In the field of high-performance thermal engineering, "heat resistance" is a continuous spectrum. For purchasing managers and designers, the most challenging issue is microstructural degradation exceeding standard thresholds.
The Limits of Inconel 625: While Inconel 625 alloys are renowned for their excellent resistance to water corrosion, their mechanical property limits are 650°C. Above 750°C (1382°F), overaging and rapid softening occur.
The Solution for Inconel 617: If your application requires structural integrity at high temperatures ranging from 900°C to 980°C (1800°F), a different metallurgical material is needed. Inconel 617 (UNS N06617) incorporates cobalt (Co) and molybdenum (Mo), providing superior creep rupture strength despite the degradation of other material properties.
At Gnee Alloy, we eliminate your doubts. As a professional Tier-1 manufacturer, we are able to provide the high-temperature stability required for your mission-critical components.
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Inconel 617 and 625 Alloy Sourcing Guide
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Inconel 617 and 625 Alloy Sourcing Guide
Purchasing Inconel 617 (UNS N06617) and 625 (UNS N06625) alloys requires matching their unique chemical composition to your specific application needs. These high-performance nickel-chromium superalloys are favored for their suitability for extreme environments, but they also have long lead times and high material costs.
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What are the disadvantages of Inconel 625?
Disadvantages: High cost: Due to its complex composition and high production costs, Inconel 625 is significantly more expensive than many other materials. Difficult to process: The toughness of Inconel 625 makes it more difficult to process, requiring specialized tools and techniques.
1. Inconel 617 and Inconel 625 Material Overview
| Parameter | Inconel 617 | Inconel 625 |
|---|---|---|
| UNS Number | N06617 | N06625 |
| Chinese Equivalent | GH3617 | GH3625 |
| Material Type | Wrought Nickel-based High-Temperature Alloy | Wrought Nickel-based Corrosion Resistant Alloy |
| Strengthening Mechanism | Solid-solution strengthening (Co + Mo + Cr) | Solid-solution strengthening (Mo + Nb) |
| Product Forms | Bar, plate, tube, strip | Bar, plate, tube, strip, wire |
| Typical Applications | Gas turbine combustors, afterburners, high-temperature heat exchangers | Chemical processing, marine engineering, FGD scrubbers, aerospace |
| Maximum Service Temperature (Load-Bearing) | ~900 – 950°C | ~600°C |
| Maximum Service Temperature (Oxidation) | ~1100°C | ~980°C |
| Delivery Condition | Solution treated (annealed) – not age-hardenable | Solution treated (annealed) – not age-hardenable |
2. Comparison of chemical composition of Inconel 617 and Inconel 625 (wt%)
| Element | Inconel 617 | Inconel 625 | Key Difference |
|---|---|---|---|
| Nickel (Ni) | 44.5 min (Balance) | ≥ 58.0 (Balance) | 625 has higher Ni |
| Chromium (Cr) | 20.0 – 24.0 | 20.0 – 23.0 | Similar |
| Cobalt (Co) | 10.0 – 15.0 | ≤ 1.0 | 617 contains high Co |
| Molybdenum (Mo) | 8.0 – 10.0 | 8.0 – 10.0 | Similar |
| Niobium (Nb) | - | 3.15 – 4.15 | 625 contains Nb |
| Aluminum (Al) | 0.8 – 1.5 | ≤ 0.40 | 617 contains higher Al |
| Titanium (Ti) | ≤ 0.6 | ≤ 0.40 | 617 may contain Ti |
| Iron (Fe) | ≤ 3.0 | ≤ 5.0 | 625 has higher Fe |
| Carbon (C) | 0.05 – 0.15 | ≤ 0.10 | 617 higher C |
| Manganese (Mn) | ≤ 1.0 | ≤ 0.50 | - |
| Silicon (Si) | ≤ 1.0 | ≤ 0.50 | - |
| Phosphorus (P) | ≤ 0.015 | ≤ 0.015 | Similar |
| Sulfur (S) | ≤ 0.015 | ≤ 0.015 | Similar |
| Boron (B) | ≤ 0.006 | - | 617 contains B |
| Copper (Cu) | ≤ 0.5 | ≤ 0.07 | - |
3. Comparison of room temperature mechanical properties of Inconel 617 and Inconel 625
| Property | Inconel 617 (Annealed) | Inconel 625 (Annealed) | Advantage |
|---|---|---|---|
| Tensile Strength, Ultimate (MPa) | ~750 (109 ksi) | ≥ 830 (120 ksi) | 625 (~11% higher) |
| Tensile Strength, Yield (MPa) | ~345 (50 ksi) | ≥ 415 (60 ksi) | 625 (~20% higher) |
| Elongation (%) | ≥ 45 | ≥ 30 | 617 (more ductile) |
| Reduction of Area (%) | ≥ 50 | ≥ 40 | 617 |
| Hardness | ~89 HRB (~20 HRC) | ~22 HRC (96 HRB) | 625 harder |
| Modulus of Elasticity (GPa) | ~211 | ~207 | Similar |
| Poisson's Ratio | 0.30 | 0.29 – 0.30 | Similar |
| Density (g/cm³) | 8.36 | 8.44 | 617 lighter |
Click to download the Inconel 625 alloy PDF file now
4. Introduction to Inconel 617 and Inconel 625 Alloys
Inconel 617
Inconel 617: Primarily used for extreme high-temperature resistance and metallurgical stability (up to 1150°C/2100°F). Its cobalt and molybdenum content makes it a preferred choice for gas turbines and petrochemical furnaces.
Inconel 625
Inconel 625: Performs excellently in highly corrosive environments (e.g., seawater and chemical processing) while maintaining excellent mechanical properties at temperatures up to 980°C. Its added molybdenum and niobium provide excellent resistance to pitting and crevice corrosion.
5. Inconel 625 Alloy Specifications and Availability
These two alloys are expensive and typically require large-volume custom production; however, some suppliers keep standard sizes in stock. You can usually source from the following suppliers:
• Tubes
• Plates
• Round and flat bars
• Forged billets
6. Comparison of corrosion resistance between Inconel 617 and Inconel 625
| Environment | Inconel 617 | Inconel 625 | Advantage |
|---|---|---|---|
| Oxidizing Acids (HNO₃) | Good | Excellent | 625 |
| Reducing Acids (H₂SO₄, HCl) | Fair | Excellent | 625 |
| Chloride Pitting | Good | Excellent | 625 |
| Crevice Corrosion | Good | Excellent | 625 |
| Chloride SCC | Excellent | Excellent | Similar |
| Seawater | Moderate | Excellent | 625 |
| High-Temperature Oxidation (to 1100°C) | Excellent | Good to 980°C | 617 |
| Carburization Resistance | Excellent | Good | 617 |
| Sulfidation Resistance | Good | Good | Similar |
Corrosion Resistance Rating (1-5, 5 = best)
| Environment | 617 | 625 |
|---|---|---|
| High-Temp Oxidation (1000°C) | 5 | 4 |
| Sulfuric Acid | 3 | 5 |
| Hydrochloric Acid | 2 | 5 |
| Seawater | 3 | 5 |
| Chloride SCC | 4 | 5 |
| Carburization | 5 | 4 |
7. Inconel 617 and Inconel 625 Selection Recommendations
| Requirement | Recommended Alloy |
|---|---|
| Highest temperature service (800-950°C) | Inconel 617 |
| High-temperature load-bearing (up to 950°C) | Inconel 617 |
| Carburization resistance | Inconel 617 |
| Superior corrosion resistance (acids, chlorides, seawater) | Inconel 625 |
| Highest room temperature strength | Inconel 625 |
| Seawater / marine service | Inconel 625 |
| Sour gas / H₂S service | Inconel 625 |
| Better ductility | Inconel 617 |
| Better machinability | Inconel 625 |
| Lower density / weight saving | Inconel 617 (8.36 vs 8.44) |
| Cost-sensitive (between these two) | Inconel 625 (generally lower cost) |
Why Choose Gnee as Your Nickel-Based Alloy Supplier
✅️VIM + VAR Melting: Ensuring ultra-pure chemistry to maximize fatigue life and thermal stability.
✅️Full Traceability: Every bar and pipe is delivered with an EN 10204 3.1 MTC documenting exact creep-rupture data.
✅️Wholesale Inventory: Massive stock of Seamless Tubes and Forged Bars ready for Fast Global Shipping.
✅️Custom Fabrication: We offer precision cutting, laser blanking, and specialized thermal treatment.
Gnee Alloy inconel 625 Certificate
📦 Packaging and Shipping
All Nickel Based Alloy products are packaged using the following methods:
Wooden pallets or crates
Moisture-proof packaging
Labels with furnace number, standard, and size labels
Shipped worldwide by sea, air, or express
Gnee Alloy 625 Alloy Product Packing
Contact us for the latest export price quote for 625 Alloy
FAQ
Q1: Can I weld Inconel 617 directly to Inconel 625?
A: Yes. Both have excellent weldability. We recommend using matching Inconel 617 (ERNiCrCoMo-1) filler metal to maintain joint stability across the thermal gradient.
Q2: Which alloy is more cost-effective for a chemical plant?
A: If the environment is purely high-temp air/steam under 700°C, Inconel 625 is the more Cost-effective Solution. If the environment exceeds 850°C under load, Inconel 617 is mandatory to prevent catastrophic equipment replacement costs.
Q3: Does Inconel 617 handle nitriding atmospheres better than 625?
A: Absolutely. The high nickel and chromium content in Inconel 617 provides elite resistance to both nitriding and carburization in furnace environments.
Q4: Do you offer trial orders for prototype reactor components?
A: Yes. We support Innovation and R&D by offering Flexible MOQs on our in-stock inventory of solution-treated 617 and 625 materials.
