1. Introduce
– Low carbon, high nickel, molybdenum stainless steel
– Stainless steel designed to withstand environments containing sulfuric acid
→ Suitable for various concentrations of sulfuric acid below 70
– Used in applications where the corrosion properties of 316L, 317L are not adequate
– High content of Mo added to provide chloride stress corrosion cracking resistance, oxidation resistance, and erosion resistance superior to 316L
– 304L and 316L are susceptible to chloride stress corrosion cracking under certain conditions, but 904L has excellent resistance to chloride stress corrosion cracking
– UNS S08904, N08904
* Chloride Stress Corrosion Cracking (SCC)
– Resistance to SCC increases with increasing content of Ni and Mo
* UNS
- Abbreviation for the Unified Numbering System for Metals and Alloys
- Unified unique numbering system for metals and alloys
- A representative number compatible with metals and alloys defined in several material-related codes, including ASTM, AISI, ASME, AWS, etc.
* S : Heat and corrosion resistant (stainless) steel
2. Property
– Chloride stress corrosion cracking resistance, erosion resistance, corrosion resistance, corrosion resistance, excellent corrosion resistance
| Element | Impact |
|---|---|
| Ni, Cr | Provides corrosion resistance |
| Mo | Provides corrosion resistance, localized corrosion resistance, oxidation resistance |
| Cu | Provides sulfuric acid corrosion resistance |
[904L Chemical Composition (%)]
| C | Mn | P | S | Si | Cr |
|---|---|---|---|---|---|
| Max. 0.020 | Max. 2.00 | Max. 0.045 | Max. 0.035 | Max. 1.00 | 23.0~28.0 |
| Ni | Mo | Cu | N | Fe | |
|---|---|---|---|---|---|
| 19.0~23.0 | 4.0~5.0 | 1.0~2.0 | Max. 0.10 | Bal. |
[904L Mechanical Properties]
| Tensile Strength (Mpa) | Yield Strength (Mpa) | Elongation (%) |
|---|---|---|
| Min. 490 | Min. 220 | 35 |
[904L Physical Properties]
| Density (g/㎤) | Melting Range (℃) | Specific Heat (0-100℃), J/kg*℃ |
|---|---|---|
| 7.95 | 1300~1390 | 450 |
3. Standard & Specification
– Specification : UNS S08904, N08904
| ASTM | A240, A213, A269, A312, B625 |
| ASME | SA240, SB625 |
4. Available Form
– Bar, Rod
– Sheet, Plate, Strip
– Coil, Wire
– Forgings
– Tube, Pipe
5. Application & Product
– Chemical, Oil & Gas, Marine, Atmospheric, Power Generation
| Application | Product |
|---|---|
| Chemical | Piping, Heat Exchangers |
| Oil & Gas | Offshore process equipment |
| Marine | condensers, piping |
| Atmospheric | scrubbers for coal-fired power plants |
| Power Generation | exhaust gas desulfurization equipment, absorption towers, internal components |
(1) Piping / (2) Condensers / (3) Scrubbers for coal-fired power plants / (4) Exhaust gas desulfurization equipment
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