Summary
Inconel 690 was developed as a higher-chromium alternative to 600 for service where 600 suffers stress-corrosion cracking, most notably steam generator tubing. The two can look alike as tube and bar.
Because chromium is the only big difference, a single XRF reading is enough. Material from nuclear plant needs its own clearance documents before it can be traded at all. See Inconel 690 scrap and nuclear industry scrap.
Side by Side
| Inconel 600 | Inconel 690 | |
|---|---|---|
| Chromium | About 15.5% | About 29% |
| Iron | About 8% | About 9% |
| Key XRF marker | Chromium near 15% | Chromium near 29% |
| Typical service | Furnace parts, caustic evaporators | Steam generator tubes, nitric acid equipment |
| Common scrap forms | Pipe, plate, sheet | Tube, tube sheet offcuts, bar |
Composition Compared
Nominal compositions compared element by element. Values are the nominal figures from each grade page; change either grade to compare others.
On a handheld XRF: the clearest differences between Inconel 600 and Inconel 690 are nickel (76% vs 62%), chromium (15.5% vs 29%) and iron (8% vs 9%). Light elements such as aluminium, silicon, carbon and nitrogen need a light-element instrument, OES or a laboratory.
On the XRF
Switch the grade to see how the fingerprint changes. See how XRF sorts nickel alloys.
FAQ
What is the main difference between Inconel 600 and Inconel 690?
Inconel 690 has about 29% chromium against about 15.5% in Inconel 600. Iron is similar, around 8–9%, and neither carries molybdenum or niobium.
Can Inconel 600 and Inconel 690 scrap be mixed?
No. Keep them separate. Because each melt is made to one grade, Inconel 690 hidden in an Inconel 600 lot shifts the heat chemistry and the buyer adjusts the offer to match.
What are the UNS numbers of Inconel 600 and Inconel 690?
Inconel 600 is UNS N06600 and Inconel 690 is UNS N06690.
Which has more nickel, Inconel 600 or Inconel 690?
Inconel 600, with about 76% nickel against about 62% in Inconel 690, using the nominal values on this site.
Sources and Review
Composition figures on this page are the nominal values from each grade's own page on this site, where the producer datasheet or standard is named in full. The comparison widget reads the same values. The sources behind the grades are listed below.
- Special Metals Corporation, Product Handbook of High-Performance Nickel Alloys: Inconel 600 Buyer, Importer and Exporter
- Special Metals Corporation, INCONEL alloy 690 (SMC-079, 2009): Inconel 690 Buyer, Importer and Exporter
Published by Mipra Steel, Khetwadi, Mumbai · Last updated