EN 10253-2 Type B buttweld pipe fittings in 2.4633 — Inconel 617 (NiCr22Co12Mo, N06617). A nickel-chromium-cobalt-molybdenum alloy combining exceptional high-temperature mechanical strength with oxidation resistance to 1100°C. The cobalt addition (12%) provides solid-solution strengthening at temperature — key advantage over Inconel 600/601 which are not designed for sustained high-temperature mechanical loading. Used in gas turbine components, steam reformers, and advanced ultra-supercritical power plant piping.
| Element | Min | Max | Role |
|---|---|---|---|
| Ni (Nickel) | 44.5% | — | Base; matrix |
| Cr (Chromium) | 20.0% | 24.0% | Oxidation and corrosion resistance |
| Co (Cobalt) | 10.0% | 15.0% | Solid-solution strengthening at high temperature |
| Mo (Molybdenum) | 8.0% | 10.0% | Additional solid-solution strengthening |
| Al (Aluminium) | 0.8% | 1.5% | Al₂O₃ scale — oxidation protection |
| W.Nr. | 2.4633 |
| EN Name | NiCr22Co12Mo |
| ASTM UNS | N06617 |
| Trade Name | Inconel 617 |
Filler: ERNiCrCoMo-1 (matching 617). No PWHT required. Solution anneal 1175°C for optimal creep properties in high-temperature service.
