329 vs 2304 Duplex
These two grades are listed as equivalents of each other: their chemistry windows overlap and they serve the same applications. They are not always identical — check the differences below before substituting, especially in certified designs.
329
Stainless Steel
329 is the original commercial duplex stainless (the JIS SUS329J1 family), a 25% chromium, low-nickel ferritic-austenitic grade that predates the modern lean and 2205 duplexes. It still appears in Japanese and legacy specifications for chemical and seawater-adjacent equipment.
Standards: DIN 1.4460 · AISI 329 (UNS S32900) · JIS SUS329J1
2304 Duplex
Stainless Steel
2304 is a lean duplex grade with corrosion resistance comparable to 316L and roughly double its yield strength, without the molybdenum cost of 2205. It is used for tanks, structural parts and bridges in mildly aggressive environments.
Standards: DIN 1.4362 · AISI UNS S32304 · GB 022Cr23Ni4MoCuN
Chemical composition compared (%)
| Element | 329 | 2304 Duplex |
|---|---|---|
| C | ≤0.08 | ≤0.030 |
| Si | ≤0.75 | ≤1.00 |
| Mn | ≤1.00 | ≤2.50 |
| P | ≤0.040 | ≤0.040 |
| S | ≤0.030 | ≤0.030 |
| Cr | 23.00–28.00 | 21.50–24.50 |
| Ni | 2.50–5.00 | 3.00–5.50 |
| Mo | 1.00–2.00 | 0.05–0.60 |
| Cu | — | 0.05–0.60 |
| N | — | 0.05–0.20 |
Properties compared
| Property | 329 | 2304 Duplex |
|---|---|---|
| Delivery condition | Solution annealed | Solution annealed |
| Hardness | ≤277 HB | ≤290 HB |
| Tensile strength | ≥620 MPa | 600–820 MPa |
| Yield strength | ≥450 MPa | ≥400 MPa |
| Density | 7.80 g/cm³ | 7.80 g/cm³ |
| Magnetic | Yes | Yes |
Sourcing either grade?
Nasteel stocks both families from Shenzhen with EN 10204 3.1 mill certificates by heat number.
Ask for a quotationSee full data sheets: 329 · 2304 Duplex. Substitution decisions for certified parts stay with the design authority.