ASTM SAE AISI 904L Stainless Steel (UNS N08904)
AISI 904L stainless steel (UNS N08904) is a high-alloy austenitic stainless steel. Compared with 316L, SS904L has lower carbon (C) content, higher chromium (Cr) content and approximately twice the nickel (Ni) and molybdenum (Mo) content of 316L, which makes it have greater resistance to oxidation in high temperatures, corrosion resistance, and resistance to reducing acids (e.g. sulfuric acid). Nitrogen (N) can reduce the precipitation rate of chromium carbide, thereby reducing the sensitivity of sensitization, and also improves the resistance to pitting and crevice corrosion caused by chlorides. Especially its addition of copper (Cu) makes it useful for all concentrations of sulfuric acid.
Datasheet and specification
The following data sheet summarizes the chemical composition, properties, heat treatment and equivalent grade of 904L stainless steel (SS904L).
Chemical composition
The following data sheet provides the chemical composition of SS 904L stainless steel.
| Chemical composition, % | |||||||||||||
| ASTM | UN | Type | C, ≤ | Yes, ≤ | Mn, ≤ | P, ≤ | S, ≤ | Cr | No | Mo | N, ≤ | Ass | Notes (Product) |
| ASTM A276/A276M | UNS S08904 | 904L | 0.02 | 1.00 | 2:00 | 0.045 | 0.030 | 19.0-23.0 | 23.0-28.0 | 4.0-5.0 | 0.10 | 1.0-2.0 | Bars and Shapes |
| ASTM A240/A240M | Plate, Sheet and Strip | ||||||||||||
Mechanical properties
The following table lists the mechanical properties of Rolex 904L stainless steel (SS904L), such as yield strength, tensile strength, elongation, and hardness.
| Mechanical properties of AISI ASTM 904L steel | |||||||
| ASTM | AISI type | Tensile strength, MPa (ksi), ≥ | 0.2% yield strength, MPa (ksi), ≥ | Elongation by 50 mm (2 in.), %, ≥ | Rockwell hardness (HRBW), ≤ | Product Forms | Conditions |
| ASTM A276/A276M | 904L (UNS N08904) | 490 (71) | 220 (31) | 35 | – | Bars and Shapes | Annealed, hot finished or cold finished |
| ASTM A240/A240M | 490 (71) | 220 (31) | 35 | 90 | Plate, Sheet and Strip | ||
Heat treatment
Annealing: Recommended annealing temperatures for 904L forged steel are 1095°C (2000°F).
Corrosion
Type 304 stainless steel can handle mild foods and vegetables, but sauces and pickle liquors are more corrosive and can even cause pitting corrosion to type 316 stainless steel. To improve corrosion resistance, high-alloy 904L stainless steel ( SS904L) should be considered.
Forms
Stainless steel 904L (SS904L) is used in petroleum, chemicals, fertilizers, marine development towers, tanks, pipes and tubes, and heat exchangers. Rolex and other watch manufacturers also use it to make watches.
Equivalent class SS 904L
The datasheet below summarizes the equivalent grade of Rolex 904L stainless steel, such as European EN (German DIN EN, British BS EN, French NF EN…), Chinese GB, ISO, Japanese JIS standard.
| Material equivalent to AISI 904L | |||||||||||||||||
| USA | European Union | ISO | Japan | China | Australia | India | Russia | Korea | |||||||||
| Standard | Type | Standard | Class (Steel Number) | Standard | ISO name (ISO number) | Standard | Note | Standard | Note | Standard | Note | Standard | Note | Standard | Note | Standard | Note |
| AISI-SAE; ASTM | 904L (UNS N08904) | EN 10088-2; EN 10088-3 | X1NiCrMoCu25-20-5 (1.4539) | ISO 15510 | X1NiCrMoCu25-20-5 (4539-089-04-I) | JIS G4303 | SUS 890L | GB/T 20878; GB/T 4237; GB/T 3280 | 015Cr21Ni26Mo5Cu2 | ||||||||
