Bars
Round, square, rectangular, flat and hexagonal bar. Black, rough-turned, peeled or machined to drawing.
Duplex stainless / Grade sheet
SS 2324 Forgings EN 1.4460 · X3CrNiMoN27-5-2 · AISI 329 · UNS S32900
SS 2324 is the Swedish designation for a 25–27 % Cr, 5 % Ni, 1.5 % Mo austenitic-ferritic duplex stainless steel, cross-referenced to EN 1.4460, AISI 329 and UNS S32900. Within the duplex family its defining trait is improved machinability: it cuts considerably better than 1.4462 (2205), with slightly lower corrosion resistance in exchange. That trade is why it has been the long-standing choice for heavily machined parts running in salt water and chloride-bearing media.
We melt and forge this grade on one site in Jiangyin, Jiangsu. Bars, hollow bars, rolled rings, discs and finished shafts, certified from the melt number.
01
Chemical composition
Two rows matter here, and most published datasheets mix them up.
Specification note
The Swedish SS 2324 range and the European EN 1.4460 range are cross-referenced but not identical. SS 2324 allows carbon to 0.10 % and sets no nitrogen range; EN 1.4460 caps carbon at 0.05 % and specifies 0.05–0.20 % N. A great many supplier pages print the 1.4460 chemistry under an SS 2324 heading. Both are given below. State the governing standard on your enquiry and we will order the melt to it.
| Standard / designation | C | Si | Mn | P | S | Cr | Ni | Mo | N |
|---|---|---|---|---|---|---|---|---|---|
| EN / DIN — X3CrNiMoN27-5-2 (1.4460) | ≤ 0.05 | ≤ 1.00 | ≤ 2.0 | ≤ 0.035 | ≤ 0.030 | 25.0–28.0 | 4.5–6.5 | 1.30–2.00 | 0.05–0.20 |
| SS (Sweden) — 2324 | ≤ 0.10 | ≤ 1.00 | ≤ 2.0 | ≤ 0.045 | ≤ 0.030 | 24.0–27.0 | 4.5–7.0 | 1.30–1.80 | — |
| ASTM — AISI 329 / S32900 / Alloy 7Mo | ≤ 0.08 | ≤ 0.75 | ≤ 1.0 | ≤ 0.040 | ≤ 0.030 | 23.0–28.0 | 2.5–5.0 | 1.00–2.00 | — |
| AFNOR — Z5CND27-05 Az | ≤ 0.05 | ≤ 0.75 | ≤ 2.0 | ≤ 0.035 | ≤ 0.025 | 26.0–27.0 | 4.5–5.0 | 1.30–2.00 | 0.05–0.20 |
| UNE — X8CrNiMo26-6 (F-3552) | ≤ 0.10 | ≤ 1.00 | ≤ 2.0 | ≤ 0.045 | ≤ 0.030 | 24.0–27.0 | 4.5–7.0 | 1.30–1.80 | ≤ 0.10 |
| UNE — X8CrNiMo27-05 (F-3309) | ≤ 0.10 | ≤ 1.00 | ≤ 2.0 | ≤ 0.045 | ≤ 0.030 | 26.0–28.0 | 4.0–5.0 | 1.30–2.00 | — |
| ASTM cast — CD6MN / J93371 / A781 Gr. 3A | ≤ 0.06 | ≤ 1.00 | ≤ 1.0 | ≤ 0.040 | ≤ 0.040 | 24.0–27.0 | 4.0–6.0 | 1.75–2.50 | 0.15–0.25 |
| ASTM — S31200 / 44LN / Grade F50 | ≤ 0.03 | ≤ 1.00 | ≤ 2.0 | ≤ 0.045 | ≤ 0.030 | 24.0–26.0 | 5.5–6.5 | 1.20–2.00 | 0.14–0.20 |
02
Mechanical and physical data
Values apply to the solution-annealed condition. The mill certificate for the actual heat governs.
| Property | Symbol | Value |
|---|---|---|
| Tensile strength | Rm | 620–880 MPa |
| 0.2 % proof strength | Rp0.2 | ≥ 450 MPa |
| Elongation at fracture, min. | A | ≥ 20 % |
| Brinell hardness, max. | HB | ≤ 260 |
| Modulus of elasticity, 20 °C | E | approx. 200 GPa |
| Density | ρ | approx. 7.80 kg/dm³ |
| Property | 100 °C | 200 °C | 300 °C |
|---|---|---|---|
| 0.2 % proof strength Rp0.2 | > 360 MPa | > 310 MPa | — |
| Modulus of elasticity E | 194 GPa | 186 GPa | 180 GPa |
| Linear expansion coefficient | 13.0 ×10⁻⁶ K⁻¹ | 13.5 ×10⁻⁶ K⁻¹ | 14.0 ×10⁻⁶ K⁻¹ |
Temperature limit
The comparable DIN grade carries a service range of −60 °C to +350 °C. This is not a hot-service grade. Hold time in the intermediate range causes embrittlement: IMOA's duplex fabrication guidance identifies 300–525 °C as the critical band for alpha-prime formation, with sigma and chi phases forming higher up. Any anneal must be followed by a fast quench through that band.
03
Equivalent designations
Listed only where a published cross-reference supports it.
| Standard body | Designation | Note |
|---|---|---|
| SS / SIS, Sweden | 2324 | Subject of this sheet |
| EN 10088 / EN 10297-2 | 1.4460 · X3CrNiMoN27-5-2 | Current European grade |
| SEW 400, Germany | X4CrNiMoN27-5-2 | Named as comparable to 1.4460 |
| AISI, USA | 329 | Wrought |
| UNS, USA | S32900 | Also sold as Alloy 7Mo |
| AFNOR, France | Z5CND27-05 Az | Narrower Cr and Ni bands |
| UNE, Spain | X8CrNiMo26-6 (F-3552) | Higher C limit |
| UNE, Spain | X8CrNiMo27-05 (F-3309) | Higher C limit |
| ASTM, castings | CD6MN · J93371 · A781 Gr. 3A | Cast counterpart, not interchangeable with wrought |
These are comparisons, not drop-in substitutes. As BSSA puts it in the duplex table these rows come from, such listings are comparisons only and cannot be assumed to be direct equivalent grades. Chemistry windows, delivery condition and acceptance testing all differ between standards. Before you substitute, check the governing specification and tell us which one applies.
04
Forms we forge in SS 2324
Every item is forged from one piece of steel melted on site. No welding, no casting, no purchased billet of unknown origin.
Hollow bars and cylinders
Forged hollow bar, sleeves, bushes, barrels, casings, shells, hubs and housings, bored from solid forged blanks.
Seamless rolled rings
Rolled on radial-axial mills to 6,000 mm outside diameter, rectangular or contoured section.
Forged rings
Upset and punched rings for sections outside the ring-mill envelope, and for heavy-reduction work.
Discs, blocks and plate
Solid forged discs, tube sheets, covers and blocks, supplied proof-machined for volumetric inspection.
Shafts and machined parts
Propeller shafting, pump shafts, spindles, pistons, piston rods, stirrers, bolts and nuts.
| Item | Limit | Set by |
|---|---|---|
| Seamless rolled rings | up to OD 6,000 mm | 6 m radial-axial ring mill |
| Minimum ring size | from OD 50 mm | Upset-and-punch route |
| Shafts, turned length | up to 14,000 mm | C61160 lathe; 15 m well furnace for vertical quench |
| Discs and blocks, machined dia. | up to 5,000 mm | 5,000 mm vertical lathe |
| Bored cylinders | up to 1,600 mm dia × 10,000 mm | CNC deep-hole drilling machine |
| Single piece weight | up to 30,000 kg | 60 t heat size, 6,300 t press |
| Minimum order | 10 kg | No minimum piece count |
| Lead time | 20 to 60 days | Size, heat treatment and testing scope |
05
Where the grade is used
Chloride resistance, high strength and above-average machinability put it on rotating and reciprocating parts in wet, salty and acidic duty.
Documented application areas are propeller and pump shafting, pump and valve parts, pistons, stirrers, bolts and nuts. The steel resists pitting, crevice corrosion, stress corrosion cracking and corrosion fatigue, which is what keeps it in sea-water service long after cheaper austenitic grades fail. It also appears in heat exchangers for power engineering, radiators, tanks, chlorine-bearing housings and valves.
Beyond marine work it is used in acetic acid duty and in the photographic, cellulose and dyeing industries. It carries high wear resistance and good running properties, and it takes a mirror finish, which matters on shaft journals and seal faces. Because resistance to intercrystalline corrosion holds in the welded condition as well as the as-delivered condition, it suits fabrications that cannot be solution annealed again after welding.
06
Heat treatment, welding, machining
Heat treatment
Supplied solution annealed. The anneal dissolves carbides and intermetallic phases and restores the ferrite-austenite balance, and it has to be followed by a fast quench so sigma, chi and secondary austenite do not form on the way down. A cycle widely published for this grade is a solution anneal in the region of 1020–1100 °C with a water quench, and stress relief, where it is called for, at 600–650 °C followed by air cooling. Treat those as indicative. We heat treat to the procedure your specification calls for and report it on the certificate. Fourteen furnaces on site cover the range, including two 15 m well furnaces for vertical quenching of long shafts.
Welding
The grade welds without filler metal matching the parent composition. Weld it as an austenitic material with the lowest heat input you can work with. Resistance to intercrystalline corrosion is retained after welding.
Machining and forming
This is the grade's commercial argument. It is machinability-improved and cuts markedly better than 1.4462, which makes it worth specifying wherever a part loses most of its weight on the lathe. It can be cold formed and hot formed. Like every duplex steel it work-hardens, so keep tools sharp, rake positive, setups rigid and cuts continuous.
07
SS 2324 or 2205
Both are duplex. They sit at opposite ends of one trade-off.
1.4462 / 2205 (A182-F51) carries around 3 % Mo with tightly held low carbon, and returns higher corrosion performance and better behaviour in the weld zone. SS 2324 / 1.4460 carries 1.3 to 2.0 % Mo and is formulated to machine. Pick 1.4460 when the part is machining-heavy and the environment is moderate. Pick 2205, or a super duplex such as F53 / 2507, F55 / Zeron 100 or F61 / Ferralium 255, when corrosion decides the part's life.
Send us the medium, temperature, chloride level and the machining allowance, and we will say which way we would go before you commit a forging to it.
08
Quote an SS 2324 forging
Send a drawing, a rough size, or just the finished weight and the grade. You get back a price, the forging route, the heat-treatment plan and a lead time, normally inside two working days. Minimum order 10 kg, no minimum piece count. Works approvals: CCS, BV, DNV, LR, NK.
09
Questions we get asked
What is SS 2324 steel?
SS 2324 is the Swedish designation for an austenitic-ferritic duplex stainless steel cross-referenced to EN 1.4460 (X3CrNiMoN27-5-2), AISI 329 and UNS S32900. Nominally 25 to 27 % chromium, 5 % nickel and 1.5 % molybdenum. It is used for propeller shafts, pump shafts, pistons, stirrers, bolts and nuts in chloride-bearing service.
What is SS 2324 equivalent to?
EN 1.4460 / X3CrNiMoN27-5-2, AISI 329, UNS S32900 (also sold as Alloy 7Mo), German X4CrNiMoN27-5-2 to SEW 400, AFNOR Z5CND27-05 Az, Spanish UNE F-3552 and F-3309, and the cast grade CD6MN / J93371 / ASTM A781 Grade 3A. These are comparisons, not guaranteed substitutes, because the specified ranges differ between standards.
What are the mechanical properties of SS 2324?
Solution annealed: tensile strength 620 to 880 MPa, 0.2 % proof strength at least 450 MPa, elongation at fracture at least 20 %, Brinell hardness up to 260 HB. At temperature the proof strength falls to above 360 MPa at 100 °C and above 310 MPa at 200 °C, while the modulus drops from about 200 GPa at room temperature to 180 GPa at 300 °C.
Is SS 2324 weldable?
Yes. It does not need filler matching the parent composition and should be welded as an austenitic material at the lowest practical heat input. Resistance to intercrystalline corrosion is retained in the welded condition.
What is the maximum service temperature?
The comparable DIN grade is rated from −60 °C to +350 °C. Above that the steel embrittles, with 300 to 525 °C identified as the critical band for alpha-prime formation. It is not a grade for sustained hot service.
How does SS 2324 compare with 2205?
SS 2324 / 1.4460 machines considerably better than 1.4462 / 2205 and has slightly lower corrosion resistance. Choose 1.4460 for machining-heavy parts, 2205 or a super duplex where corrosion governs.
What sizes can you forge?
Rolled rings to 6,000 mm outside diameter and from 50 mm up, shafts to 14,000 mm turned length, discs and blocks to 5,000 mm machined diameter, bored cylinders to 1,600 mm diameter by 10,000 mm, and single pieces to 30 tonnes. Minimum order 10 kg with no minimum piece count.
Who forges SS 2324 in China?
Jiangyin Jiangnan Metal Co., Ltd., an integrated melting works and open-die forge at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, operating since 1997 with CCS, BV, DNV, LR and NK approvals. Telephone +86 189 2135 9659, email sales@steelforgepieces.com.