Alloy 20 Tube Fittings are made to Alloy 20, UNS N08020 for sulphuric acid service. Double and single ferrule compression fittings connect Alloy 20 instrument and control tubing.
Raaj Fittings machines Alloy 20 tube fittings in-house at our two plants in India, in metric and imperial tube sizes, 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 | Alloy 20, UNS N08020 |
|---|---|
| Tube OD | Metric 3 to 25 mm; imperial ⅛" to 1" |
| Fitting types | Double ferrule and single ferrule compression fittings; unions, connectors, elbows, tees, bulkheads and adapters |
| End connections | Compression tube ends; NPT (ASME B1.20.1), BSPT and BSPP (BS 21 / ISO 7-1) threads |
| 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 tube fittings are machined from certified bar and used with Alloy 20 tubing in instrument, sampling and injection lines carrying aggressive media. Fittings and tubing must be the same alloy so the ferrules grip correctly.
Bar stock is PMI-verified and traceable by heat number; bodies, nuts and ferrules are dimensionally inspected and threads gauge-checked. Every order is supplied with EN 10204 3.1 certificates, with EN 10204 3.2 certification and third-party inspection by the buyer's nominated agency on request.
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.
They should be used with Alloy 20 tubing. Matching the materials ensures the ferrules grip correctly and that no part of the joint becomes the weak point for corrosion.
Every order is supplied with EN 10204 3.1 mill test certificates showing heat chemistry and mechanical properties to Alloy 20, UNS N08020. EN 10204 3.2 certification and inspection by your nominated third-party agency are available on request.