Alloy 20 Buttweld Fittings are made to ASTM B366 / ASME SB366 WP20CB (UNS N08020) for sulphuric acid service. Elbows, tees, reducers and caps are dimensioned to ASME B16.9 and bevelled for welding into Alloy 20 pipe.
Raaj Fittings manufactures Alloy 20 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 | ASTM B366 / ASME SB366 WP20CB (UNS N08020) |
|---|---|
| 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 |
Alloy 20 (UNS N08020) is a nickel-iron-chromium alloy with copper and molybdenum, stabilised with niobium. It was developed specifically for sulphuric acid service and is often called "Carpenter 20" or "20Cb-3".
| Element, % | N08020 |
|---|---|
| Carbon (C) | 0.07 max |
| Manganese (Mn) | 2.00 max |
| Phosphorus (P) | 0.045 max |
| Sulphur (S) | 0.035 max |
| Silicon (Si) | 1.00 max |
| Chromium (Cr) | 19.0 – 21.0 |
| Nickel (Ni) | 32.0 – 38.0 |
| Molybdenum (Mo) | 2.0 – 3.0 |
| Copper (Cu) | 3.0 – 4.0 |
| Niobium + tantalum (Nb + Ta) | 8 × C min, 1.00 max |
| Property | Alloy 20 |
|---|---|
| Tensile strength, min. | 551 MPa (80 ksi) |
| Yield strength (0.2%), min. | 241 MPa (35 ksi) |
| Elongation, min. | 30% |
| UNS | Werkstoff Nr. | EN / DIN | Other |
|---|---|---|---|
| N08020 | 2.4660 | NiCr20CuMo | Carpenter® 20Cb-3 |
Alloy 20 fittings are formed from pipe, plate or bar and supplied in the solution-annealed condition. Light-wall schedules (5S, 10S, 40S) are common because the alloy's strength and corrosion resistance allow thin walls. Weld with matching nickel alloy filler and low heat input.
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.
Alloy 20 was designed for sulphuric acid and is widely used in acid production, pickling, chemical and pharmaceutical plants where stainless steels would corrode.
Carpenter 20Cb-3 is a trade name for UNS N08020. Fittings are supplied to the ASTM specifications for N08020.
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 ASTM B366 WP20CB (UNS N08020). EN 10204 3.2 certification and inspection by your nominated third-party agency are available on request.