904L Stainless Steel Plate
904L (UNS N08904) is a super austenitic stainless steel plate with a critical Copper addition, offering extreme resistance to sulfuric/phosphoric acids and chloride SCC. Thickness 0.3-100mm. Supplied with EN 10204 3.1 MTC.
| Material | Super Austenitic Stainless Steel |
|---|---|
| Grade / Standard | 904L / UNS N08904 |
| Thickness | 0.3mm - 100mm (Thicker plates available upon request) |
| Width | 1000mm / 1219mm / 1500mm / 2000mm / 2500mm |
| Length | 2000mm / 2438mm / 3000mm / 6000mm / Custom Lengths |
| Delivery Condition | hot_rolled / cold_rolled |
| Surface Treatment | bare / shot_blasting / polished |
| MOQ | 1 Ton |
| Delivery Time | 15-30 Days / Select Sizes In Stock |
| Loading Port | Tianjin / Shanghai / Qingdao |
Overview of 904L Stainless Steel Plate
904L is a premium, highly alloyed super austenitic stainless steel plate designed to conquer the most aggressive corrosive environments where standard 300-series grades like 316L and 317L fail. Specified under ASTM B625 / ASTM A240 and EN 1.4539 standards with the UNS designation N08904, 904L bridges the performance gap between conventional austenitic stainless steels and highly expensive nickel-based superalloys. Its defining metallurgical feature is the deliberate addition of 1.0% to 2.0% Copper, which, when combined with its massive Nickel (23-28%) and Molybdenum (4-5%) content, grants it extraordinary resistance to strong reducing acids, most notably sulfuric acid and phosphoric acid.
Due to its exceptionally high alloy chemistry, 904L stainless steel plate is virtually immune to chloride-induced stress corrosion cracking (SCC)—a catastrophic failure mode that frequently plagues 304 and 316L in warm, chloride-rich environments. Furthermore, its ultra-low carbon content (≤0.020%) prevents carbide precipitation during welding and high-temperature processing, maintaining the material’s structural integrity and corrosion resistance in the as-welded condition. Whether used for heavy chemical pressure vessels, marine scrubbers, or fertilizer processing equipment, 904L plate offers unmatched lifecycle value and operational security.
Key Features and Manufacturing Methods
Manufacturing 904L stainless steel plate requires advanced metallurgical control to ensure the homogeneous distribution of its high-alloy elements. Hot Rolled (HR) plates are rolled at high temperatures to thicknesses ranging from 3.0mm up to 100mm and above. They are supplied with a No.1 finish (annealed and descaled), providing maximum structural integrity for fabricating heavy-walled pressure vessels, tanks, and thick flanges. Cold Rolled (CR) sheets are precision-rolled at room temperature for thicknesses between 0.3mm and 3.0mm, yielding a smooth 2B finish and extremely tight dimensional tolerances, ideal for lighter fabrication and paneling.
Because 904L is highly alloyed, it is susceptible to the formation of detrimental intermetallic phases if cooled slowly. Therefore, all 904L plates undergo a rigorous solution annealing process at temperatures between 1090°C and 1175°C, followed by rapid water quenching to lock the alloying elements in a solid austenitic solution. We supply these plates in standard widths of 1219mm, 1500mm, and 2000mm, with custom lengths available. Every plate undergoes rigorous quality control, including 100% PMI (Positive Material Identification) to verify Cu, Ni, and Mo levels, and Ultrasonic Testing (UT) for thicker plates to guarantee internal soundness.
Main Applications of 904L Stainless Steel Plate
904L stainless steel plate was originally engineered specifically to withstand sulfuric acid, and it remains the ultimate material for fabricating storage tanks, heat exchangers, and piping systems handling this aggressive chemical across a wide range of concentrations and temperatures. In the Fertilizer Industry, 904L is indispensable for phosphate-based fertilizer production, heavily utilized to fabricate reactors and vessels processing hot, concentrated phosphoric acid.
The massive Nickel and Molybdenum content gives 904L exceptional resistance to pitting and crevice corrosion in seawater and brackish water. Consequently, the Marine and Offshore Oil & Gas sectors utilize 904L plates for seawater cooling systems, desalination plant evaporators, subsea equipment housings, and offshore platform components. In the Environmental sector, it is a primary material for fabricating Flue Gas Desulfurization (FGD) scrubbers in coal-fired power plants, where it easily withstands highly acidic, chloride-bearing condensates. The Pulp and Paper industry also heavily relies on 904L plates for bleaching equipment and chemical recovery boilers where standard stainless steels suffer rapid localized corrosion.
Why Choose Us for 904L Stainless Steel Plate
Shandong Tanglu Metal Material Co., Ltd. is a specialized supplier of super austenitic stainless steels and high-nickel alloys. We understand that sourcing 904L requires absolute confidence in material chemistry. Our 904L plates are procured exclusively from top-tier, ISO 9001 and PED-certified mills. We strictly guarantee adherence to the UNS N08904 chemical composition, verifying that the critical balance of Copper (1.0-2.0%), Nickel (23-28%), and Molybdenum (4-5%) perfectly matches ASTM and EN standards for maximum acidic resistance.
We maintain a strategic standing inventory of 904L plates in thicknesses from 1mm to 50mm, enabling rapid response to urgent chemical plant turnarounds and offshore maintenance schedules. Beyond material supply, our advanced processing center offers high-precision CNC laser, plasma, and waterjet cutting, allowing us to supply custom-cut profiles, rings, discs, and complex parts that are ready for immediate fabrication. Every shipment is meticulously packed in export-grade wooden pallets with waterproof protection, accompanied by complete traceability and original EN 10204 3.1 Mill Test Certificates. Third-party inspections (SGS, TUV, BV, DNV) are fully supported to meet your most stringent engineering requirements.
📐 Dimension & Size Table
| Thickness (mm) | Theoretical Weight (kg/m²) | Common Widths (mm) | Surface Finish |
|---|---|---|---|
| 0.5 | 4.03 | 1000 / 1219 | 2B (Cold Rolled) |
| 1.0 | 8.05 | 1000 / 1219 | 2B (Cold Rolled) |
| 1.5 | 12.08 | 1219 / 1500 | 2B (Cold Rolled) |
| 2.0 | 16.10 | 1219 / 1500 | 2B (Cold Rolled) |
| 3.0 | 24.15 | 1219 / 1500 | 2B / No.1 |
| 4.0 | 32.20 | 1500 | No.1 (Hot Rolled) |
| 5.0 | 40.25 | 1500 / 2000 | No.1 (Hot Rolled) |
| 6.0 | 48.30 | 1500 / 2000 | No.1 (Hot Rolled) |
| 8.0 | 64.40 | 1500 / 2000 | No.1 (Hot Rolled) |
| 10.0 | 80.50 | 1500 / 2000 | No.1 (Hot Rolled) |
| 12.0 | 96.60 | 1500 / 2000 | No.1 (Hot Rolled) |
| 16.0 | 128.80 | 1500 / 2000 | No.1 (Hot Rolled) |
| 20.0 | 161.00 | 1500 / 2000 | No.1 (Hot Rolled) |
| 25.0 | 201.25 | 1500 / 2000 | No.1 (Hot Rolled) |
| 30.0 | 241.50 | 1500 / 2000 | No.1 (Hot Rolled) |
| 40.0 | 322.00 | 1500 / 2000 | No.1 (Hot Rolled) |
| 50.0 | 402.50 | 1500 / 2000 | No.1 (Hot Rolled) |
| 80.0 | 644.00 | 1500 / 2000 | No.1 (Hot Rolled) |
* Custom sizes available upon request. Tolerances per relevant international standards.
🔬 Chemical Composition
| Element | Min | Max | Display Value | Note |
|---|---|---|---|---|
| C | - | 0.020 | ≤0.020 | Ultra-low carbon prevents sensitization |
| Cr | 19.00 | 23.00 | 19.00-23.00 | Primary oxidation resistance |
| Ni | 23.00 | 28.00 | 23.00-28.00 | Massive Ni ensures SCC immunity & tough matrix |
| Mo | 4.00 | 5.00 | 4.00-5.00 | High Mo for severe pitting resistance |
| Cu | 1.00 | 2.00 | 1.00-2.00 | Crucial for sulfuric & phosphoric acid resistance |
| Mn | - | 2.00 | ≤2.00 | |
| Si | - | 1.00 | ≤1.00 | |
| P | - | 0.045 | ≤0.045 | |
| S | - | 0.035 | ≤0.035 |
* Chemical composition may vary by heat, thickness and specification. Please refer to the actual mill test certificate.
⚙️ Mechanical Properties
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength (Rm) | ≥490 | MPa | Solution annealed |
| Yield Strength (Rp0.2) | ≥220 | MPa | 0.2% proof stress |
| Elongation (A) | ≥35 | % | Gauge length 50mm |
| Hardness (HRB) | ≤90 | HRB | Max 70-90 HRB typical |
| PREN | ≥34 | - | PREN = %Cr + 3.3x%Mo + 16x%N |
| Density | 8.05 | g/cm³ | Heavier than standard 300-series due to Ni/Mo/Cu |
* Values shown are minimum requirements unless otherwise stated.
📦 Commercial Information
| Packaging | Due to the premium value of 904L, plates are packed to the highest seaworthy export standards to prevent surface damage and edge deformities. Cold Rolled (2B) sheets are interleaved with craft paper or coated with a PVC/PE protective film to prevent scratches, then securely fastened onto heavy-duty, ISPM-15 fumigated wooden pallets. The pallets are wrapped in waterproof plastic and secured with steel strapping and edge protectors. Hot Rolled (No.1) heavy plates are tightly bound with steel straps onto heavy wooden dunnage or shipped loose (for extreme thicknesses) with secure bracing. All packaging includes clear waterproof metal tags indicating Heat Number, UNS N08904 grade, and dimensions. |
|---|---|
| Payment Terms | T/T (Telegraphic Transfer),L/C (Letter of Credit),D/P (Documents against Payment) |
| Price Term | FOB,CFR,CIF,EXW |
| Supply Capacity | 500 Tons/Month (Super Austenitic Plates) |
| Loading Port | Tianjin / Shanghai / Qingdao |
Why Choose Our 904L Stainless Steel Plate?
Ultimate Sulfuric Acid Resistance
The deliberate addition of 1-2% Copper gives 904L an extraordinary ability to resist sulfuric acid, phosphoric acid, and other reducing acids across a wide range of concentrations and temperatures, vastly outperforming 316L.
Immunity to Chloride SCC
With a massive Nickel content (23-28%), 904L is virtually immune to Chloride Stress Corrosion Cracking (SCC), a devastating failure mechanism that frequently destroys standard 304 and 316L plates in warm, chloride-rich environments.
Excellent Weldability (Low Carbon)
The ultra-low carbon content (max 0.020%) ensures that 904L plates are highly resistant to intergranular corrosion (sensitization) during welding, requiring no post-weld heat treatment for heavy vessel fabrication.
Precision Cutting & Profiling
We offer comprehensive in-house processing. Utilizing high-power waterjet, plasma, and laser cutting, we can supply 904L plates pre-cut into precise custom profiles, rings, and discs, saving you significant fabrication time.
100% PMI & Ultrasonic Tested
Given the critical nature of the alloy, every single plate undergoes Positive Material Identification (PMI) to guarantee precise levels of Cu, Ni, and Mo. Heavy thickness plates undergo mandatory UT testing to ensure internal soundness.
🏭 Applications of 904L Stainless Steel Plate
904L stainless steel plate is engineered specifically for harsh environments where standard austenitic and duplex grades cannot survive. Its primary domain is the Chemical Processing Industry, specifically in the construction of reactors, storage tanks, and heat exchangers handling sulfuric acid and phosphoric acid. The Fertilizer Industry relies heavily on heavy-gauge 904L plates to fabricate vessels for processing hot, concentrated phosphate streams. Due to its extreme resistance to chloride pitting and SCC, the Marine and Offshore sectors utilize 904L plates to fabricate critical seawater cooling systems, desalination evaporators, and offshore platform structural components. In the Environmental sector, 904L is highly specified for Flue-Gas Desulfurization (FGD) scrubbers in power plants, where it easily withstands the highly acidic, chloride-bearing condensates that destroy lesser alloys. Furthermore, the Pulp and Paper industry utilizes 904L for bleaching equipment and chemical recovery systems operating in highly corrosive, chloride-bearing environments.
📋 Quality & Certification
Our Certifications
- ✅ ISO 9001:2015
- ✅ CE Marking
- ✅ ABS
- ✅ DNV GL
- ✅ Lloyd's Register (LR)
- ✅ Bureau Veritas (BV)
- ✅ SGS Certified
- ✅ NK
- ✅ RINA
Mill Certificate Type
- 📋 EN 10204 3.1
- 📋 EN 10204 3.2
- 📋 Original Mill Certificate
- 📋 Third Party Inspection Available
- 📋 Certificate of Origin
❓ Frequently Asked Questions
What is the difference between 316L and 904L stainless steel plate?
904L is a 'super austenitic' stainless steel containing vastly more alloying elements than 316L. While 316L has ~10% Nickel and 2% Molybdenum, 904L features 23-28% Nickel, 4-5% Molybdenum, and crucially, 1-2% Copper. This extreme chemistry makes 904L vastly superior to 316L in handling strong reducing acids (like sulfuric and phosphoric acid) and makes it virtually immune to chloride stress corrosion cracking (SCC), a major weakness of 316L.
Why is copper added to 904L stainless steel?
The defining feature of 904L is its deliberate addition of 1.0% to 2.0% Copper. In metallurgy, Copper specifically enhances a metal's resistance to reducing environments. In 904L, the copper addition was engineered specifically to provide exceptional resistance to sulfuric acid across a broad range of concentrations and temperatures. Without this copper addition, the steel would rapidly dissolve in highly aggressive sulfuric environments.
Is 904L stainless steel magnetic?
No, 904L is strictly non-magnetic in all conditions. Because of its massive Nickel content (23-28%), it maintains a completely stable austenitic microstructure. Unlike some lower-alloy austenitic grades (like 304) which can become slightly magnetic after heavy cold-working, 904L remains non-magnetic even after severe cold forming.
How do you cut and fabricate 904L plates?
904L can be cut using standard industrial methods, but because it is highly alloyed, it is very tough and has a high work-hardening rate. For cutting, high-definition plasma, laser, or abrasive waterjet cutting are the preferred methods. If mechanical cutting or drilling is required, rigid setups, slow speeds, heavy feeds, and copious amounts of coolant must be used to get under the work-hardened layer. For welding, over-alloyed fillers (like AWS A5.14 ERNiCrMo-3 / Alloy 625) are typically used to ensure the weld seam matches the base metal's corrosion resistance.
What is the standard specification for 904L stainless steel plates?
904L plates are predominantly manufactured and certified to ASTM B625, which is the standard specification for UNS N08904 alloys. It is also frequently found cross-referenced in ASTM A240 (the general standard for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels). In Europe, it is specified under EN 10028-7 as grade 1.4539.
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