Alloy 904L (UNS N08904) is a superaustenitic stainless steel that is designed for moderate to high corrosion resistance in a wide range of process environments. The combination of high chromium and nickel content, coupled with additions of molybdenum and copper, assure good to excellent corrosion resistance. With its highly alloyed chemistry—25% nickel and 4.5% molybdenum, 904L provides good chloride stress corrosion cracking resistance, pitting and general corrosion resistance superior to 316L and 317L molybdenum enhanced stainless steels. Alloy 904L was originally developed to withstand environments containing dilute sulfuric acid. It also offers good resistance to other inorganic acids such as hot phosphoric acid as well as most organic acids. Alloy 904L is easily welded and processed by standard shop fabrication practices.
Standards
ASTM ............... A 240, B 625
ASME ............... SA 240, SB 625
Chemical Analysis
Weight % (all values are maximum unless a range is otherwise indicated)
| Nickel | 23.0 min. – 28.0 max. | Silicon | 1.00 |
| Chromium | 19.0 min. – 23.0 max | Phosphorus | 0.045 |
| Molybdenum | 4.0 min.– 5.0 max | Sulfur | 0.035 |
| Copper | 1.0–2.0 max. | Iron | Balance |
| Manganese | 2.00 | | |
Physical Properties
Density
0.287 lbs/in3
7.95 g/cm3
Electrical Resistivity
33.5 Microhm-in at 68°F
95.2 Microhm-cm at 20°C
Melting Range
2372–2534°F
1300–1390°C
Specific Heat
0.11 BTU/lb-°F (32–212°F)
450 J/kg-°K (0–100°C)
Modulus of Elasticity
28.0 x 106 psi
190 GPa
Thermal Conductivity 212°F (100°C)
6.8 BTU/Ft-hr-°F
12.9 W/m-°K
Mechanical Properties
Typical Values at 68°F (20°C) (minimum values, unless specified)
| Yield Strength 0.2% Offset | | Ultimate Tensile Strength | | Elongation in 2 in. | Hardness |
| psi | (MPa) | psi | (MPa) | % | |
| 31,000 | 220 | 71,000 | 490 | 36 | 70–90 Rockwell B |
We can provide 904L material in the form of flange, fittings, pipes.
|
|
904L 1.4539 UNS N08904 SO slip-on flange Images
|
