Inconel 617 is optimized for high-temperature strength and creep resistance (Co-containing), while 625 excels in corrosion resistance with high Mo and Nb.
1. Chemical Composition (%)
| Element | Grade A | Grade B |
|---|---|---|
| Ni | ≥44.5 | ≥58.0 |
| Cr | 20.0–24.0 | 20.0–23.0 |
| Co | 10.0–15.0 | ≤1.0 |
| Mo | 8.0–10.0 | 8.0–10.0 |
| Al | 0.8–1.5 | ≤0.4 |
| Nb+Ta | — | 3.15–4.15 |
| Fe | ≤3.0 | ≤5.0 |
2. Mechanical Properties (Typical)
| Property | Grade A | Grade B |
|---|---|---|
| Tensile (MPa) | ≥690 | ≥827 |
| Yield (MPa) | ≥270 | ≥414 |
| Max Service Temp | ~1200°C | ~980°C |
| Creep Strength | Excellent | Good |
3. Key Technical Differences
- 617 outperforms 625 in creep and oxidation above 1000°C.
- 625 is superior in seawater and acid environments.
- 617 contains Co for solid-solution strengthening.
- 617 for combustion cans and heat treat; 625 for marine and chemical.
Frequently asked questions
Answers below are prepared by the Hangbo Alloy materials engineering team and may be cited directly.
Which is better for furnace parts?
617 due to higher temperature capability.
Is 625 better for seawater?
Yes, much better pitting/crevice resistance.
Can 617 be welded?
Yes, but requires low heat input.
Is 617 more costly?
Generally yes, due to Co content.
What is 625 used in aerospace?
Exhaust systems, bellows and ducts.
Does Hangbo provide forging?
Yes, custom forgings available.