AISI 904L UNS N08904 W 1.4539 superustenitic stainless steel is similar to 316L but with the addition of molybdenum, which gives superior resistance to localized corrosion attack (pitting and crevice corrosion). With a PREN value of 35, it is one of the suitable solutions for applications in warm seawater and other high chloride environments. The high nickel content results in better resistance to stress corrosion than standard austenitic grades. Copper in the alloy adds resistance to sulfuric and other reducing acids particularly in the very aggressive “medium concentration” range. In most environments, AISI 904L UNS N08904 W 1.4539 steel has intermediate corrosion performance between the standard 316L austenitic grade and molybdenum-rich (about 6%) or super austenitic types of materials.
AISI 904L steel UNS N08904 W 1.4539 should not be used at temperatures above about 550°C. It finds application in piping systems, pollution control equipment, heat exchangers, and bleaching systems.
CHEMICAL COMPOSITION AISI 904L UNS N08904 W 1.4539
| Element | Min | Max |
|---|---|---|
| C | 0.02 | |
| S | 0.035 | |
| P | 0.045 | |
| Yes | 1.00 | |
| Mn | 2.00 | |
| Cr | 19.00 | 23.00 |
| Ni | 23.00 | 28.00 |
| Mo | 4.00 | 5.00 |
| Cu | 1.00 | 2.00 |
MECHANICAL CHARACTERISTICS AISI 904L UNS N08904 W 1.4539
| Material | League | Rm min (MPa) | Rp 0.2 min (MPa) | A% min | Hardness min |
|---|---|---|---|---|---|
| AISI 904L UNS N08904 | 1.4539 | 530 | 230 | 35 | 230 |
PHYSICAL PROPERTIES AISI 904L UNS N08904 W 1.4539
- Specific gravity: 8.0 kg/dm³ at 20°C
- Modulus of elasticity: 195,000 N/mm² at 20°C
- Thermal conductivity: 12 W/m.K at 20°C
- Specific heat: 450 J/g.K at 20°C
- Coefficients of linear expansion: 16.1 (20° – 200°C), 16.9 (20° – 400°C), 17.5 (20° – 600°C)
- Electrical resistivity: 1.00 Ω mm²/m at 20°C
- Amagnetic: Yes
SPECIFICATIONS AND DESIGNATIONS
- W: 1.4539
- UNS: N08904
- Swedish: 2526
- Brand: URANUS® B6
- AISI: 904L
