GRADE PROFILE
Alloy 600 — N06600
Alloy 600 carries at least 72% nickel and 14 to 17% chromium, with no molybdenum. Its performance comes from nickel: chloride stress corrosion cracking, high-purity water, caustic media, carburising and nitriding atmospheres at temperature. Its PREN of 15 is the most misleading figure in the catalogue.
- Nickel alloy
- PREN 14–17 †
- Cost index 365
When to choose it
On furnace and retort components, in chemical and food processing, on high-purity water, in caustic media with sulphur compounds present, and in carburising and nitriding atmospheres. In nuclear engineering it is used for steam generators.
What these uses share is the absence of aggressive chlorides and the presence of conditions — high purity, caustics, hot reducing atmospheres — where nickel outweighs chromium.
When not to choose it
In aqueous chlorinated media. It resists chloride stress corrosion cracking, which is not the same as resisting pitting: without molybdenum, pitting starts easily, and the PREN of 15 says so correctly.
In stagnant seawater, where it is susceptible to pitting and crevice corrosion: prefer a 625 or a super duplex.
In concentrated hot caustic, without full stress relief before service.
In red-hot service with sulphur present, where the high nickel content becomes a liability.
And without building the loss of hot yield strength into the design.
Composition
| Element | % | Note |
|---|---|---|
| Ni | ≥ 72 | cobalt inclus |
| Cr | 14–17 | — |
| Fe | 6–10 | — |
| C | ≤ 0.15 | — |
| Mn | ≤ 1 | — |
| Cu | ≤ 0.5 | — |
| Si | ≤ 0.5 | — |
| S | ≤ 0.015 | — |
Mechanical properties
| Standard | Form | Rm (MPa) | Rp0.2 (MPa) | A (%) | Hardness |
|---|---|---|---|---|---|
| — | état recuit, température ambiante | 655 | 310 | 45 | — |
| — | état recuit, 550 °C | 550 | 180 | 42 | — |
Designations and standards
| Reference | Designation |
|---|---|
| EN (numeric) | 2.4816 |
| EN (symbolic) | — |
| ASTM / AISI | Alloy 600 |
| UNS | N06600 |
| JIS | — |
| AFNOR | NC 15 Fe |
Tube product standards :
- ASTM B163
- ASTM B167
- ASTM B516
- ASTM B517
- ASME SB163
- ASME SB167
- DIN 17751
Availability
Available in welded and seamless tube to ASTM B163, B167, B516 and B517. Structured dimensional data for this grade is not yet documented in our reference set: send us your sizes. EN 10204 3.1 material certificates supplied with the goods.
Related grades
- Alloy 625 (2.4856) — molybdenum added, for chlorides and acids.
- Alloy 800 (N08800) — less nickel, more iron, for hot oxidising service.
- Alloy 825 (N08825) — the molybdenum-copper pairing for acids.
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Frequently asked questions
- Why a PREN of 15 on such an expensive alloy?
- Because PREN only measures pitting in chlorinated media, and 600 is not built for that. Its value lies in stress corrosion cracking, high-purity water and caustic media, which no index summarises. Reading that PREN as a general score would point to a 304L, which would be absurd.
- 600 or 625?
- 625 as soon as chlorides or acids are present: its molybdenum changes everything. 600 where the medium is caustic, high-purity, or a hot carburising atmosphere, where it is both sufficient and cheaper.
- Is it suitable for seawater?
- No, particularly not stagnant seawater, where it is susceptible to pitting and crevice corrosion.