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Name | Supler Duplex Hex Domed Cap Nut |
Standard | DIN1587 |
Size Range | M5-M64 or non-standard as requested |
Finish | Bright&Clean |
Marking | HT&FST or customization |
Material | Duplex2507,UNS S32750,F51,1.4410 |
Grade | Grade 80 |
Certificates | EN10204-3.1B |
Non-standards | OEM is available, according to drawing or samples |
Samples | Samples available |
Package | Bulk in box and then in cartons, then on pallets, or according to customers' requirement. |
| Payment | T/T,Western Union |
Super Duplex S32750
UNS | ID | AISI/ASTM | W.Nr |
| S32750 | F53 | 2507 | 1.4410 |
Chemical composition of Super Duplex 2507 Nut
| Alloy | % | Ni | Cr | Mo | N | C | Mn | Si | S | P | Cu |
| 2507 | Min. | 6.0 | 24 | 3.0 | 0.24 | 0.08 | |||||
| Max. | 8.0 | 26 | 5.0 | 0.32 | 0.03 | 1.2 | 0.08 | 0.02 | 0.035 | 0.5 |
Minimum mechanical properties of Super Duplex 2507 Nut alloy at room temperature
| Tensile strength Rm N/mm2 | Yield strength RP0.2 N/mm2 | Elongation rate A5% | Brinell hardness HB |
| 800 | 550 | 15 | 310 |
The Super Duplex 2507 Hex Domed Cap Nut is a premium fastener designed for high-strength, high-corrosion resistance in severe industrial environments, manufactured from Super Duplex Stainless Steel 2507 (UNS S32750). Combining the benefits of a domed cap design (protecting bolt threads from damage) with the superior properties of super duplex steel, this nut offers exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking, while providing twice the yield strength of conventional austenitic stainless steels. Ideal for offshore, chemical, and energy applications, it ensures secure, long-lasting connections in high-pressure, high-chloride environments.
1. Superior Mechanical Properties: Super Duplex 2507 boasts a yield strength of 550 MPa (79,760 PSI) and tensile strength of 750 MPa (108,800 PSI), making it suitable for high-load applications like pipeline flanges and structural connections. Its duplex microstructure (50% ferrite, 50% austenite) provides excellent fatigue resistance and impact toughness (-40°C/-40°F).
2. Exceptional Corrosion Resistance: With a PREN (Pitting Resistance Equivalent Number) of 43, it resists pitting in seawater, chloride solutions (up to 20,000 ppm Cl⁻), and sour gas (H2S + CO2) environments. It outperforms 316L in marine atmospheres, with a corrosion rate <0.02mm/year in 3.5% NaCl spray.
3. Domed Cap Design: The rounded top (radius: 1.5x thread diameter) protects exposed bolt threads from mechanical damage, moisture ingress, and debris accumulation, extending the service life of the fastener assembly.
4. Thread Standards and Finish: Available in UNC/UNF (ASME B1.1) and metric (ISO 965-1) threads with Class 2B fit, featuring a passivated surface (to remove machining oils) or optional PTFE coating (5-10μm) for reduced friction during installation.
5. Temperature Range: Performs optimally from -50°C (-58°F) to 300°C (572°F), with resistance to hydrogen embrittlement in low-temperature applications like LNG terminals.
• Offshore Oil and Gas: Secures riser connections, subsea valves, and platform structures exposed to seawater and high-pressure H2S/CO2, reducing downtime from fastener replacement by 50%.
• Chemical Processing: Used in chlor-alkali plants, pulp/paper mills, and fertilizer production, resisting corrosion from bleaching agents (ClO⁻) and ammonium sulfate solutions.
• Power Generation: Fastens components in desulfurization systems (FGD) and geothermal plants, enduring high-chloride steam and acidic condensates.
• Structural Engineering: Ideal for bridges, stadiums, and coastal buildings, where its high strength and corrosion resistance reduce maintenance costs in harsh climates.
Q: What is the key advantage of the domed cap design?
A: The domed shape prevents water pooling on the nut surface, reducing crevice corrosion by 70% compared to flat-top nuts in wet environments.
Q: Can these nuts be used with carbon steel bolts?
A: Not recommended due to galvanic corrosion. Pair with Super Duplex 2507 bolts or use a non-conductive washer to isolate dissimilar metals.
Q: What is the maximum working pressure for these nuts?
A: Rated for pressures up to 1000 bar (14,500 PSI) in flange connections, provided proper torque tensioning (10-15% below yield strength) is applied.
Q: Are these nuts compliant with NACE MR0175 for sour gas?
A: Yes, Super Duplex 2507 meets NACE MR0175/ISO 15156-3 for H2S environments up to 150°C (302°F) and 3.5% NaCl content.
Q: How to inspect for hydrogen embrittlement in cold environments?
A: Perform regular magnetic particle inspection for surface cracks, as duplex steel is less prone to hydrogen embrittlement than martensitic grades but should still be lubricated during installation in sub-zero conditions.
Name | Supler Duplex Hex Domed Cap Nut |
Standard | DIN1587 |
Size Range | M5-M64 or non-standard as requested |
Finish | Bright&Clean |
Marking | HT&FST or customization |
Material | Duplex2507,UNS S32750,F51,1.4410 |
Grade | Grade 80 |
Certificates | EN10204-3.1B |
Non-standards | OEM is available, according to drawing or samples |
Samples | Samples available |
Package | Bulk in box and then in cartons, then on pallets, or according to customers' requirement. |
| Payment | T/T,Western Union |
Super Duplex S32750
UNS | ID | AISI/ASTM | W.Nr |
| S32750 | F53 | 2507 | 1.4410 |
Chemical composition of Super Duplex 2507 Nut
| Alloy | % | Ni | Cr | Mo | N | C | Mn | Si | S | P | Cu |
| 2507 | Min. | 6.0 | 24 | 3.0 | 0.24 | 0.08 | |||||
| Max. | 8.0 | 26 | 5.0 | 0.32 | 0.03 | 1.2 | 0.08 | 0.02 | 0.035 | 0.5 |
Minimum mechanical properties of Super Duplex 2507 Nut alloy at room temperature
| Tensile strength Rm N/mm2 | Yield strength RP0.2 N/mm2 | Elongation rate A5% | Brinell hardness HB |
| 800 | 550 | 15 | 310 |
The Super Duplex 2507 Hex Domed Cap Nut is a premium fastener designed for high-strength, high-corrosion resistance in severe industrial environments, manufactured from Super Duplex Stainless Steel 2507 (UNS S32750). Combining the benefits of a domed cap design (protecting bolt threads from damage) with the superior properties of super duplex steel, this nut offers exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking, while providing twice the yield strength of conventional austenitic stainless steels. Ideal for offshore, chemical, and energy applications, it ensures secure, long-lasting connections in high-pressure, high-chloride environments.
1. Superior Mechanical Properties: Super Duplex 2507 boasts a yield strength of 550 MPa (79,760 PSI) and tensile strength of 750 MPa (108,800 PSI), making it suitable for high-load applications like pipeline flanges and structural connections. Its duplex microstructure (50% ferrite, 50% austenite) provides excellent fatigue resistance and impact toughness (-40°C/-40°F).
2. Exceptional Corrosion Resistance: With a PREN (Pitting Resistance Equivalent Number) of 43, it resists pitting in seawater, chloride solutions (up to 20,000 ppm Cl⁻), and sour gas (H2S + CO2) environments. It outperforms 316L in marine atmospheres, with a corrosion rate <0.02mm/year in 3.5% NaCl spray.
3. Domed Cap Design: The rounded top (radius: 1.5x thread diameter) protects exposed bolt threads from mechanical damage, moisture ingress, and debris accumulation, extending the service life of the fastener assembly.
4. Thread Standards and Finish: Available in UNC/UNF (ASME B1.1) and metric (ISO 965-1) threads with Class 2B fit, featuring a passivated surface (to remove machining oils) or optional PTFE coating (5-10μm) for reduced friction during installation.
5. Temperature Range: Performs optimally from -50°C (-58°F) to 300°C (572°F), with resistance to hydrogen embrittlement in low-temperature applications like LNG terminals.
• Offshore Oil and Gas: Secures riser connections, subsea valves, and platform structures exposed to seawater and high-pressure H2S/CO2, reducing downtime from fastener replacement by 50%.
• Chemical Processing: Used in chlor-alkali plants, pulp/paper mills, and fertilizer production, resisting corrosion from bleaching agents (ClO⁻) and ammonium sulfate solutions.
• Power Generation: Fastens components in desulfurization systems (FGD) and geothermal plants, enduring high-chloride steam and acidic condensates.
• Structural Engineering: Ideal for bridges, stadiums, and coastal buildings, where its high strength and corrosion resistance reduce maintenance costs in harsh climates.
Q: What is the key advantage of the domed cap design?
A: The domed shape prevents water pooling on the nut surface, reducing crevice corrosion by 70% compared to flat-top nuts in wet environments.
Q: Can these nuts be used with carbon steel bolts?
A: Not recommended due to galvanic corrosion. Pair with Super Duplex 2507 bolts or use a non-conductive washer to isolate dissimilar metals.
Q: What is the maximum working pressure for these nuts?
A: Rated for pressures up to 1000 bar (14,500 PSI) in flange connections, provided proper torque tensioning (10-15% below yield strength) is applied.
Q: Are these nuts compliant with NACE MR0175 for sour gas?
A: Yes, Super Duplex 2507 meets NACE MR0175/ISO 15156-3 for H2S environments up to 150°C (302°F) and 3.5% NaCl content.
Q: How to inspect for hydrogen embrittlement in cold environments?
A: Perform regular magnetic particle inspection for surface cracks, as duplex steel is less prone to hydrogen embrittlement than martensitic grades but should still be lubricated during installation in sub-zero conditions.
