SS 904L Buttweld Fittings are made to UNS N08904 to the ASTM specification on your order for sulphuric acid and chloride service. Elbows, tees, reducers and caps are dimensioned to ASME B16.9 and bevelled for welding into SS 904L pipe.
Raaj Fittings manufactures SS 904L buttweld fittings in-house at our two plants in India, seamless and welded, from ½" upwards, and exports them to EPC contractors, fabricators and stockists across the Middle East, Europe and the Americas, with full traceability and EN 10204 certificates.
| Material specification | UNS N08904 to the ASTM specification on your order |
|---|---|
| Construction | Seamless and welded |
| Dimensional standards | ASME B16.9, MSS SP-43; bevelled ends to ASME B16.25 |
| Size range | ½" to 48" NPS; larger sizes to order |
| Wall thickness | SCH 5S, 10S, 40S, 80S and heavier walls to order |
| Certification | EN 10204 3.1 mill test certificate as standard; EN 10204 3.2 on request |
SS 904L is a super-austenitic stainless steel with about 25% nickel, 20% chromium, 4.5% molybdenum and 1.5% copper. The copper gives outstanding resistance to sulphuric acid, and the high nickel and molybdenum resist chloride pitting and stress corrosion cracking far better than 316L.
| Element, % | N08904 |
|---|---|
| Carbon (C) | 0.020 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.040 max |
| Sulphur (S) | 0.030 max |
| Silicon (Si) | 1.00 max |
| Chromium (Cr) | 19.0 – 23.0 |
| Nickel (Ni) | 23.0 – 28.0 |
| Molybdenum (Mo) | 4.0 – 5.0 |
| Copper (Cu) | 1.0 – 2.0 |
| Property | SS 904L |
|---|---|
| Tensile strength, min. | 490 MPa (71 ksi) |
| Yield strength (0.2%), min. | 215 MPa (31 ksi) |
| Elongation, min. | 35% |
| UNS | Werkstoff Nr. | EN / DIN | Other |
|---|---|---|---|
| N08904 | 1.4539 | X1NiCrMoCu25-20-5 | — |
SS 904L fittings are hot-formed seamless from pipe or made from plate and welded pipe, then solution annealed so that formed and welded areas regain full corrosion resistance. Welded fittings can be ordered with fully radiographed (WX) or ultrasonically tested (WU) seams.
Every heat is PMI-verified and its chemistry and mechanical properties are confirmed against the material specification before the buttweld fittings are released. Each piece is marked with grade, size, rating and heat number for traceability to its EN 10204 3.1 mill test certificate. EN 10204 3.2 certification and inspection by the buyer's nominated third-party agency are available on request, as are PED 2014/68/EU compliance for European projects and IBR certification for Indian boiler applications.
904L has far more nickel (23–28%), more molybdenum (4–5%) and added copper. It resists sulphuric acid and chloride pitting much better than 316L and is used where 316L corrodes.
It is classed as a super-austenitic stainless steel, with UNS number N08904 because of its high nickel content.
Yes. Smaller sizes are normally seamless and larger sizes welded, with weld examination as the specification and your order require. Tell us the size, schedule and any construction requirement.
Every order is supplied with EN 10204 3.1 mill test certificates showing heat chemistry and mechanical properties to UNS N08904 to the ASTM specification on your order. EN 10204 3.2 certification and inspection by your nominated third-party agency are available on request.