UNS S32900 summary
UNS S32900 is a duplex austenitic-ferritic stainless steel, also designated AISI 329, EN 1.4460 / X3CrNiMoN27-5-2 and SS 2324. To ASTM A240 it contains 23.000 to 28.000 % chromium, 2.000 to 5.000 % nickel and 1.000 to 2.000 % molybdenum, with 0.080 % carbon maximum, balance iron, and is supplied solution annealed.
In that condition ASTM A240 calls for a tensile strength of 620 MPa minimum, a yield strength of 485 MPa minimum, elongation of 15 % minimum and hardness of 269 HBN maximum. Density is 7.80 g/cm³. The alloy content is slightly lower than grade 2205, and the grade costs less.
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging factory at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. We forge S32900 into bars, hollow bars, seamless rolled rings, discs, blocks and shafts to customer drawing. Enquiries to sales@steelforgepieces.com or +86-189-2135-9659.
Chemical composition of UNS S32900
The limits below are those of ASTM A240, the standard specification for chromium and chromium-nickel stainless steel plate, sheet and strip for pressure vessels and general applications. We order and certify material against these limits, and the actual heat analysis appears on every mill certificate.
| Element | Symbol | Content, % |
|---|---|---|
| Carbon | C | 0.080 max. |
| Silicon | Si | 0.750 max. |
| Manganese | Mn | 1.000 max. |
| Phosphorus | P | 0.040 max. |
| Sulphur | S | 0.030 max. |
| Chromium | Cr | 23.000 to 28.000 |
| Nickel | Ni | 2.000 to 5.000 |
| Molybdenum | Mo | 1.000 to 2.000 |
| Iron | Fe | Balance |
Heat treatment condition: solution annealing. Limits per ASTM A240 for UNS S32900.
Mechanical properties
Two sets of figures matter when buying S32900 forgings. The first is the guaranteed minimum of the purchase specification, which is what the inspector checks. The second is the typical value you can expect from correctly annealed material, which is useful for design comparison between alloys. They are kept apart below.
Specified requirements, ASTM A240 S32900
| Property | Requirement |
|---|---|
| Tensile strength | 620 MPa min. |
| Yield strength | 485 MPa min. |
| Elongation | 15 % min. |
| Hardness | 269 HBN max. |
Typical annealed values, grade 329H reference data
| Property | Metric | Imperial |
|---|---|---|
| Tensile strength, ultimate | 725 MPa | 105,000 psi |
| Yield strength at 0.2 % offset | 550 MPa | 79,800 psi |
| Elongation at break, in 50 mm | 25 % | 25 % |
| Charpy impact | 54 J | 39.8 ft-lb |
| Elastic modulus | 190 to 210 GPa | 27,557 to 30,458 ksi |
| Poisson's ratio | 0.27 to 0.30 | 0.27 to 0.30 |
| Hardness, Brinell | 230 HB | 230 HB |
| Hardness, Vickers, converted | 242 HV | 242 HV |
| Hardness, Knoop, converted | 253 | 253 |
| Hardness, Rockwell B | 96 HRB | 96 HRB |
| Hardness, Rockwell C, converted | 20 HRC | 20 HRC |
Typical values are not a guarantee of performance. Section size, product form and test direction all affect results.
Physical and thermal data
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.80 g/cm³ | 0.282 lb/in³ |
| Thermal expansion coefficient, 20 to 815 °C | 14.4 µm/m·°C | 8 µin/in·°F |
Equivalent grades and related standards
| System | Designation | Remark |
|---|---|---|
| UNS, USA | S32900 | Wrought duplex stainless steel |
| AISI, USA | 329 | Common trade designation |
| EN and DIN, Europe | 1.4460, X3CrNiMoN27-5-2 | Austenitic-ferritic grade, EN 10088-3 |
| Sweden | SS 2324 | Reported equivalent |
| Cast grades, ASTM | A890 Gr 3A, A995 Gr 3A, UNS J93371, CD6MN | Cast counterparts cross-referenced to S32900 |
Product-form standards in which the grade appears include ASTM A240 and ASME SA240 for plate, sheet and strip, ASTM A268 and ASME SA268 and ASTM A511 for tubing, and ASTM A789 and ASTM A790 for seamless and welded duplex tube and pipe. Bars, shapes and forged piping components fall under separate standards, so confirm the specification you need on the purchase order and we will verify grade availability against the current edition before accepting the order.
Forged product forms in UNS S32900
Each item below is produced by open-die forging, with ring rolling where the shape calls for it, then solution annealed, machined to your allowance and inspected before shipment.
Forged bars
Round bars and rods, square, rectangular and flat bars, hex bars, supplied black, peeled or rough turned.
Hollow bars and sleeves
Forged hollow bars, sleeves, bushes and bushings, pipe and tube blanks, barrels, casings, shells, cylinders, hubs and housings.
Seamless rolled rings
Seamless rolled rings and forged rings with circumferential grain flow for loaded ring sections.
Blocks, discs and plates
Forged blocks, discs and plate-type forgings for valve bodies, closures, tube sheets and tooling.
Shafts and spindles
Propeller shafts, pump shafting, spindles, pistons, stirrers and forged bolt blanks.
Made to drawing
Near-net open-die forgings and finish-machined components produced to your drawing, specification and test plan.
Typical applications
The two-phase structure gives this grade high strength along with resistance in chloride-bearing and mildly acidic service. Published applications for 1.4460 and AISI 329 include pumps and pump components, screws and fasteners, shafts, heat exchangers for power engineering, radiators, tanks and vessels, chlorine-bearing housings and valve parts. On that basis the grade is commonly specified for seawater and brine handling, oil and gas process equipment, desalination plant, chemical and petrochemical vessels, pulp and paper equipment, and heat exchanger tube sheets and shells.
Forging route, heat treatment and inspection
S32900 is a duplex steel, so the balance between austenite and ferrite decides whether the finished forging has the properties you paid for. Hot working and heat treatment are controlled more tightly than for a plain austenitic grade, and we agree the route with you in writing before production starts.
Our normal route is refined ingot or billet, upset and draw forging on open dies with recorded start and finish temperatures, solution annealing followed by rapid quench to restore the phase balance and avoid intermetallic precipitation, then rough or finish machining. Standard deliverables are the certified heat analysis, room temperature tensile and hardness results, ultrasonic examination to an agreed acceptance class, liquid penetrant examination where specified, a dimensional report and a mill test certificate to EN 10204 3.1. Witness inspection and release by your own inspector or by a third-party agency can be arranged.
Send us the service conditions with your enquiry if the part will be welded, exposed to chloride stress-corrosion cracking risk, or run away from ambient temperature. Duplex grades have temperature limits in both directions, and sometimes a different grade is the correct answer. We will tell you if that is the case. Related options on this site include A182 F51, A182 F53, A182 F55 and 904L.
Questions we are asked
What is UNS S32900 stainless steel?
A duplex austenitic-ferritic stainless steel, also called AISI 329, EN 1.4460 and X3CrNiMoN27-5-2. ASTM A240 specifies 23.000 to 28.000 % Cr, 2.000 to 5.000 % Ni, 1.000 to 2.000 % Mo, 0.080 % C max, 1.000 % Mn max, 0.750 % Si max, 0.040 % P max and 0.030 % S max, balance iron.
What are the minimum mechanical properties of ASTM A240 S32900?
Tensile strength 620 MPa minimum, yield strength 485 MPa minimum, elongation 15 % minimum and hardness 269 HBN maximum, in the solution annealed condition.
Is S32900 the same as 2205 duplex?
No. They are separate grades with separate UNS numbers. Published data describes the 329 family as having slightly lower alloy content than 2205 at lower cost. Where a drawing names 2205 or A182 F51, supply that grade. S32900 is not a substitute unless your engineering authority approves it in writing.
Why does the chemistry quoted for 329 differ between suppliers?
Because two different things get quoted. Some sources list the ASTM A240 specification limits for UNS S32900, namely 0.080 % C max, 1.000 % Mn max, 0.750 % Si max, 23 to 28 % Cr, 2 to 5 % Ni and 1 to 2 % Mo. Others list a typical analysis for grade 329H at around 28 % Cr, 4.5 % Ni, 1.5 % Mo and 0.10 % C. The 329H figures exceed the A240 limits for carbon, manganese and silicon, so the two must not appear in the same table.
What is the PREN of S32900?
Pitting resistance equivalent number is calculated from the certified chromium, molybdenum and nitrogen contents of the actual heat, not from the grade name, and the A240 range for S32900 is wide. Tell us the minimum PREN your specification requires and we will select and certify a heat that meets it.
Which test certificate is supplied?
A mill test certificate to EN 10204 3.1 as standard, covering chemical analysis, mechanical test results, heat treatment condition, non-destructive examination results and dimensional conformity. Other certificate levels and third-party inspection are available on request.
What is the minimum order quantity and lead time?
Open-die forging suits single pieces and small batches as well as series production. Lead time depends on raw material availability, piece weight and test requirements. Send your drawing to sales@steelforgepieces.com for a confirmed schedule with the quotation.
Request a quotation for UNS S32900 forgings
Send the grade, shape, rough or finished dimensions, quantity, applicable specification and the certificate level you need. Drawings in PDF, DWG or STEP are all workable. Technical enquiries come back with a material proposal, not only a price.
- Company Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
- Address No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone +86-189-2135-9659
- Email sales@steelforgepieces.com
- Website steelforgepieces.com
- Capability Forged bars, hollow bars, seamless rolled rings, discs, blocks and shafts in carbon, alloy, tool and stainless steels and nickel alloys
Related grades
Notes on the data
Composition limits and required mechanical properties are those of ASTM A240 for UNS S32900, which also carries the cross-reference to the cast grades A890 Grade 3A and A995 Grade 3A, UNS J93371. Typical annealed values, density, thermal expansion and the list of related product standards follow published grade 329H data sheets. The EN designation, the austenitic-ferritic classification and the density figure for 1.4460 follow EN 10088-3 data, and the equivalence of 1.4460, AISI 329, S32900 and SS 2324 together with the application list follow European stockist grade descriptions. Published data of this kind is indicative and does not replace the full specification or the certified analysis of the heat supplied.
Page last reviewed 8 October 2026 by the engineering department of Jiangyin Jiangnan Metal Co., Ltd.