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.
Continue reading
- Inconel 625 vs Duplex 2205: Nickel Superalloy or Duplex Stainless?Inconel 625 (UNS N06625) and Duplex 2205 (UNS S32205) both serve chloride and acid duty; 625 tolerates higher
- Inconel 718 vs Inconel 625: The Ultimate Comparison Guide for Engineers and ProcurementInconel 718 (UNS N07718) reaches about 1275 MPa after ageing against 830 MPa for Inconel 625 (UNS N06625), but
- Invar 36 vs Kovar (4J29): Controlling Thermal Expansion for Precision ApplicationsInvar 36 (UNS K93600) and Kovar (UNS K94610) are both controlled-expansion Fe-Ni alloys: Invar holds near-zero
- Invar 36 vs Super Invar: Ultra-Low Thermal Expansion Alloys ComparedInvar 36 is the classic iron-nickel alloy with near-zero thermal expansion around room temperature. Super Inva
- Kovar (4J29) vs Invar 36: Glass-Sealing Alloy vs Ultra-Low Expansion StandardKovar (4J29) is engineered for one critical purpose — hermetic sealing to hard glass and ceramics. Invar 36 is
- All 44 Alloy Comparisons guides
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.