
5. Total Cost of Ownership Analysis
Case study: Offshore cooling system bolt procurement (per km):
Case study: Offshore cooling system bolt procurement (per km):
| Material | Initial Cost (¥10k/km) | Service Life (Years) | 20-Year Cost (¥10k) |
| 2507 | 80 | 20+ | 80 |
| C276 | 400 | 25+ | 400 |
| 254SMO | 150 | 15 | 150 (potential replacement) |
Conclusion: Super Duplex Steel 2507 Bolts deliver 90% of nickel alloy performance in moderate corrosion environments at 80% cost reduction - the optimal technical-economic solution for critical fastening.
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