Inconel 825 or Incoloy 825? The same alloy, explained
They are the same alloy. The correct trade name is Incoloy 825; "Inconel 825" is a widely used market name for the same material. Both mean Alloy 825 — UNS N08825, W.Nr 2.4858 — a nickel–iron–chromium alloy with molybdenum, copper and titanium. Order it by UNS number and ASTM standard (B424 plate, B423 pipe, B366 fittings, B564 flanges) and the name no longer matters.
Why there are two names
Inconel and Incoloy are both trademark families of Special Metals Corporation. Inconel is used for nickel–chromium alloys such as 600, 625 and 718; Incoloy for nickel–iron–chromium alloys such as 800, 800H and 825. Because 825 sits among the "Inconel" alloys on most price lists and in most plants, buyers and even drawings often call it Inconel 825. Other mills sell the same composition under their own names, for example Nicrofer 4221.
Inconel 825 at a glance
What Alloy 825 actually is
| Element | Weight % |
|---|---|
| Nickel | 38.0 – 46.0 |
| Iron | 22.0 min |
| Chromium | 19.5 – 23.5 |
| Molybdenum | 2.5 – 3.5 |
| Copper | 1.5 – 3.0 |
| Titanium | 0.6 – 1.2 |
| Carbon | 0.05 max |
The nickel gives resistance to chloride stress-corrosion cracking; molybdenum and copper give resistance to sulphuric and phosphoric acid; titanium stabilises the alloy against intergranular attack after welding. Nickel is the largest element by weight, so 825 is a nickel alloy, not a stainless steel — which is also why it is classified in HS chapter 75 rather than 72.
How to order it without confusion
- Write the UNS number: UNS N08825 (and W.Nr 2.4858 for European specifications).
- Name the product standard: ASTM B424 for plate and sheet, B423 for seamless pipe, B366 WPNICMC for fittings, B564 for flanges.
- Ask for EN 10204 3.1 certificates that show the UNS number, and NACE MR0175 compliance if the service is sour.
- Treat "Inconel 825", "Incoloy 825" and "Alloy 825" as the same line item when comparing quotes.
825 compared with 625, 800H and 904L
| Grade | What it is chosen for |
|---|---|
| Alloy 825 | Sulphuric and phosphoric acid, chloride stress-corrosion cracking and sour gas |
| Inconel 625 | Seawater, high strength and high temperature in one alloy |
| Incoloy 800H | High-temperature strength in furnaces and heaters — not acid resistance |
| SS 904L | A cheaper super-austenitic stainless steel for milder acid duty |
Products we supply in Alloy 825
Sheet, plate, coil, pipe and tube, buttweld and forged fittings, flanges and fasteners, each with its standard, sizes and weights.