DIN 1.4539 904L Stainless Steel Pipe Alloy 904L Small Diameter Pipes
Products Specification
| Products Name | 904L Stainless Steel Seamless Pipe |
Grade: | 304 304L 309S 310S 314 316L 316Ti 321 329 347H 410 2205 2507 S32760 904L 254SMO and equal grade in GB JIS EN DIN Standard |
| Standards: | ASTM A213M-94b ASTM A249M-94a ASTM A269-94a
ASTM A312M-94b,ect. |
| DIN 17456-85 DIN 17458-85 DIN 17459-92.ect |
| JIS G3446-1994 JIS G3448-1997 JIS G3459-1997 JIS G3463-1994,ect. |
| GB13296-1991 GB14975-2002 GB14976-2002,ect. |
| Size: | ND5 - DN400 |
| Length: | 6m length or cutting any length as request |
| Applications: | fluid and gas transport, structure , boiler, heat exchanger, super heater |
904L Stainless Steel: A High-Performance Super Austenitic Alloy
904L stainless steel (UNS N08904) is a premium low-carbon, high-alloy austenitic stainless steel renowned for its exceptional corrosion resistance, particularly in aggressive environments where standard stainless steels like 304 or 316L fail. Originally developed for sulfuric acid handling, its unique composition makes it a critical material in demanding industries.
Key Characteristics & Advantages:
Superior Corrosion Resistance: Excels against:
Sulfuric Acid: Outstanding resistance across a wide concentration range, even at elevated temperatures.
Phosphoric Acid: Excellent performance.
Chloride Environments: Highly resistant to pitting, crevice corrosion, and stress corrosion cracking (SCC) due to its high Molybdenum (Mo) and Chromium (Cr) content, making it suitable for seawater applications.
Organic Acids (Acetic, Formic) & Inorganic Acids (Nitric).
High Alloy Content: Rich in critical elements:
Nickel (Ni): Stabilizes the austenitic structure, enhancing toughness and overall corrosion resistance.
Chromium (Cr): Provides the fundamental passive oxide layer for corrosion resistance.
Molybdenum (Mo): Significantly boosts resistance to localized corrosion (pitting/crevice) and chloride attack.
Copper (Cu): Specifically enhances resistance to sulfuric acid and reducing acids.
Low Carbon (C): Minimizes carbide precipitation during welding, maintaining corrosion resistance in welded sections.
Good Fabricability & Weldability: Can be readily formed and welded using standard austenitic stainless steel techniques (though it work-hardens faster than 304/316).
Excellent Mechanical Properties: Offers high strength and toughness.
Typical Chemical Composition (Weight %):
| Element | Min % | Max % | Primary Role |
| Iron (Fe) | Bal. | Bal. | Base Metal |
| Chromium (Cr) | 19.0 | 23.0 | Corrosion Resistance (Passive Layer) |
| Nickel (Ni) | 23.0 | 28.0 | Austenite Stabilizer, Toughness, Corrosion Resistance |
| Molybdenum (Mo) | 4.0 | 5.0 | Pitting/Crevice Resistance, Chloride Resistance |
| Copper (Cu) | 1.0 | 2.0 | Sulfuric Acid Resistance |
| Manganese (Mn) | - | 2.0 | Austenite Stabilizer, Deoxidizer |
| Silicon (Si) | - | 1.0 | Deoxidizer |
| Carbon (C) | - | 0.02 | Minimizes Carbide Precipitation (Intergranular Corrosion) |
| Phosphorus (P) | - | 0.045 | - |
| Sulfur (S) | - | 0.035 | - |
| Nitrogen (N) | - | 0.1 | Strength Enhancement |
Comparison vs. Common 316L Stainless Steel:
| Property | 904L (UNS N08904) | 316L (UNS S31603) | Advantage for 904L |
| Nickel (Ni) | 23-28% | 10-14% | Better austenite stability, higher corrosion resistance |
| Molybdenum (Mo) | 4-5% | 2-3% | Significantly better pitting/crevice corrosion resistance |
| Copper (Cu) | 1-2% | - | Crucial for sulfuric acid resistance |
| Pitting Resistance Equivalent (PRE<sub>N</sub>)<sup>*</sup> | ~36-40 | ~24-26 | Far superior localized corrosion resistance |
| Sulfuric Acid Resistance | Excellent (Broad conc. & temp.) | Limited (Low conc./temp only) | Dramatically better performance |
| Chloride SCC Resistance | Very High | Moderate (can fail) | Much more reliable in seawater/high chloride |
| Cost | Significantly Higher | Lower | Higher initial material cost |
<sup>*</sup> PRE<sub>N</sub> = %Cr + 3.3x(%Mo) + 16x(%N) - Common indicator for pitting resistance.
Primary Applications:
Chemical & Petrochemical Processing: Reactors, tanks, piping, heat exchangers handling sulfuric, phosphoric, and other acids.
Oil & Gas (Downhole & Offshore): Components exposed to sour gas (H₂S), chlorides, and seawater.
Pollution Control (FGD - Flue Gas Desulfurization): Ducts, dampers, absorber towers handling corrosive flue gases/slurries.
Pharmaceutical & Food Processing: Equipment requiring high purity and resistance to aggressive cleaning agents.
Seawater Handling: Heat exchangers, pumps, valves, piping systems.
Pulp & Paper Industry: Digesters, bleaching equipment.
High-End Medical Implants: Due to biocompatibility and excellent corrosion resistance in body fluids.
Important Considerations:
Cost: 904L is substantially more expensive than standard austenitic grades due to its high nickel and molybdenum content.
Machining: Its high work hardening rate and toughness make machining more challenging than 304/316; requires appropriate tools and techniques.
Availability: Less readily available than commodity grades; often requires specialized suppliers or mills.
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DIN 1.4539 904L Stainless Steel Pipe Alloy 904L Small Diameter Pipes Images
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