Inconel 625 (UNS N06625): Ni-Cr-Mo Superalloy
ASTM B443/B446 · Updated: 2026-05-25
Inconel 625 (UNS N06625) is a nickel-chromium-molybdenum-niobium superalloy (≥58% Ni, 20-23% Cr, 8-10% Mo, 3.15-4.15% Nb+Ta) providing exceptional corrosion resistance and high strength from cryogenic to 980°C. The niobium addition enables precipitation strengthening without the age-hardening heat treatment required for Inconel 718—625 achieves its properties in the solution-annealed condition. Resistant to pitting, crevice corrosion, intergranular attack, and chloride stress corrosion cracking. Standard material for chemical processing, marine exhaust systems, aerospace ducting, nuclear reactor components, and undersea equipment. PREN >45—far exceeding all stainless steels. Weldable with ERNiCrMo-3 (IN625) filler for both joining and overlay cladding of less corrosion-resistant steels.
Quick Facts
| Category | Nickel Alloy |
| Standard | ASTM B443/B446 |
| Density | 8.44 g/cm³ |
| Yield Strength | 414 MPa (60 ksi) annealed |
| Tensile Strength | 827 MPa (120 ksi) annealed |
Global Equivalents & Cross-Reference
| Alternative Standard / Grade | Action |
|---|---|
| EN NiCr22Mo9Nb | Compare |
| DIN 2.4856 | Compare |
| JIS NCF625 | Compare |
| GH625 | Compare |
| ISO NiCr22Mo9Nb | Compare |
Related Materials
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Frequently Asked Questions
When is Inconel 625 preferred over 316L stainless?
Choose 625 when: (1) PREN requirements exceed 40 (severe pitting environments), (2) service temperature exceeds 500°C where 316L loses strength, (3) chloride stress corrosion cracking is a risk (austenitic SS is susceptible above 60°C in chlorides), (4) sour service (H2S) in oil & gas per NACE MR0175. 625 costs approximately 15-20× more than 316L—only justified when 316L, 2205, or 904L have proven inadequate.