Super Duplex Zeron 100 – Chemical Composition, Equivalents & Products
Super duplex Zeron 100 is the trade name of a super duplex stainless steel to UNS S32760 (WNR 1.4501), with about 25% chromium, 7% nickel, 3.5% molybdenum, 0.25% nitrogen and additions of copper and tungsten. Like super duplex 2507, it has a pitting resistance equivalent number of at least 40, about twice the yield strength of 316L, and excellent resistance to pitting, crevice corrosion and chloride stress corrosion cracking in seawater and brines.
Giriraj Impex supplies UNS S32760 material in every product form – we manufacture flanges, fittings, bars and fasteners, and stock and supply pipes, tubes, plates and sheets – to the ASTM specifications for the generic grade.
Chemical composition
The table compares S32760 with the other duplex grades; S32760 is the last row.
| UNS | Grade | C | Mn | P | S | Si | Cr | Ni | Mo | N | Other elements |
|---|---|---|---|---|---|---|---|---|---|---|---|
| S31803 | 2205 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 21.0–23.0 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 | – |
| S32205 | 2205 | 0.030 | 2.00 | 0.030 | 0.020 | 1.00 | 22.0–23.0 | 4.5–6.5 | 3.0–3.5 | 0.14–0.20 | – |
| S32750 | 2507 | 0.030 | 1.20 | 0.035 | 0.020 | 0.80 | 24.0–26.0 | 6.0–8.0 | 3.0–5.0 | 0.24–0.32 | Cu 0.50 |
| S32760 | Zeron 100 type | 0.030 | 1.00 | 0.030 | 0.010 | 1.00 | 24.0–26.0 | 6.0–8.0 | 3.0–4.0 | 0.20–0.30 | Cu 0.50–1.00, W 0.50–1.00 |
S32760 also requires a minimum PREN of 40. Footnotes as given in the standards.
For S32760, PREN is calculated as %Cr + 3.3 × (%Mo + 0.5 × %W) + 16 × %N and must be at least 40. Copper improves resistance to some acids, and tungsten adds to pitting resistance.
Mechanical properties
| UNS | Tensile strength, MPa (ksi) | Yield strength, MPa (ksi) | Elongation in 50 mm, % |
|---|---|---|---|
| S31803 | 620 (90) | 450 (65) | 25 |
| S32205 | 655 (95) | 485 (70) | 25 |
| S32750 | 800 (116) | 550 (80) | 15 |
| S32760 | 750 (109) | 550 (80) | 25 |
Hardness limits as given in the standard.
Values for pipe to ASTM A790. Plate to ASTM A240 has similar requirements. The high strength allows thinner walls and lighter piping than 316L or 6Mo austenitic steels.
Equivalent grades
| Designation | Value |
|---|---|
| UNS | S32760 |
| EN number | 1.4501 |
| EN name | X2CrNiMoCuWN25-7-4 |
| ASTM A182 forging grade | F55 |
| ASTM A815 fitting grade | WPS32760 |
| Trade name | Zeron® 100 |
See the full grade equivalent chart for other grades.
S32760 or 2507?
Super duplex 2507 (UNS S32750) and S32760 are both super duplex steels with PREN of 40 or more and similar strength. S32760 adds copper and tungsten and has a slightly different chemistry balance; some owners specify one or the other, and many project specifications accept either. The choice is usually set by the project material specification and the availability of all product forms in the same grade. Duplex 2205 is used where conditions are less severe.
S32760 products we supply
- Super duplex pipes and tubes – ASTM A790, A928, A789.
- Super duplex sheets and plates – ASTM A240.
- Super duplex flanges – ASTM A182 F55.
- Super duplex pipe fittings – ASTM A815 WPS32760; A182 F55 forged fittings.
- Super duplex round bars – ASTM A479, A276.
All duplex grades are on the duplex and super duplex steel page.
Where S32760 is used
S32760 is used offshore and onshore for seawater cooling and injection, firewater ring mains and deluge systems, produced water, subsea manifolds and connectors, desalination high-pressure piping, and chemical process lines carrying chlorides. It is also used for pump and valve bodies, shafts and fasteners in seawater service.
Physical properties
S32760 has a density of about 7.8 g/cm³, slightly lower than austenitic stainless steels, and, because of its ferrite content, it is magnetic. Its thermal expansion is lower than that of austenitic stainless steel and closer to carbon steel, which reduces thermal stresses in mixed-material systems. Thermal conductivity is higher than for austenitic grades. Because of the risk of embrittlement, super duplex steels are generally limited to service below about 250 °C, and impact testing is used for low-temperature service.
Specifying S32760
Project specifications for S32760 often add requirements beyond the ASTM product standard: a minimum PREN (commonly 40 or 41), a ferrite range in the base metal and welds, Charpy impact energy at a low test temperature, ASTM A923 Method A and C or ASTM G48 testing, and hardness limits for sour service. These requirements apply to every product form – pipe, fittings, flanges, plates, bars and bolting – so a complete package from one supplier with matching certification simplifies inspection. Please send the specification with the enquiry.
Sizes and supply
S32760 is supplied as seamless and welded pipe in schedules 10S to 80S and heavier walls, plate and sheet, forged flanges and fittings in all ASME B16.5 classes, butt-weld fittings to ASME B16.9, and round bars for valves, shafts and fasteners. Availability of each size is confirmed with the quotation. Every piece is marked with grade and heat number and supplied with mill test certificates.
Fabrication and testing
Like other super duplex steels, S32760 must be welded within controlled heat-input and interpass limits with over-alloyed filler, so that the weld keeps a balanced austenite–ferrite structure and no intermetallic phases form. Hot-formed and heat-treated parts are solution annealed and rapidly cooled. Common supplementary tests are ferrite measurement, Charpy impact testing at low temperature, ASTM A923 testing for intermetallic phases and ASTM G48 pitting testing. Material can be supplied to NACE MR0175 / ISO 15156 on request for sour service.
Frequently Asked Questions
Zeron 100 is the trade name of a super duplex stainless steel to UNS S32760 (WNR 1.4501), with copper and tungsten additions.
At least 40, calculated as %Cr + 3.3 × (%Mo + 0.5 × %W) + 16 × %N.
Both are super duplex grades with similar strength and pitting resistance; S32760 adds copper and tungsten.
ASTM A182 grade F55 covers S32760 forgings and flanges.
S32760 corresponds to WNR 1.4501, X2CrNiMoCuWN25-7-4.
In seawater, firewater, produced water, desalination and chloride-bearing process systems.
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Zeron® 100 is a trademark of Rolled Alloys.