SS 904L
SS 904L: Specifications | Grades & Standards | Product Types | Equivalent | Chemical | Mechanical | BW Fittings | Forged Fittings | Flanges | FAQ
ASTM A182 / A403 SS 904L Flanges & Pipe Fittings – 904L Buttweld Elbows, Tees, Reducers, Stub Ends, and Crosses. UNS N08904 Forged Fittings including Couplings, Unions, Nipples, Bushings, Plugs, Trusted SS WNR 1.4539 WNRF, RTJ, & SORF Flanges Exporter to Middle East, Europe, and USA for high-performance, corrosion-resistant piping applications.
Best Export Prices: sales@midlandforgefittings.com
Midland Forge and Fittings Pvt. Ltd. is a leading manufacturer and exporter of high-performance stainless steel 904L pipe fittings, flanges, and forged components. Specializing in buttweld elbows, tees, reducers, stub ends, forged fittings, and flanges, the company ensures products meet international standards for durability, corrosion resistance, and high-temperature performance.
Combining state-of-the-art manufacturing technology with skilled craftsmanship, the team delivers reliable, long-lasting piping solutions for industries such as oil & gas, petrochemical, power, and chemical processing. With a global footprint across India, the Middle East, Europe, and the USA, certified and precision-engineered products ensure timely delivery and high-performance results in the most demanding industrial applications.
SS 904L is a high-alloy austenitic stainless steel designed for exceptional corrosion resistance and high-temperature performance. It contains high chromium (19–23%), nickel (24–28%), and molybdenum (4–5%), along with low carbon content, which minimizes carbide precipitation during welding and enhances resistance to intergranular corrosion. The material is engineered to withstand oxidizing, reducing, and mildly corrosive chemical environments, making it suitable for chemical, petrochemical, marine, and offshore piping systems.
SS 904L pipe components are manufactured as buttweld and forged fittings, including elbows, tees, reducers, stub ends, couplings, unions, and flanges. Forged and flanged components conform to ASTM A182 (flanges) and ASTM A403 (buttweld fittings) standards, ensuring dimensional accuracy, wall thickness consistency, and high mechanical strength. Flanges are available in WNRF (weld neck) and SORF (slip-on) designs, providing reliable sealing under high-pressure and high-temperature conditions.
SS 904L exhibits excellent tensile and yield strength, creep resistance, and thermal stability, maintaining performance in high-pressure and high-temperature piping applications. The material also offers superior weldability and formability, allowing fabrication into complex piping networks without compromising corrosion resistance or mechanical integrity. Conformance to UNS N08904 and Werkstoff 1.4539 ensures the long-term reliability and durability of piping systems in demanding industrial environments.
ASTM A403 SS 904L Buttweld Fittings - Specifications
A182 SS 904L Threaded Fittings – Grades & Standards
| Grade | Buttweld Fittings Standards | Forged Fittings Standards | Flanges Standards |
|---|---|---|---|
| 904L | ASTM A403 / ASME B16.9 / MSS-SP-43 | ASTM A182 / ASME B16.11 | ASTM A182 / ASME B16.5 / B16.47 |
SS 904L – Industrial Flanges, Fittings & Piping Products
904L SS Slip On Flange - Equivalent Grades
| Standard / Region | Designation / Equivalent |
|---|---|
| UNS | N08904 |
| Werkstoff (WNr) | 1.4539 |
| ASTM / ASME | A182 / A240 / A403 |
| EN (DIN) | X1NiCrMoCu25-20-5 |
| JIS | SUS 904L |
| GOST (Russia) | 08Х22Н6Т |
| BS | 904S16 |
| AFNOR (France) | Z2CNDU25-20 |
Stainless Steel 904L Pipe Fittings - Chemical Composition
| Element | Composition (%) |
|---|---|
| Carbon (C) | ≤ 0.02 |
| Chromium (Cr) | 19 – 23 |
| Nickel (Ni) | 24 – 28 |
| Molybdenum (Mo) | 4 – 5 |
| Copper (Cu) | 1 – 2 |
| Manganese (Mn) | ≤ 2 |
| Silicon (Si) | ≤ 1 |
| Phosphorus (P) | ≤ 0.03 |
| Sulfur (S) | ≤ 0.01 |
| Nitrogen (N) | ≤ 0.10 |
| Iron (Fe) | Balance |
SS WP904L Buttweld Fittings - Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength (MPa) | 520 – 750 |
| Yield Strength (MPa) | 215 – 275 |
| Elongation (%) | 40 – 50 |
| Hardness (HB) | ≤ 200 |
| Hardness (HRB) | ≤ 90 |
| Hardness (HRC) | ≤ 22 |
| Modulus of Elasticity (GPa) | 193 |
| Poisson’s Ratio | 0.30 |
| Density (g/cm³) | 8.0 |
ASTM A403 WP904L Fittings – Seamless & Welded
ASTM A182 F904L Flanges – Types and Industrial Applications
A182 Stainless Steel 904L Forged Fittings – Complete Range
What standards and certifications govern SS 904L fittings and flanges?
Fittings Standards: Buttweld fittings conform to ASTM A403 / ASME B16.9 / MSS-SP-43, ensuring dimensional accuracy and pressure ratings.
Forged Components: Forged fittings are manufactured per ASTM A182 / ASME B16.11 for mechanical strength and weld integrity.
Flanges: Flanges adhere to ASTM A182 / ASME B16.5 / B16.47, guaranteeing compatibility with piping systems and pressure classes.
International Equivalents: Includes UNS N08904, Werkstoff 1.4539, and EN X1NiCrMoCu25-20-5, enabling global application in chemical, petrochemical, and offshore industries.
Can SS 904L fittings and flanges be welded safely?
Excellent Weldability: SS 904L can be welded using TIG, MIG, and arc welding techniques without compromising corrosion resistance.
No Sensitization Risk: The low carbon content minimizes chromium carbide precipitation, avoiding intergranular corrosion near weld zones.
Post-Weld Treatment: While not always required, solution annealing can be performed for maximum corrosion resistance in critical applications.
Industrial Advantage: Welded assemblies maintain mechanical integrity and chemical resistance, making SS 904L ideal for complex piping networks.
What makes SS 904L suitable for highly corrosive environments?
High Alloy Content: SS 904L contains 19–23% chromium, 24–28% nickel, 4–5% molybdenum, and 1–2% copper, providing superior resistance to oxidation, pitting, and crevice corrosion.
Low Carbon Content: With ≤0.02% carbon, SS 904L resists intergranular corrosion, even after welding or prolonged high-temperature exposure.
Copper Addition: Enhances resistance to reducing acids, such as sulfuric and phosphoric acid, making it ideal for chemical processing industries.
Industrial Impact: This combination allows buttweld fittings, forged components, and flanges to perform reliably in aggressive chemical, petrochemical, marine, and offshore applications.