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Duplex Steel nuts are robust fasteners made from duplex stainless steel, which boasts a unique microstructure that balances austenite and ferrite. This dual-phase design gives them impressive mechanical strength, exceptional corrosion resistance, and increased durability, making them perfect for tough environments like chemical plants, marine settings, and industrial applications. They stand out for their ability to resist pitting, crevice corrosion, and stress corrosion cracking caused by chlorides, ensuring they hold up well in critical situations.
Typically, Duplex Steel nuts contain about 22–25% chromium, 4–7% nickel, 2–4% molybdenum, and nitrogen, all of which boost their corrosion resistance and mechanical properties. They deliver a tensile strength of roughly 620–850 MPa and a yield strength of around 450–550 MPa, along with excellent toughness, ductility, and fatigue resistance. The balanced duplex microstructure also provides thermal stability and guards against intergranular corrosion, making them suitable for high-pressure and high-temperature applications.
|
Material |
Specification |
Standards |
Size
|
Length |
|
Duplex Steel
|
IS
BS
ASTM
|
ASTM / ASME – A/ SA 479 / 479 |
3 mm
to
200 mm
|
M02 to M30
|
| Cr | N | Ni | C | Mn | Si | P | S | Mo | |
|---|---|---|---|---|---|---|---|---|---|
| S31803 | min: 21.0 max: 23.0 | min: 0.08 max: 0.20 | min: 4.5 max: 6.5 | 0.03 max | 2.0 max | 1.0 max | 0.03 max | 0.02 max | min: 2.5 max: 3.5 |
| S32205 | min: 22.0 max: 23.0 | min: 0.14 max: 0.20 | min: 4.5 max: 6.5 | 0.03 max | 2.0 max | 1.0 max | 0.03 max | 0.02 max | min: 3.0 max: 3.5 |
Grade | Tensile Strength (MPa) min | Elongation (% in 50mm) | Yield Strength 0.2% Proof (MPa) min | Hardness Rockwell C (HR C) |
|---|---|---|---|---|
UNS-S 31803 | 650-880 | 25 | 448 | |
UNS-S 32205 | 621 | 25 | 448 | 21 max |
At Themban Nickel Alloys, we take pride in being the largest supplier, exporter, and manufacturer of Duplex Steel Nuts in Cape Town , South Africa, providing cutting-edge solutions for all your piping needs. Our state-of-the-art production plants are strategically located in the Cape Town, allowing us to maintain a vast inventory of over 16,000 tons of premium-quality materials readily available in stock. We are dedicated to delivering superior products and services, ensuring reliability and excellence for our global clientele.
Contact us to get a quick quote for your requirement.
You’ll find Duplex Steel nuts commonly used in pipelines, pressure vessels, heat exchangers, offshore platforms, and structural assemblies that face harsh conditions like seawater, acids, and various chemicals. Their blend of high strength, corrosion resistance, and durability guarantees secure fastening, a long service life, and minimal maintenance in demanding industrial and marine environments.