Jiangyin Jiangnan Metal Co., Ltd. forges AISI 329 austenitic-ferritic duplex stainless steel into shafts, rolled rings, discs, hollow bars, blocks and near-net valve and pump components at our open-die forging shop in Jiangyin, Jiangsu, China. Material is supplied solution annealed and certified per heat.
Section 01Grade overview
A 27 % chromium duplex grade with roughly 5 % nickel and 1.5 % molybdenum, combining the strength of a ferritic steel with the toughness and weldability of an austenitic one.
AISI 329 is an austenitic-ferritic chromium-nickel-molybdenum stainless steel. The two-phase microstructure, together with the low carbon content, gives it markedly better resistance to chloride pitting, crevice corrosion, stress corrosion cracking and corrosion fatigue than fully austenitic grades of the Type 316 class, while roughly doubling the proof strength.
Published datasheets describe the grade as having a lower alloy content than grade 2205 and being less expensive. Against 1.4462 (2205) its corrosion resistance is characterised as slightly inferior, so 329 is generally selected where chloride resistance and strength are needed at a lower alloy cost, rather than as a direct 2205 substitute.
Why engineers select 329
High strength, high toughness, excellent machinability, and excellent resistance to pitting, crevice corrosion, stress corrosion and corrosion fatigue, particularly in chloride-bearing media.
Where it needs care
The steel becomes embrittled when held in the 300 to 900 °C range, so it is not a high-temperature grade. Scaling temperature in air is approximately 1070 °C.
Section 02Designations and standards
| System | Designation |
|---|---|
| AISI / SAE | 329 |
| UNS | S32900 |
| EN number | 1.4460 |
| EN designation | X3CrNiMoN27-5-2 |
| Sweden, SS | SS 2324 (1.4460 replaces SS 2324-02) |
| France, AFNOR | Z5CND27-05 Az |
| Spain, UNE | X8CrNiMo27-05, F-3309; X8CrNiMo26-6, F-3552 |
| Cast counterpart | CD6MN, UNS J93371, ASTM A781 Grade 3A |
| Trade and brand names | Duplex, Alloy 7Mo, 10RE51, SS44 |
| Standard | Scope |
|---|---|
| EN 10250-4 | Open steel die forgings for general engineering purposes, stainless steels |
| EN 10088-1 / -3 / -5 | List of stainless steels; delivery conditions for semi-finished products, bars, rods, wire, sections and bright products |
| EN 10297-2 | Seamless circular steel tubes for mechanical and general engineering, stainless steel |
| ASTM A240 | Plate, sheet and strip |
| ASTM A268, ASME SA268 | Seamless and welded ferritic and martensitic tubing |
| ASTM A789 / A790 | Seamless and welded ferritic-austenitic tubing and pipe |
| ASTM A511 | Seamless stainless mechanical tubing |
EN 10250-4 covers open die forgings and is the usual reference standard for forged 1.4460. Confirm the governing standard on your enquiry so the mill certificate is issued against it.
Section 03Chemical composition
The ASTM and EN limits for this grade are not interchangeable. Nickel and nitrogen differ substantially, so the composition must be ordered against a named standard.
| Element | ASTM, AISI 329 / S32900 | EN 10088, 1.4460 |
|---|---|---|
| Carbon, C | 0.08 max | 0.05 max |
| Chromium, Cr | 23.0 – 28.0 | 25.0 – 28.0 |
| Nickel, Ni | 2.5 – 5.0 | 4.5 – 6.5 |
| Molybdenum, Mo | 1.00 – 2.00 | 1.30 – 2.00 |
| Nitrogen, N | not specified | 0.05 – 0.20 |
| Manganese, Mn | 1.0 max | 2.0 max |
| Silicon, Si | 0.75 max | 1.00 max |
| Phosphorus, P | 0.040 max | 0.035 max |
| Sulfur, S | 0.030 max | 0.030 max |
| Iron, Fe | Balance | |
A typical mill analysis published for 1.4460 in the solution annealed condition is C 0.025 %, Cr 25.4 %, Ni 5.75 %, Mo 1.5 %. Some suppliers quote a tighter sulfur maximum of 0.015 % for 1.4460. Tighter customer limits are available on request.
Check the nickel range before substituting.
The ASTM 329 window starts at 2.5 % nickel, the EN 1.4460 window starts at 4.5 %. Material that satisfies ASTM 329 at the low end of nickel will not satisfy 1.4460, and ASTM 329 carries no nitrogen requirement at all. If your drawing calls out 1.4460 or X3CrNiMoN27-5-2, order to EN rather than to AISI 329.
Section 04Mechanical properties
| Property | Value |
|---|---|
| Tensile strength, Rm | 620 – 880 N/mm² |
| Proof strength, Rp0.2 | 460 N/mm² minimum |
| Elongation, A5 | 20 % minimum |
| Impact energy, KV at room temperature | 85 J/cm² minimum |
| Hardness | 260 HB maximum |
| Modulus of elasticity at 20 °C | 200 kN/mm² |
Both the EN 10088-3 datasheet and an independent multi-standard reference give the same tensile band and the same 260 HB ceiling. One trader datasheet quotes a slightly lower set, 450 N/mm² proof strength and 620 to 800 N/mm² tensile, so where a design sits close to the limit, order against EN 10088-3 explicitly and we will certify to those minimums.
329 and 329H are not the same numbers.
A widely republished datasheet for grade 329H lists 725 MPa tensile, 550 MPa yield, 25 % elongation, 54 J Charpy and 230 HB at a nominal 28 % Cr, 4.5 % Ni, 1.5 % Mo and 0.10 % C. Those figures belong to 329H, not to EN 1.4460, and the 0.10 % carbon exceeds both limits in Table 3. Do not carry 329H values onto a 1.4460 drawing. Tell us which designation governs and we will quote and certify against it.
Section 05Elevated temperature values
| Property | 20 °C | 100 °C | 200 °C | 300 °C |
|---|---|---|---|---|
| Proof strength Rp0.2, MPa | 460 min | 360 min | 310 min | – |
| Modulus of elasticity, GPa | 200 | 194 | 186 | 180 |
| Mean thermal expansion from 20 °C, 10-6 K-1 | – | 13.0 | 13.5 | 14.0 |
Strength falls away steadily with temperature and, more importantly, the grade is susceptible to embrittlement across 300 to 900 °C. Duplex stainless steels are therefore specified for ambient and moderately warm service, not for sustained hot work. Confirm the design temperature on your enquiry.
Section 06Physical properties
| Density | 7.8 g/cm³ |
|---|---|
| Modulus of elasticity | 200 kN/mm² |
| Thermal conductivity | 15 W/m·K |
| Specific heat capacity | 500 J/kg·K |
| Electrical resistivity | 0.8 Ω·mm²/m |
| Scaling temperature in air | approximately 1070 °C |
| Magnetic response | Ferromagnetic, from the ferrite phase |
Section 07Corrosion behaviour
The grade shows very good corrosion resistance, particularly in chloride-bearing environments. Resistance to chloride-driven attack, meaning pitting, crevice corrosion, stress corrosion and corrosion fatigue, is described as much better than that of fully austenitic stainless steels of the Type 316 class.
In most cases it also outperforms Type 316 for general corrosion in reducing and oxidising acids. The two-phase microstructure and low carbon content give better resistance to intercrystalline corrosion after sensitisation in the 500 to 900 °C interval.
Published descriptions also credit the grade with resistance to intercrystalline, fatigue, crevice and stress corrosion as delivered and after welding, which is why it appears in chlorine-bearing service and as a bearing material in chlorine environments.
Where extremely high demands are placed on pitting and crevice resistance, machining of the surface should be followed by pickling or passivation. We can arrange pickling and passivation as part of the order.
Section 08Forging and heat treatment
Duplex grades depend on a balanced ferrite-austenite ratio. That balance is set by the solution anneal and destroyed by slow cooling, so the final heat treatment is not optional.
- ForgingOpen-die forged and ring rolled on our presses. Duplex grades have a narrower hot working window than austenitic steels and need an even through-heat, so section size and reduction schedule are set per part. Send the drawing and we will confirm the route.
- Solution annealing950 to 1000 °C, holding approximately 30 minutes at temperature, followed by cooling in water. This is the standard delivery condition, designated +AT.
- Avoid the embrittlement rangeThe steel is susceptible to embrittlement when held between 300 and 900 °C. Nothing in the production route may dwell in that band, and the water quench from the solution anneal exists to pass through it quickly.
- Post-weld restorationAnnealing at 980 °C followed by water quenching restores the corrosion resistance of a weld to that of the base material.
- No hardening by heat treatmentThe grade is not hardened and tempered. Strength comes from the duplex microstructure, with the hardness ceiling in the annealed condition set at 260 HB.
Section 09Machining data
The grade is described as not a free-cutting stainless but an easy-to-machine steel, suited to parts needing extensive machining, with excellent machinability among its listed characteristics.
| Operation | Tool group | Depth of cut, mm | Feed, mm/rev | Cutting speed, m/min |
|---|---|---|---|---|
| Rough turning | Carbide P15–P25 | 2 – 5 | 0.3 – 0.6 | 150 – 180 |
| Finish turning | Carbide P10–P15 | 0.5 – 2 | 0.05 – 0.3 | 180 – 280 |
| Turning | High speed steel | 0.5 – 2 | 0.05 – 0.2 | 25 – 33 |
| Thread cutting, internal | Carbide | – | – | 100 – 130 |
| Thread cutting, external | Carbide | – | – | 70 – 90 |
| Thread cutting, internal | High speed steel | – | – | 13 – 18 |
| Thread cutting, external | High speed steel | – | – | 18 – 23 |
| Drill diameter, mm | Uncoated HSS, m/min | Uncoated HSS feed, mm/rev | Coated HSS, m/min | Coated HSS feed, mm/rev |
|---|---|---|---|---|
| 5 – 10 | 13 – 18 | 0.2 – 0.3 | 14 – 20 | 0.2 – 0.3 |
| 10 – 20 | 13 – 18 | 0.3 – 0.4 | 14 – 20 | 0.3 – 0.4 |
| 20 – 30 | 13 – 18 | 0.4 – 0.5 | 14 – 20 | 0.4 – 0.5 |
| 30 – 40 | 13 – 18 | 0.5 – 0.6 | 14 – 20 | 0.5 – 0.6 |
Cutting data published for 1.4460 bar in the solution annealed condition. Short-range drills are quoted at 200 to 250 m/min with feeds of 0.08 to 0.14 mm/rev depending on diameter. Treat all figures as starting points and adjust for your setup, tooling and coolant.
Section 10Welding
The grade possesses good weldability and can be welded in the same manner as austenitic material. Welding should be carried out without preheating and with small weld beads, that is with as little heat input as possible. Consumables of the same grade are not required and austenitic consumables may be used; filler materials listed for the grade include 1.4330, 1.4337 and 1.4430.
Where a welded part then goes into highly corrosive service, welding can reduce corrosion resistance. Annealing at 980 °C followed by water quenching restores the weld to base-material corrosion resistance. State the service environment at enquiry stage so we can advise whether post-weld solution treatment is needed.
Section 11Forged forms we supply
| Form | Description |
|---|---|
| Shafts | Propeller shafting, pump shafts, stepped and straight shafts, spindles and stirrer shafts |
| Seamless rolled rings | Ring-rolled rings and forged flanges for pumps, valves and rotating assemblies |
| Forged bars | Round, square, flat and hexagonal, rough turned, machined or ground surface |
| Hollow bars and sleeves | Bored sleeves, bushings, cylinders, housings and forged tube sections |
| Discs, blocks and blanks | Upset forged discs, closures, blinds, pistons and machining blanks |
| Valve and pump components | Bodies, bonnets, stems, seat rings, impeller and compressor wheel blanks |
| Fasteners and near-net shapes | Bolting and nut blanks, anchors, nozzles and parts forged close to final profile |
Section 12Typical applications
Pumps and rotating equipment. Propeller shafting, pump shafting, pump parts, pistons, spindles, stirrers and compressor wheels.
Valves and pressure parts. Valve parts, chlorine-bearing housings, tanks, pipelines and special anchors.
Heat transfer. Heat exchangers for power engineering and radiators, where chloride pitting governs material choice.
Fastening. Bolting, nuts and sleeves in chloride-bearing service.
Industries. Shipbuilding and marine, chemical process, pulp and paper, cryogenic and aviation.
Bearings. Commonly used as a bearing steel in chlorine-containing environments.
Section 13How we supply AISI 329
Forged in our own shop
Shafts, rings, bars, hollows, discs and blocks forged on our presses in Jiangyin, so the heating and reduction schedule stays under our control.
Solution annealed and quenched
Supplied in the +AT condition, water quenched from the solution anneal, with the delivery condition stated on the certificate.
Certified per heat
Chemical analysis and mechanical test results per heat, certified to EN 10250-4, EN 10088-3 or the ASTM or customer specification named on your order, with EN 10204 3.1 or witnessed 3.2 certificates.
Finishing and testing
Rough turning, machining or grinding of bar surfaces, pickling and passivation, plus hardness, impact and ultrasonic testing arranged with the order.
Section 14Questions on AISI 329
What is AISI 329 stainless steel?
AISI 329, UNS S32900, is an austenitic-ferritic duplex chromium-nickel-molybdenum stainless steel. The European equivalent is EN 1.4460, designation X3CrNiMoN27-5-2, with 25 to 28 % chromium, 4.5 to 6.5 % nickel, 1.30 to 2.00 % molybdenum and 0.05 to 0.20 % nitrogen.
Is AISI 329 the same as EN 1.4460?
They are cross-referenced to one another but the limits differ. ASTM 329 allows 2.5 to 5.0 % nickel, up to 0.08 % carbon and specifies no nitrogen, while EN 1.4460 requires 4.5 to 6.5 % nickel, caps carbon at 0.05 % and specifies 0.05 to 0.20 % nitrogen. Order against whichever standard your drawing names.
How does 329 compare with 2205?
329 carries a lower alloy content than grade 2205 and is less expensive. Its corrosion resistance is described as slightly inferior to 1.4462, which is 2205. Where the duty has been qualified on 2205, confirm with your process engineer before substituting.
What are the mechanical properties of 1.4460?
In the solution annealed condition to EN 10088-3: tensile strength 620 to 880 N/mm², proof strength Rp0.2 460 N/mm² minimum, elongation A5 20 % minimum, room temperature impact energy 85 J/cm² minimum and hardness 260 HB maximum.
What heat treatment does the grade receive?
Solution annealing at 950 to 1000 °C, held approximately 30 minutes, then cooled in water. The grade is not hardened and tempered.
Which temperature range must be avoided in service?
300 to 900 °C, where the steel is susceptible to embrittlement. Scaling temperature in air is approximately 1070 °C, so the grade is not intended for sustained high-temperature duty.
Can AISI 329 be welded?
Yes. It has good weldability and welds much like austenitic material, without preheat and with small beads at low heat input. Austenitic consumables are acceptable. Annealing at 980 °C with a water quench restores weld corrosion resistance to that of the base material.
Is AISI 329 magnetic?
Yes. The ferrite in the duplex microstructure makes it ferromagnetic, unlike fully austenitic grades such as 316L.
Does the grade machine well?
Excellent machinability is one of its listed characteristics. It is not a free-cutting stainless, but it is regarded as an easy-to-machine steel suitable for parts needing extensive machining. Starting cutting data is given in Tables 7 and 8.
What sizes can you forge?
Shafts, rings, bars, hollows, discs and blocks are forged to customer drawings. Send dimensions or the drawing with weight, quantity and the governing specification to sales@steelforgepieces.com and we will confirm feasibility and lead time.
Section 15Request a quotation
Send the drawing or rough dimensions with weight, quantity, governing specification, surface condition and certification level. We reply with price and lead time.
- CompanyJiangyin Jiangnan Metal Co., Ltd.
Open-Die Forging Factory - AddressNo.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone, WhatsApp, WeChat+86-189-2135-9659
- Emailsales@steelforgepieces.com
Section 17References
Composition, mechanical, physical, machining and welding data compiled from the Valbruna Nordic EN 10088-3 datasheet for 1.4460 PRODEC, the Metalcor datasheet for 1.4460 / AISI 329, the Virgamet multi-standard comparison for 1.4460 / X3CrNiMoN27-5-2 / AISI 329 / UNS S32900, the Steelnumber record for X3CrNiMoN27-5-2 listing the applicable EN standards, and the published datasheet for grade 329H where identified as such in Section 04.
Figures are typical or specified values for guidance and first orientation and are not guaranteed properties. Standards are revised periodically, so confirm against the current edition at order placement. Certified values for your order appear on the mill test certificate issued with each heat.
Page last reviewed 1 October 2026 by the technical sales team, Jiangyin Jiangnan Metal Co., Ltd.