When to pick IN625 over IN718
IN625 is solid-solution strengthened — no precipitation aging step, simpler heat treatment, more ductile. It is the better choice when corrosion resistance dominates and peak strength does not.
Pick it for marine and subsea fittings, downhole tools, exhaust gas paths, and chemical reactors. For turbine-section structural parts use IN718.
Defects and post-processing
L-PBF IN625 has 0.3–0.6 % porosity and ~5 % anisotropy. HIP is optional for non-critical parts; stress-relief at 980 °C / 1 h is sufficient for most applications. The microstructure is fully γ with secondary δ-phase precipitates at grain boundaries.
Suggested parameters
Starting recipe at 40 µm layer.
- Layer thickness: 40 µm
- Laser power: 285 W
- Scan speed: 1050 mm/s
- Hatch spacing: 110 µm
- Atmosphere: argon, O₂ < 100 ppm
Frequently asked questions
Do I need HIP for IN625?
For static-load corrosion-service parts, no. For fatigue-critical parts, yes — HIP closes residual porosity and recovers 10–20% of fatigue life.
Can IN625 replace Hastelloy in AM?
For many marine and chemical environments, yes. For very aggressive acids or higher-temperature service, Hastelloy C-276 still wins.
Sources
- ASTM B443 / AMS 5666 (wrought reference)
- EOS NickelAlloy IN625 datasheet
- NIST AM IN625 benchmark series