In the complex world of superalloy assembly, a single mistake in material matching can trigger a multi-million-dollar catastrophic failure. For welding engineers and procurement managers, the core pain point is weld zone vulnerability.
Using the wrong filler metal or an uncertified base metal leads to:
Hot cracking – Poorly controlled niobium (Nb) levels cause solidification cracks right in the weld pool.
Corrosion loss – Molybdenum (Mo) dilution in the weld seam leads to early pitting in acidic environments.
Mechanical embrittlement – Incompatibility between dissimilar metals creates brittle joints under thermal cycling.
At Gnee Alloy, we bridge that gap. We don't just supply metal - we deliver the industrial durability required for zero-leakage fabrication.
Click to get an Inconel 625 product quote
Inconel 825 vs 625: What's the Difference
Inconel 825 vs 625: What's the Difference
Inconel 625 is a high-strength, corrosion-resistant base material, while Inconel 825 is a specialized welding material (AWS ERNiCr-3). Inconel 625 is used to manufacture components suitable for harsh environments such as marine and aerospace, while Inconel 825 is used to fill welds and join these alloys or dissimilar metals.
Are Alloy 625 and Inconel the same material?
Both materials can withstand temperatures up to 1120°C (2048°F), but above this temperature, their performance differences become very significant; Alloy 625 can withstand temperatures up to 1400°C (2550°F), while Inconel 625 can withstand temperatures up to 1500°C (2730°F).
1. Inconel 825 and Inconel 625 Material Overview
| Parameter | Inconel 825 | Inconel 625 |
|---|---|---|
| UNS Number | N08825 | N06625 |
| Material Type | Nickel-based Alloy Welding Wire / Electrode | Wrought Nickel-based Corrosion Resistant Superalloy |
| Product Forms | Welding wire, welding electrode | Bar, plate, tube, strip, wire |
| Typical Applications | Filler metal for welding Inconel, stainless steel, dissimilar metals | Chemical equipment, marine engineering, aircraft components |
| Maximum Service Temperature (Load-Bearing) | - (as filler metal) | ~600°C |
| Maximum Service Temperature (Oxidation) | ~980°C | ~980°C |
2. Comparison of chemical composition between Inconel 825 and Inconel 625 (wt%)
| Element | Inconel 825 | Inconel 625 | Key Difference |
|---|---|---|---|
| Nickel (Ni) | ≥ 67.0 (Balance) | ≥ 58.0 (Balance) | 825 has higher Ni |
| Chromium (Cr) | 18.0 – 22.0 | 20.0 – 23.0 | 625 slightly higher |
| Iron (Fe) | ≤ 3.0 | ≤ 5.0 | Similar |
| Manganese (Mn) | 2.5 – 3.5 | ≤ 0.50 | 825 has much higher Mn |
| Niobium (Nb) | 1.0 – 2.5 | 3.15 – 4.15 | 625 has higher Nb |
| Molybdenum (Mo) | - | 8.0 – 10.0 | 625 contains Mo (significant) |
| Titanium (Ti) | ≤ 0.75 | ≤ 0.40 | 825 may contain Ti |
| Aluminum (Al) | - | ≤ 0.40 | - |
| Carbon (C) | ≤ 0.10 | ≤ 0.10 | Similar |
| Silicon (Si) | ≤ 0.50 | ≤ 0.50 | Similar |
| Phosphorus (P) | ≤ 0.030 | ≤ 0.015 | 625 stricter |
| Sulfur (S) | ≤ 0.015 | ≤ 0.015 | Similar |
| Copper (Cu) | ≤ 0.50 | ≤ 0.07 | - |
| Cobalt (Co) | - | ≤ 1.0 | - |
3. Comparison of corrosion resistance between Inconel 825 and Inconel 625
| Corrosion Type | Inconel 825 | Inconel 625 |
|---|---|---|
| Pitting & Crevice | Better resistance in non-chloride environments | Excellent resistance due to high Mo content in chloride environments |
| Stress Corrosion Cracking | Less resistant | Superior resistance |
| Intergranular Corrosion | Better resistance | Lower resistance |
| Oxidation Resistance | Excellent | Excellent |
4. Inconel 825 and Inconel 625 Main Functions and Forms
Inconel 625: A base material (UNS N06625) supplied in sheet, tube, rod, and foil form. It is used for structural fabrication in demanding environments such as aerospace, marine applications, and chemical processing.
Inconel 825: A welding consumable (UNS N08825, AWS ERNiCr-3) supplied in coiled welding wire or cut electrode form. It is used as filler metal for welding Inconel 625, Inconel 600, or joining dissimilar metals such as carbon steel and stainless steel.
5. Inconel 825 and Inconel 625 Strength and Corrosion Resistance
Inconel 625: Possesses excellent mechanical strength (minimum yield strength of 414 MPa) and excellent resistance to strong reducing acids and seawater.
Inconel 825: As a weld metal, its strength is slightly lower than Inconel 625 due to the lack of molybdenum and niobium, but it is very stable at high temperatures and prevents hot cracking when joining complex base materials.
6. Inconel 825 and Inconel 625 Typical Applications
Inconel 625: Suitable for acid gas production, nuclear reactor components, chemical tank linings, and marine exhaust systems.
Inconel 825: Used for pressure vessel surfacing, piping construction, and weld transition joints between low-alloy steel and stainless steel.
Why Choose Gnee as Your Nickel-Based Alloy Supplier
As a specialized Superalloy Specialist, we solve your procurement bottlenecks:
✅️VIM + VAR melting: Ultra-clean melting for both base and filler metals to ensure Zero-Defect welds.
✅️MTC 3.1 Traceability: Full EN 10204 3.1 Mill Test Certificates provided for every order.
✅️Wholesale Pricing: Benefit from Direct Factory Price on bulk tonnage of 625 pipes and 825 wire.
✅️Global Logistics: Fast and secure shipping to Europe, USA, and Southeast Asia.
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 GH4169 Alloy
FAQ
Q1: Can I use Inconel 625 filler metal to weld Inconel 600?
A: Yes. Inconel 625 filler (ERNiCrMo-3) is often preferred over Inconel 825 for environments where extreme pitting resistance is required in the weld seam.
Q2: Why is Inconel 825 better for cladding?
A: Inconel 825 offers a very stable molten pool and is less sensitive to "dilution" from the carbon steel base material, making it the more Cost-effective Solution for large-scale surface cladding.
Q3: Is your material NACE MR0175 compliant?
A: Absolutely. Our Inconel 625 base materials are specifically heat-treated to meet strict hardness and microstructural limits for Sour Gas (H2S) service.
Q4: Do you support small trial orders for welding qualification?
A: Yes. We support Innovation and R&D projects with Flexible MOQs for both 625 tubing and 825 welding consumables.
