ZERON 100 Type Super Duplex Forgings — UNS S32760 / ASTM A182 F55 / 1.4501
Maintained by Jiangyin Jiangnan Metal Co., Ltd. · Last updated 11 October 2026
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging works in Jiangyin, Jiangsu Province, China, making super duplex stainless steel forgings in UNS S32760, the grade sold under the name ZERON 100 and designated ASTM A182 F55 and W.Nr. 1.4501. We forge rings, seamless rolled rings, flanges, round bars, discs, shafts, sleeves, bushings, tube sheets and hollow forgings to drawing, solution anneal them in house, and ship with EN 10204 3.1 or 3.2 certification.
1. What ZERON 100 (UNS S32760) is
ZERON 100 is a super duplex stainless steel carrying the UNS designation S32760. Nominal chemistry is around 25 percent chromium, 7 percent nickel and 3.6 percent molybdenum, with deliberate copper and tungsten additions, and the microstructure is a balanced 50-50 mix of austenite and ferrite. That structure, together with nitrogen alloying, gives yield strength roughly double that of the 300 series austenitics, plus better resistance to chloride pitting, crevice corrosion and stress corrosion cracking.
The grade is made to a minimum pitting resistance equivalent number of 40, the figure that separates super duplex from standard duplex. It resists chloride induced stress corrosion cracking and sulphide stress cracking in sour gas conditions. The copper gives it useful resistance to non oxidising acids, sulphuric acid in particular, which is why it turns up in acid leach mining and steel pickling plant.
The term super duplex came out of this alloy. Development work at Mather+Platt concluded that the best corrosion performance came from a low carbon duplex with PREN 40, alloyed with chromium, nickel, molybdenum, copper, tungsten and nitrogen.
2. Chemical composition
| C | Cr | Ni | Mo | Cu | W |
|---|---|---|---|---|---|
| 0.030 max | 24.0 – 26.0 | 6.0 – 8.0 | 3.0 – 4.0 | 0.50 – 1.00 | 0.50 – 1.00 |
| N | Mn | Si | P | S | Fe |
| 0.20 – 0.30 | 1.00 max | 1.00 max | 0.030 max | 0.010 max | Balance |
Melting route here is EAF plus VOD, with ESR remelt available where the project specification or a heavy section calls for it. Every heat comes with a ladle analysis, and a product analysis on request.
3. Mechanical properties
| Property | Imperial | Metric |
|---|---|---|
| Ultimate tensile strength, min | 109,000 psi | 751 MPa |
| Yield strength, 0.2 percent offset, min | 80,000 psi | 552 MPa |
| Elongation in 50 mm, min | 25 percent | 25 percent |
| Hardness | To purchase order. Sour service orders commonly cap hardness, 28 HRC being a typical limit | |
Impact behaviour is one reason buyers pick this grade for cold duty. There is no sharp ductile to brittle transition, only a gradual fall in impact energy as temperature drops, and welded material sits only slightly below parent metal. Charpy testing at low temperature, minus 46 degrees Celsius for example, can be added to any order.
4. Heat treatment and forging practice
Solution anneal at 1100 to 1140 degrees Celsius (2012 to 2084 degrees Fahrenheit), then water quench. The quench has to be fast. Cooling slowly through the critical range lets sigma and other intermetallics form, and that costs you both impact toughness and pitting resistance. Our route for S32760 runs: billet inspection, heating, open-die forging or ring rolling with controlled finish temperature, full solution anneal and water quench, rough machining, NDT, mechanical and corrosion testing, then final machining and marking.
Machinability
S32760 will not machine like an austenitic. Against 316 or 316L, drop cutting speed by about 50 to 55 percent when turning with coated cemented carbide, and the same thinking applies to other operations. Reduce feed only slightly, and carefully, because too light a feed work hardens the surface and the next pass suffers.
5. Testing and certification
| Item | Standard or practice |
|---|---|
| Ultrasonic testing | EN 10228-3, SEP 1921, ASTM A388, acceptance class per order |
| Penetrant or magnetic particle | ASTM E165, ASTM E709 as applicable |
| Microstructure and intermetallic check | Metallographic examination, ASTM A923 type evaluation on request |
| Pitting corrosion test | ASTM G48 Method A, temperature and acceptance per project specification |
| Ferrite and austenite balance | Point count or image analysis, range per purchase order |
| Certification | EN 10204 3.1 works certificate, or 3.2 with third party such as BV, SGS, TUV, DNV, LRS |
6. What we forge in UNS S32760
| Product form | Typical end use |
|---|---|
| Seamless rolled rings and forged rings | Pump casings, compressor cases, valve seat rings, flange blanks, bearing housings |
| Forged flanges, weld neck, blind and hub | Seawater, firewater and subsea pipework, risers and manifolds |
| Forged round bars, spindles, shafts, eccentric shafts | Pump and mixer shafts, stems, power transmission, gearboxes, turbines |
| Forged discs and disks | Valve components, closure blanks, subsea and deepwater hardware |
| Sleeves, bushings, hollow bars | Industrial air compressors, power and nitrogen generators, wear parts |
| Forged tubes, pipes, tube sheets | Heat exchangers, separators, pressure vessels, desalination and RO plant |
| Valve bodies, blocks, stems, chokes, connectors | Ball, gate, globe, check and plug valves, chokes, manifolds |
| Nozzles, manifolds, forged rolls and wheels | Pulp and paper digesters and liquor tanks, FGD systems, paper machines |
Industries we ship this grade to include oil and gas including subsea and sour service, seawater and desalination, chemical and petrochemical, mining and minerals, pulp and paper, power generation including FGD, marine and pharmaceutical.
7. S32760 against neighbouring grades
| Grade | UNS | Family | What sets it apart |
|---|---|---|---|
| ZERON 100 type, A182 F55 (this page) | S32760 | Super duplex | 25Cr-7Ni-3.6Mo with copper and tungsten, PREN 40 min |
| A182 F53, 2507 type | S32750 | Super duplex | Super duplex without the tungsten and copper of S32760 |
| A182 F44 | S31254 | 6 percent Mo austenitic | Fully austenitic alternative for chloride service |
| 904L | N08904 | High alloy austenitic | Acid service austenitic, lower strength than super duplex |
| Alloy 20 | N08020 | Nickel iron chromium | Sulphuric acid service, higher nickel cost base |
Pick the grade against the real service environment, temperature and code requirement. We are happy to quote two or three grades side by side, but we never substitute a grade without written approval from the buyer.
8. Common questions
What is ZERON 100?
A super duplex stainless steel designated UNS S32760 and 1.4501, nominally 25 percent chromium, 7 percent nickel and 3.6 percent molybdenum with copper and tungsten, a 50-50 austenite ferrite structure, and PREN of at least 40. ZERON 100 is a registered trademark of Rolled Alloys Inc.
What is the ASTM forging grade for ZERON 100?
ASTM A182 Grade F55. The alloy is also covered by A240, A276, A314, A473, A479, A790, A815, A928 and NORSOK MDS 055.
What are the minimum mechanical properties?
109,000 psi or 751 MPa tensile, 80,000 psi or 552 MPa yield at 0.2 percent offset, and 25 percent minimum elongation at room temperature.
What heat treatment is required?
Solution annealing at 1100 to 1140 degrees Celsius, 2012 to 2084 degrees Fahrenheit, followed by water quenching.
Why is copper added to this alloy?
Copper gives resistance to sulphuric acid and other non oxidising acids, which is why the grade is specified for acid leach mining, steel pickling and similar duties.
Can you forge to our drawing, and what do you need to quote?
Yes, everything is made to order. To quote we need the drawing or rough dimensions, OD by ID by height for a ring or diameter by length for a bar, the grade and specification edition, quantity, required testing and certification level, and the delivery condition, meaning as forged, rough machined or finish machined.
Who supplies UNS S32760 open-die forgings from China?
Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Telephone +86-189-2135-9659, email sales@steelforgepieces.com.
9. Request a quotation
Send the drawing or size list for your UNS S32760 and A182 F55 forging and we will come back with price, weight and lead time. Mixed enquiries covering duplex, super duplex and nickel alloys in one package are welcome.
Jiangyin Jiangnan Metal Co., Ltd. — Open-Die Forging Factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
Telephone +86-189-2135-9659
Email sales@steelforgepieces.com
Web www.steelforgepieces.com