Kalpataru Piping Solutions is a top 904L stainless steel flanges supplier as well as 904L stainless steel flanges manufacturer in Mumbai, India. ASTM A182 F904L flanges are engineered for exceptional corrosion resistance in harsh chemical environments and are a specialty of ours. We offer a complete line of ANSI B16.5, B16.47 and International size and standard weld neck flanges, slip on flanges, blind flanges and socket weld and threaded flanges in SS 904L. We have been manufacturing for over 15 years and are a certified A182 F904L flange supplier for the petrochemical, marine and pharmaceutical sectors all over the world.
Unlike other SS 904L flanges, our super austenitic stainless steel precision forged flanges have an outstanding resistance to chlorides, sulfuric acid and pitting corrosion. Every flange is hydrostatically tested and non-destructively examined (NDT) to meet the ASTM A182 and ASME SA182 standards. We are a certified SS 904L Flanges Exporter and have ready stock in Mumbai for sudden order from domestic and international customers and dispatch within 3-5 working days. For the wider stainless steel flanges range, see our Stainless Steel Flanges hub or browse related Duplex Steel Flanges.
As a UNS N08904 Flanges Supplier, we manufacture slip on, weld neck, blind, socket weld, and threaded flange styles in sizes ranging from 1/2” to 48” with pressure classes from 150 to 2500. In the most demanding applications, such as chemical processing plants, oil & gas refineries, marine & offshore platforms, pharmaceutical manufacturing units, pulp & paper mills, pollution control systems and similar settings where the standard austenitic stainless steels cannot withstand the high levels of corrosion, stainless steel 904L flanges are engineered to meet the challenge.
- Why Choose 904L Stainless Steel Flanges?
- Stainless Steel 904L Flanges Specification
- ASTM A182 Stainless Steel 904L Flanges Equivalent Standard Grade
- Stainless Steel 904L Flanges Types
- ASTM A182 F904L Stainless Steel Flanges Chemical Composition
- ASME SA182 Stainless Steel 904L Flanges Mechanical Properties
- Other Available Stock of ASTM A182 SS 904L Flanges
- Stainless Steel 904L Flanges Price
- ASTM A182 904L Stainless Steel Flanges Pressure Ratings
- Dimensions and Weight Chart (Class 150 RF)
- Check Our Related Products
- Quality Testing & Inspection
- Applications of Stainless Steel 904L Flanges
- FAQ’s About Stainless Steel 904L Flanges
Why Choose 904L Stainless Steel Flanges?
SS 904L flanges offer significantly higher corrosion resistance than standard austenitic grades like 316L. The elevated nickel (24 to 26 percent) and molybdenum (4 to 5 percent) content provides exceptional performance against sulfuric acid, phosphoric acid, and chloride induced stress corrosion cracking. Unlike 316L, which fails in dilute sulfuric acid environments, 904L maintains structural integrity across a wide concentration range at elevated temperatures. The copper addition (1 to 2 percent) further enhances resistance to reducing acids. For critical applications where downtime costs exceed material investment, 904L SS Flanges Stockist grade material delivers superior lifecycle value through extended service life and reduced maintenance requirements.
Stainless Steel 904L Flanges Specification
Specification | Details |
Primary Material Standard | ASTM A182 F904L / ASME SA182 F904L (forged steel pipe flanges and fittings) |
Raw Material Reference | ASTM B649 / ASME SB649 (bars and shapes of N08904 used to produce the forgings) |
Dimensional Standards | ANSI/ASME B16.5, B16.47 Series A & B, B16.48, BS 4504, BS 10, EN-1092, DIN, GOST, AWWA |
Size Range | 1/2 inch (15 NB) to 48 inch (1200 NB), DN10 to DN5000 |
Pressure Class / Rating | Class 150 lb, 300 lb, 400 lb, 600 lb, 900 lb, 1500 lb, 2500 lb, PN6 to PN64 |
Flange Face Type | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ), Lap Joint Face (LJF), Large Male-Female (LMF), Small Male-Female (SMF), Tongue and Groove |
HS Code | 73071910 (stainless steel flanges; confirm with export documentation team) |
ASTM A182 Stainless Steel 904L Flanges Equivalent Standard Grade
Standard | Werkstoff Nr. | UNS | JIS | BS | KS | AFNOR | EN |
SS 904L | 1.4539 | N08904 | SUS 904L | 904S13 | STS 317J5L | Z2 NCDU 25-20 | X1NiCrMoCu25-20-5 |
ASTM A182 F904L Stainless Steel Flanges Chemical Composition
Grade | C max | Mn max | Si max | P max | S max | Cr | Mo | Ni | Cu | N max |
SS 904L | 0.020 | 2.00 | 1.00 | 0.040 | 0.030 | 19.00-23.00 | 4.00-5.00 | 23.00-28.00 | 1.00-2.00 | 0.10 |
ASME SA182 Stainless Steel 904L Flanges Mechanical Properties
Property | Value |
Tensile Strength (min) | 490 MPa (71,000 psi) |
Yield Strength 0.2% Offset (min) | 220 MPa (32,000 psi) |
Elongation (min) | 35% |
Hardness (max) | 217 HB |
Physical Properties of SS 904L Stainless Steel Flanges
Property | Unit | Value |
Density | g/cm3 | 7.95 to 8.05 |
Melting Range | deg C (deg F) | 1300 to 1390 (2370 to 2530) |
Specific Heat | J/kg K | 500 |
Thermal Conductivity | W/m K (at 100 deg C) | 12.0 |
Coefficient of Thermal Expansion | micro m/m K (20 to 100 deg C) | 15.0 |
Elastic Modulus | GPa (ksi) | 195 (28,200) |
Electrical Resistivity | micro ohm metre | 0.90 |
Magnetic Permeability | N/A | Non-magnetic in all conditions |
SS 904L vs 316L vs 317L Corrosion Resistance Comparison
904L flanges are specified when standard austenitic grades reach their corrosion limits. The table below shows how the three grades compare across the environments where the material selection matters most:
Environment / Test | SS 904L | SS 317L | SS 316L |
Sulfuric acid (dilute, <10%) | Excellent | Good | Poor |
Sulfuric acid (concentrated, >50%) | Good | Fair | Poor |
Phosphoric acid | Excellent | Good | Fair |
Hydrochloric acid | Limited | Poor | Poor |
Chloride (seawater) | Very Good | Good | Fair |
Pitting resistance (PREN approx.) | 36 to 40 | 33 to 36 | 24 to 28 |
Stress corrosion cracking | Very Good | Good | Fair |
Crevice corrosion | Very Good | Good | Fair |
Intergranular corrosion (sensitised) | Good | Good | Fair |
Non-magnetic in all conditions | Yes | Yes | Yes |
Relative material cost | High | Medium-High | Medium |
Stainless Steel 904L Flanges Types
Existing product photography to be retained for each type:
- SS 904L Weld Neck Flanges: high pressure applications with a long tapered hub that provides reinforcement and smooth flow transition
- SS 904L Slip On Flanges: cost effective, slides over the pipe end before welding; suitable for low-pressure applications
- SS 904L Blind Flanges: closes off pipe ends, valves, or pressure vessel openings; essential for system testing and inspection
- Socket Weld Flanges: smooth bore and high structural strength for small-diameter, high-pressure piping
- Threaded Flanges: internal threads for pipe connection without welding; used where welding is restricted
- Lap Joint Flanges: used with stub ends for systems requiring frequent dismantling
- Ring Type Joint (RTJ) Flanges: available in customised sizes and shapes for high-pressure seal applications
- Long Weld Neck, Spectacle Blind, Orifice, Reducing, Square, Nipo, Bleed Ring, and Plate Flanges also available
Stainless Steel 904L Flanges Price Factors
904L Flanges Price varies based on the following factors. Contact our sales team for a firm quotation:
- Flange type (weld neck, blind, slip-on; weld neck and RTJ typically cost more than slip-on or blind)
- Size and pressure class (larger NPS and higher pressure classes require more material and machining)
- Quantity (bulk orders of 10 tonnes or more qualify for volume pricing)
- Certification and testing requirements (EN 10204 3.2 with witnessed inspection is priced higher than standard 3.1)
- Face type (RTJ machining and RTJ ring stock add to cost vs. standard RF or FF face)
- Current nickel and molybdenum market rates (904L has higher alloy content than 316L and its price follows nickel markets closely)
ASTM A182 904L Stainless Steel Flanges Pressure Ratings
Standard | Flange Types | Pressure Classes |
ASME/ANSI B16.5 | Weld Neck, Slip On, Blind, High Hub Blind, Socket Weld, Lap Joint, Threaded, RTJ | 150, 300, 400, 600, 900, 1500, 2500 |
ASME/ANSI B16.47 | Weld Neck, Blind (Series A & B) | 75, 150, 300, 400, 600, 900 |
ASME/ANSI B16.36 | Weld Neck, Slip On, Threaded | 300, 400, 600, 900, 1500, 2500 |
BS 4504 Sec 3.1 | Weld Neck, Hubbed Slip On, Plate, Loose Plate, Blank | PN 2.5 to PN 40 |
BS 1560 / BS 10 | Weld Neck, Socket Weld, Slip On, Blind, Screwed, Lap | Tables D, E, F, H | Class 150 to 2500 |
DIN Flanges | All DIN flange types (DIN 2527, 2566, 2573, 2576, 2631-2638, 2673) | PN 6 to PN 100 |
Dimensions and Weight Chart (Class 150 RF, ASME B16.5)
Nominal Size | OD (mm) | Bolt Circle (mm) | Bolt Holes | Thickness (mm) | Approx Weight (kg) |
1 inch | 108 | 79 | 4 | 14 | 1.5 |
1.5 inch | 127 | 98 | 4 | 16 | 2.3 |
2 inch | 152 | 121 | 4 | 16 | 2.9 |
2.5 inch | 178 | 149 | 4 | 18 | 3.7 |
3 inch | 190 | 152 | 4 | 19 | 4.8 |
4 inch | 229 | 191 | 8 | 24 | 7.2 |
5 inch | 254 | 216 | 8 | 24 | 9.6 |
6 inch | 279 | 241 | 8 | 26 | 11.5 |
8 inch | 343 | 298 | 8 | 29 | 18.0 |
10 inch | 406 | 362 | 12 | 31 | 26.5 |
12 inch | 483 | 432 | 12 | 32 | 38.0 |
14 inch | 533 | 476 | 12 | 35 | 50.0 |
16 inch | 597 | 540 | 16 | 37 | 66.0 |
18 inch | 635 | 578 | 16 | 40 | 80.0 |
20 inch | 699 | 635 | 20 | 44 | 100.0 |
24 inch | 813 | 749 | 20 | 52 | 148.0 |
Quality Testing & Inspection
Every SS 904L flange undergoes rigorous testing to ensure compliance with ASTM A182 and ASME SA182 standards:
Test Type | Method / Standard | Purpose |
Chemical Analysis (PMI) | OES / XRF Spectrometry | Verify alloy composition against A182 F904L specification |
Mechanical Testing | Tensile, yield, elongation per ASTM E8 | Confirm strength meets minimum specification values |
Hardness Testing | Brinell per ASTM E10 | Check max hardness (217 HB max) |
Hydrostatic Pressure Test | ASME B16.5 Section 8 (1.5x design pressure) | Ensure no leakage under pressure |
Intergranular Corrosion Test | ASTM A262 Practice E | Confirm resistance to sensitization |
Ultrasonic Testing (UT) | ASTM E114 | Detect subsurface defects in forging |
Dye Penetrant / Magnetic Particle | ASTM E165 / E709 | Surface crack detection |
Dimensional Inspection | ASME B16.5 tolerance check | Verify OD, bore, thickness, bolt circle |
Applications of Stainless Steel 904L Flanges
- Chemical Processing: SS 904L flanges are widely used in sulfuric acid concentrators (up to 98% at 180 degrees C) and phosphoric acid production lines due to their excellent resistance to acidic corrosion.
- Oil and Gas: Used in sour gas piping systems, wellhead equipment, and offshore platforms where hydrogen sulfide and chloride exposure demand exceptional material performance.
- Power Plants and Pollution Control: Commonly installed in flue gas desulfurization (FGD) systems where strong corrosion resistance to sulfur dioxide and sulfuric acid condensate is required.
- Marine and Offshore Systems: Suitable for seawater cooling systems on offshore platforms and marine heat exchangers because of their strong resistance to chloride corrosion.
- Pharmaceutical Processing: Used in reactor vessels handling chlorinated organic compounds and other aggressive chemicals where product purity and corrosion resistance must both be maintained.
- Desalination Plants: 904L flanges withstand long term exposure to concentrated brine and high temperature seawater, making them the preferred choice in multi-effect distillation and reverse osmosis systems.
- Pulp and Paper Mills: Used in bleaching systems and chemical recovery circuits handling highly corrosive acidic and chlorinated process streams.
- Textile and Synthetic Fiber Industry: Specified in equipment handling sulfuric acid, acetic acid, and other aggressive solvents used in fiber production and dyeing processes.
Export Markets
Kalpataru Piping Solution exports ASTM B649 904L Flanges and A182 F904L grade material to clients across the Middle East, Europe, Southeast Asia, Africa, and the Americas, including key markets such as the United Arab Emirates, Saudi Arabia, Singapore, the United Kingdom, and the United States. For a shipment quote, contact our export team.
Other Available Stock of ASTM A182 SS 904L Flanges
- Stainless Steel 904L WNRF Flanges Dealer
- AISI 904L Spectacle Blind Flanges Stockist
- ASTM A182 F904L Long Weld Neck Flanges
- ASME SA182 Stainless Steel 904L RTJ Flanges
- ANSI/ ASME B16.5 SS 904L Blind Ring Flanges
- Stainless Steel A182 F904L BLRF Flanges
- SS 904L Lap Joint Flanges Distributors
- SA 182 SS 904L LJRF Flanges Manufacturer
- Stainless Steel 904L Slip-on Raised Face Flanges
- Stainless Steel 904L SORF Flanges Stockholder
- SS ASTM A182 F904L Screwed Flanges Trader
- ANSI B16.5 Stainless Steel 904L SWRF Flanges
- Stainless Steel 904L Reducing Flanges Stock
- SS 904L Tongue & Groove Flanges Supplier
- ASTM A182 Stainless Steel 904L Weldoflange
- Grade 904L Stainless Steel Raised Face Flanges
- A182/ SA182 904L SS Blind Raised Face Flange
- SS 904L Forged Flanges Wholesaler
- B16.5 Stainless Steel 904L Expander Flanges
- SS 904L Ring Spacers (Paddle Spacers)
- SUS 904L Male & Female Flanges in Mumbai
- Stainless Steel 904L Flat Face Flanges
- Stainless Steel 904L Flat Flanges
- SS UNS N08904 Flanges Exporter
- Stainless Steel DIN 1.4539 Flange
- SS 904L High Hub Blind Flanges
- SS 904L ASME B16.5 Loose Flanges
- 904L Stainless Steel Orifice Flanges in India
FAQ’s About Stainless Steel 904L Flanges
Stainless Steel 904L is a super austenitic stainless steel (UNS N08904) known for its high corrosion resistance and excellent durability in aggressive environments. It contains high levels of chromium, nickel, molybdenum, and copper, which provide strong resistance to acids, pitting, and crevice corrosion.
Both grades have good corrosion resistance, but 904L generally offers significantly better performance in highly corrosive environments. Stainless Steel 904L has a higher nickel (24 to 28 percent vs 10 to 14 percent) and molybdenum content (4 to 5 percent vs 2 to 3 percent), which improves resistance to chlorides, sulfuric acid, and other aggressive chemicals. 316L is more cost-effective and suitable for general industrial applications where extreme corrosion resistance is not required.
SS 904L contains much higher nickel and molybdenum content than 304, making it far more resistant to pitting, crevice corrosion, and acidic environments. SS 304 is a standard austenitic stainless steel suitable for general environments but will not withstand highly corrosive chemical conditions that 904L handles reliably.
904L stainless steel flanges are used in chemical processing plants (sulfuric and phosphoric acid), oil and gas facilities, marine equipment, pharmaceutical production, pulp and paper industries, desalination plants, and pollution control systems where standard stainless grades fail.
SS 904L has higher nickel content (23 to 28 percent vs 11 to 15 percent) and slightly higher molybdenum (4 to 5 percent vs 3 to 4 percent) than 317L, giving it a higher PREN value and better overall corrosion resistance. 904L is the preferred choice in the most aggressive acid environments; 317L is a cost-effective step up from 316L where moderate improvement is sufficient.
Standard supply includes EN 10204 3.1 Mill Test Certificates from a NABL approved laboratory, with PMI reports, hydrostatic test reports, dimensional inspection records, and heat traceability documentation. EN 10204 3.2 third party witnessed inspection is available on request via TUV, Bureau Veritas, Lloyds, SGS, or DNV.
The 904L Flanges Price depends on flange type, size, pressure class, certification, quantity, and current nickel/molybdenum market rates. SS 904L carries a premium over 316L due to its higher alloy content. Contact Kalpataru with your specifications for a firm, itemised quotation.