UNS NO8904, commonly known as stainless steel 904L, is a low carbon high alloy austenitic stainless steel which is widely used in applications where the corrosion properties of AISI stainless steel 316L and AISI stainless steel 317L are not adequate.
The addition of copper to this grade gives it corrosion resistant properties superior to the conventional chrome nickel stainless steels, in particular to sulphuric, phosphoric and acetic acids. However, there is limited use with hydrochloric acids. It also has a high resistance to pitting in chloride solutions, a high resistance to both crevice and stress corrosion cracking. Stainless Steel 904L performs better than other austenitic stainless steels due to the higher alloying of nickel and molybdenum.
The grade is non-magnetic in all conditions and has excellent formability and weldability. The austenitic structure also gives this grade excellent toughness, even down to cryogenic temperatures.
The high chromium content promotes and maintains a passive film which protects the material in many corrosive environments.Stainless Steel 904L has a greater resistance to precipitation of ferrite and sigma phases on cooling and welding than other stainless steels containing molybdenum such as stainless steel 316L and stainless steel 317L. There is no risk of intercrystalline corrosion on cooling or welding due to the low carbon content. Its maximum service temperature is at 450°C.
This grade is particularly useful in control and instrumentation tubing applications where stainless steel 316 and stainless steel 317Lare not suitable.
Available stainless steel tubes product forms
- Straight
- Coiled
- Seamless
Typical Applications
- Seawater cooling equipment
- Chemical processing for sulphuric, phosphoric and acetic acids
- Gas washing
- Condenser stainless steel tubes
- Control and instrumentation
- Heat exchangers
- Aircraft piston engine manifolds
- Stainless Steel Pipe Fittings
- Ball Valves
- Thermal oxidizers
- Refinery equipment
- Stainless Steel flanges
- Expansion joints
- High temperature chemical process equipment
Typical manufacturing specifications
- ASTM A213
- ASTM A269
- ASTM A312
- BS EN 10216 pt.5
- Also individual customer specifications.
Industries predominantly using this grade
- Chemical processing
- Oil and gas
- Pharmaceutical
TECHNICAL DATA
Mechanical Properties
| Temper | Annealed | |
|---|---|---|
| Tensile Rm | 71 | ksi (min) |
| Tensile Rm | 490 | MPa (min) |
| R.p. 0.2% Yield | 32 | ksi (min) |
| R.p. 0.2% Yield | 220 | MPa (min) |
| Elongation (2” or 4D gl) | 35 | % (min) |
Physical Properties (Room Temperature)
| Specific Heat (0-100°C) | 450 | J.kg-1.°K-1 |
| Thermal Conductivity | 11.5 | W.m -1.°K-1 |
| Thermal Expansion | 15.8 | mm/m/°C |
| Modulus Elasticity | 190 | GPa |
| Electrical Resistivity | 9.52 | μohm/cm |
| Density | 7.95 | g/cm3 |
Chemical Composition (% by weight)
| Element | Min | Max |
|---|---|---|
| C | - | 0.2 |
| Mn | - | 2 |
| Ni | 23 | 28 |
| Cr | 19 | 23 |
| S | - | 0.3 |
| Mo | 4 | 5 |
| N | - | 0.1 |
| Cu | 1 | 2 |
| P | - | 0.03 |
| Si | - | 0.7 |
Zhejiang Yaang Pipe Industry Co., Limited offers 904L Stainless Steel Pipes, 904L Stainless Steel Tubes, 904L Stainless Steel Flanges, 904L Stainless Steel Pipe Fittings, etc.
Source: Yaang Pipe Industry (www.yaang.com)
